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Статті в журналах з теми "Estuarine mudflats"
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Braat, Lisanne, Thijs van Kessel, Jasper R. F. W. Leuven, and Maarten G. Kleinhans. "Effects of mud supply on large-scale estuary morphology and development over centuries to millennia." Earth Surface Dynamics 5, no. 4 (October 9, 2017): 617–52. http://dx.doi.org/10.5194/esurf-5-617-2017.
Повний текст джерелаАнотація:
Abstract. Alluvial river estuaries consist largely of sand but are typically flanked by mudflats and salt marshes. The analogy with meandering rivers that are kept narrower than braided rivers by cohesive floodplain formation raises the question of how large-scale estuarine morphology and the late Holocene development of estuaries are affected by cohesive sediment. In this study we combine sand and mud transport processes and study their interaction effects on morphologically modelled estuaries on centennial to millennial timescales. The numerical modelling package Delft3D was applied in 2-DH starting from an idealised convergent estuary. The mixed sediment was modelled with an active layer and storage module with fluxes predicted by the Partheniades–Krone relations for mud and Engelund–Hansen for sand. The model was subjected to a range of idealised boundary conditions of tidal range, river discharge, waves and mud input. The model results show that mud is predominantly stored in mudflats on the side of the estuary. Marine mud supply only influences the mouth of the estuary, whereas fluvial mud is distributed along the whole estuary. Coastal waves stir up mud and remove the tendency to form muddy coastlines and the formation of mudflats in the downstream part of the estuary. Widening continues in estuaries with only sand, while mud supply leads to a narrower constant width and reduced channel and bar dynamics. This self-confinement eventually leads to a dynamic equilibrium in which lateral channel migration and mudflat expansion are balanced on average. However, for higher mud concentrations, higher discharge and low tidal amplitude, the estuary narrows and fills to become a tidal delta.
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Kleinhans, Maarten G., Lonneke Roelofs, Steven A. H. Weisscher, Ivar R. Lokhorst, and Lisanne Braat. "Estuarine morphodynamics and development modified by floodplain formation." Earth Surface Dynamics 10, no. 2 (April 29, 2022): 367–81. http://dx.doi.org/10.5194/esurf-10-367-2022.
Повний текст джерелаАнотація:
Abstract. Rivers and estuaries are flanked by floodplains built by mud and vegetation. Floodplains affect channel dynamics and the overall system's pattern through apparent cohesion in the channel banks and through filling of accommodation space and hydraulic resistance. For rivers, effects of mud, vegetation and the combination are thought to stabilise the banks and narrow the channel. However, the thinness of estuarine floodplain, comprised of salt marsh and mudflats, compared to channel depth raises questions about the possible effects of floodplain as constraints on estuary dimensions. To test these effects, we created three estuaries in a tidal flume: one with recruitment events of two live vegetation species, one with mud and a control with neither. Both vegetation and mud reduced channel migration and bank erosion and stabilised channels and bars. Effects of vegetation include local flow velocity reduction and concentration of flow into the channels, while flow velocities remained higher over mudflats. On the other hand, the lower reach of the muddy estuary showed more reduced channel migration than the vegetated estuary. The main system-wide effect of mudflats and salt marsh is to reduce the tidal prism over time from upstream to downstream. The landward reach of the estuary narrows and fills progressively, particularly for the muddy estuary, which effectively shortens the tidally influenced reach and also reduces the tidal energy in the seaward reach and mouth area. As such, estuaries with sufficient sediment supply are limited in size by tidal prism reduction through floodplain formation.
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Fouet, Marie P. A., David Singer, Alexandra Coynel, Swann Héliot, Hélène Howa, Julie Lalande, Aurélia Mouret, Magali Schweizer, Guillaume Tcherkez, and Frans J. Jorissen. "Foraminiferal Distribution in Two Estuarine Intertidal Mudflats of the French Atlantic Coast: Testing the Marine Influence Index." Water 14, no. 4 (February 18, 2022): 645. http://dx.doi.org/10.3390/w14040645.
Повний текст джерелаАнотація:
This study focuses on the foraminiferal distribution on intertidal mudflats of two contrasted estuaries (Auray and Vie) along the French Atlantic coast. In both estuaries, the foraminiferal communities are dominated by Haynesina germanica and the Ammonia tepida group. Stations located near the outlets show a high diversity and abundance of species of the genus Elphidium. Stations in the inner estuary show a higher proportion of agglutinated species (Ammotium salsum, Ammobaculites agglutinans). Multivariate statistical analysis suggests that the distance to the sea and the percentage of fine sediment (<63 µm) are the two main parameters explaining the foraminiferal distribution. Chemical analyses of the sediment show that the two studied estuaries are not affected by major anthropogenic pollution, so that the faunas should mainly reflect the natural controlling parameters. Three indices of environmental quality commonly used in coastal areas show counter-intuitive differences between stations, suggesting that these indices may be less reliable for use in intertidal estuarine mudflats. The newly developed Marine Influence Index (MII) integrates three major ecological factors: the position of the sampling point on the salinity gradient, the emergence time at low tide and the relative importance of fresh water discharge. In our dataset, MII shows significant correlations with the controlling environmental parameters (distance to the sea, percentage grains < 63 µm), as well as with the foraminiferal patterns (PCA axis 1, species richness, percentage of Elphidium spp. and Quinqueloculina spp.). These results suggest that the MII explains a substantial part of the faunal variability on estuarine intertidal mudflats, and can be used to detect deviations from the natural distribution patterns in response to anthropogenic pollution.
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Defew, E. C., T. J. Tolhurst, and D. M. Paterson. "Site-specific features influence sediment stability of intertidal flats." Hydrology and Earth System Sciences 6, no. 6 (December 31, 2002): 971–82. http://dx.doi.org/10.5194/hess-6-971-2002.
Повний текст джерелаАнотація:
Abstract. The factors that influence the sediment stability and the transport of estuarine mudflats are not yet fully understood but knowledge of them is essential in coastal engineering applications and pollution ecology studies. The suggestion that variation in predictive models of sediment stability might be due to site-specific characteristics is investigated using data from four estuarine mudflats (Eden Estuary, Scotland, the Biezelingsche Ham, Zandkreek, and Molenplaat mudflats in The Netherlands). These estuaries differ in their environmental conditions, macrofaunal species composition and local features (e.g. Enteromorpha mats, migratory biofilms). Stable and unstable sediments were compared, and mean chlorophyll-a concentrations and granulometry of the sediments were significantly different between the two groups. Step-wise multiple linear regressions were applied to the sediment stability data of all sites to establish the influences on erosion threshold of microphytobenthic biomass, water content, granulometry, organic carbon content and the abundance of dominant macrofaunal species. The stability of each site was influenced by different factors. Sediment stability of the Eden Estuary was affected by the Enteromorpha bloom; Biezelingsche Ham was influenced by the highly migratory nature of the diatom biofilms and the abundance of Corophium volutator; the polychaete worm Arenicola marina had a net negative effect on sediment stability of the Zandkreek; and the Molenplaat was influenced by microphytobenthic biomass. This research highlights the need for site-specific calibration of models and suggests that a universal proxy parameter for sediment stability is unlikely to be obtained. Keywords: sediment stability; erosion threshold; cohesive strength meter; microphytobenthos; Enteromorpha spp.
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Kumaraguru, Arumugam, Rosette Celsiya Mary, and Vijayaraghavalu Saisaraswathi. "A review about fish walking on land." Journal of Threatened Taxa 12, no. 17 (December 26, 2020): 17276–86. http://dx.doi.org/10.11609/jott.6243.12.17.17276-17286.
Повний текст джерелаАнотація:
Mudskippers are amphibious species inhabiting semi-terrestrial ecosystems like mudflats, mangroves, marshy swamps, intertidal regions, and estuaries. Around 34 diversified species are found across the globe. Mudskipper belongs to the Oxudercidae family and the subfamily is Oxudercinae. The occurrence of species is vastly found across the Indo-West Pacific region, the tropical western coast of Africa and in the Indian Ocean. Mudskippers are known for being the biological indicator and also an indicator of estuarine safety monitoring. They are used by people for prey-catching baits. This review paper explains the ecological indicators, taxonomy, species diversity, habitat, behavioural pattern, respiration & kinematics, feeding ecology, reproduction, nutrition content & its medicinal value, and threats to mudskippers.
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Sapkale, J. B., T. R. Jamadar, S. J. Sapkale, and G. S. Shinde. "Estimation of Physicochemical Properties in the Estuarine Water of Mithbav Tidal Mud Flats (Downstream Part), Coastal Maharashtra." Research Journal of Chemistry and Environment 27, no. 10 (September 15, 2023): 10–20. http://dx.doi.org/10.25303/2710rjce010020.
Повний текст джерелаАнотація:
Estuarine environments have become crucial in coastal areas nowadays. Mangrove swamps, mudflats and related estuarine environments provide a habitat for animals and encourage plant growth. For the people of coastal areas, estuaries are one of the vital sources of food and other economic activity. The imbalance in the quality and quantity of Estuarine water in terms of its physicochemical parameters causes adverse effects on marine life. In the present study, an attempt has been made to estimate the physicochemical properties of the estuarine water of Mithbav tidal mud flats (downstream part) of coastal Maharashtra. Several methods have been used to evaluate the variations in physical and chemical properties of estuarine water in Mithbav including standard water testing,1 the titration method and Winkler's method. Salinity, turbidity, pH, total hardness, DO, TDS, EC, nitrate, fluoride, phosphate, ammonium, magnesium, calcium, carbonate, chloride, sodium, potassium and sulphate were examined for the seven cross-sectional sites of Mithbav estuarine water. Some parameters show levels of contamination that exceed the maximum limit. For instance, during the post-monsoon season, the average value of dissolved oxygen (DO) was recorded as 11.57mg/L whereas it has been recorded as 8.07mg/L during the summer season. The total dissolved solids (TDS) showed an average increase from 141.54 to 348.57ppt between pre and post-monsoon seasons. The electrical conductivity (EC) also increased from 45558.17μ S/Cm to 31445.85 μ S/Cm respectively from the dry to the wet season. The fluoride levels during the post-monsoon season ranged from 1.07 mg/L at CS-1 to 4.2 mg/L at CS-6. The study shows that the Mithbav coastal ecosystem and nearby areas are at significant risk of contamination from physiochemical parameters that could harm the environment.
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Mathes-Schmidt, Margret, Denis Moiriat, Hervé Jomard, Klaus Reicherter, and Stéphane Baize. "The Holocene sedimentary record of the flood plain of the Saint-Ciers-Sur-Gironde marsh (Gironde estuary, France)." Zeitschrift für Geomorphologie, Supplementary Issues 62, no. 2 (October 1, 2019): 295–322. http://dx.doi.org/10.1127/zfg_suppl/2019/0605.
Повний текст джерелаАнотація:
The Holocene sedimentary record of the flood plain of the Saint-Ciers-Sur-Gironde marsh was examined on sediment cores from the right bank of the Gironde estuary with regard to the evolution of the marsh and its potential to preserve high-energy deposits. Sedimentological, geochemical, geophysical and micropaleontological methods were applied. Radiocarbon ages in the central part of the investigation area reach back to 7,971 ± 44.5 BP. The sediments of the Saint-Ciers-sur-Gironde marsh reflect the condi- tions of a Holocene estuarine salt marsh before human activity and draining. The interpretation of the core data showed that the study area includes different facies during development from the pre-Holocene to recent times: tidal mudflats in the northwest at Mortagne and Beaumont, and a fluvial facies develop- ing into an estuarine facies in the southeast near Camp and Saint-Ciers-Sur-Gironde. The last stage is the formation of the saltmarsh. The changes in grain size reflect different transport mechanisms during the development from a fluvial environment to the recent marsh. First gravel, then sand and finally muddy sediments were deposited in the estuary and finally in the marsh area.. Below the salt marsh deposits in Mortagne-Sur-Gironde, there is some evidence of deposits from energy-rich events in tidal mudflats. The southern and central part, in which estuarine clays were deposited, was probably most of the time outside the range of storms. On the marshland surface, erosion, pedogenesis and bioturbation processes destroy storm relevant layers in a very short time.
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Groeneveld, Johan C., Fiona MacKay, Baraka Kuguru, and Boniventure Mchomvu. "Socio-ecological change in the Ruvu Estuary in Tanzania, inferred from land-use and land-cover (LULC) analysis and estuarine fisheries." Western Indian Ocean Journal of Marine Science, no. 1/2021 (December 23, 2021): 75–91. http://dx.doi.org/10.4314/wiojms.si2021.1.6.
Повний текст джерелаАнотація:
Ecosystem goods and services derived from estuaries have sustained coastal livelihoods in the Western Indian Ocean (WIO) region throughout recorded history. Estuaries provide fertile and seasonally irrigated space for planting crops, mangrove products for construction and fuel, and fish as a protein source. Human population growth and an escalating demand for natural resources threaten estuarine critical habitats and their functioning, exacerbated by the effects of climate change. Decadal and seasonal land-use and land-cover (LULC) changes in the Ruvu Estuary in Tanzania were investigated through analysis of Landsat 5/8 and Sentinel-2 satellite images. The estuary is river-dominated and truncated near the coast during high river flow, with tidal influence extending approximately 12 km upstream during low river flow. LULC change detection targeting nine classes (water, developed, barren, forest, grasslands, cultivated, mangroves, wetlands and mudflats) showed that estuary-associated wetlands and mangroves had declined significantly over the past two decades (1995-2016) making way for developed land (growth of Bagamoyo Town), cultivated land (agricultural expansion with increasing population) and grasslands (coastal habitat changes). Seasonal LULC changes were conversion of wetlands to cultivated land after the wet season, and transformation of fallow wetlands to grasslands. The estuarine fishery relied on a small number of mainly freshwater and marine migrant species, compared to a highly diverse mix of mainly marine species in the nearby coastal fishery. The sparsity of quantitative fisheries data, spectral confusion when modelling land-cover change, and absence of household survey data to assess livelihood activities remain major information gaps. Generalized recommendations for improving socio-ecological change studies in WIO estuarine systems are provided.
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Deusdado, Pedro, Magno Guedes, André Silva, Francisco Marques, Eduardo Pinto, Paulo Rodrigues, André Lourenço, et al. "Sediment Sampling in Estuarine Mudflats with an Aerial-Ground Robotic Team." Sensors 16, no. 9 (September 9, 2016): 1461. http://dx.doi.org/10.3390/s16091461.
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Berthe, Thierry, Aurélie Touron, Julie Leloup, Julien Deloffre, and Fabienne Petit. "Faecal-indicator bacteria and sedimentary processes in estuarine mudflats (Seine, France)." Marine Pollution Bulletin 57, no. 1-5 (January 2008): 59–67. http://dx.doi.org/10.1016/j.marpolbul.2007.10.013.
Повний текст джерелаДисертації з теми "Estuarine mudflats"
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Hughes, Susan Helen. "The geochemical and mineralogical record of the impact of historical mining within estuarine sediments : Fal Estuary, Cornwall, UK." Thesis, University of Exeter, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341192.
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Davis, Helen. "A study of an estuarine benthic community subjected to petrochemical effluents." Thesis, University of Stirling, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249931.
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Daviray, Maxime. "Fonctionnement biogéochimique des écosystèmes transitionnels colonisés par les bactéries filamentaires électriques : réponse des biocénoses et thanatocénoses de foraminifères benthiques." Electronic Thesis or Diss., Angers, 2024. http://www.theses.fr/2024ANGE0031.
Повний текст джерелаАнотація:
L’objectif de cette thèse est d’évaluer l’effet de l’acidification provoquée par l’activité des cable bacteria sur la géochimie du sédiment des environnements intertidaux, et les conséquences de ce processus de dissolution sur les communautés de foraminifères benthiques et la préservation de leur test dans les sédiments. Cette étude combine des campagnes de suivis de vasières intertidales dans différents estuaires de la façade atlantique et de la Manche (France) par des approches à haute résolutions et des incubations en conditions contrôlées au laboratoire. L’activité des cable bacteria présente une variabilité saisonnière, avec un maximum d’activité durant la période été-automne, et tend à fortement structurer la succession verticale des zones oxique-suboxique-anoxique. La bioturbation associée à la macrofaune ou au réseau racinaire des zostères introduit de l’hétérogénéité latérale dans la géochimie et génère des microhabitats. L’effet structurant du pH sur la distribution successive des différentes espèces de foraminifères dans le sédiment a été mise en évidence. La réponse des foraminifères à l’acidification de leur environnement apparait espèce-dépendante et implique autant leur particularité métabolique que comportementale.L’activité des cable bacteria engendre une perte importante des tests carbonatés dans l’enregistrement sédimentaire. Leur temps de résidence est estimé à une douzaine de jours.L’accumulation de tests agglutinés et de membranes organiques, à défaut des tests carbonatés, pourraient être utilisée pour fournir une revue historique des processus de dissolution dans les sédiments marinsThis thesis aims to assess the effect of acidification caused by cable bacteria activity on the sediment geochemistry in intertidal environments, and the consequences of this dissolution process on benthic foraminiferal communities and the preservation of their shell in sediments. This study combines intertidal mudflats monitoring in various estuaries on the Atlantic coast and in the English Channel (France) using high-resolution approaches and incubation under controlled conditions in the laboratory.. The cable bacteria activity varies according to the season, with maximum activity during the summer-autumn period, and strongly structures the vertical oxic-suboxic-anoxic redox zone succession. Bioturbation associated with macrofauna or the eelgrass roots introduces late--ral heterogeneity into this system and generate microhabitats. The structuring effect of pH on the successive distribution of foraminiferal species within sediment has been demonstrated. The response of foraminifera to the acidification of their environment seems to depend on the species and involves both their metabolic and behavioural characteristics. The activity of the cable bacteria results in a significant loss of calcareous shells in the sedimentary record. Their residence time is estimated about a dozen days. The accumulation of agglutinated shells and organic linings despite of calcareous shells could be used to provide a historical review of dissolution processes in marine sediments
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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.
Повний текст джерелаАнотація:
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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Fox, Daniel. "Cohesive sediment dynamics on a mudflat within the macrotidal Conwy Estuary, North Wales, U.K." Thesis, Bangor University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327514.
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Vennin, Arnaud. "Etude de l'interface eau-sédiment dans les géosystèmes estuariens : approche couplée biogéochimie et modélisation par l'évaluation des flux de nutriments (C,N,P)." Thesis, Normandie, 2018. http://www.theses.fr/2018NORMR023/document.
Повний текст джерелаАнотація:
L’estuaire de Seine est un géosystème macrotidal présentant un hydrodynamisme fort lié à la combinaison des courants fluviatiles et tidaux. Ces phénomènes entrainent l’érosion et le dépôt des sédiments au niveau des vasières intertidales. Au sein des vasières, l’interface eau-sédiment est une zone importante car c’est à cet endroit que se réalise les échanges en nutriment (C, N, P) entre le sédiment et la colonne d’eau. L’objectif de cette thèse est d’évaluer l’impact des forçages hydrodynamiques, physiques et thermiques sur les flux de nutriment à cette interface en utilisant une double approche expérimentale de terrain et de modélisation. Dans ce but, une vasière d’embouchure et une vasière amont de l’estuaire sont échantillonnées au cours des mois de mars-avril 2017. Des échantillonneurs passifs ainsi que des instruments de mesure en continu sont implantés dans le sédiment. Les données obtenues sont ensuite intégrées en entrée dans des modèles de diffusion et d’advection afin d’estimer la contribution relative de la diffusion et des mouvements d’eau dans les flux de nutriment. Les résultats expérimentaux obtenus montrent les différences de fonctionnement hydrodynamiques des deux vasières du fait de leur localisation différente dans l’estuaire. Ils mettent aussi en avant l’hétérogénéité des sédiments des deux vasières d’un point de vue hydrodynamique, physique et biogéochimique. Enfin ils permettent de comprendre la dynamique de la température du sédiment en lien avec le cycle diurne et la marée. La partie modélisation de cette étude est divisée en deux parties distinctes : l’étude de la diffusion et de l’advection à l’interface eau-sédiment. La diffusion est étudiée de façon horizontale et verticale. Le facteur prépondérant de la dynamique de diffusion est la température, celle-ci est modulée par plusieurs paramètres. Les flux potentiels de diffusion sont aussi calculés pour les deux vasières. L’étude de l’advection au sein du sédiment est réalisée à l’aide de deux modèles : le modèle VFLUX et le modèle 1DTempPro. Les vitesses d’écoulement de l’eau interstitielle sont fonction du phasage-déphasage du cycle diurne avec celui de la marée. Ces résultats mettent en avant le rôle prédominant de l’advection par rapport à la diffusion dans la dynamique des flux de nutriment et permettent de proposer un modèle conceptuel des échanges thermiques et de l’advection-diffusion au sein des vasières intertidalesThe Seine estuary is a macrotidal geosystem with a strong hydrodynamism linked to the combination of fluvial and tidal currents. These phenomena cause erosion and sediment deposition on the intertidal mudflats. Within the mudflats, the water-sediment interface is an important area because it is there that nutrient exchanges (C, N, P) take place between the sediment and the water column. The objective of this thesis is to evaluate the impact of hydrodynamic, physical and thermal forcing on nutrient fluxes at this interface using a dual experimental field and modelling approach. For this purpose, a mudflat situated at the mouth of the river and an upstream mudflat of the estuary are sampled during the months of March-April 2017. Passive samplers and continuous measuring instruments are implanted in the sediment. The resulting data are then integrated into diffusion and advection models to estimate the relative contribution of water diffusion and movement in nutrient fluxes.The experimental results show differences in the hydrodynamic functioning of the two mudflats due to their different location in the estuary. They also highlight the heterogeneity of the sediments of the two mudflats from the hydrodynamic, physical and biogeochemical points of view. Finally, they allow us to understand the dynamics of sediment temperature in relation to the diurnal cycle and the tide. The modelling part of this study is divided into two distinct parts: the study of diffusion and advection at the water-sediment interface. The diffusion is studied in a horizontal and vertical direction. The main factor of diffusion dynamics is temperature, which is modulated by several parameters. The potential diffusion fluxes are also calculated for the two mudflats. The study of advection within the sediment is performed using two models: the VFLUX model and the 1DTempPro model. Interstitial water flow velocities are a function of the phase-diphase shift of the diurnal cycle with that of the tide. These results highlight the predominant role of advection compared to diffusion in the dynamics of nutrient flows and allow to propose a conceptual model of heat exchange and advection-diffusion within intertidal mudflats
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Armitage, Anna Ruth. "Community structure and trophic interactions in restored and natural estuarine mudflats complex trophic cascades and positive and negative effects of nutrients /." 2003. http://catalog.hathitrust.org/api/volumes/oclc/55525909.html.
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Pedro, Sílvia. "Metal cycling in salt marshes and intertidal mudflats : influence of plants, invertebrates and fishes." Doctoral thesis, 2014. http://hdl.handle.net/10451/17710.
Повний текст джерелаАнотація:
Tese de doutoramento, Biologia (Ecologia), Universidade de Lisboa, Faculdade de Ciências, 2015Estuaries face different anthropogenic pressures as a consequence of their privileged location and high productivity, and thus a diverse array of pollutants enter the ecosystem. Metals are of particular concern, due to their persistent and non-degradable character and pernicious effects exerted on the biota. Metals are found in several compartments of the estuarine ecosystem. They may be in dissolved or particulate forms in the water column, sorbeb on the sediments or accumulated in the biota. This thesis aimed to determine the effect of the sediment-organism interactions in metals’ cycling in salt marsh and intertidal sediments. Special attention was given to metal speciation, to assess the mobility and bioavailability of such elements. Total metal concentration was determined in tissues of two fish species occupying different levels in the estuarine trophic web, as well as in bottom sediments, to assess metal exposure and accumulation in fish tissues. Sequential extractions were made in rhizosediments of three halophytes and adjacent bare mud flat sediments from two different salt marshes. Operationally defined fractions were obtained using solution of increasing strength and acidity, to evaluate the effect of halophytes on metal availability. Two laboratory trials were conducted in which metal fractionation was assessed in on sediments before and after passing through the gut of the two species. The results of these works indicate that metal accumulation in estuarine sediments can affect the accumulation in fish tissues. Sediment-organism interactions alter metal mobility in the sediments. Salt marsh plants tend to immobilize metals in their rhizosediments, while the ingestion of sediment by and detritivorous species, and subsequent excretion of fecal pellets, makes some metals more bioavailable to the estuarine trophic web.
Os estuários enfrentam diferentes pressões antropogénicas inerentes à sua localização privilegiada e elevada produtividade, e têm como consequência a presença mais ou menos acentuada de diversos tipos de poluentes. A persistência e o carácter não degradável dos metais no ambiente é particularmente preocupante, tendo em conta os efeitos nocivos que podem exercer no biota. Os metais podem ocupar vários compartimentos num estuário, e.g., na coluna de água (dissolvidos ou particulados), adsorvidos ao sedimento ou acumulados nos organismos. A presente tese teve como objetivo avaliar o efeito das interações organismo-sedimento na dinâmica de metais em sedimentos de sapal e áreas intertidais adjacentes, incidindo em particular na especiação dos metais e na sua disponibilização para a teia trófica estuarina. Para avaliar a exposição de duas espécies de peixes de diferentes níveis da teia trófica estuarina à contaminação por metais no sedimento, determinaram-se as concentrações totais em tecidos e em sedimentos superficiais. Analisou-se também a especiação dos metais nos sedimentos entre raízes de três halófitas e nos sedimentos sem coberto vegetal, em dois sapais. Extraíram-se sequencialmente frações operacionais com soluções de força e/ou acidez crescente, para avaliar o impacto dos organismos na mobilidade dos metais. Realizaram-se ainda duas experiências em que se determinou a especiação dos metais no sedimento antes e depois da ingestão por duas espécies de diferentes grupos taxonómicos. Concluiu-se que a acumulação de metais no sedimento estuarino pode afetar a acumulação nos tecidos das espécies selecionadas. A interação sedimento-organismo conduz a alterações da dinâmica dos metais; a ação das plantas de sapal potencia a imobilização de alguns elementos, sendo o efeito da ingestão de sedimento por organismos detritívoros aparentemente contrário, disponibilizando os metais sob formas mais acessíveis à teia trófica estuarina
Fundação para a Ciência e a Tecnologia (FCT), SFRH/BD/37926/2007, projetos PEst-OE/MAR/UI0199/2014, POCI/MAR/58548/2004
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Arvai, Joseph Louis. "The population dynamics and production of Corophium salmonis (S.) and Macoma balthica (L.) on an estuarine mudflat in response to effluent diversion from a sewage plant, Sturgeon Bank, British Columbia." Thesis, 1997. http://hdl.handle.net/2429/6305.
Повний текст джерелаАнотація:
In an attempt to determine the biological changes that have taken take place in the
Fraser Estuary following the cessation of direct disposal of primary treated sewage
effluent, the population dynamics and productivity of two robust indicator invertebrates, the amphipod Corophium salmonis and bivalve Macoma balthica, were monitored for a period of 2 1/4 years. Monitoring of these species, which took place between 10 May 1994 and 22 November 1996, involved assessing their in situ density, biomass, and production at four sampling stations on Sturgeon and Roberts Bank in the Fraser River Estuary, British Columbia. These stations were located on the nearby mudflats at various distances south of the direct effluent dumping zone at the Iona Island Sewage Treatment Plant.
For both species, extensive recolonization of the previously azooic zone was
observed. At control stations, Corophium salmonis density was similar to that observed
prior to the cessation of direct effluent dumping which occurred in 1988. However, the
observed biomass in this study exceeded that observed in previous research, indicating
that individuals of this species were likely living longer and/or growing larger. In terms
of productivity, values observed for C. salmonis (a maximum level of 0.78 g m-2 y-1 afdw) in this study were lower than those observed for this and other species of the same genus in other research. Within this study, high winter density, biomass, and productivity were observed at the two stations that were still under the influence of effluent disposal. It is likely that food availability, longer potential feeding times, and sediment grain preference contribute to this finding at these stations.
For Macoma balthica, population and productivity parameters were found to be
more stable over the study period than those determined for Corophium salmonis. In
general, density observed at contaminated stations exceeded values found in previous
studies at the same locations. Densities at control stations, however, were found to be
similar to those found at the same stations in previous research. M. balthica productivity (a maximum level of 1.86 g m-2 y-1 afdw) on Sturgeon and Roberts Bank was found to be similar to values observed in other areas around the world. Therefore, it was concluded that the M. balthica population and productivity has recovered (from an azooic condition) since effluent diversion with respect to its population dynamics and productivity. The processes supporting these improvements are likely associated with sediment grain preferences of the organism, food availability, and nutrient assimilation times. Also, a lessening of toxicity associated with effluent disposal (metals, organics,
etc.) on Sturgeon Bank may also explain this observation. No relationship was observed between mortality and body size, sampling time, or density for either species. Many agents of individual loss probably act upon all age and size classes of these organisms at any given time obscuring mortality relationships. More study in this area is necessary within field enclosures or in a laboratory to determine the relative importance of the various mortality agents present in these organisms' environment.
Частини книг з теми "Estuarine mudflats"
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Deusdado, Pedro, Eduardo Pinto, Magno Guedes, Francisco Marques, Paulo Rodrigues, André Lourenço, Ricardo Mendonça, et al. "An Aerial-Ground Robotic Team for Systematic Soil and Biota Sampling in Estuarine Mudflats." In Advances in Intelligent Systems and Computing, 15–26. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-27149-1_2.
Повний текст джерела
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Nayak, G. N., and K. T. Singh. "Source, Processes, and Depositional Environments of Estuarine Mudflat Core Sediments, Central Western Coast of India." In Geochemical Treasures and Petrogenetic Processes, 123–52. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-4782-7_6.
Повний текст джерела
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Little, Colin. "Estuarine ecosystems." In The Biology of Soft Shores and Estuaries, 187–99. Oxford University PressOxford, 2000. http://dx.doi.org/10.1093/oso/9780198504276.003.0010.
Повний текст джерелаАнотація:
Abstract In previous chapters we have emphasized the variety of habitats within estuaries. These habitats do not, of course, exist in isolation, but interact with each other, both physically and biologically. For example, mangroves and salt marshes provide organic detritus that may fuel food webs on adjacent flats, while fish and crustaceans move backwards and forwards between the mudflats and the marshes. Indeed, fish may spend much of their time outside estuarine areas, providing a link with the open sea.
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Deloffre, Julien, and Robert Lafite. "Sedimentary Processes on Estuarine Mudflats." In Environmental and Ecological Risk Assessment, 19–30. CRC Press, 2009. http://dx.doi.org/10.1201/9781420062618.ch2.
Повний текст джерела
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Little, Colin. "Salt marshes and mangrove swamps." In The Biology of Soft Shores and Estuaries, 91–118. Oxford University PressOxford, 2000. http://dx.doi.org/10.1093/oso/9780198504276.003.0005.
Повний текст джерелаАнотація:
Abstract On their upper tidal levels, most marine and estuarine mudflats are hidden by vegetation. In temperate zones, salt-tolerant grasses and other herbaceous plants form what is called salt marsh. Here in spring and summer the white flowers of scurvy grass or the yellow of asters and the purple of sea lavender form colourful swathes against a background of cordgrass, while in winter the vegetation dies back to brown remnants.
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Little, Colin. "Introduction: organisms, sediments, and water movements." In The Biology of Soft Shores and Estuaries, 1–11. Oxford University PressOxford, 2000. http://dx.doi.org/10.1093/oso/9780198504276.003.0001.
Повний текст джерелаАнотація:
Abstract During winter, the intertidal mudflats of the Chesapeake Bay, a large estuarine system on the east coast of North America, are crowded with wading birds. Dunlin (Calidris alpma), dowitchers (Limnodromus spp.), and oystercatchers (Haematopus spp.) accumulate in large feeding flocks. Meanwhile, mudflats in the Severn estuary, in southwest England, are visited by up to 2000 curlew (Numenius arcata), 2000 redshank (Tringa totanus), and 50 000 dunlin. As well as these mobile armies, the richness of the habitats is emphasized by the extensive fringing salt marshes, where cordgrasses (Spartina spp.) dominate meadows that are flooded by sea water at high spring tides. These salt marshes are some of the most productive areas in the world, vying with tropical rain forests and coral reefs for the highest rates at which carbon is fixed.
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LU, Y. J., Q. Z. HOU, Y. LU, Y. H. WANG, C. W. XU, and R. Y. JI. "ADVANCES IN DEVELOPMENT AND MANAGEMENT OF ESTUARINE AND COASTAL MUDFLATS." In Asian And Pacific Coasts 2011, 749–57. WORLD SCIENTIFIC, 2011. http://dx.doi.org/10.1142/9789814366489_0088.
Повний текст джерела
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Roberts, W., and R. J. S. Whitehouse. "Predicting the profile of intertidal mudflats formed by cross-shore tidal currents." In Coastal and Estuarine Fine Sediment Processes, 263–85. Elsevier, 2000. http://dx.doi.org/10.1016/s1568-2692(00)80126-6.
Повний текст джерела
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"Fish Habitat: Essential Fish Habitat and Rehabilitation." In Fish Habitat: Essential Fish Habitat and Rehabilitation, edited by David B. Packer and Tom Hoff. American Fisheries Society, 1999. http://dx.doi.org/10.47886/9781888569124.ch8.
Повний текст джерелаАнотація:
<em>Abstract.</em> —To satisfy the essential fish habitat (EFH) mandate of the reauthorized Magnuson-Stevens Fishery Conservation and Management Act, the Mid-Atlantic Fishery Management Council (MAFMC) and the National Marine Fisheries Service (NMFS) are developing objective, generic criteria to describe and identify the essential habitats for their managed species. Summer flounder or fluke <em>Paralichthys dentatus </em> is an important commercial and recreational species that occurs from shallow estuaries to the outer continental shelf from Nova Scotia to Florida. It is most abundant within the Middle Atlantic Bight from New England to Cape Hatteras, and this region is the focus of this paper. Summer flounder make seasonal inshore–offshore migrations; adults and juveniles normally inhabit shallow coastal and estuarine waters during the warmer months of the year and mostly move offshore with declining water temperature and day length during autumn. Adults spawn during the fall and winter migrations. The best habitat information available on summer flounder is for the estuarinedependent transforming larvae and juveniles. They use several different estuarine habitats as nursery areas, including salt-marsh creeks, sea grass beds, mudflats, and open bay areas. In these habitats, water temperature affects the seasonal occurrence of summer flounder, drives the inshore–offshore migration, and, particularly during winter and spring, affects first-year growth and survival and thus subsequent year-class strength. The distribution of transforming larvae and juveniles within the estuaries is significantly influenced by salinity gradients and substrate. Transforming larvae and juveniles show a preference for sandy substrates in the laboratory but also have been captured on mud or mixed substrates. Juveniles are attracted to eelgrass and macroalgae habitats because of the presence of prey but remain in nearby sand to avoid predators as well as conceal themselves from the prey. The MAFMC used the life history and habitat parameter information developed by the NMFS Northeast Fisheries Science Center (NEFSC) to precisely describe the EFH of summer flounder by life stage. Because summer flounder are overexploited, the MAFMC wanted to be conservative in its EFH identification. Therefore, 90% of the areas where each life history stage has been collected from offshore surveys were identified as EFH. The MAFMC proposed that 100% of the estuaries where larvae and juveniles were identified as being present be identified as EFH because these life stages are estuarine dependent. Nursery habitats within the estuaries are essential because they provide the best conditions for growth and survival of the transforming larvae and juveniles. Submerged aquatic vegetation beds are especially vulnerable and were identified as habitat areas of particular concern. As more habitatrelated density data become available from various local, state, and federal fishery-independent surveys, updated maps of distribution and abundance will be produced.
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"Fish Habitat: Essential Fish Habitat and Rehabilitation." In Fish Habitat: Essential Fish Habitat and Rehabilitation, edited by David B. Packer and Tom Hoff. American Fisheries Society, 1999. http://dx.doi.org/10.47886/9781888569124.ch8.
Повний текст джерелаАнотація:
<em>Abstract.</em> —To satisfy the essential fish habitat (EFH) mandate of the reauthorized Magnuson-Stevens Fishery Conservation and Management Act, the Mid-Atlantic Fishery Management Council (MAFMC) and the National Marine Fisheries Service (NMFS) are developing objective, generic criteria to describe and identify the essential habitats for their managed species. Summer flounder or fluke <em>Paralichthys dentatus </em> is an important commercial and recreational species that occurs from shallow estuaries to the outer continental shelf from Nova Scotia to Florida. It is most abundant within the Middle Atlantic Bight from New England to Cape Hatteras, and this region is the focus of this paper. Summer flounder make seasonal inshore–offshore migrations; adults and juveniles normally inhabit shallow coastal and estuarine waters during the warmer months of the year and mostly move offshore with declining water temperature and day length during autumn. Adults spawn during the fall and winter migrations. The best habitat information available on summer flounder is for the estuarinedependent transforming larvae and juveniles. They use several different estuarine habitats as nursery areas, including salt-marsh creeks, sea grass beds, mudflats, and open bay areas. In these habitats, water temperature affects the seasonal occurrence of summer flounder, drives the inshore–offshore migration, and, particularly during winter and spring, affects first-year growth and survival and thus subsequent year-class strength. The distribution of transforming larvae and juveniles within the estuaries is significantly influenced by salinity gradients and substrate. Transforming larvae and juveniles show a preference for sandy substrates in the laboratory but also have been captured on mud or mixed substrates. Juveniles are attracted to eelgrass and macroalgae habitats because of the presence of prey but remain in nearby sand to avoid predators as well as conceal themselves from the prey. The MAFMC used the life history and habitat parameter information developed by the NMFS Northeast Fisheries Science Center (NEFSC) to precisely describe the EFH of summer flounder by life stage. Because summer flounder are overexploited, the MAFMC wanted to be conservative in its EFH identification. Therefore, 90% of the areas where each life history stage has been collected from offshore surveys were identified as EFH. The MAFMC proposed that 100% of the estuaries where larvae and juveniles were identified as being present be identified as EFH because these life stages are estuarine dependent. Nursery habitats within the estuaries are essential because they provide the best conditions for growth and survival of the transforming larvae and juveniles. Submerged aquatic vegetation beds are especially vulnerable and were identified as habitat areas of particular concern. As more habitatrelated density data become available from various local, state, and federal fishery-independent surveys, updated maps of distribution and abundance will be produced.
Тези доповідей конференцій з теми "Estuarine mudflats"
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Goldstein, Jason M. "Permitting, Designing, and Constructing a Compensatory Saltmarsh Along the Savannah River." In 2006 International Pipeline Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/ipc2006-10029.
Повний текст джерелаАнотація:
Southern LNG Inc. (SLNG), located near Savannah, Georgia, is one of only four LNG import terminals currently operating in the continental United States. In 1999, SLNG proposed to increase their existing turning basin to alleviate a navigation bottleneck and to accommodate safer docking for the tankers of ever-increasing size that navigate the Savannah River. Additionally, in 2001, SLNG proposed an expansion project which included the creation of a new slip. The expansion of the existing turning basin and the creation of the slip was predicted to permanently impact 3.29-acres of saltmarsh and 0.80-acres of protected estuarine mudflats. Since no saltmarsh mitigation banks are located in the State of Georgia, SLNG designed a mitigation plan to develop an in-kind compensatory wetland that was sited on the southern end of SLNG’s property. The created wetland was established in July 2003 and is undergoing a seven-year monitoring period. To date, the created wetland is functioning similarly to adjacent, naturally-occurring saltmarsh systems that are also located in the Savannah River.