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Muon, Ratha. "Termite bioturbation in Cambodia - From characterization to application." Electronic Thesis or Diss., Sorbonne université, 2022. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2022SORUS383.pdf.
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La biodiversité des sols joue un rôle clé dans la régulation des fonctions écologiques clés du sol et dans la fourniture de biens et services écosystémiques essentiels aux sociétés humaines. Parmi les organismes du sol, les termites jouent un rôle de premier plan dans les sols tropicaux, en tant qu'éléments des réseaux trophiques et en tant qu'ingénieur de l'écosystème avec des effets sur la dynamique des sols et la biodiversité à différentes échelles spatiales et temporelles. Bien que les termitières caractérisent les paysages des rizières dans le bassin inférieur du Mékong, leur abondance, leurs propriétés et leurs utilisations par les agriculteurs restent inconnues. L'objectif de cette étude était donc d'analyser les interactions entre les termitières et les agriculteurs dans les zones cultivées de cette région. À cette fin, nous avons évalué l'abondance et les propriétés de deux types de termitières (les monticules ou "buttes termitiques" et les "nids") dans les rizières du bassin versant de Chrey Bak au Cambodge. Nous avons montré que la densité des buttes termitiques atteint ~ 2 termitières ha-1, et que ces constructions sont susceptibles de trouver leur origine dans l'activité de construction de Macrotermes gilvus. Nous avons mis en évidence que les buttes et les nids peuvent être considérés comme des points chauds (ou ‘hotspots’) de fertilité dans les paysages avec des teneurs plus élevées en carbone et en nutriments, et des propriétés physiques du sol améliorées (teneur en argile plus élevée, capacité de rétention d'eau et conductivité hydraulique saturée...). Enfin, à partir d'entretiens réalisés dans 13 villages, nous avons montré que les termitières fournissent un grand nombre de services aux populations locales, faisant partie des pratiques culturales et contribuant à la diversité alimentaire et à la santé (par exemple, l'utilisation du sol des buttes termitiques comme amendement, l'accès aux plantes médicinales, et une moindre utilisation d'engrais chimiques et de pesticides). En conclusion, cette recherche interdisciplinaire a mis en évidence l'urgence d'une meilleure compréhension des impacts environnementaux et sociaux de la biodiversité, et notamment de l'activité des termites, et des facteurs déterminants leur préservation par les agriculteursSoil biodiversity plays a key role in regulating key ecological functions and in providing essential ecosystem goods and services to human societies. Among soil organisms, termites play a prominent role in tropical soils, as elements of the food web and as ecosystem engineers with effects on soil dynamics and biodiversity at different spatial and temporal scales. Although termite mounds are conspicuous features of the landscapes in the lower Mekong basin, their abundance, properties and utilization by farmers remain unknown. Thus, the aim of this study was to analyze the interactions between termite constructions and farmers in cultivated areas in this region. To this end, we assessed the abundance and properties of two termite constructions (lenticular mounds and mound nests) in paddy fields in Chrey Bak catchment in Cambodia. We showed that termite lenticular mound density reaches ~ 2 mounds ha-1, and that these constructions are likely to find their origin in the building activity of Macrotermes gilvus. We evidenced that termite lenticular mounds and nests can be seen as fertility and biogeochemical hotspots in the landscapes with higher carbon and nutrients contents, and improved soil physical properties (higher clay content, water holding capacity and saturated hydraulic conductivity). Finally, using interviews realized in 13 villages, we showed that termite mounds provide a large number of services to local people, being part of the cultivation practices and contributing to food diversity and health (e.g., utilization of mound soil as amendment, access to medical plants, and lower use of chemical fertilizers and pesticides). To conclude, this interdisciplinary research evidenced the urgent need for a better understanding of the environmental and social impacts of biodiversity, and especially termite activity, and on the driving factors controlling their preservation by farmers
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Gerino, Magali. "Etude expérimentale de la bioturbation en milieux littoral et profond : quantification des structures de bioturbation et modélisation du remaniement biologique du sédiment." Aix-Marseille 2, 1992. http://www.theses.fr/1992AIX22057.
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Les objectifs de cette etude ont ete de definir les potentialites de bioturbation par le macrobenthos, quantifier les structures de bioturbation, modeliser et estimer l'intensite du melange biologique du sediment sur les sites choisis et mettre en evidence l'incidence de ces phenomenes sur les flux a travers l'interface eau-sediment. Les recherches ont ete developpees en milieu littoral dans le golfe de fos et en milieu profond dans 3 canyons mediterraneens (toulon, grand-rhone, lacaze-duthiers) et en atlantique dans le canyon du cap ferret. D'une maniere generale, on constate une relation positive entre l'abondance du macrobenthos et la densite des structures, mais dans la couche superficielle du sediment, les structures sont rapidement detruites par le remaniement biologique. A l'aide des resultats d'experiences in vitro, les organismes d'une communaute benthique peuvent etre regroupes dans 3 categories en fonction de leur mode de bioturbation: les biodiffuseurs, les convoyeurs et les regenerateurs. Les modeles employes pour quantifier le remaniement sedimentaire contiennent un terme decrivant le melange biodiffusif et un autre pour le melange non-local a l'origine d'une transport vertical de matiere. Les experiences in situ basees sur l'introduction ponctuelle de traceurs; luminophores et/ou radionucleides, ont permis de quantifier le remaniement biologique qui est globalement 10 fois plus eleve en milieu littoral qu'en milieu profond. En milieu littoral, les flux de solutes sortant du sediment sont augmentes d'un facteur entre 1,5 et 2 par l'activite du macrobenthos. La bioturbation intervient au niveau du stockage, de la transformation et de l'exportation de la matiere sedimentaire. Elle augmente les possibilites d'echanges de materiel soluble et est a l'origine d'importants flux particulaires a travers l'interface eau-sediment
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Araújo, Júnior José Moacir de Carvalho. "Nitrous oxide emissions and metal biogeochemistry in coastal wetland soils in response to bioturbation by Ucides cordatus." reponame:Repositório Institucional da UFC, 2016. http://www.repositorio.ufc.br/handle/riufc/21598.
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ARAUJO JUNIOR, José Moacir de Carvalho. Nitrous oxide emissions and metal biogeochemistry in coastal wetland soils in response to bioturbation by Ucides cordatus. 2016. 96 f. Tese (Doutorado em Ecologia e Recursos Naturais)-Universidade Federal do Ceará, Fortaleza, 2016Submitted by Anderson Silva Pereira (anderson.pereiraaa@gmail.com) on 2017-01-18T18:50:17Z No. of bitstreams: 1 2016_tese_jmcaraújojúnior.pdf: 2643973 bytes, checksum: 686137e3708d928ac9abbba589125bb3 (MD5)
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Coastal wetlands, among them the mangroves, are ecosystems with high biodiversity. In these environments, the crabs stand out both for its large number of species as by its economic and ecological importance, mainly due to the dens formation process (bioturbation. In this work, the effects of bioturbation by Ucides cordatus crabs from the Jaguaribe River mangrove (Ceará, Brazil) were analyzed under the concentrations of the different biogeochemical forms of the iron, zinc and manganese metals in the nearby soil and in the tissues of these animals, besides the variations in the (N2O) in areas with and without these crustaceans, comparing the values found between the rainy and dry periods. Soil samples were collected at low tide period in the demarcated two collection areas, one with and one without crabs. Measurements of bioecological parameters of crabs, soil physical and chemical parameters and concentrations of the metals associated with the different soil fractions (exchangeable, carbonate, ferridrite, lepidocrocite, goethite and pyrite) and Ucides cordatus crab Determination of the N2O flow. The results clearly showed a significantly greater variation of bioturbation activity in the dry period, with consequent increase in oxidation and acidification of the soil in the areas with crab. The more oxidized forms of the metals were predominantly larger in the area with crab burrows in relation to the control area, while those of pyrite were smaller. However, the emission of nitrous oxide fluxes was higher in the control area in both climatic periods, which indicates that the bioturbation activity of the crab promotes reduction of the emissions of this gas. The results allowed us to understand the role of bioturbation in GHG emissions and dynamics of biogeochemical processes in coastal wetlands soils, and identify possible seasonal variations in these values and the determination of GHG emissions and contamination of soil and crabs in these areas by trace metals, to improve environmental monitoring.
As zonas úmidas costeiras, dentre elas os manguezais, são ecossistemas com elevada biodiversidade. Nesses ambientes, os caranguejos destacam-se tanto por seu grande número de espécies quanto por sua importância econômica e ecológica e econômica, principalmente devido ao processo de formação de tocas (bioturbação). Neste trabalho foram analisados os efeitos da bioturbação realizada por caranguejos Ucides cordatus de manguezais do Rio Jaguaribe (Ceará, Brasil) sob as concentrações das diferentes formas biogeoquímicas dos metais ferro, zinco e mangânes no solo próximo e no tecido desses animais, além das variações no fluxo de óxido nitroso (N2O) em áreas com e sem esses crustáceos, comparando os valores encontrados entre os períodos chuvoso e seco. Os solos foram coletados no período de maré baixa em duas 2 áreas de coleta, uma com caranguejos e outra sem. Foram realizadas medições de parâmetros bioecológicos dos caranguejos, de parâmetros físico-químicos do solo e as concentrações dos metais associados às diferentes frações do solo (trocável, carbonato, ferridrita, lepidocrocita, goethita e pirita) e nos tecidos do caranguejo Ucides cordatus, além da determinação do fluxo de N2O. Os resultados demonstraram claramente uma variação significativamente maior de atividade bioturbadora no período seco, com consequente aumento na oxidação e acidificção do solo nas áreas com caranguejo. As formas mais oxidadas dos metais foram predominantemente maiores na área com tocas de caranguejos em relação a área control, enquanto as de pirita foram menores. Entretanto, a emissão de fluxos de óxido nitroso foi maior na área controle em ambos os períodos climáticos estudados, o que indica que a atividade bioturbadora do caranguejo promove redução das emissçoes desse gás. Os resultados obtidos permitiram compreender o papel da bioturbação na emissão de GEE e na dinâmica dos processos biogeoquímicos nos solos de zonas úmidas costeiras, além de identificar possíveis variações sazonais nesses valores e a determinação das emissões de GEE e da contaminação dos solos e caranguejos dessas áreas por metais traços, de forma a melhorar o monitoramento ambiental.
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Tambo, Guillermo Eduardo Willis-Jones. "The indirect impacts of ecosystem engineering by invasive crayfish." Thesis, Queen Mary, University of London, 2018. http://qmro.qmul.ac.uk/xmlui/handle/123456789/46825.
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Bioturbation by invasive crayfish can significantly alter sediment properties and its transport in invaded water bodies; however, the indirect impacts of this on ecosystem functioning are poorly understood. In this thesis I present data from mesocosm and field manipulation experiments used to assess the effect of bioturbation by three widely distributed invasive crayfish species (Procambarus clarkii, Pacifastacus leniusculus and Astacus leptodactylus) on a variety of ecosystem properties across seasons. In the mesocosm experiments, P. clarkii caused significantly more bioturbation than the other species, although increased bioturbation by all species in the spring and/or summer was associated with: reduced dissolved oxygen concentrations in near-surface water, indicating a large increase in oxygen demand by the water column; increased methane oxidation potential within the water (MOPwat), indicating the re-suspension of methane oxidising bacteria (MOB) along with the sediment; and a shift in zooplankton community structure towards dominance by large cladoceran species. Stable isotope analysis of the zooplankton showed a strong relationship between δ13C and MOPwat, suggesting that bioturbation increases MOB consumption. Given the importance of zooplankton as a trophic link to the higher food web, crayfish bioturbation may increase the importance of methane derived (chemosynthetic) carbon in invaded ecosystems. Temperature was identified as the key driver of seasonal variations in crayfish bioturbation intensity through laboratory mesocosm experiments, enabling estimation of the full annual pattern of bioturbation intensity for each species. The optimal temperature for P. clarkii was much higher than for the other species meaning that its bioturbation impacts exhibited large seasonal fluctuations whilst P. leniusculus and A. leptodactylus maintained a lower but more consistent level. Field manipulation experiments of enclosed sections of Chalgrove Brook, Oxfordshire, found significant bioturbation activity by P. leniusculus in early autumn; however, the increase in turbidity was too small to detect other effects observed in the mesocosm experiments.
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Hedman, Jenny E. "Fate of contaminants in Baltic Sea sediment ecosystems : the role of bioturbation." Doctoral thesis, Stockholms universitet, Systemekologiska institutionen, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-8315.
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Aquatic sediments are of major importance for the cycling of environmental pollutants, acting as both sinks and secondary sources of contaminants to the ecosystem. Sediment-living organisms can affect the fate and transport of contaminants through activities like feeding and burrowing, collectively called bioturbation. Apart from high contaminant levels, the Baltic benthic ecosystem is affected by stressors such as eutrophication-induced anoxic conditions and invading alien species. The main objectives of this thesis were to determine the effects of bioturbation on contaminant fluxes in Baltic Sea sediments and to increase the understanding of how these other stressors act together upon contaminant fate in the benthic ecosystem. Bioturbation affected contaminants in a species-specific way. The native species Monoporeia affinis and Macoma balthica increased the incorporation of BDE-99 and Cd deposited on the sediment surface, enhancing their retention in the sediment. The invasive polychaete Marenzelleria sp. did not contribute to the incorporation of surface-deposited contaminants, however, significantly increased the release of contaminants back to the water column. Reoxygenation of anoxic laminated sediments and bioturbation by Marenzelleria increased the sediment-to-water flux of dissolved organic contaminants. When the bioturbation-driven release of PCB was compared to the release caused by physical sediment resuspension, results indicated that the continuous activities of benthic infauna can be just as, or even more, important than physical disturbance for the remobilization of sediment-bound contaminants. Bioaccumulation was significantly higher when contaminants were deposited associated to phytoplankton compared to lignin or sediment, suggesting that there are likely seasonal differences in the mobilization of contaminants in the benthic ecosystem. In summary, bioturbation is an important process influencing contaminant fate in Baltic Sea sediments, and the risk of remobilization of historically buried contaminants may increase with improved benthic redox conditions and the invasion of new deeper-digging species, such as Marenzelleria.
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Grigg, Nicola Jane, and nicky grigg@csiro au. "Benthic Bulldozers and Pumps: Laboratory and Modelling Studies of Bioturbation and Bioirrigation." The Australian National University. Centre for Resource and Environmental Studies, 2003. http://thesis.anu.edu.au./public/adt-ANU20060228.104425.
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Aquatic sediments are the recipients of a continual rain of organic debris from the water column. The decomposition reactions within the sediment and the rates of material exchange between the sediment and water column are critically moderated by the transport processes within the sediment. The sediment and solute movement induced by burrowing animals bioturbation and bioirrigation far exceed abiotic transport processes such as sedimentation burial and molecular diffusion. Thalassinidean shrimp are particularly abundant burrowing animals. Living in high density populations along coastlines around the world, these shrimp build complex burrow networks which they actively maintain and irrigate.¶
I used a laser scanner to map thalassinidean shrimp (Trypaea australiensis) mound formation. These experiments measured rapid two-way exchange between the sediment and depth. Subduction from the sediment surface proved to be just as important as sediment expulsion from depth, yet this is not detected by conventional direct entrapment techniques. The experiments demonstrated that a daily sampling frequency was needed to capture the extent of the two-way exchange.¶
I derived a one-dimensional non-local model accounting for the excavation, infill and collapse (EIC) of burrows. Maximum likelihood analyses were used to test the model against 210Pb and 228Th profiles taken from sediment cores in Port Phillip Bay, Melbourne. The maximum likelihood approach proved to be a useful technique for quantifying parameter confidence bounds and allowing formal comparison with a comparable biodiffusion model. The EIC model generally outperformed the biodiffusion model, and in all cases best EIC model parameter estimates required some level of burrow infill with surface material. The EIC model was expanded to two and three dimensions, which allowed the representation of lateral heterogeneity resulting from the excavation, infill and collapse of burrow structures. A synthetic dataset generated by the two-dimensional model was used to demonstrate the effects of heterogeneity and core sampling on the mixing information that can be extracted from one-dimensional sediment core data.¶
Burrow irrigation brings oxygenated water into burrow depths, and can affect the nitrogen cycle by increasing the rates of coupled nitrification and denitrification reactions. I modelled the nitrogen chemistry in the annulus of sediment surrounding an irrigated burrow using a radially-symmetrical diffusion model. The model was applied to three published case studies involving thalassinidean shrimp experiments and to field data from Port Phillip Bay. The results highlighted divergences between current theoretical understanding and laboratory and field measurements. The model further demonstrated potential limitations of measurements of burrow characteristics and animal behaviour in narrow laboratory tanks. Activities of burrowing animals had been hypothesised to contribute to high denitrification rates within Port Phillip Bay. Modelling work in this thesis suggests that the model burrow density required to explain these high denitrification rates is not consistent with the sampled density of thalassinidean shrimp in the Bay, although dense burrows of other animals are likely to be important. Limitations of one-dimensional representations of nitrogen diagenesis were explored via comparisons between one-dimensional models and the full cylinder model.
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Cho, Eun-ah. "Bioturbation as a novel method to characterize the toxicity of aquatic sediment." NCSU, 2005. http://www.lib.ncsu.edu/theses/available/etd-02282005-111535/.
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Bioturbation, the biological process through which many species of infaunal benthic invertebrates suspend bottom sediments into the water column through their burrowing, feeding, respiratory, and locomotor activities, may be a sub-lethal endpoint that can be exploited to assess the toxicity of aquatic sediments. Therefore, we developed a novel test method that used bioturbation (BioTurbTox test) generated by the activities of second in-star Chironomus tentans larvae as the toxicity endpoint (Chapter 2). To validate this method, copper (Cu) and fluoranthene were individually spiked into relatively uncontaminated aquatic sediment to assess changes in bioturbation and mobilization of the chemicals into the overlying water. Turbidity production responded to the chemicals in the sediment in a concentration-dependent manner and was an excellent indicator of sediment toxicity. Moreover, substantial concentrations of Cu were released into the overlying water from the Cu-spiked sediment, whereas little fluoranthene was mobilized into the overlying water from the fluoranthene-spiked sediment. Sediment samples were then collected from the field and used to evaluate the similarity of response of the BioTurbTox test to other more standardized toxicity tests. In the summer of 2003, sediment samples were collected at six sites in the Neuse River of North Carolina tested for toxicity, and analyzed for chemical contaminants (Chapter 3). Atrazine was the most frequently detected current-use pesticide and pyrene and fluoranthene were measured at relatively high concentrations from the Neuse River sites. Concentrations of fluoranthene were correlated with results from the Ceriodaphnia dubia porewater and BioTurbTox tests. We concluded that the new BioTurbTox test was useful as a rapid screening method for sediment toxicity information, but required normalization to the clay content or to the total organic carbon content of field collected sediments. In Chapter 4, the toxicity of environmental pharmaceuticals and personal care products (PPCPs) were evaluated with the BioTurbTox and C. dubia reproductive tests. Fluoxetine and bisphenol A significantly affected bioturbation caused by C. tentans, especially at high concentrations (1-2 mg/L), and the turbidity change induced by caffeine, fluoxetine, and bisphenol A showed a concentration-response relation. Triclosan affected reproduction of C. dubia at relatively low concentrations (IC50: 85.4 ?Ýg/L). However, most of the tested PPCPs were not acutely toxic at environmentally relevant concentrations, but were relatively toxic at high concentrations. In Chapter 5, two sediment-spiking methods (extract mixing vs. whole sediment dilution methods) were compared with the BioTurbTox test and a gradient response was observed from both methods. Based on the similarity of the toxic response, we determined that either of the spiking methods was appropriate for estimating the toxicity of aquatic sediments in screening level assessments. The overall conclusion from this research was that the newly developed BioTurbTox test shows promise as a tool to assess the toxicity and mobilization of contaminants from aquatic sediments.
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Bird, James Vernon Jr. "Taphonomy of Sediments| Bioturbation in the Triassic Moenkopi Formation in Southwestern Utah." Thesis, Loma Linda University, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10131425.
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Measurement of bioturbation reflects physical and biological processes operating over time and can be used to reveal information about paleo-environments. The purpose of this study was to determine the intensity of bioturbation in Triassic Moenkopi Formation at Hurricane Mesa in Southwestern Utah. This formation is interpreted as having been deposited mostly in large ancient river channels, tidal flats, delta and shallow marine environments. Five stratigraphic sections measured in the Virgin Limestone Member provided the basis for this study. Detailed descriptions and quantification of bioturbation were recorded in each of the sections. Similar treatment was given to additional study sites in the rest of the formation, above the Virgin Limestone. Treatments on selected samples were implemented to better reveal evidence of bioturbation. In these treatments samples were coated with water or oil, etched with HCL and viewed under blacklight. Integrating the results of the treatments with x-ray diffraction and petrographic analysis suggest that there was minimal bioturbation. These findings are consistent with more rapid deposition than previously reported by other researchers.
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Vardaro, Michael F. "Deep-sea bioturbation and the role of the sea urchin Echinocrepis rostrata." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC IP addresses, 2008. http://wwwlib.umi.com/cr/ucsd/fullcit?p3316112.
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Thesis (Ph. D.)--University of California, San Diego, 2008.Title from first page of PDF file (viewed Sept. 4, 2008). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references.
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Hedman, Jenny. "Fate of contaminants in Baltic Sea sediment ecosystems : the role of bioturbation /." Stockholm : Department of Systems Ecology, Stockholm university, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-8315.
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Baranov, Viktor. "Influence of bioturbation on sediment respiration in advection and diffusion dominated systems." Doctoral thesis, Humboldt-Universität zu Berlin, 2018. http://dx.doi.org/10.18452/18792.
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Ökosystem-Ingenieure sind Organismen, deren Auswirkung auf die Funktion von Ökosystemen im Vergleich zu ihrer Anzahl und Biomasse überproportional groß ist. Ein klassisches Beispiel für Ökosystem-Ingenieure sind grabende Organismen, deren Aktivitäten (Bioturbation) sowohl die Sedimentmatrix als auch das Porenwasser in aquatischen Sedimenten beeinflussen. Solche Tiere wirken auf eine große Anzahl von biogeochemischen Prozessen in benthischen Ökosystemen ein, unter anderem auf die aerobe Atmung (Respiration). Die Respiration aquatischer Sedimente umfasst häufig über 50 % der gesamten Respiration von aquatischen Systemen und spielt eine große Rolle im globalen Kohlenstoffkreislauf. Die vorliegende Doktorarbeit beschäftigt sich mit den Auswirkungen der physikalischen Umwelt (Sedimenteigenschaften, am meistens hydraulischer Leitfähigkeit) auf die mikrobielle Respiration von Sedimenten, in denen Bioturbation durch Chironomidenlarven stattfindet. Um die Auswirkungen von Bioturbation auf Respiration zu messen und zu identifizieren, wurde eine neue Messmethode entwickelt (Kapitel 4.1). Kapitel 4.2 zeigt, dass der Einfluss von Bioturbation auf die Respiration des Sediments mit zunehmender Temperatur ansteigt. Kapitel 4.3 belegt, dass Resazurin auch für die Messung der Respiration in marinen Sedimenten geeignet ist. Kapitel 4.4 vergleicht und begutachtet die große Anzahl und Vielfalt hydrologischer, biogeochemischer und ökologischer Tracer einschließlich Resazurin. Die physikalische Umwelt (Sedimentmatrix) kontrolliert wie stark die Auswirkungen der Bioturbation auf die Respiration des Sedimentes sind. Dementsprechend liefert diese Doktorarbeit die Basis für das Verständnis der Auswirkungen benthischer Bioturbation auf Respiration und Kohlenstoffumsatz in limnischen und marinen Sedimenten.Ecosystem engineers are organisms, whose impact on ecosystem functioning is disproportionally large compared to their abundance and biomass. A classic example of ecosystem engineers are burrowing organisms whose activities (bioturbation) affect the sediment matrix and pore solutes in aquatic sediments. Bioturbating animals are impacting on a number of biogeochemical processes in benthic ecosystems, including, among others, aerobic respiration. Respiration of aquatic sediments often comprises over 50% of the total respiration of aquatic systems, and plays a tremendous role in the global carbon cycle. The present thesis deals with the impacts of the physical environment (sediment characteristics, mainly hydraulic conductivity and grain fractions) on the (microbial) respiration of bioturbated sediments. In order to disentangle the effects of bioturbation on respiration, a novel measurement method has been developed (Chapter 4.1). Chapter 4.2 reveals that the impact of bioturbation on sediment respiration increases with increasing temperature. Chapter 4.3 shows that resazurin can also be used for the measurement of respiration in bioirrigated marine sediments. Chapter 4.4 reviews the large number and diversity of hydrological, biogeochemical and ecological tracers including resazurin. The present thesis shows that in sediments with low hydraulic conductivity (diffusion-dominated sediments) (Chapters 4.1,4.2) bioturbation is altering sediment respiration to a larger extent than in sediments with high hydraulic conductivity (advection-dominated sediment) (Chapter 4.3). The physical environment (sediment matrix) controls the intensity of the impacts of bioturbation on sediment respiration. Thus, this thesis provides a basis for understanding the impact of benthic bioturbators on respiration and carbon sequestering in freshwater and marine sediments.
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Grigg, Nicola Jane. "Benthic bulldozers and pumps : laboratory and modelling studies of bioturbation and bioirrigation /." View thesis entry in Australian Digital Theses Program, 2003. http://thesis.anu.edu.au/public/adt-ANU20060228.104425/index.html.
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Teal, Lorna Rachel. "The influence of infaunal bioturbation on ecosystem processes in the sediment mixed layer." Thesis, University of Aberdeen, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.521246.
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The significant contribution of infaunal mediated particle movement to depth of the mixed layer, the subduction rates of phytodetritus, the recycling of nutrients and the flux of materials from the sediment to the water column as well as the diversification of marine life and the global extent of bioturbation, makes it a key process in the marine ecosystem, which is well recognized. The present thesis investigates specifically the links between bioturbation (ecosystem process) and ecosystem function (the depth of sediment mixing, trace metal cycling) through the development of novel in situ methodology and analytical techniques. It is clear that a standardisation and validation of current proxies used for benthic habitat quality assessments are necessary to inform the management of habitat frameworks and that these must consider the influence of a multitude of environmental processes on bioturbation function relations. The simultaneous use of multi-disciplinary techniques allows biogeochemical processes to be interpreted in light of recent infaunal activity, facilitating a better understanding of underlying mechanisms of species-function relations. In situ studies highlight the inherent heterogeneity in marine sediment environments, as well as the scale and context dependant nature of species-function relations. Together, this thesis highlights the need for simultaneous acquisition of high resolution spatio-temporal data under natural environmental conditions to understand underlying mechanisms of how different processes influence and interact with each other. An immediate challenge for linking in situ species-function-environment relations is to reconcile the difference in spatial and temporal scales of the different processes in question.
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Rowden, Ashley Alun. "The burrowing mud shrimp Callianassa subterranea (Decapoda) and bioturbation in the North Sea." Thesis, University of Plymouth, 1993. http://hdl.handle.net/10026.1/2218.
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A muddy-sand site in the North Sea was studied to identify the role of the benthic macrofauna in the resuspension of sediment. The macrobenthic community contained species capable of significant bioturbation. In particular, the presence and the temporal occurrence of the brittle star Amphiura filiformis was correlated with seasonal geotechnical and geophysical properties of the seabed. In addition, the extensive burrowing habit of the mud shrimp, Callianassa subterranea (Montagu), make this species potentially the most important contributor to the degree of bioturbation experienced at the site. Mud shrimps were an abundant and stable member of the study site's macrobenthic community [mean= 11.4 indiv./0.25m²(1SD±2.1)]. The sexually dichotomous individuals live between 2-3 years, and reproduction and recruitment primarily occurred in the summer (though an additional late winter/early spring period was hypothesised). Resin casting of burrows constructed by C. subterranea in the laboratory revealed a consistent morphological pattern with particular size- and sex-specific details of dimension and design. Mud shrimps, recovered from the site, were returned to the laboratory to investigate the influence of body size and temperature upon the amount of sediment expelled. A clear relationship between these variables and the quantity of expelled sediment was identified, and a well-defined temporal pattern of expulsion activity and inactivity was demonstrated. These experimental data, together with field information on seawater temperatures and mud shrimp population dynamics from the site, allow the construction of an annual sediment turnover budget [11 kg(dry)/m²/yr] with a confidence to date unrealised. Field observations at the North Sea site show that the sediment expelled by the mud shrimp occasionally forms a multitude of unconsolidated volcano-like mounds, which significantly modify seabed surface topography. The dimensions of these surface features were measured from bottom photographs and used to determine values of boundary roughness length (Zo) for the site (eg, September Zo= 0.79cm). The mud shrimps' contribution to resuspension was estimated by calculating the derived lateral sediment transport rate of 7 kg/m/month (from values of the site's near-bed current velocity, modified boundary roughness length and predicted sediment turnover rates). The links between sediment resuspension and the fluxes of trace metals, carbon and nutrients established by associated studies, demand that the bioturbatory activities of Callianassa subterranea must be included in any discusssion of the fate of contaminants and the future modelling of associated water quality in the North Sea.
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Limia, Jose M. "Bioturbation of intertidal sediments : an experimental approach involving the amphipod Corophium volutator (Pallas)." Thesis, University of Aberdeen, 1989. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU027714.
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The effect of dense accumulations of macroalgae on the mudflat invertebrate populations, was investigated in Newburgh South Quay. In order to partition the effects of the physical presence of weed and the consequent anoxic conditions of the sediment, the distribution of macro- and meiofauna was examined within a range of redox potential (Eh) and weed cover. No obvious trend was found for any species within the gradient of Eh. However, the number of individuals of Capitella, Tubificoides and Pygospio were significantly more abundant under weed cover, whereas Corophium disappeared almost completely in areas covered by weed. The relationship between Corophium burrows and depth of the chemocline (defined here as the line of colour change dividing the oxic from the anoxic zones of the sediment), was investigated by means of a photographic survey of sediment profiles. The depth of the chemocline was found to be closely associated with the bioturbational processes of Corophium, considered here only as the number and depth of its burrows. To demonstrate that Corophium is a significant bioturbator, and through bioturbation it might affect the invertebrate mudflat community, field and laboratory experiments were carried out, where the densities of Corophium were manipulated. The field experiment showed an increase in the organic matter of the sediment in the treatment with high density of Corophium; also, a decrease in the number of young Hydrobia was found in the same treatment. This field experiment revealed an adult-recruit interaction in Corophium. In the laboratory experiment, Corophium showed a significant increase in the redox potential, and organic matter of the sediment. There was also, an increased percentage of nematodes in deeper sections of the sediment in the treatment with high density of Corophium. This might be associated with a greater availability of oxygen near the burrows, or to an enhancement of the bacterial population upon which nematodes feed. Following the indications that Corophium by bioturbation can affect the depth of the chemocline, redox potential and distribution of nematodes with depth, its potential in the recovery of organically polluted sediments was investigated. Field and laboratory experiments were carried out in which Corophium was added to almost azoic and grossly enriched mud. In the laboratory experiment the chemocline was located significantly deeper in the treatment with Corophium, and in the field, numbers of nematodes, Manayunkia (and possibly Pygospio) increased in the treatment with Corophium. This field experiment demonstrated again an adult-recruit interaction in Corophium. It was concluded that the increase in areas covered by weed could lead eventually to the disappearance from the estuary of Corophium, which is the major prey item of many of the shorebirds and fish. Corophium is also an important sediment bioturbator and probably plays a significant role in the recovery of organically polluted sediments.
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García, Ibarra Fátima Abigail. "Résistance des fourmis à l'augmentation de température : approche comparative des effets de la précipitation, des traits morphologiques et de l'activité de bioturbation dans les sols." Electronic Thesis or Diss., Sorbonne université, 2024. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2024SORUS066.pdf.
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Le changement climatique est l'un des phénomènes les plus pertinents pour les écosystèmes aujourd'hui. Bien que ce soit un phénomène complexe qui affecte pratiquement tous les aspects du climat, l'augmentation de la température se distingue comme l'un des aspects les plus importants en raison de son impact direct sur tous les niveaux d'organisation des organismes. Bien que pratiquement toutes les formes de vie subissent déjà les conséquences de cette augmentation de la température, les invertébrés, en particulier les insectes tels que les fourmis, sont particulièrement susceptibles. Étant donné qu'ils ne peuvent pas réguler directement leur température corporelle, ils dépendent de la température ambiante pour réguler leur métabolisme.Les fourmis, l'un des groupes les plus importants d'insectes, sont présentes dans presque tous les environnements terrestres, occupant diverses niches écologiques et jouant un rôle fondamental dans la génération de services écosystémiques. Comprendre comment l'augmentation des températures mondiales affecte les populations de fourmis est crucial pour comprendre les stratégies qu'elles utilisent pour faire face au changement climatique.L'une des activités les plus significatives des fourmis est la bioturbation, qui implique la mobilisation des particules du sol et la modification de ses propriétés. Cette activité confère aux fourmis le rôle d'ingénieures de l'écosystème, car leurs actions modifient, maintiennent et même génèrent des habitats tant pour elles-mêmes que pour d'autres organismes.Bien que l'approche classique pour analyser la résistance à la température chez les fourmis se base sur la température critique maximale (CTmax), cette méthode se concentre uniquement sur les adaptations physiologiques sans tenir compte d'autres facteurs importants dans la détermination de la résistance. Cette thèse avait par objectif analyser la réponse des fourmis à l'augmentation de la température dans différents environnements, en observant des aspects cruciaux de leur biologie à plusieurs niveaux d'organisation.Au niveau de l'organisme, j'ai exploré la relation entre la CTmax et certains traits morphologiques fonctionnels dans des populations de divers environnements. J'ai étudié si le polymorphisme conférait un avantage en termes de résistance à la température. À l'échelle de la colonie, je me suis intéressé aux effets de différentes températures en surface et leurs impacts sur l'architecture des nids souterrains et le développement de la colonie dans une espèce d'environnement tempéré. Enfin, au niveau de la communauté, j'ai étudié la manière dont différentes conditions abiotiques, y compris l'humidité, modifient l'abondance, la richesse et la structure d'une communauté de fourmis dans un environnement tempéré, et comment cela se répercute sur leur activité de bioturbation.Cette approche intégrale a permis de développer un modèle d'analyse de la résistance à la température qui, autant que je le sache, n'a pas été proposé auparavant. Dans ce modèle, il est proposé que la résistance à la température, évaluée par la CTmax et/ou des traits morphologiques en tant qu'indicateurs, dépend de la capacité bioturbatrice et de la résilience de l'habitat. Selon ce modèle, les fourmis pourront maintenir leur résistance actuelle en augmentant leur activité bioturbatrice, en adaptant les nids aux températures lorsque l'environnement le permet. Cependant, cette capacité est limitée par la résilience du milieu, car on s'attend à ce que les environnements tempérés offrent davantage de niches potentielles pour les fourmis, tandis que dans les environnements xériques, les niches pourraient être encore plus rares qu'actuellementClimate change is one of the most relevant phenomena for biodiversity today. Although it is a complex phenomenon that affects practically all aspects of the climate, the increase in temperature stands out as one of the most important aspects due to its direct impact on all levels of organism organization. Despite virtually all forms of life already experiencing the consequences of this temperature increase, invertebrates, especially insects such as ants, are particularly susceptible. Since they cannot directly regulate their body temperature, they depend on ambient temperature to regulate their metabolism.Ants, being one of the most important groups of insects, are present in almost all terrestrial environments, occupying various ecological niches and playing a fundamental role in generating ecosystem services. Understanding how the increase in global temperatures affects ant populations is crucial to comprehend the strategies they use to cope with climate change.One of the most significant activities of ants is bioturbation, involving the mobilization of soil particles and the modification of its properties. This activity gives ants the role of ecosystem engineers, as their actions modify, maintain, and even generate habitats for themselves and other organisms.Although the classical approach to analysing temperature resistance in ants relies on the analysis of the Critical Thermal Maximum (CTmax), this method focuses solely on physiological adaptations without considering other important factors in determining resistance. This thesis aimed to analyse the response of ants to temperature increase in different environments, observing crucial aspects of their biology at various levels of organization.At the organism level, I explored the relationship between CTmax and some morphological functional traits in populations from diverse environments. I investigated whether polymorphism conferred any advantage in terms of temperature resistance. At the colony scale, I examined the effects of different temperatures on the surface and their impacts on the architecture of underground nests and colony development in a species from a temperate environment. Finally, at the community level, I focused on how abiotic conditions, including humidity, modify the abundance, richness, and structure of an ant community in a temperate environment, and how this affects their bioturbation activity.This comprehensive approach allowed for the development of a model for analysing temperature resistance that, to the best of my knowledge, has not been proposed before. In this model, I suggest that temperature resistance, assessed by CTmax and/or morphological traits as indicators, depends on bioturbation capacity of ants and habitat resilience. According to this model, ants may maintain their current resistance by increasing their bioturbation activity, adapting nests to temperatures when the environment allows it. However, this capacity is limited by habitat resilience, as temperate environments are expected to offer more potential niches for ants, while in xeric environments, niches could be even scarcer than they are currently under increased temperatures
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Michael, Taylor. "Invertebrate Activities in Wetland Sediments Influence Oxygen and Nutrient Dynamics at the Sediment-water Interface." Kent State University Honors College / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ksuhonors1525568331200468.
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Shields, Mark Aiden. "Gradients in benthic community structure and bioturbation potential along the Nordic Seas continental margin." Thesis, University of the Highlands and Islands, 2008. https://pure.uhi.ac.uk/portal/en/studentthesis/gradients-in-benthic-community-structure-and-bioturbation-potential-along-the-nordic-seas-continental-margin(ec1e3a76-38af-443f-b33b-1219e52e817f).html.
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The Nordic Seas region marks a transitional zone between the temperate North Atlantic Ocean and the polar Arctic Ocean. The influence of contrasting fluxes of organic matter on benthic community structure and function within the deep waters of the region were investigated. Samples of the macrofaunal community were collated throughout the region employing a standardised method. In the summer of 2002, during the RRS James Clark Ross 75 cruise, replicated samples were obtained with the SMBA multiple corer and the USNEL boxcorer from four stations located at similar sampling depths along a latitudinal transect at the Norwegian Sea continental margin. Additional replicated samples were obtained with a megacorer at six stations located along two bathymetric transects across the Norwegian Sea continental margin in the summer of 2005 during the RRS James Clark Ross 127 cruise. Contrasting fluxes of organic matter influenced benthic community structure, functional ecology and bioturbation potential. Species known to adopt the feeding strategy of the sub-surface storage of organic matter occurred in areas characterised by a seasonal input of organic matter. Species richness and diversity was highest at the Svalbard Margin, located within the marginal ice zone. Bathymetric patterns of macrofaunal biomass were comparable with previously reported global patterns. However, bathymetric patterns of macrofaunal abundance were higher than global patterns. The previously reported rapid subduction of organic matter by the sipunculan Nephasoma sp. and associated deep burrow networks on the Voring Plateau was linked to the species Nephasoma lilljeborgi. It is proposed that N. lilljeborgi is an ecosystem engineer.
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Cooper, Rachel. "The interactive effect of sandprawn (Callichirus kraussi) stebbing bioturbation and nutrients on macrofaunal communities." Master's thesis, University of Cape Town, 2011. http://hdl.handle.net/11427/10317.
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My thesis combined an observational study and field and laboratory experiments to investigate how nutrients and bioturbation by C. kraussi interact to structure macrofaunal communities and how ambient temperatures influence these factors.
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Kopcznski, Karen A. "Bioturbation in Supratidal Carbonates: Georadar Characterization of the Patterns and Structure of Decapod Burrows." Master's thesis, Temple University Libraries, 2017. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/462532.
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GeologyM.S.
Bioturbation in supratidal carbonate substrates has only recently received attention from ichnologists, relying primarily on traditional ground-based techniques. This study is the first high-resolution geophysical investigation of three decapod species inhabiting adjacent coastal biotopes on San Salvador Island. Extensive (>2 km) 800 MHz georadar surveys captured a diverse suite of >120 burrows of ghost (Ocypode quadrata), blackback (Gecarcinus lateralis) and blue (Cardisoma guanhumi) land crabs. Site-specific post-processing protocols were used to establish characteristic attributes that distinguish unfilled burrows from other discordant anomalies based on signal polarity structure. Variably oriented 2D and quasi-3D (~0.75-1.25 wavelength line separation) images allow the diagnostic signature of G. lateralis burrows to be distinguished from those of O. quadrata based on: 1) higher density of point-source diffractions (0.9-1.9/m vs. 0.01-0.06/m) and 2) shallower inclination angle (21-46° vs. >60°). C. guanhumi burrows are differentiated by: 1) larger diameter; 2) presence of an end chamber (where the radar signal is not attenuated by saline groundwater); 3) low electromagnetic signal velocity (~9 cm/ns vs. ~11 cm/ns) in organic-rich muddy substrate and 4) rapid signal decay. The migrated inclination angle (a) and the effective range (t0; time window of strongest reflectors) offer the best combination that differentiates between the three end-member structures and matrix properties. This study establishes GPR as a viable non-invasive subsurface imaging technique, with potential implications for: 1) identification of shifting ichnocoenoses, as exemplified by intense hurricane impacts (2015/2016); 2) recognition and mapping of similar biogenic structures in buried or lithified carbonates and, 3) quantification of a near-surface ichnofabric index and the dual porosity/permeability structure of prospective hydrocarbon reservoirs. Furthermore, the basic attributes of subsurface visualization can be readily extended to other mesoscale biogenic structures in evaporite and siliciclastic media.
Temple University--Theses
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Pham, Quang. "Relationships between functional traits, bioturbation and water transfers of earthworms sampled in northern Vietnam." Electronic Thesis or Diss., Sorbonne université, 2023. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2023SORUS606.pdf.
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Les vers de terre, de par la production de turricules et de galeries jouent un rôle majeur dans la formation et l'entretien de la structure du sol avec des conséquences sur les transferts d'eau. Cependant, la majeure partie de nos connaissances concerne la famille des Lumbricidae, tandis que la famille la plus diversifiée, les Megascolecidae, est largement sous-étudiée. Par conséquent, cette thèse visait à mieux comprendre l'impact des vers de terre tropicaux de la famille des Megascolecidae sur la structure du sol et les transferts d'eau, en particulier en utilisant leurs traits morpho-anatomiques comme proxy.Pour ce faire, deux expériences ont été menées en laboratoire. Dans la première, 23 espèces de vers de terre ont été échantillonnées dans le nord du Vietnam et leurs traits morpho-anatomiques ont été mesurés. Les vers de terre ont été classés en quatre catégories écologiques en fonction de leur traits morpho-anatomiques. Les vers de terre ont ensuite été incubés dans des mésocosmes afin d'y mesurer le volume et la compaction de leur drilosphere ainsi que l'infiltration de l'eau. Dans la deuxième expérience, l'effet individuel et interactif du ver anécique Amynthas zenkevichi et du ver endogé Pontoscolex corethrurus sur la structure du sol et les transferts d'eau ont été mesurés. Les réseaux de galerie ont été caractérisés à l'aide de la tomographie aux rayons X et les transferts d'eau ont été caractérisés en termes d'infiltration d'eau, d'évaporation et d'humidité du sol.Les résultats de la première expérience ont montré (i) une bonne correspondance entre le volume des différentes parties du drilopshere et les quatre catégories écologiques, alors que les différences étaient moins nettes pour la compaction des turricules ou la compaction autour des galeries ; ii) les vers de terre avaient soit un effet positif ou neutre sur l'infiltration de l'eau du sol sans distinction nette entre les quatre catégories écologiques ; (iii) l'utilisation possible des traits morpho-anatomiques pour prédire l'impact des vers de terre sur l'infiltration de l'eau du sol et la compaction de la drilopshere. Les résultats de la deuxième expérience ont montré que la présence des espèces A. zenkevichi et P. corethrurus ensemble avait un léger effet synergique positif sur la résistance du sol à la perte d'eau par évaporation.Pour conclure, ce travail montre que les vers de terre tropicaux peuvent être classés en catégories écologiques, mais que les liens avec le fonctionnement du sol ne sont pas toujours cohérents. Cette thèse met en évidence de nouvelles pistes de recherche basées sur les traits d'effet, qui peuvent être utilisées pour identifier les effets des vers de terre tropicaux sur la structure du sol et l'infiltration de l'eauEarthworms are known to play a major role in soil structure formation and maintenance through the production of casts and burrows with consequences on soil water transfers. However, most of the literature is based on Lumbricidae species, while the most diverse family, the Megascolecidae, is comparatively understudied Therefore, this thesis aimed at providing a better understanding of the impact of tropical earthworms from the Megascolecidae family on soil structure and water transfers, particularly using their morpho-anatomical traits as a proxy.To do so, two experiments were conducted in laboratory conditions. In the first, 23 earthworm species were sampled in northern Vietnam and their morpho-anatomical traits were measured. Earthworms were assigned into four ecological categories based on the morpho-anatomical traits selected by Bottinelli et al. (2020) for Lumbricidae species. Earthworms were incubated in mesocosms and the whole drilosphere (i.e., volume of surface and belowground casts, empty burrows and lateral soil compaction and bulk density of casts and the lateral compaction) was characterized by X-ray computed tomography. In addition, the soil water infiltration was measured. In the second experiment, the individual and interactive effect of the anecic Amynthas zenkevichi and the endogeic Pontoscolex corethrurus on soil structure and resultant effects on water transfers were investigated. Burrow systems were characterized using X-ray tomography and soil water transfers were characterized in terms of water infiltration, evaporation, and moisture.Results of the first experiment showed (i) a good match between the volume of the different parts of the drilopshere and the four ecological categories, whereas differences were less clear for the bulk density of casts or at the vicinity of burrows; (ii) earthworms had no or a positive effect on soil water infiltration without clear distinction between the four ecological categories; (iii) the possible use of both morpho-anatomical traits and machine learning to predict the impact of earthworms on soil water infiltration and bulk density variations of the drilosphere. Results of the second experiments showed that the presence of A. zenkevichi and P. corethrurus species together had a slight, synergistic, positive effect on soil resistance to water loss by evaporation.To conclude, this thesis showed that tropical earthworms can be assigned into ecological categories, but links with soil functioning can somehow be wrong. This thesis highlights new avenues of research based on effect traits, that can be used to identify the effects of tropical earthworms on soil structure and water infiltration
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Sauzet, Ophélie. "Quantification par approche micromorphologique couplée à de l’analyse d’images de l’effet de la mise en culture et de l’apport de matières organiques sur l’intensité et la dynamique des processus de lessivage et de bioturbation à l’échelle pluri décennale." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLA024/document.
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La capacité du sol à fournir de nombreux services écosystémiques dépend de propriétés qui évoluent en permanence sous l’effet de multiples processus. Or, malgré leur importance, les dynamiques des processus de lessivage et de bioturbation de la fraction < 2 μm sont peu connues. Nous nous sommes alors fixés pour objectifs de i) développer et valider une méthode de quantification par analyse d’images de l’intensité de ces deux processus, ii) quantifier l’effet d’un à deux siècles de mise en culture et d’une dizaine d’années d’apports répétés de fumier sur leur intensité, et iii) d’en déduire des informations sur leur dynamique. Notre procédure d’analyse d’images repose sur une approche colorimétrique et texturale permettant de prendre en compte les différents niveaux d’organisation des sols. Le volume de sol bioturbé depuis 10 000 à 15 000 ans, est compris entre 65% du volume total à 40 cm de profondeur et 20 à 30% du volume total à 150 cm de profondeur soit une masse de sol déplacée de l’ordre de 6 500 t.ha-1 ou 1 700 t.ha-1 de fraction fine. Le processus d’illuviation est, quant à lui, à l’origine d’un flux de fraction fine de 1 100 t.ha-1. Les processus étudiés se sont montrés sensibles et étonnement réactifs aux forçages anthropiques. Deux cents ans de mise en culture ont eu pour résultats : i) une évolution de la structuration des sols sur au moins un mètre de profondeur, ii) une modification de l’architecture du volume de sol remanié par les vers de terre, et iii) une intensification du processus de lessivage. Une dizaine d’années d’apports répétés de fumier ont à l’inverse été en mesure de tamponner la plupart de ces évolutions. Cette réactivité inattendue des sols représente une opportunité en ce qu’il est possible d’orienter ces évolutions en fonction d’un objectif d’atténuation des effets du changement climatique notammentThe intensity at which soils provide ecosystem services are function of soil properties that permanently evolved according to numerous processes. Lessivage and bioturbation are of crucial importance as they imply the clay size fraction but are still poorly characterized. This study aims at i) developing a digital 2D image analysis method to quantify both processes intensity, ii) quantifying the effect of two centuries of continuous cultivation and of a decade of organic amendments spreading on their intensity, and iii) characterizing their dynamics. We succeeded in quantifying those processes by carefully considering different levels of soil organization while combining a colorimetric and a textural approach. The percentage volume of worm-worked soil since 10 000 to 15 000 years is 65% at 40 cm depth and between 20 and 30% at 150 cm depth that corresponds to a soil mass flow of 6 500 t.ha-1, i.e. 1 700 t.ha-1 of clay size fraction. Illuviation is responsible for a clay size fraction mass flow of 1 100 t.ha-1. On a time scale as short as two centuries, cultivation was found to induce i) a change of the soil poral network characteristics until 1 meter depth, ii) a modification of the structure of the worm-worked soil volume, and finally iii) an increase of the lessivage intensity. A decade of organic matter spreading tended to lower the intensity of lessivage. Finally, our study points out the fact that soils are highly reactive and that our method may be particularly helpful to predict soil evolution while facing climate change among others
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Nahmani, Johanne. "Impact des métaux sur la structure et le role fonctionnel des communautés de macroinvertebres et de microorganismes de sols du Nord-Pas-de-Calais : une approche multiscalaire." Paris 6, 2003. http://www.theses.fr/2003PA066462.
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Hedberg, Johanna. "Effects of meiofauna and cable bacteria on oxygen, pH and sulphide dynamics in Baltic Sea hypoxic sediment." Thesis, Stockholms universitet, Institutionen för ekologi, miljö och botanik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-188795.
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Norling, Karl. "Ecosystem functions in benthos : importance of macrofaunal bioturbation and biodiversity for mineralization and nutrient fluxes /." Göteborg : Dept. of Marine Ecology,Göteborg University, 2007. http://www.loc.gov/catdir/toc/fy0801/2007423873.html.
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Hippolyte, Jacques. "Recherches sur Microtus arvalis pallas en altitude (Pyrénées occidentales). : Ecologie et rôle dans la bioturbation." Pau, 1987. http://www.theses.fr/1987PAUU3015.
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Hippolyte, Jacques. "Recherches sur Microtus arvalis (Pallas) en altitude (Pyrénées occidentales) écologie et rôle dans la bioturbation /." Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb37605926r.
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Ekman, Söderholm Agnes. "Påverkan av Asellus aquaticus (sötvattensgråsugga) på resuspension av partiklar i våtmarker." Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-69716.
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Anlagda våtmarker i avrinningsområden från jordbruksmarker mottar ofta vatten med höga halter av partikelbunden fosfor. Den viktigaste processen för avskiljning av inkommande partikelbunden fosfor är sedimentation. Resuspension är en process som motverkar netto-sedimentationen av partiklar och kan således minska våtmarkers förmåga att hålla kvar fosfor. Syftet med den här studien var att undersöka om A. aquaticus påverkar resuspensionen av partiklar, och om större tätheter av A. aquaticus orsakar större turbiditet i vattenmassan. Två försök genomfördes i plastakvarier med sediment insamlat från våtmarker anlagda på lerjord. Varje försöksuppställning bestod av en behandling och en kontroll utan några djur. I det första försöket innehöll behandlingen A. aquaticus motsvarande en täthet på 2083 individer m-2 och i det andra försöket en täthet på 500 individer m-2. Turbiditeten mättes med en turbidimeter en gång per dag under sju dygn. Aktiviteten hos A. aquaticus orsakade en signifikant högre turbiditet i vattenmassan i behandlingen än i kontrollen. Turbiditeten var i genomsnitt 161 NTU i akvarier med 2083 individer m-2 och 37 NTU i akvarier med 500 individer m-2. Slutsatsen som drogs är att förekomst av A. aquaticus skulle kunna öka resuspensionen av partiklar i våtmarker. Detta kan i sin tur ha en påverkan på våtmarkers förmåga att hålla kvar fosfor som är bundet till lerpartiklar.Constructed wetlands in agricultural catchments with clay soils often receive water with high concentrations of particle-bound phosphorus. Sedimentation of particle-bound phosphorus is the main retention process. Resuspension is a process that counteracts net sedimentation of the particles and can therefore reduce phosphorus retention in wetlands. The aim of this study was to investigate if A. aquaticus through bioturbation affects the resuspension of particles, and if a larger density of A. aquaticus causes a larger turbidity in the water column. The experimental design included plastic aquariums with sediment collected from wetlands constructed on clay soils. There were two experiments, each with a treatment and a control with no animals. In the first experiment, the treatment contained A. aquaticus at a density of 2083 individuals m-2. In the second experiment the treatment contained A. aquaticus at a density of 500 individuals m-2. Turbidity was measured with a turbidimeter once a day over the course of seven days. The bioturbation activity of the A. aquaticus caused a significantly larger turbidity in the water column in the treatment than in the control. The turbidity was on average 161 NTU in the presence of 2083 individuals m-2 and 37 NTU in the presence of 500 individuals m-2. The conclusion was that the presence of A. aquaticus can increase resuspension of particles in wetlands. This could have a negative impact on the ability of wetlands to retain phosphorus that is bound to particles.
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Deldicq, Noémie. "Evaluation expérimentale du comportement de déplacement des foraminifères benthiques : implications dans les processus de remaniement sédimentaire des écosystèmes intertidaux." Electronic Thesis or Diss., Université de Lille (2018-2021), 2021. http://www.theses.fr/2021LILUR019.
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L’objectif de cette thèse est de décrire le rôle des foraminifères benthiques dans les processus de bioturbation en se focalisant sur les flux sédimentaires à l’interface eau-sédiment. Plus spécifiquement, les objectifs sont (i) de caractériser le comportement de déplacement à l’interface eau-sédiment des espèces dominants les vasières intertidales des côtes Est de la Manche pour notamment les classer dans les groupes fonctionnels de bioturbation, (ii) de quantifier le remaniement sédimentaire de surface de ces espèces, (iii) de comprendre comment les facteurs biotiques et abiotiques vont moduler le mode et l’intensité du remaniement sédimentaire de l’espèce Haynesina germanica, enfin, (iv) de décrire la dynamique du déplacement verticale, des structures biogéniques et de quantifier le taux de bioturbation de H. germanica. Pour cela, les paramètres suivants ont été mesurés : la distance parcourue, la vitesse de déplacement, la position, l’indice d’activité et la complexité de la trajectoire. La dynamique du déplacement a été étudiée sur les espèces suivantes : Haynesina germanica, Cribroelphidium williamsoni, Quinqueloculina seminulum, Ammonia tepida et Miliammina fusca. Bien que toutes identifiées comme appartenant au groupe fonctionnel des biodiffuseurs, les espèces occupent des positions verticales distinctes dans la colonne sédimentaire. Ainsi, C. williamsoni est un biodiffuseur épifaune, Q. seminulum, M. fusca et H. germanica sont des biodiffuseurs de galeries tandis que A. tepida est un biodiffuseur de surface. Ceci suggère ainsi des effets différents sur la redistribution spatiale des particules. L’intensité du remaniement sédimentaire est contrôlée par les traits spécifiques ainsi que par les facteurs biotiques et abiotiques. En effet, la distance parcourue, la vitesse, le niveau d’activité et la complexité de la trajectoire varient à la fois entre et au sein des espèces. Par conséquent, les taux de remaniement sédimentaire varient aux échelles spécifiques, individuelles et fonctionnelles. Spécifiquement, l’étude d’H. germanica montre que la taille du test, la densité, la température et la concentration en matière organique sont des éléments clefs structurant son activité de bioturbation. Ce travail illustre la capacité des foraminifères benthiques à contribuer au processus de remaniement sédimentaire à l’interface eau-sédiment mais également en profondeur. Il ouvre de nouvelles perspectives sur la compréhension de l’écologie des foraminifères et leur rôle non négligeable dans la bioturbation des écosystèmes intertidauxThe aim of this PhD is to describe the role of benthic foraminifera in bioturbation processes focusing on particulate fluxes at the sediment-water interface. Specifically, the objectives are fourfold: (i) characterising the motion behaviour of key benthic foraminiferal species inhabiting intertidal mudflats from the Eastern English Channel at the sediment water interface to further classify them into functional groups of bioturbation, (ii) quantifying surface sediment reworking rates of the above-mentioned species, (iii) understanding how biotic and abiotic parameters may drive the mode and the intensity of surface sediment reworking of the dominant species Haynesina germanica, and (iv) further describing the vertical burrowing dynamics and the biogenic structures built by Haynesina germanica to quantify its bioturbation rates. To do so, the following parameters are described: the travelled distance, the velocity, the vertical position, the activity level and the tortuosity of the path. The motion-behaviour is described for the following species: Haynesina germanica, Cribroelphidium williamsoni, Quinqueloculina seminulum, Ammonia tepida and Miliammina fusca. Although they are all classified in the functional group of biodiffusors, these species differ in their preferential vertical position within the sediment. Specifically, C. williamsoni is an epifaunal-biodiffusor, Q. seminulum, M. fusca and H. germanica are gallery-biodiffusors while A. tepida is a surficial biodiffusor. This therefore means that the mode of sediment reworking is species-specific in benthic foraminifera. Its intensity is mediated by specific traits as well as biotic and abiotic factors. Indeed, travelled distance, velocity, activity level and tortuosity of the path would vary between and within species. As a consequence, the rate and the mode of sediment reworking are species-, individual- and functional group-dependant. Specifically, the surface area of the test, the species density, the temperature and the organic matter concentration are key parameters that control the bioturbation activity of H. germanica. The present work highlights the role of benthic foraminifera in sediment reworking processes taking place at the sediment-water interface and in the sediment column. It opens new perspectives on the understanding of the ecology of foraminifera and their putative non-negligible role in bioturbation processes in intertidal ecosystems
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Massé, Cécile. "Effets de la bioturbation sur la diversité des communautés bactériennes du sédiment : approches expérimentale et in-situ : de Melinna palmata aux communautés de la vasière Ouest-Gironde." Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0039/document.
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Le lien entre la macrofaune et les communautés bactériennes benthiques a été déterminé selon deux approches : (1) une approche expérimentale à l’échelle de l’individu ciblée sur les effets de l’activité et de la bioturbation du polychète déposivore de surface Melinna palmata sur la distribution des communautés bactériennes des premiers millimètres de l’interface eau-sédiment ; (2) une approche in situ à l’échelle de la communauté de mise en corrélation des patrons spatiaux de distribution des communautés de macrofaune et de bactéries.Melinna palmata appartient à un nouveau groupe fonctionnel de bioturbation décrit pour la première fois, convoyeur de surface. L’utilisation de ce nouveau modèle biologique a permis de mettre en évidence que les activités de prospection et d’égestions modifient significativement la distribution des communautés bactériennes de la couche oxique de l’interface eau-sédiment. Ce lien est à la fois influencé par l’apport de matière organique de différentes qualités, et impacte la consommation et la minéralisation de cette matière organique.Le lien entre les patrons spatiaux de distribution des communautés de macrofaune et de bactéries a été étudié in situ, dans la vasière Ouest-Gironde. Les deux compartiments ont évolué le long d’un gradient avéré de teneur en matière organique et de taille des particules dans cette vasière.La corrélation des matrices biologiques n’a cependant pas été statistiquement significative et nécessite d’être approfondiThe link between benthic macrofauna and bacterial communities was assessed with two different approaches: (1) an experimental approach at the individual scale, focused on the effects of behaviour and bioturbation of the deposit feeder polychaete Melinna palmata on the bacteria lcommunity distribution on the very sediment-water interface; (2) an in situ approach at the scale of the community, focused on the correlation between spatial distribution patterns of the two biological compartments. Melinna palmata belongs to a new functional group of bioturbation described for the first time: surface conveyor. Its use allowed determining that prospection and egestion induced a significant change of bacterial communities on the sediment-water interface. This link was influenced by organic matter enrichment while influencing its fate. In a second part, the link between spatial distribution patterns of the communities was assessed in situ in the West-Gironde mud patch. Both macrofauna and bacteria changed along a gradient of organic matter quantity and quality and of particles size described in this system. However, the correlation between matrices was not statistically significant and needs to be more developed
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Navon, Maxime. "Hétérogénéité sédimentaire et micro-habitats benthiques : approches in situ et expérimentale." Caen, 2016. https://hal-normandie-univ.archives-ouvertes.fr/tel-01922479.
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La sédimentologie de l’estuaire de la baie de Seine orientale se caractérise par une complexité de structures sédimentaires favorisant les hétérogénéités spatiales et verticales. Ce système fortement variable implique des relations macrofaune benthique - sédiments complexes qui n’ont cependant pas été précisément définies. Une nouvelle approche pour l’étude de ces relations a combiné prélèvements in situ et expérimentations en mésocosmes à l’échelle réduite de l’individu. La dimension tridimensionnelle du sédiment a été prise en compte afin de caractériser la distribution verticale de la macrofaune en présence de sédiments hétérométriques. Couplées à des analyses de volumes de vie par CAT-Scan, 98 % de la macrofaune étudiée se situe dans les dix premiers centimètres de sédiment avec la présence de deux pics d’abondance, en surface entre 0 et 2 cm de profondeur et entre 5 et 7 cm de profondeur. Cette forte abondance entre 5 et 7 cm concerne principalement deux espèces, le bivalve Kurtiella bidentata et les polychètes Chaetozone spp. Représentant 80 % de l’abondance à cette profondeur. Cette forte abondance entre 5 et 7 cm n’a toutefois pas pu être expliquée. L’approche expérimentale a mis en évidence le potentiel de remaniement sédimentaire du polychète Lagis koreni et sa grande capacité à déstructurer une colonne sédimentaire, pouvant être reliée aux observations des prélèvements in situ. Ce travail préliminaire a montré le potentiel des méthodologies employées et les résultats suggèrent l’approfondissement de la méthodologieThe eastern Bay of Seine is characterized by complex sediment structures with high spatial and vertical heterogeneities. Its variability involves complexes animal-sediment relationships still unclear. A new approach based on the individual scale combines in situ sampling with experiments. The macrofauna vertical distribution and quantification of biogenics structures have shown the main concentration of the fauna in the first 10 cm depth, such as 98 % of the total abundance. Two abundance pics have been observed, the first close to the surface between 0 and 2 cm depth and the other one between 5 to 7 cm depth, mainly due to two species, Kurtiella bidentata and Chaetozone spp. , which represent almost 80 % of the abundance from 5 to 7cm. Their presence within this depth is still unknown. Experiments have shown the great sediment reworking skill of the worm Lagis koreni and its ability to destroy the sediment structure, which can be linked to the in situ samples. This preliminary work has shown the interest of the technics used and makes us going further
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Monard, Cécile. "Biodégradation des herbicides en sols tempérés - Contrôle des communautés bactériennes dégradantes par la bioturbation du sol." Phd thesis, Université Rennes 1, 2008. http://tel.archives-ouvertes.fr/tel-00350389.
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L'intensification de l'agriculture s'est accompagnée d'une utilisation importante de pesticides qui a généré une pollution généralisée des sols et des eaux, problème environnemental majeur et actuel. Sous la pression de sélection liée à l'usage régulier de pesticides (molécules xénobiotiques) des bactéries du sol se sont adaptées à ces molécules et ont acquis la capacité de les utiliser comme source nutritive et donc de les dégrader. La biodégradation constitue un service écologique majeur fournit par le sol, puisqu'elle est à la base des capacités épuratrices du sol et au-delà, de la résilience des écosystèmes. Le sol étant également un grand réservoir de biodiversité, ces bactéries dégradantes sont sous contrôle de différentes interactions biotiques et notamment celles impliquant les lombriciens, qualifiés d'organismes ingénieurs des sols de par leur action de bioturbation. Grâce à un développement méthodologique important et novateur (RT-qPCR, SIP-ARN), nous avons étudié l'impact de la bioturbation du sol par la macrofaune lombricienne sur les communautés bactériennes du sol intervenant dans la biodégradation de molécules xénobiotiques. L'atrazine a été utilisée comme molécule modèle à double titre : d'un point de vu fondamental, son utilisation pendant plus de 50 ans en France a permis aux bactéries du sol de s'adapter et au titre de l'actualité, bien qu'elle soit interdite en France depuis 2003, il s'agit toujours du principal polluant retrouvé dans les eaux souterraines et de surface. Nous avons analysé par une double approche quantitative et qualitative l'impact de la bioturbation du sol par les lombriciens sur l'abondance, l'activité et la diversité des bactéries indigènes du sol et sur celles dégradant l'atrazine. Nous avons mis en évidence que : (i) la digestion du sol par les lombriciens stimule l'activité d'une partie des bactéries du sol mais qu'une autre fraction ne résiste pas au passage dans le tube digestif des vers, (ii) la bioturbation du sol par les lombriciens génère des ‘hot spot' pour l'activité de dégradation de l'atrazine. Ainsi dans les parois de galeries les bactéries dégradantes sont sélectionnées, la dissipation de l'atrazine est rapide et les premiers acteurs du processus de dégradation ont été identifiés, (iii) la dégradation accélérée de l'atrazine dépend d'espèces bactériennes clés interagissant au sein de consortia dégradants, ainsi la diversité des bactéries dégradantes n'est pas corrélée à la fonction de dégradation. L'ensemble des résultats obtenus nous montre également que l'impact de la bioturbation par la macrofaune lombricienne sur l'activité de dégradation dépend des propriétés physico-chimiques et biologiques initiales du sol. L'ensemble de ces connaissances présente un intérêt dans un contexte de bioremédiation in situ des sols pollués puisque les lombriciens constituent une grande part de la macrofaune dans nos sols tempérés et qu'ils modifient significativement les bactéries dégradant l'atrazine au sein des microsites de sols qu'ils génèrent.
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Blankson, Emmanuel Robert. "The Effect of Bioturbation on Transport, Bioavailability and Toxicity of Lead (Pb) in Freshwater Laboratory Microcosms." Thesis, University of Louisiana at Lafayette, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10163300.
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Sediment bioturbators play an important ecological role and may both be affected by contaminants in the sediment and affect the fate and distribution of these contaminants. This is especially important for the many contaminants, like lead, for which sediments serve as a sink upon the contaminants’ release into the environment. In this study, I investigated the toxicity of sediment Pb to a freshwater bioturbator, the effect of bioturbation on the environmental distribution of the Pb, the effect of sediment characteristics on the bioturbation-mediated transfer of Pb from the sediment to the water column, and this transfer’s toxicological consequences for planktonic organisms. Experiments were conducted in microcosms with control sediment or Pb-spiked sediment, the freshwater oligochaete Lumbriculus variegatus served as the model bioturbator, and the water flea Daphnia magna served as the model planktonic organism. The rate of bioturbation of the oligochaete was quantified using luminophores.
The bioturbation resulted in the transfer of Pb from the sediment to the water column. However, it did not affect Pb levels in the worm tissue or in the sediment. The environmental distribution of Pb among water column, biota, and sediment in the presence of the bioturbator was dependent on sediment characteristic like organic content, silt/clay content, and the pH of the sediment. Bioturbation by L. variegatus increased bioaccumulation of Pb in D. magna; however, this Pb had no toxic effect on survival, reproduction, and biomass of D. magna under the specific conditions used here. Quantification of the bioturbation rates of L. variegatus showed that the intensity of the bioturbation was enhanced at higher densities of the oligochaete but reduced at high sedimentary Pb concentrations. Overall this study demonstrated that bioturbation by L. variegatus can transfer Pb from the sediment to the water column, and that this transfer is dependent on sediment characteristics. The Pb transferred as a result of the bioturbation can enhance Pb availability to organisms in the water column, and potentially cause toxic effects in these organisms.
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Massias, Delphine. "Devenir in situ des hydrocarbures anthropiques dans un sédiment marin côtier soumis aux processus de bioturbation." Aix-Marseille 2, 2002. http://www.theses.fr/2002AIX22039.
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Ciutat, Aurélie. "Impact de la bioturbation des sédiments sur les tranferts et la biodisponibilité des métaux : approches expérimentales." Bordeaux 1, 2003. http://www.theses.fr/2003BOR12693.
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"Les recherches ont reposé sur l'analyse expérimentale, à partir de modèles multicompartimentaux (microcosmes), des effets de la bioturbation sur les flux métalliques (principalement le cadmium) à l'interface "eau/sédiment", la source initiale de contamination étant soit la colonne d'eau, soit le compartiment sédimentaire. Les microcosmes étaient composés d'un biotope mixte "colonne d'eau – sédiment naturel", avec deux modèles biologiques : des organismes "bioturbateurs" (larves d'éphémère : Hexagenia rigida ; oligochètes tubificidés) et des organismes indicateurs de la biodisponibilité des métaux présents dans la colonne d'eau (bivalves filtreurs : Corbicula fluminea). Cette étude résolument pluridisciplinaire s'est appuyée sur l'utilisation de plusieurs techniques complémentaires : analyses physico-chimiques, traceurs particulaires fluorescents, dosages métalliques, micro-électrodes polarographiques, radioscopie RX. . . Deux modes de remaniement sédimentaire distincts ont été quantifiés : une forte bioadvection pour les tubificidés, accompagné d'un granulo-classement, alors que les larves d'H. Rigida, creusant de larges galeries, sont à l'origine d'une biodiffusion. En présence de métaux dans l'eau, les oligochètes augmentent d'un facteur 2 le piégeage du métal dans le sédiment. Lorsque la source initiale de contamination est le compartiment sédimentaire, H. Rigida entraîne un relargage de Cd vers la colonne d'eau environ 10 fois plus important que les tubificidés. Ce relargage, principalement sous forme particulaire, est expliqué par la remise en suspension des particules sédimentaires, générée par les larves d'H. Rigida ; par contre, le cadmium transféré dans la colonne d'eau n'est pas biodisponible pour le bivalve C. Fluminea"The research was based on experimental studies of the effects of bioturbation on metal fluxes (essentially cadmium) at the "water/sediment" interface, using multi-compartment indoor models (microcosms). The initial contamination sources were the water column or the sediment compartment. The microcosms were made of a mixed biotope "water column and natural sediment", with two biological models: bioturbating organisms (burrowing mayfly nymphs, Hexagenia rigida and tubificid oliogochaetes) and benthic bivalves (Corbicula fluminea) as indicators of metal bioavailability from the water compartment. These multidisciplinary studies used several complementary techniques: physico-chemical measurements, fluorescent particulate tracers, trace-metal determination, polarographic micro-electrodes, X-ray radioscopy. . . Two types of sediment reworking were analyzed: high bioadvection from tubificids, leading to a sediment grading, and biodiffusion for the nymphs of H. Rigida, owing to their large burrows. When cadmium was added to the water column, metal storage in the sediment layers inhabited by tubificids was increased by a factor close to 2. When the initial contamination source was the sediment, the Cd release induced by H. Rigida nymphs was 10 times higher than those measured in presence of tubificids. This release, essentially under the particulate form, was linked to the resuspension of sediment particles; the cadmium transferred to the water column was not bioavailable for the benthic bivalves
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Lundberg, Johanna. "Påverkan av Asellus aquaticus (sötvattensgråsugga) på resuspension av partiklar i våtmarker." Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-69688.
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Fosfor (P) är ofta det begränsande ämnet i akvatiska system och kan i höga mängder bidra till övergödning i sjöar och hav. För att minska tillförseln av partikelbunden fosfor som läcker från jordbruksmark kan våtmarker anläggas i avrinningsområdet. För en effektiv avskiljning är det viktigt att partiklar sedimenterar i våtmarken och stannar i sedimentet. Studier har visat att vissa karpfiskar och märlkräftor genom bioturbation kan orsaka resuspension av partiklar, samt att effekten ökar med ökad täthet. Syftet med denna studie var att undersöka om även makroevertebraten Asellus aquaticus (sötvattensgråsugga) kan orsaka resuspension av partiklar. Två hypoteser undersöktes: (i) A. aquaticus orsakar resuspension av sedimenterade partiklar; (ii) ökad täthet av A. aquaticus ger ökad resuspension. Två försök genomfördes och varje försöksuppställning bestod av 15 akvarier, varav finpartikulärt sediment och bäckvatten tillsattes till tio stycken medan fem innehöll endast bäckvatten. I hälften av akvarierna med sediment tillsattes A. aquaticus i olika täthet för försöken. Försöken pågick i sju dygn med dagliga mätningar av vattnets grumlighet. Resultat från försöken bekräftade båda hypoteserna. Genomsnittlig grumlighet efter sju dygn var 161 NTU (143 mg L-1 TSS) vid en täthet på 2083 A. aquaticus m-2 och 37 NTU (26 mg L-1 TSS) vid 500 A. aquaticus m-2. Studiens resultat indikerar att A. aquaticus kan ha en negativ påverkan på retentionen av partikelbunden fosfor i våtmarker.Phosphorus (P) is often the limiting nutrient in aquatic systems and can in excessive quantities cause eutrophication in lakes and seas. To reduce the input of particle-bound phosphorus leaking from agricultural land, wetlands can be constructed as traps for particles. It is important that particles settle in the wetland and remain in the sediment. Studies have shown that bioturbation by e.g. common carp and amphipods can cause resuspension of settled particles, and that the effect increases with an increasing density of organisms. The purpose of this study was to examine if the macroinvertebrate Asellus aquaticus can also cause resuspension of particles. Two hypotheses were tested: (i) bioturbation by A. aquaticus will cause resuspension of particles; (ii) an increased density of A. aquaticus increases the resuspension of particles. This was tested in two experiments, each of which included 15 aquaria. In ten of these, sediment and stream water were added. To five of the aquaria with sediment, A. aquaticus were added in different densities for the two experiments. Water turbidity was measured daily for seven days. The results confirmed both hypotheses. Average turbidity after seven days was 161 NTU (143 mg L-1 TSS) at a density of 2083 m-2 and 37 NTU (26 mg L-1 TSS) at 500 m-2. The results indicate that the presence of A. aquaticus may have a negative impact on the retention of particle-bound phosphorus in wetlands.
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Duport, Eric Marc Yann. "Quantification de la bioturbation dans les écosystèmes marins côtiers : caractérisation des groupes fonctionnels responsables du remaniement sédimentaire." Aix-Marseille 2, 2006. http://theses.univ-amu.fr.lama.univ-amu.fr/2006AIX22054.pdf.
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Afin de déterminer les facteurs biologiques et environnementaux jouant un rôle sur la variation de l’intensité du remaniement sédimentaire, deux voies de recherche complémentaires ont été suivies : une expérimentation in vitro sur une population monospécifique à Nereis diversicolor et deux études temporelles sur des communautés macrobenthiques issues d’environnements méditerranéens différents, le canal St. Antoine (golfe de Fos) et l’étang de Thau. Une première partie de ce travail a été de déterminer les espèces présentes dans chacun des sites et de leur attribuer un groupe fonctionnel de bioturbation en fonction des connaissances actuelles sur leur comportement, notamment trophique et de locomotion. Une deuxième partie de ce travail a été de quantifier le remaniement sédimentaire induit par ces organismes en utilisant des traceurs particulaires (luminophores). L’impact des différents facteurs étudiés sur l’intensité de remaniement sédimentaire a pu être évalué à l’aide d’un modèle 1-D. Les résultats de l’expérience in vitro ont montré l’existence d’une relation non-linéaire de densité-dépendance pour l’intensité de remaniement sédimentaire réalisé par le diffuseur à galeries N. Diversicolor. L’intensité du transport biodiffusif (Db) et du biotransport (r) augmente tout d’abord avec la densité pour atteindre ensuite une valeur maximale. Cette expérimentation a montré l’importance de la densité de population qui apparaît comme un facteur clé dans le fonctionnement de l’écosystème sédimentaire. Les études portant sur des communautés in situ ont permis de mettre en évidence l’importance primordiale des traits fonctionnels des espèces et de la diversité fonctionnelle des communautés sur la dynamique du mélange sédimentaire. Ce travail nous a permis de montrer que les variations temporelles de l’intensité de remaniement sédimentaire sont complexes. Elles sont dues à l’association de plusieurs facteurs biologiques (composition fonctionnelle de la communauté, densité), associés à l’influence directe et/ou indirecte de facteurs environnementaux (température de l’eau, concentration en oxygène dans les sédiments, quantité de matière organique dans la colonne sédimentaire et taille des particules)In order to define the biological and environmental factors playing a role in the sediment reworking intensity changes, works have been carried out both on monospecific Nereis diversicolor population (in vitro) and in situ macrobenthic communities. The studies about in situ communities were realised over time in contrasted Mediterranean environments : St. Antoine canal (Gulf of Fos) and Thau Lagoon. The first part of this work was to characterize the species and more particularly their belonging bioturbation functional group according to their tropic and locomotive behaviors. In the second part, using particle tracers (luminophores), intensity of sediment reworking induced by organisms was quantified. The impact of the different studied factors on sediment reworking intensity was assessed with 1-D model. The results of the in vitro experiment showed the existence of a non-linear relationship between density of gallery-diffusor N. Diversicolor and sediment reworking intensity. The intensity of biodiffusive transport (Db) and the biotransport (r) first increased with the density and then reached a maximal value. This experimentation showed the importance of the population density which appears as a key factor in the sedimentary ecosystem functioning. The studies related to in situ communities allowed to highlight the crucial importance of the species functional traits and the functional diversity of the communities on the sediment mixing dynamics. This work has enabled us to show that temporal changes in sediment reworking are a complex phenomenon which can be explain by combined influence of biological factors (functional composition and density of the community), associated with the direct and indirect influence of environmental (temperature of water, oxygen concentration in the sediments, organic quantity of matter in the sedimentary column and particle size)
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Dedeh, Amina. "Impact d'un sédiment dopé aux nanoparticules d'or ou de sulfure de cadmium sur un invertébré et un poisson d'eau douce." Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0068/document.
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Le but de cette thèse était de déterminer l’impact de deux types de nanoparticules métalliques (sulfure de cadmium – CdS - et or - Au) sur deux organismes aquatiques modèles (vers tubifex et poisson zèbre Danio rerio). L’approche a consisté à doper le sédiment de la Garonne avec les deux types de nanoparticules et caractériser l’effet de cette contamination sur les deux organismes en utilisant plusieurs marqueurs à différents niveaux d'organisation biologique (réponses biochimiques, activité de neurotransmission, génotoxicité, expression génétique et activité de bioturbation). Les effets ont été évalués après exposition aux sédiments contaminés dans des systèmes expérimentaux de types microcosmes durant une vingtaine de jours. Dans un certain nombre de cas, ce travail a révélé un effet des nanoparticules qui n’était pas dû au métal mais aux propriétés nanoparticulaires. En effet, dans le cas des nanoparticules de CdS, nous avons observé des altérations du génome ainsi que la modification de l’activité de bioturbation des vers tubifex en réponse à la contamination aux nanoparticules mais pas à celle de la forme ionique. Dans ce travail nous avons pu observer le relargage des nanoparticules d’or depuis le sédiment vers la colonne d’eau, et sa biodisponibilité potentielle pour les poissons. Ces nanoparticules provoquaient des altérations de l’ADN chez les deux organismes, la modification de l’expression de certains gènes et l’augmentation de l’activité de l’acétylcholinestérase chez le poisson zèbre. Les résultats de bioturbation n’ont pas montré d’effets des nanoparticules d’or sur le mouvement des versThe aim of this thesis was to determine the impact of two types of metal nanoparticles (cadmium sulphide - CdS - and gold - Au) on two aquatic models (tubifex worms and zebrafish Danio rerio). The approach has been to dope the Garonne sediment with the two types of nanoparticles and characterize the effect of this contamination on the two animals using multiple markers at different levels of biological organization (biochemical responses, neurotransmission activity, genotoxicity, gene expression and bioturbation activity). The effects were evaluated after exposure to contaminated sediment in experimental microcosms systems for twenty days. In a number of cases this work revealed an effect of the nanoparticles that was not due to metal but to the nanoparticulate properties. Indeed, in the case of CdS nanoparticles, we observed alterations in the genome as well as the modification of the bioturbation activity of worms tubifex in response to the contamination of nanoparticles but not to that of the ionic form. In this work we observed the release of gold nanoparticles from the sediment into the water column, and its potential bioavailability to fish. These nanoparticles were causing DNA damage in both organisms, modifying the expression of certain genes and increased acetylcholinesterase activity in zebrafish. Bioturbation results showed no effects of gold nanoparticles on the movement of worms
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Bonaglia, Stefano. "Benthic metabolism and sediment nitrogen cycling in Baltic sea coastal areas : the role of eutrophication, hypoxia and bioturbation." Licentiate thesis, Stockholms universitet, Institutionen för geologiska vetenskaper, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-85261.
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Eutrophication is one of the greatest threats for the Baltic Sea, and one of its more critical consequences is bottom water hypoxia. Nutrient enrichment and oxygen-depletion affect both the deep central basins and a number of coastal areas, even though strategies for nutrient reduction have lately been implemented. In order to better understand why those threats are expanding and formulate more effective remediation strategies two main achievements are needed: (1) new data on benthic nutrient dynamics should be available in order to develop updated budgets for sensitive Baltic areas; (2) the main transformation processes and their regulation mechanisms (i.e. oxygen availability, presence of macrofauna, different organic loading scenarios) should be better constrained. Paper I was able to demonstrate that re-oxygenation of previously anoxic sediment has a positive effect on the ecosystem because of better retention of nutrients and efficient conversion of fixed nitrogen to nitrogen gas. Sediment colonization by the invasive genus Marenzelleria counteracts some of the positive aspects provided by benthic oxygenation (in particular, nutrient retention, N2 loss). A possible explanation for this reversal can be that Marenzelleria does stimulate anaerobic more that aerobic metabolism. Results from Paper II suggest that at the outermost stations of Himmerfjärden denitrification follows a pronounced seasonal pattern, primarily regulated by bottom water temperatures. At the innermost and impacted site oxygen level in the bottom water varies considerably during the year and causes denitrification/DNRA predominance to be the main nitrate reduction pathway. On an annual scale, the net amount of lost N2 is comparable at the four sampling sites and accounts for 96% of the total DIN discharged from the sewage treatment plant, suggesting that denitrification in the estuarine sediment acts as a major nitrogen sink for external N inputs.
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Hoang, Trung Kien. "Ingénierie écologique pour la biorémédiation des systèmes aquatiques : effets du couplage de la bioturbation avec la phytoremediation sur le cadmium et l'atrazine." Thesis, Toulouse 3, 2018. http://www.theses.fr/2018TOU30348/document.
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Ce sujet de recherche vise mieux comprendre les processus de bio remédiation qui participent à la réduction des charges en polluants dans les écosystèmes aquatiques du type zones humides, en tant que question d'actualité en ingénierie écologique. L'efficacité des processus de phytoremédiation a été largement démontrée par des applications individuelles sur le sol et les sédiments. Cette thèse a pour objectif de démontrer la participation d'une population d'invertébrés dans l'efficacité de la réduction de polluants des sédiments aquatiques en combinant le processus de bioturbation avec la phytoremédiation. Les hypotheses de recherche ont été testée expérimentalement en conditions de laboratoire à l'aide d'une série de microcosmes reproduisant chacun une portion d'interface eau/ sédiments similaire aux conditions en zones humides. Dans nos expériences, la bioturbation est réalisée par une population d'oligochètes Tubificidae bien connue comme un ingénieur écologique. La phytoremédiation associée est effectuée par une plante aquatique Typha latifolia connue pour sa capacité à extraire les polluants organiques et inorganiques des sédiments par l'accumulation dans leur biomasse. L'influence de cette biodiversité sur les flux et bilan de masse de polluants modèles, a été démontré à l'aide de 2 expériences de laboratoire mettant en oeuvre des séries de microcosmes contaminées avec du Cadmium en tant que métal trace avec une concentration initiale de 20 µg.L-1, dans l'eau surnageante, et de l'atrazine marquée avec une concentration de 5 µg.g-1 de sédiment frais en tant que micropolluant organique persistant et herbicide. Les résultats de ces expériences démontrent que le bio-transport créé par la population de tubificidae ainsi que la bioremédiation sont toujours actifs en présence de contamination ce qui confirme le potentiel de dévelopement de ces organismes en ingénierie écologique. La bioadvection du sédiment et des contaminants par les tubificidae est quantifiée grâce à l'utilisation de luminophores (traceurs particulaires). [...]The development of efficient bioremediation techniques to reduce pollutant loads in aquatic ecosystems is a challenging research question for ecological engineering. The accuracy of phytoremediation processes has been primarily demonstrated by individual applications on soils or water sediments. The present Ph.D. aims to demonstrate the interest of additional bioturbation combined to phytoremediation processes for the improvement bioremediation efficiency of aquatic sediments. This strategy benefits are tested experimentally in controlled laboratory conditions with a serie of microcosms reproducing each a portion of water/sediment interface such as in wetland areas. In our experiments, bioturbation was carried out by a conveyor-belt invertebrate population, the tubificidae oligochaetes Tubifex tubifex, well known as an active ecological engineer. The phytoremediation was conducted by the riparian plant Typha latifolia known for its ability to remove organic and inorganic pollutants from sediments by accumulation into its biomass. The experiments were managed to demonstrate the effects of this biological influence (plant and inveterbrate) on the mass balances and fluxes of one metal and one pesticide as models of pollutants. Cadmium as a heavy, inorganic and conservative metal pollutant was introduced as a pulse input in the overlying water of the contaminated microcosms, with a cadmium concentration of 20 µg.L-1 in at the initial time of the experiment that lasted one month. In a second experiment, atrazine was mixed in the whole sediment column at the initial time in order to reach a concentration of 5 µg.g-1 of fresh sediment as a source of organic micropollutant and herbicide in the microcosms. The pesticide was radiolabeled with 14C. Fluxes from water to sediment, and from sediment to plants were assessed in experimental conditions with several treatments (+/- plants, +/- bioturbation, +/- pollutants) allowing to demonstrate the effects of the biological influence. Our results indicated that the tubificids and the related bioremediation influences are still efficient under cadmium and atrazine contaminations in aquatic systems. Biotransport due to tubificids changed the distribution of cadmium across the sediment column and enhanced the pumping of cadmium from the water to surface sediment and then to the anoxic underlying sediment surrounding the plant roots. [...]
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Thibault, de Chanvalon Aubin. "Transformation de la phase solide à travers l’estuaire de la Loire en relation avec son environnement chimique et biologique." Nantes, 2016. https://archive.bu.univ-nantes.fr/pollux/show/show?id=8d3b8b35-fbc9-4ed5-991d-08dedc59a835.
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Avant d’atteindre l’océan, les particules drainées par la Loire subissent d’importantes transformations chimiques dans l’estuaire. L’objectif de cette étude est d’identifier et de caractériser les processus majeurs de transformation impliquant le fer (et dans une moindre mesure Al, Mn, PO43- et les terres rares). L’analyse de particules en suspension a montré une diminution de 15% du fer contenu dans les particules traversant l’estuaire. La dissolution réductive des oxydes de fer durant leurs périodes de dépôt apparait comme l’une des voies réactionnelles principales. Cependant les dépôts sont caractérisés par une forte hétérogénéité spatiale due aux activités de la macrofaune benthique. Pour surmonter cette difficulté, de nouvelles méthodes de calcul, d’analyses à haute résolution et en deux dimensions de la composition de l’eau interstitielle, des particules déposées et de la méiofaune benthique ont été développées. Ainsi, nous montrons que l’activité de la macrofaune semble responsable de 80% du flux de fer dissous du sédiment vers la colonne d’eau, estimé à 0,5 mmol. M-2. D-1. Ces vitesses de réaction requièrent un temps de résidence dans le sédiment d’une dizaine d’années pour expliquer la perte visible de fer dans les particules en suspension, temps largement supérieur au temps de résidence moyen dans l’estuaire. Il apparait donc nécessaire de prendre en compte la réactivité des dépôts dans une plus large zone qui s’étendrait jusqu’aux vasières externes pour rendre compte des transformations du fer solide à travers l’estuaireBefore reaching the ocean, riverine particles from the Loire watershed undergo important chemical transformations in the estuary. This study aims to identify and characterize main processes involving iron (and to a lesser extent Al, Mn, PO43- and rare earths elements). Suspended particulate matter data show that 15% of their iron is lost through the estuary. Reductive iron dissolution during deposition periods is likely to explain most of this loss. However, estuarine sediments are characterized by high spatial heterogeneity due to macrofaunal activities. To overcome this difficulty, new methodologies of high resolution and two-dimensional analyses and calculation of pore water, sediment and benthic meiofauna were developed. These developments enable to estimate the impact of macrofaunal activity to 80% of dissolved iron export from sediment towards water column, and a total flux of 0. 5 mmol m-2 d-1. Such kinetics requires a 10-year of residence time of particles within the sediment in order to match to observed iron loss on suspended particles. This time is much longer than the mean particle residence time in the estuary. Therefore, sediment reactivity over a larger surface that stretches to the external mudflats has to be taken into account to explain transformation of solid iron through the estuary
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Jagercikova, Marianna. "Kinetic quantification of vertical solid matter transfers in soils by a multi-isotopic approach." Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4307/document.
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Le lessivage du lutum (0-2 µm) est un de processus majeurs de la pédogenèse, qui a néanmoins été peu quantifié et modélisé. Ce processus ainsi que la bioturbation ont été quantifiés ici en couplant des différents systèmes isotopiques (137Cs, 210Pb (xs), 10Be atmosphérique, 206/207Pb, δ13C, 14C) à une modélisation numérique par une équation de diffusion-convection à paramètres variables avec la profondeur. Cette méthode originale a été appliquée sur des anthroposéquences de Luvisols développées sur du loess et différantes de par leur utilisation (culture, prairie ou forêt) et leurs pratiques agricoles (travail du sol, apport du fumier). Nos résultats montrent que 91 ± 9 % du 137Cs et 80 ± 9 % du 10Be sont associés au lutum et ainsi peuvent effectivement tracer des transferts verticaux de matière solide dans les sols à pH > 5 et à teneur en carbone organique faible. Le partage du plomb entre les différentes phases solides est plus complexe. En considérant deux compartiments pour les isotopes (macropores ou la matrice de sol), nous avons conçu un modèle multi-isotopique permettant de quantifier la contribution des transferts de matière solide à la distribution verticale de la fraction 0-2 µm actuelle. Le lessivage est responsable de 9 à 66 % de l'accumulation de lutum dans l'horizon Bt. Le coefficient de diffusion permet de quantifier le taux de mélange par la bioturbation. La modélisation multi-isotopique est une méthode de prédilection pour les études modernes de la pédogenèse et des processus de la zone critiqueClay translocation is one of the major soil forming processes, howeverit is poorly quantified and modeled. We propose to quantify it togetherwith bioturbation by combining different isotopic systems (137Cs , 210Pb (xs),meteoric 10Be, 206/207Pb, δ13C, 14C) with numerical modeling based on a nonlineardiffusion-convection equation with depth dependent parameters. Thisnovel method has been applied on Luvisol anthroposequences developed onloess, differing by their land use (cropping versus grassland or forest) andtheir agricultural practices (reduced tillage, no tillage and manure input).Our results show that as much as 91 ± 9 % and 80 ± 9 % of 137Cs and10Be, respectively, are associated to the clay size fraction (0-2 µm) and canthus effectively trace vertical solid matter transfers in soils with pH > 5 andlow organic carbon. Lead partitioning between different solid phases is morecomplex. Considering two spatial distributions of isotopes (macropores or soilmatrix), we built up a multi-isotopic modelling approach that simulates theexperimental data with the common set of transfer parameters and allowedus to quantify the relative contributions of vertical solid matter transfers topresent-day 0-2 µm vertical distributions. Clay translocation is responsiblefor 9 to 66 % of the clay accumulations in the Bt-horizon. The diffusion coefficientalso quantifies the rate of soil mixing by bioturbation. Modeling of thekinetics of solid matter transfer at multiple spatio-temporal scales should becomea method of predilection in modern pedogenic and critical zone studies
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Pascal, Ludovic. "Rôle de l'espèce ingénieure Upogebia pusilla dans le fonctionnement biogéochimique des écosystèmes intertidaux à herbier (Zostera noltei) du bassin d'Arcachon." Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0017/document.
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Dans le bassin d’Arcachon, le crustacé thalassinidé Upogebia pusilla habite préférentiellement les vasières intertidales colonisées par les zostères naines (Zostera noltei) où il trouve la stabilité sédimentaire indispensable à l’établissement durable de son terrier. Du fait de la profondeur de ce dernier (> 30 cm) et de sa grande mobilité, cette espèce ingénieure a souvent été négligée dans les études antérieures ayant pour objectif de mieux comprendre le rôle des communautés macro-benthiques dans le fonctionnement des herbiers de phanérogames et les conséquences de leur régression rapide. Ce manuscrit présente une étude intégrée du rôle d’U. pusilla dans le fonctionnement de son écosystème en s’attachant particulièrement à caractériser et quantifier les relations entre (1) ses différentes activités (fouissage, ventilation, locomotion, …), (2) les modes de bioturbation qui en résultent et (3)leurs impacts respectifs sur la dynamique biogéochimique sédimentaire. Ce travail montre qu’U. pusilla engendre un remaniement et une bioirrigation intenses de la matrice sédimentaire qui l’entoure. Sa présence stimule ainsi fortement la reminéralisation de la matière organique sédimentée et les échanges de solutés à travers l’interface eau-sédiment.Bien que l’influence d’U. pusilla sur ces processus écologiques et biogéochimiques soit très dépendante des conditions environnementales (e.g., saisonnalité, prévalence parasitaire),l’ensemble de mes résultats suggère que le déclin progressif de ses populations, conséquence directe de la dégradation de son habitat, est susceptible de fortement altérer le fonctionnement global des écosystèmes du bassin d’ArcachonIn Arcachon bay, the endobenthic thalassinid crustacean Upogebia pusilla is tightly associated with the intertidal dwarf grass Zostera noltei providing the sediment stability required for the construction of (semi-)permanent burrows. Because of the depth and complex architecture of their burrow (> 30 cm), this high mobile engineer species have been largely ignored in previous studies aiming at better understanding the role of macrobenthic communities in the functioning of seagrass ecosystems and the consequences of their rapid decline. This manuscript presents an integrated study regarding the role played by U. pusillain the functioning of its ecosystem, with particular emphasis on the characterisation and quantification of the relationships between (1) its different activities (burrowing, ventilating,walking…), (2) both bioturbation modes and rates and (3) their respective impacts on the sedimentary biogeochemical dynamics. This work shows that mud shrimp activity leads tohigh mixing and bioirrigation of the surrounding sediment matrix, thus strongly enhancing organic matter mineralisation processes and solute exchanges across the sediment-water interface. Although the influence of U. pusilla on ecological and biogeochemical processes largely depends on environmental conditions (e.g., seasonality and parasitism), altogether my results suggest that the gradual decline of its population in Arcachon bay, as a direct consequence of benthic habitat degradation, may greatly alter the overall functioning of this vulnerable marine ecosystem
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Dairain, Annabelle. "Sensibilité de l’espèce bioturbatrice Upogebia cf. pusilla dans un environnement littoral soumis à différents stress : infestations parasitaires et contamination métallique." Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0331/document.
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Les processus de bioturbation constituent un exemple classique d’ingénierie de l’écosystème. Ils sont le fait d’espèces bioturbatrices qui contribuent à la structuration physique et biogéochimique des environnements sédimentaires. Dans les environnements marins meubles, les thalassinidés comptent parmi les bioturbateurs les plus influents. Ainsi, la crevette de vase Upogebia cf. pusilla est à l’origine d’un important remaniement sédimentaire et d’une large bioirrigation des sédiments dans le bassin d’Arcachon. Ces activités de bioturbation modulent les processus de minéralisation de la matière organique et les flux biogéochimiques à l’interface eau-sédiment. L’intensité de la bioturbation de U. cf. pusilla dépend de son état physiologique, celui-ci pouvant être altéré par divers facteurs de stress. Une approche couplant études de terrain et expérimentations en laboratoire a permis d’évaluer l’influence du parasitisme et de la contamination métallique sur les activités de U. cf. pusilla. Ce travail avait pour objectifs de (1) caractériser la pression parasitaire chez U. cf. pusilla à l’échelle locale, (2) déterminer les niveaux de base des éléments métalliques chez cet organisme dans le bassin d’Arcachon et d’évaluer le potentiel rôle des parasites dans les processus d’accumulation des métaux et (3) estimer l’impact du parasitisme et de la contamination métallique, seuls et en interaction, sur U. cf. pusilla et ce à deux échelles d’organisation, moléculaire et comportementale. In situ, un suivi spatial et un suivi temporel ont permis de caractériser la dynamique spatio-temporelle de deux parasites chez U. cf. pusilla¸ un bopyre infestant la cavité branchiale (Gyge branchialis), et un trématode (Maritrema sp.), infectant l’ensemble des organes de l’animal. Au sein de leur hôte, ces deux parasites sont négativement associés, le bopyre limitant probablement les processus d’infection par le trématode. Par ailleurs, un suivi saisonnier d’un an a permis de noter de faibles concentrations en métaux chez U. cf. pusilla, dans le bassin d’Arcachon. Ces concentrations ont été mises en parallèle avec le statut parasitaire des spécimens échantillonnés. Aucune corrélation n’a été notée entre la présence des trématodes et les quantités de métaux accumulées. A l’inverse, les observations de terrain ont permis d’envisager que le parasite bopyre puisse interférer avec les processus d’accumulation des métaux chez cet organisme. Cette dernière hypothèse a été testée en laboratoire au cours d’expérimentations visant à évaluer l’influence d’une contamination métallique (en utilisant le cadmium comme contaminant modèle) et du parasite bopyre, seuls et en interaction, sur U. cf. pusilla. A l’échelle moléculaire, le bopyre n’a été associé à aucune modification de l’expression d’une dizaine de gènes cibles. Par ailleurs, à l’échelle comportementale, ce parasite réduit peu le remaniement sédimentaire de son hôte, à l’inverse de ce qui avait été montré au cours d’une étude antérieure. En ce qui concerne l’influence du cadmium, ce métal module amplement l’expression de gènes codant notamment des protéines impliquées dans la réponse au stress oxydant et dans les mécanismes de détoxication. Ces observations suggèrent que U. cf. pusilla est capable de mettre en place des mécanismes de lutte contre le stress métallique. Au niveau comportemental, le cadmium semble stimuler le remaniement sédimentaire des organismes. Finalement, les expériences « doubles stress » ont montré un effet antagoniste du bopyre et du cadmium à la fois à l’échelle génique et à l’échelle comportementale. Ainsi, cette étude souligne la complexité des interactions entre facteurs de stress multiples et la nécessité d’effectuer de telles expérimentations. [...]Bioturbation is a typical example of ecosystem engineering. Bioturbating species are mainly epi- or endobenthic organisms, which profoundly affect the physical structure and biogeochemical properties of sediments. In marine soft-bottom environments, thalassinidean mud shrimp are considered as one of the most prominent bioturbating organisms. Among these species is the mud shrimp Upogebia cf. pusilla, which is recognized as an important sediment reworker, also significantly contributing to the bioirrigation of sediments. In fine, this species greatly modulates organic matter mineralization and biogeochemical fluxes at the sediment-water interface. The influence of U. cf. pusilla in ecosystem functioning depends on the intensity of its bioturbation and thus on its fitness. Several factors can affect the physiological status of organisms, potentially resulting in behavioural changes and causing modifications of their activities. Amongst potential stressors, we evaluated the influence of parasitism and trace metal contamination on the mud shrimp U. cf. pusilla in Arcachon Bay, France. Field surveys and laboratory experiments were undertaken in order to evaluate (1) the parasite infestation levels in the mud shrimp at the local scale, (2) the metal contamination background and potential relationship between the metal accumulation and the parasitic status of organisms in the field and (3) estimate the distinct and interactive impacts of parasitism and metal contamination on two scales of organisation, by targeting a molecular (gene expression) and a behavioural (sediment reworking) endpoint.A large spatial and temporal survey conducted in Arcachon Bay showed that at least two parasites species occur in mud shrimp: a bopyrid isopod (Gyge branchialis), living in one of the gill chambers of its host, and a trematode parasite (Maritrema sp.), infecting the whole body of mud shrimp. These two parasite species are negatively associated within their host, in which the bopyrid likely interferes with trematodes establishment. Additionally, a one year seasonal sampling demonstrated that mud shrimp displayed very low levels of metals in Arcachon Bay. The bopyrid parasite could interfere with the process of metal accumulation in mud shrimp, while such correlation was not found for the trematode parasite. Finally, complementary laboratory experiments highlighted that, at the molecular level, the bopyrid parasite did not affect the expression of the genes targeted in this study in mud shrimp. Similarly, at the behavioural level, and conversely to a previous study, the effects of the bopyrid parasite were minor, i.e. only associated to small modifications of the bioturbation activity of its host. Indeed, the intensity of the sediment reworking of mud shrimp was slightly reduced when organisms were infested with this parasite. Regarding trace metal contamination, we noticed that mud shrimp largely accumulated cadmium. This accumulation was associated to an important modulation of gene expression, especially of genes encoding proteins involved in detoxification processes, highlighting, at this organisation level, the capability of mud shrimp to deal with the deleterious effect of cadmium. At the behavioural scale, cadmium contamination positively affected the sediment reworking activity of mud shrimp. Finally, double-stress experiments evidenced an antagonistic effect of both stressors on the two targeted endpoints. This study highlights the complexity of the interactions between multiple stressors and that the response of organisms cannot be predicted from “single-stress” experiments. [...]
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Murphy, Gwendolyn Ann. "HABITAT PREFERENCES OF GULF COAST FIDDLER CRABS AND RESPONSES OF PLANT AND SOIL CHARACTERISTICS TO THEIR BURROWING." OpenSIUC, 2020. https://opensiuc.lib.siu.edu/theses/2714.
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Research in salt marshes dominated by the grass Sporobolus alterniflorus indicates that plant characteristics affect fiddler crab burrowing and in turn, crab activity can enhance primary productivity by increasing soil oxygen and nutrient cycling. Crab-plant interactions are less understood in microtidal Gulf Coast marshes compared to Atlantic Coast tidal marshes. It is unknown how structure of the dominant Gulf Coast vegetation zones (salt marsh, brackish marsh, fresh marsh and salt pannes) affects density of crab burrows and how burrows may influence primary productivity. I hypothesized that fiddler crabs would be most abundant in marsh zones with intermediate substrate hardness and vegetation density (Goldilocks Hypothesis). A seasonal habitat preference study was conducted during 2016-2017 in tidal marshes at Grand Bay National Estuarine Research Reserve in coastal Mississippi using burrow density as a proxy for crab abundance. Plant above- and below-ground biomass, burrow proximity to vegetation, and soil hardness were also surveyed as potential drivers of fiddler crab populations. The results indicated that fiddler crabs burrow in all four zones, but to varying degrees, and that burrow density was highest during autumn. The fresh marsh had the highest average density of burrows, as well as vegetation and soil parameters most representative of intermediate habitat, thereby supporting the “Goldilocks Hypothesis”. The brackish marsh also proved to be important fiddler crab habitat. Preferential fiddler crab usage of habitat upslope of salt marsh, e.g., fresh and brackish marsh, in Gulf Coast sites suggests that they may avoid immediate impacts of rising sea levels and possibly even migrate to higher ground if needed.
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Mazik, Krystina. "The influence of a petrochemical discharge on the bioturbation and erosion potential of an intertidal estuarine mudflat (Humber estuary, UK)." Thesis, University of Hull, 2004. http://hydra.hull.ac.uk/resources/hull:7047.
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The influence of sedimentary variables on the structure and function of infaunal estuarine and marine communities is well studied but less is known of the influence of biota on sediment properties. Feeding and burrowing activity, locomotion, the production of faecal pellets and biological secretions (bioturbation) have important implications for sediment structure, chemistry, transport characteristics and the flux of nutrients and contaminants. Although spatial and temporal patterns in bioturbation have been studied to some extent, little attention has been given to the effects of pollution. The present study examines the effects of an intertidal petrochemical discharge into the Humber estuary (UK), from BP chemicals (Saltend) Ltd on the structure and function of the communities. Field and laboratory techniques were used to determine the effects of community change on bioturbation potential. In addition, a laboratory flume was constructed to measure sediment erosion potential with field measurements being taken using a Cohesive Strength Meter (CSM). The physico-chemical properties of the sediment, changes to the infaunal community structure, bioturbation potential and the interaction of these variables were used to explain differences between the erosion potential of sediments subject to varying levels of contamination. The main study was carried out on the Saltend mudflats near Hull, with sites at various distances from the outfall being used. A further set of control sites on the adjacent, and largely unaffected, mudflat at Paull were also used. In terms of the sediment properties, sites closest to the outfall showed the greatest degree of anoxia and the highest chlorophyll-a and carbohydrate concentrations, with all three parameters being seasonally influenced. No consistent spatial or temporal patterns were found for any of the other parameters (water and organic content, particle size). Whilst the infaunal communities were characteristic of estuarine areas, macrobenthic community response followed the Pearson & Rosenberg (1978) model for organic discharges with high abundance and low species diversity being associated with the more polluted sediments. Close to the discharge, there was an impoverished community consisting predominantly of highly abundant oligochate worms. With increasing distance from the outfall, species diversity and biomass increased with Hediste diversicolor becoming increasingly dominant and the appearance of Corophium volutator, Streblospio shrubsolii and Macoma balthica. Bioturbation potential was significantly reduced (in terms of depth and burrow volume and density) by increasing effiuent concentrations and with proximity to the discharge. The diversity of both feeding and sediment modification guilds was also reduced as a result of the discharge. Both field and laboratory studies indicated a stabilising effect of this type of pollution. Using the CSM, critical shear stress values were found to be significantly lower from unpolluted sites, indicating higher erosion potential, than those from sites close to the discharge. As a result of this, the total mass of sediment eroded from unpolluted sites was significantly higher than that from polluted areas. A similar trend was observed in the laboratory with sediments treated with an effluent concentration of 32% being considerably more stable than untreated sediments. Flume studies also indicated the stabilising effect of pollution with suspended particulate matter (SPM) concentrations and mass of sediment being transported as bedload being significantly higher for unpolluted sediments. These differences in erosion potential were attributed to the direct effects of the effiuent on the physico-chemical properties of the sediment, the effects of the effiuent and sediment type on macrofaunal community structure and function and the differences in bioturbation potential between sites. The implications of these findings in the wider context of coastal management are discussed.
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Lagauzère, Sandra. "Influence de la bioturbation des macro-invertébrés benthiques sur le comportement biogéochimique de l'uranium au sein des sédiments d'eau douce." Aix-Marseille 2, 2008. http://theses.univ-amu.fr.lama.univ-amu.fr/2008AIX22059.pdf.
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Dans les écosystèmes aquatiques continentaux, les sédiments représentent un compartiment d’accumulation pour les polluants métalliques comme l’uranium. Secondairement, ils peuvent également se comporter comme des sources endogènes de contamination, par remise en suspension (e. G. Crues, bioturbation) ou par évolution de la spéciation des métaux, laquelle va également jouer sur leur biodisponibilité. En effet, les composés métalliques peuvent être transformés en composés plus ou moins toxiques ou inertes sous l’effet de modifications des conditions physico-chimiques (pH, conditions rédox, force ionique) et microbiologiques du sédiment. Ces conditions sont elles-mêmes sous le contrôle de l’activité des macro-invertébrés benthiques via les processus de bioturbation. L’objectif principal de ce doctorat a été de déterminer l’influence de la bioturbation de deux espèces de macro-invertébrés benthiques (Chironomus riparius et Tubifex tubifex) sur la répartition et les transferts de l’uranium dans le sédiment des écosystèmes aquatiques continentaux. Pour cela, des expériences en laboratoire avec des dispositifs de type microcosmes, ont été réalisées pour (i) évaluer les effets de l’uranium sur les macro-invertébrés benthiques, plus particulièrement sur leur activité de bioturbation, (ii) déterminer l’influence de ces organismes sur le comportement de l’uranium grâce à des mesures physico-chimiques à haute résolution (e. G. Optodes à oxygène, gels DET), et (iii) appréhender les conséquences de ces interactions sur un organisme de la colonne d’eau, Xenopus laevis, via des mesures de génotoxicité (essai micronoyaux) et de biomarqueurs moléculaires (taux d'expression d'un certain nombre de gènes codant pour des protéines induites lors de stress environnementaux). Les principaux résultats obtenus montrent que l’intensité de la bioturbation des macro-invertébrés peut être diminuée dans un sédiment contaminé par de l’uranium, mais que les espèces étudiées dans cette étude présentent une bonne tolérance. Pour des concentrations en uranium élevées (>100 fois le bruit de fond géochimique naturel), les vers T. Tubifex sont capables de maintenir une activité de bioturbation suffisante pour entraîner une forte remobilisation de l’uranium initialement associé au sédiment vers la colonne d’eau. Ceci représente donc un risque potentiel pour le reste de la biocénose aquatique. Cependant, en voulant tester cette hypothèse, il a été constaté de façon surprenante que le comportement des vers pouvait être modifié en présence d’un autre organisme dans la colonne d’eau et qu’ainsi il n’entraînait plus de relargage d’uranium vers la colonne. Toutefois, l’uranium associé au sédiment, sans l’effet de la bioturbation, induit des effets négatifs sur cet organisme. Au final, ce travail de thèse a permis de décrire les interactions pouvant exister entre les organismes aquatiques, la biogéochimie du sédiment et un polluant métallique comme l’uranium. Les informations apportées sont originales et permettent d’envisager de façon plus précise les conséquences d’une pollution à l’uranium dans l’environnement aquatique. Plus globalement, les travaux de recherche entrepris dans le cadre de cette thèse contribueront à améliorer les connaissances actuelles en vue d’une meilleure évaluation des risques écologiques des écosystèmes aquatiques contaminés par des polluantsIn freshwater ecosystems, sediments act as an accumulation compartment for metallic pollutants as uranium. Secondary, there can also represent endogenous sources of contamination by resuspension (e. G. Flood, bioturbation) or changes of metal speciation that acts upon their bioavailability. Indeed, metallic compounds can be transformed in more or less toxic or inert compounds through physico-chemical (e. G. PH, redox conditions, ionic force) and microbiological variations. These conditions are themselves under the effects of benthic macro-invertebrate activities via bioturbation processes. The main objective of this PhD was to determinate the influence of two benthic macroinvertebrate species (Chironomus riparius and Tubifex tubifex) on the distribution and the transfers of uranium within freshwater sediments. To reach this goal, laboratory experiments were performed in order to (i) assess the effects of uranium on benthic macroinvertebrates, more particularly on their bioturbation activity, (ii) determine the influence of these organisms on uranium behaviour through high resolution physico-chemical measurements (e. G. Oxygen optodes, DET gel probes), and (iii) estimate the consequences of these interactions on pelagic organisms via genotoxicity measurements (micronuclei assay and molecular biomarkers analysis on Xenopus laevis). The results demonstrate that bioturbation intensity of macroinvertebrates can be affected in uranium-contaminated sediments, but the two species studied in this work show a relative tolerance. For high uranium concentrations (>100 times the geochemical background level), corresponding however to realistic concentrations in highly contaminated sites, T. Tubifex worms are able to maintain a sufficient bioturbation activity that induces a high remobilization of uranium initially associated with sediments to the overlying water (factor 2 to 10). That represents therefore a potential risk for the remaining aquatic biocenosis. However, by testing this assumption on X. Laevis, it was surprisingly noticed that the worms’ behaviour can be modified in presence of this organism in the water column. The effect of bioturbation on uranium release from the sediments was thus altered conducing to lower uranium concentrations in the water column. Nevertheless, sediment-associated uranium, without the effect of bioturbation, induces negative effects on this pelagic organism. Finally, this PhD work illustrates the interactions that can exist between aquatic organisms, sediment biogeochemistry and a metallic pollutant as uranium. The novel results obtained permit to view more precisely the consequences of uranium pollution in aquatic environment. More globally, this work will contribute to a better assessment of ecological risks in polluted aquatic ecosystems
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Mombo, Stéphane. "Transferts des métaux et métalloïdes dans le système sol-plante-atmosphère : mécanismes biogéochimiques et conséquences environnement-santé." Thesis, Toulouse, INPT, 2016. http://www.theses.fr/2016INPT0074/document.
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Des pollutions des sols (péri)urbains et urbaines fortement peuplées en métaux et metalloïdes persistants (éco)toxiques sont couramment observées à l’échelle globale. Certains éléments (Se, Cu…) ont des rôles biologiques et par contre d’autres (Pb, Cd…) ont uniquement un impact (éco)toxique qui peut être influencé par leur spéciation et compartimentation qui modifient leurs transferts et biodisponibilité. Dans une optique de gestion des sols et d’alimentation durables, des questions scientifiques pluridisciplinaires sont à creuser concernant : (i) les mécanismes en jeu dans la biodisponibilité et l’impact sur les organismes vivants des éléments inorganiques en lien avec leur spéciation ; (ii) la co-gestion des risques environnement-santé induits par des installations industrielles classées : ICPE en France (ex. usine de recyclage de batteries) avec les riverains qui cultivent des potagers ou les employés. Dans ce contexte, ont été étudiés : (i) le transfert des métaux entre phase solide et solution du sol sous l’influence des vers de terre sur un site ICPE; (ii) le transfert et la bioaccessibilité du Se en conditions contrôlées pour 2 formes chimiques; (iii) le risque sanitaire pour les riverains d’un site ICPE qui jardinent, et les facteurs influant les plombémies des professionnels (étude statistique des données). Une review bibliographique de la qualité du manioc en lien avec les pratiques culturales et culinaires et les caractéristiques de l’environnement a finalement été réalisée pour compléter la démarche « Sciences et Société » de la thèse. L’analyse des différents isotopes du plomb dans les sols aux alentours de l’usine de recyclage a permis de conclure que 84 à 100% du plomb des sols de surface est d’origine anthropique. Un comportement d’évitement des zones les plus polluées en plomb a été observé pour l’espèce de vers de terre A. caliginosa. Le transfert racinaire, la translocation du sélénium vers le maïs et sa bioaccessibilité dans le grain sont plus élevés dans le cas du séléniate (facteur de translocation de 1.1, et bioaccessibilité humaine de 89,3%) par rapport au sélénite (0.13, et bioaccessibilité de 82,7%). L’étude de la qualité des cultures des jardins proches de l’usine (à Bazoches), en relation avec la qualité du sol (faible contamination, pH basique et teneur élevée en matières organiques qui réduisent les transferts) et de l’atmosphère a mis en évidence un transfert atmosphère-plante qui dépend du métal (le Cd est le plus biodisponible) et du végétal. Les concentrations en Pb et Cd suivent respectivement les séquences : [laitue>poireau>céleri>carotte] et [laitue>céleri>carotte>poireau]. Pour réduire l’exposition des populations, un lavage soigneux des productions avant la consommation est préconiséPollution of (peri)urban soils by (eco)toxic metal(loid)s is commonly observed on a global scale. Some elements (Se, Cu ...) have biological roles and other (Pb, Cd ...) only have an (eco)toxic impact influenced by their speciation and compartmentalization that can change their transfers and bioavailability. With the perspective of sustainable management of soil and food, multidisciplinary scientific questions are digging for: (i) the mechanisms involved in the bioavailability and impact on living organisms of inorganic elements related to speciation; (ii) the co-management of environmental-health risks from industrial regulated plants (ICPE in France, such as former battery recycling plant) with residents who grow vegetable gardens or employees. In this context, were studied: (1) the transfer of metals between solid phase and soil solution under the influence of earthworms on a ICPE site; (2) the transfer and bioavailability of Se in controlled conditions for two chemical forms; (3) the health risk for the residents with gardening activities near ICPE plant and factors influencing blood lead of professionals (statistical analysis of data). A literature review of the quality of cassava in connection with the cultivation and culinary practices and characteristics of the environment was finally performed to complete the "Science and Society" process of the thesis. From the analysis of different isotopes of lead in the soil around the recycling plant it was concluded that 84 to 100% of lead in surface soils has anthropogenic origin. Avoidance behavior in the most lead polluted areas was observed for A. caliginosa earthworm species. The selenium root transfer, translocation to corn and its bioavailability in the grain are higher in the case of selenate (translocation factor of 1.1, and human bioavailability of 89.3%) compared to selenite (0.13 and bioaccessibility 82.7%). The study of crops quality in the gardens near the ICPE plant (in Bazoches), in relation to atmosphere and soil quality (low Pb contamination, alkaline pH and high organic content that reduce pollutants transfers) highlighted an atmosphere-plant transfer which depends on the metal (Cd is the most bioavailable) and plant species. Pb and Cd concentrations follow respectively the sequences: [lettuce> Leek> celery> carrot] and [lettuce> celery> carrot> leek]. To reduce population exposure, thorough washing of productions before consumption is recommended
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Bernard, Guillaume. "Mesures expérimentales et modélisation du remaniement sédimentaire dans le bassin d’Arcachon." Thesis, Bordeaux 1, 2013. http://www.theses.fr/2013BOR14821/document.
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Le remaniement sédimentaire, défini comme l’ensemble des mouvements de particules sédimentaires induits par les organismes benthiques, est l’une des deux composantes du phénomène de bioturbation. Il constitue un processus clé du fonctionnement des écosystèmes côtiers. Ce manuscrit présente une étude intégrée de ce depuis l’échelle de la simple particule sédimentaire jusqu’à celle de la communauté benthique in toto.Le développement d’une nouvelle approche expérimentale basée sur l’acquisition à haute fréquence et l’analyse de séries temporelles d’images de mouvements de luminophores le long de la paroi d’aquariums plats a permis de mesurer directement les mouvements élémentaires de particules de sédiment effectués par le bivalve A. alba. Cette approche a ainsi conduit à la première détermination expérimentale d’ « empreintes » du remaniement sédimentaire d’un invertébré marin, d’après le formalisme du modèle CTRW (Continuous Time Random Walk).Dans un second temps, le déploiement de cette nouvelle approche a permis d’évaluer, de manière dynamique (i.e. pendant des expériences de 48h) et sur l’ensemble de la partie de la colonne sédimentaire affectée par ce bivalve, le contrôle exercé par la température et par la disponibilité de matière organique fraîche sur les caractéristiques du processus de remaniement sédimentaire effectué par A. alba.Enfin, l’intensité du remaniement sédimentaire effectué par l’ensemble de la communauté benthique a été mesurée in-situ dans le Bassin d’Arcachon, à la fois dans un herbier à Zostera noltii et dans une zone de vase nue d’où celui-ci a disparu. Ceci a permis de déterminer les effets limitant de la présence d’herbier et de certaines espèces benthiques clés, sur le remaniement sédimentaireSediment particle mixing, defined as the movements of sediment particles induced by benthic fauna, is one of the two components of bioturbation by benthic organisms. It is a key process of the ecological functioning in coastal areas. This manuscript presents an integrated study of sediment particle mixing process from the single sediment particle to the whole benthic community.The development of a new experimental approach, coupling high frequency acquisition of time series images of luminophores motions along thin aquaria glass walls, allowed for the direct measurement of elementary particle motions induced by the bivalve Abra alba. This constitutes the first experimental assessment of sediment particle mixing “fingerprints” in a marine invertebrate, according to the CTRW (Continuous Time Random Walk) model formulation.The deployment of this new approach also allowed for the determination of the control of water temperature and of fresh organic matter availability on sediment particle mixing induced by Abra alba. Moreover, the temporal (i.e., during 48h experiments) and spatial (i.e., over the whole section of the sediment column affected) dynamics of these effects were considered.At last, sediment particle mixing intensities induced by the whole benthic community were assessed in-situ in Arcachon Bay, within both a Zostera noltii meadow and a bare sediment mudflat where phanerogams were previously present. These results highlighted the restrictive effect of phanerogams themselves and of a restricted number of key benthic species, on sediment particle mixing
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Baranov, Viktor [Verfasser], Jörg [Gutachter] Lewandowski, Tobias [Gutachter] Kümmerle, and Alexander [Gutachter] Milner. "Influence of bioturbation on sediment respiration in advection and diffusion dominated systems / Viktor Baranov ; Gutachter: Jörg Lewandowski, Tobias Kümmerle, Alexander Milner." Berlin : Humboldt-Universität zu Berlin, 2018. http://d-nb.info/1189427214/34.
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