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Silva, Carolina Vieira da [UNESP]. "Macroinvertebrados associados à macrófitas aquáticas flutuantes: distribuição, estrutura da comunidade e abordagem experimental." Universidade Estadual Paulista (UNESP), 2015. http://hdl.handle.net/11449/140219.
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Fundação do Instituto de Biociências (FUNDIBIO)
CAPES: 11152/13-6 BEX
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Leung, Roberto [UNESP]. "Distribuição de macrófitas aquáticas em relação a variáveis ambientais em ecossistemas lóticos da Bacia do rio Itanhaém." Universidade Estadual Paulista (UNESP), 2005. http://hdl.handle.net/11449/100647.
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leung_r_dr_rcla.pdf: 1545935 bytes, checksum: 392e9cf661ed29a1efe4f5cf02fdf7f3 (MD5)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
O objetivo deste trabalho foi estudar a distribuição das macrófitas aquáticas em rios da planície costeira da bacia do rio Itanhaém. A abordagem adotada foi uma combinação de estudos observacionais e experimentais. No primeiro capítulo, estudou-se a distribuição das macrófitas aquáticas em relação a variáveis ambientais da água e do sedimento em 97 km de rios em duas estações do ano (verão e inverno). A salinidade foi a principal variável ambiental responsável pela separação das macróf5tas aquáticas em duas comunidades distintas, a do estuário e a dos rios. As principais espécies que ocorreram no estuário foram Spartina alterniflora. Crinum procerum e Scirpus califhrnicus, sendo que a primeira ocorreu em trechos de maior salinidade, a segunda em trechos com salinidade intermediária e a última em trechos de menor salinidade. As espécies de água doce mais freqüentes foram Egeria densa, Eichhornia azurea, Eichhornia crassipes. Pistia stratiotes, e Salvínia molesta. Egeria densa tendeu a ocorrer em trechos com maior transparência. menor nitrogênio total e maior fração areia no sedimento. Eichhornia azurea tendeu a ocorrer em locais com alta transparência e baixas concentrações de nitrogénio total. Finja siratiotes tendeu a ocorrer em trechos de rios com maiores concentrações de nitrogênio total na água. A freqüência de ocorrência das principais espécies não diferiu entre o verão e o inverno, provavelmente devido a ausência de uma estação seca. No segundo capítulo, se estudou a ocorrência das macrófitas aquáticas em função da vegetação ciliar e da morfologia de canal em três trcchos distintos de rios. No estuário do rio ltanhaém. a ocorrência de macrófitas aquáticas emergentes foi correlacionada com o sombreamento das árvores de mangue e a declividadc da área litorânea... .
The aim of this research was to study the distribution of aquatic macrophytes in coastal piam rivers of ltanhaém basin. lhe research approach was based on observational and experimental studies. In the first chapter, the distribution of aquatic macrophyte was correlated to water and sediment environmental variables in 97 km of rivers and in two periods (summer and winter). Salinity was the most important environmental variable to separate the aquatie rnacrophytes in two distinct communities: estuarine and freshwater communities. The main species found in the estuary were Spartina alterniflora, Crinum procerum and Scirpus califohiicus. lhe first species was found in water with higher salinity, the second in water with intermediate salinity and the Iatter in less saline water. lhe most frequent &eshwater species were Egeria densa, Eichhornia azurea, Eichhornia crassipes, Pistia strarioles and Sal Wnia molesta. Egeria densa tended to be present in river sections with high water transparence. low total nitrogen, and high sand fraction in sediment. Eichhornia azurea tended to occur in sections with high water transparence and low total nitrogen. Pistia stratiotes tendecl to occur in river sections with high total nitrogen. lhe &equency of occurrence aquatic macrophyrtes did not significantly differed hetween sunimer and winter. due probably to the absence of a dry season. In the second chapter, we investigated the influence of riparian vegetation and stream channel morphology on aquatie rnacrophyte distribution in three streams with dstinguished landscape. In the estuary of ltanhaëm River, the occurrence of emergent rnacrophytes was correlated with mangrove shading and slope of littoral region. In Preto River... (Complete abstract, click electronic address below).
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Göthberg, Agneta. "Metal fate and sensitivity in the aquatic tropical vegetable Ipomoea aquatica /." Stockholm : Department of Applied Environmental Science (ITM), Stockholm university, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-7625.
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Bäckman, Johan. "Life Aquatic." Thesis, KTH, Arkitektur, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-123397.
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Projektet är en stad som ligger mellan Umeå och Vasa (Finland), det är den smalaste delen av Bottniska viken med bara ca 60 km öppet hav. Jag ville undersöka vad det fanns för möjligheter med en stad som utnyttjar sitt läge. Så jag planerade en offshore hamnstad som bygger sig själv och sprider sig. Varför? 60-talets men även samtida megastrukturer planerades ofta för att ge en teknisk lösning på ett visst problem. De här problemen vare sig det är bostadsbrist eller klimatförändring är fortfarande aktuella och lösningarna likaså. Därför ville jag använda min struktur som ett redskap för att testa och reflektera kring dessa idéer för boende. En jurymedlem jämförde mig kritiskt vid en skata som plockat silvret från mina referenser, men det han inte förstod var att jag plockade silvret just för att i min fiktiva värld analysera det. Analysen gjorde jag genom att hitta på invånare som med sinne och själ fick reflektera kring livet i en modul och etc.The project is a city located between Umeå and Vasa, it is the most narrow part of the Gulf of Bothnia with only 60 km of open waters. I wanted to investigate existing possibilities with a city that exploits its location. So I designed an offshore port city that builds itself and grows. Why? The megastructures of the 60’s but also contemporary ones were often planned to give a technical solution to a certain problem. These problems whether it’s housing shortage or climate change are still current and the solutions as well. This is why I wanted to use my structure as a tool to test and reflect about these concepts of living. A member of the jury critically compared me to a magpie that had picked the silver of my references, but what he didn’t understand was that I had picked the silver to analyze it in my fictional world. I made the analysis by imagining inhabitants that through their mind and soul reflected on life in a module and etc.
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Göthberg, Agneta. "Metal fate and sensitivity in the aquatic tropical vegetable Ipomoea aquatica." Doctoral thesis, Stockholms universitet, Institutionen för tillämpad miljövetenskap (ITM), 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-7625.
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The aquatic plant Ipomoea aquatica is a popular vegetable in Southeast Asia, often cultivated in nutrient rich and polluted waters. The overall aim of this thesis was to estimate potential risks for human health and reduced plant growth due to accumulation and toxicity of total-Hg, methyl-Hg, Cd and Pb. In plants from cultivations in Thailand, the concentrations of Cd and Pb in the shoots were well beneath recommended maximum values for human consumption, but at some sites the Hg concentrations were high. It was demonstrated that I. aquatica has the capacity to accumulate much higher Cd and Pb concentrations in the shoots than found in field-cultivations, before exhibiting toxic symptoms. The Hg concentrations, however, occasionally reached levels that are toxic for the plant. Up to11% of total-Hg was methyl-Hg, the most toxic Hg species, though at one site it was 50-100%. To study if methyl-Hg is formed in I. aquatica, plants were exposed to inorganic Hg through the roots. Of the Hg that reached the young, metabolically active parts of the shoots, a part was transformed to methyl-Hg. A major proportion of absorbed metals was retained in the roots, which had a high tolerance for high internal metal concentrations. The nutrient level did influence accumulation and effects of Hg, Cd and Pb in I. aquatica. Low external nutrient levels resulted in increased metal accumulation in the shoots and in metal-induced toxic effects in the plant at low external metal levels. A generous supply of sulphur or nitrogen induced formation of thiol-rich peptides in I. aquatica, compounds that have a metal detoxifying effect in plants. To conclude, the levels of Cd and Pb in field cultivated I. aquatica do not pose any apparent threat to human health or risk for reduced plant growth. The levels of Hg however, were high at some sites and could be a health threat, for children and foetuses in particular, and especially considering the presence of methyl-Hg. The use of fertilizers is favourable as it reduces the risk for increased metal concentrations in I. aquatica and for reduced crop yields.
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VandenBerg, Jeanne P. "Role of an Aquatic and Non Aquatic Environment on Trunk Muscle Activation." DigitalCommons@USU, 2011. https://digitalcommons.usu.edu/etd/992.
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Low back pain (LBP) is a widespread problem affecting a number of people. Traditionally treated by nonoperative approaches the recent development of water currents and treadmills imbedded into pools has spurred physical therapists and athletic trainers to incorporate the use of aquatic therapy into their rehabilitation programs. OBJECTIVE: Determine if select trunk muscle activity levels are different in water-based exercises compared to land-based exercises. METHODS: 11 healthy male participants age 25.9 ± 5.53 years, whom did not have a history of and were not currently experiencing LBP or injury. Muscle activity was monitored via electromyography (EMG) at the rectus abdominis (RA), external oblique (EO), lower abdominals (LA), erector spinae (ES), and lumbar multifidis (MT). Each subject performed (1) maximum voluntary contractions (MVC’s), (2) land-based exercises, and (3) water-based exercises. A paired samples t test was used to compare abdominal bracing (ABbrace), abdominal hallowing (ABhol), Anterior/Posterior pelvic tilts (APTilts), and lateral pelvic tilts (LatTilts) between comparable land and water conditions; general linear model-repeated measures was run to compare the 11 different water exercises; ABbrace, ABhol, APTilts, LatTilts, physioball push down (PBPushDown), PB lateral flexion, PB transverse rotations, stationary marching, leg abduction, and wall sits with sagittal and transverse plane arm movements. Follow-up multiple comparisons (LSD) were performed between water exercises using a Holm’s corrected alpha level set at 0.05. RESULTS: Land-based exercises elicited greater EMG activity compared to water-based activities for all muscles (%MVC land vs. %MVC water): RA %MVC (8.3-19.3 vs. 2.1-9.7, P = .003-.029); LA %MVC (27-105 vs. 5.2-25, P = .001-.016); EO %MVC (13-59 vs. 4.8-24.5, P = .001-.303); ES %MVC (19.1-37.6 vs. 7.75-22.1, P = .001-.039) and MT %MVC (16-25.4 vs. 5.9-8.8, P = .00-.005). For water comparison ABbrace and PB exercises produced the most muscle activity while WallSitSag/Trans consistently produced the least muscle activity. CONCLUSION: Even with reduced muscle activity in the water, the calculated % mean MVCs were high enough (at or below 25% MVC) to provide muscle endurance and stability gains. With the information provided from the analysis of water exercise comparison, practitioners can effectively progress patients through a rehabilitation program.
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涂康年 and Hong-nin Stanley Tho. "An aquatic leisure centre." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1997. http://hub.hku.hk/bib/B31983649.
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She, Nian. "Chaos in aquatic systems /." Thesis, Connect to this title online; UW restricted, 1995. http://hdl.handle.net/1773/6370.
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Tho, Hong-nin Stanley. "An aquatic leisure centre." Hong Kong : University of Hong Kong, 1997. http://sunzi.lib.hku.hk/hkuto/record.jsp?B2595376x.
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Silva, Renata de Souza [UNESP]. "Influência da temperatura e de cargas de nutrientes no crescimento da macrófita aquática flutuante Eichhornia crassipes (Mart.) solms cultivada em água enriquecida artificialmente." Universidade Estadual Paulista (UNESP), 2008. http://hdl.handle.net/11449/87879.
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silva_rs_me_rcla.pdf: 294151 bytes, checksum: f57b8ae02f720b25cb596e933caccae1 (MD5)Universidade Estadual Paulista (UNESP)
O objetivo deste trabalho foi avaliar o ganho de biomassa de Eichhornia crassipes cultivada em microcosmo em diferentes épocas do ano. O experimento teve duração de 189 dias e ocorreu entre abril e outubro de 2006. Indivíduos de E. crassipes foram cultivados em um sistema de recirculação de água composto por 3 unidades experimentais. O fluxo de água foi contínuo (vazão de 0,25 L min-1) e nutrientes foram adicionados semanalmente. Valores de nitrito, nitrato, ortofosfato, oxigênio dissolvido, condutividade elétrica, turbidez, pH e temperatura da água foram obtidos semanalmente. Os valores médios semanais de temperatura mínima absoluta atmosférica foram calculados através dos dados obtidos pela Estação Meteorológica CEAPLA/UNESP, localizado a aproximadamente 500 metros do local do experimento. Semanalmente as plantas foram pesadas e posteriormente devolvidas as respectivas unidades experimentais. Variações de temperatura atmosférica foram verificadas. O período com os menores valores de temperatura mínima atmosférica (junho e julho) coincidem com o período de menores valores de ganho de biomassa do vegetal. Após este período, os valores de temperatura aumentaram favorecendo o crescimento do vegetal, ocorrendo os maiores valores de ganho de biomassa.
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Holland, Angela. "BRIDGING AQUATIC AND TERRESTRIAL ECOSYSTEMS: ECOLOGY OF SEMI-AQUATIC MAMMALS IN SOUTHERN ILLINOIS." OpenSIUC, 2016. https://opensiuc.lib.siu.edu/dissertations/1269.
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Mammals in freshwater aquatic systems play important roles as ecosystem engineers, trophic transfer agents, and apex predators, thus acting as indicators of freshwater ecosystem function. Watersheds inhabited by semi-aquatic mammals have increased links between adjacent terrestrial and aquatic ecosystems compared to watersheds where they are not present. Semi-aquatic mammals not only exert top-down influences on streams, but are affected by bottom-up forces from the riparian system itself. The goal of this study was to identify variables that correlate with the presence of beaver (Castor canadensis), muskrat (Ondatra zibethicus), mink (Neovison vison), and river otter (Lontra canadensis), including their interactions, resulting in a better understanding of the areas where these semi-aquatic mammals occur and their effects on the riparian system. The objectives of this study were (1) to identify variables related to the probability of detection, initial occupancy, colonization, and extinction of the 4 semi-aquatic mammals in southern Illinois; and (2) to test if the reintroduction of river otter has changed stream food webs. To address my first objective, I sampled 120 bridge sites in 2 periods (winter: Jan-Feb; and spring: Mar-Apr) during 2012–2014 in 11 major watersheds in the southern third of Illinois (44,526 km2) to estimate multi-season occupancy. Each survey unit was a 400-m stream segment visited twice by 2 observers for a total of 4 observations per site per period. Observers recorded all mammal signs found, including sign species and type. Sites were Intensive Basin Survey Sites sampled by Illinois Department of Natural Resources (IDNR) and Illinois Environmental Protection Agency (IEPA), allowing data collected by the state to be available for explanatory variables for mammal occupancy. Data collected by the Illinois Natural History Survey (INHS) also were available for a subset of sites. I collected local- and landscape-scale habitat and weather variables for each site. I developed hypotheses regarding occupancy of sites based on land-cover, human disturbance, and stream attributes for each species. I developed additional hypotheses regarding prey availability and water quality for river otter and mink. Sites used in each analysis were dependent on data available to address the hypotheses of interest. Beaver and muskrat were present at ≥100 of 103 sites for ≥1 observation. Naïve occupancy was high (≥82%) every year for both species. Detection probabilities for beaver and muskrat were best predicted by survey period. Beaver detection remained fairly constant across survey periods except for a decrease in winter 2014, whereas muskrat detection was generally lower during winter and higher during spring. Beaver were more likely to occupy larger streams than smaller streams during the initial survey period. Sites that lacked a dominant land-cover had a lower probability of beaver colonization than sites dominated by agriculture or woody vegetation at the landscape scale. In addition, the probability that a site would be colonized by beaver during the study increased with availability of water within 1 km of the surveyed segment, increased stream density, sites at larger streams, and river otter presence during the previous period. The probability of site extinction decreased as stream size, stream density within 1 km, and water availability within 500 m of the survey segment increased. Occupancy of muskrat during the initial survey period was negatively predicted by % forest in the 1-km riparian area, channel incision, and amount mercury in the sediment. Colonization by muskrats was lower during the long spring to winter intervals than the short winter to spring intervals, and was positively related to the amount of organic carbon in the sediment. The probability of site extinction by muskrat increased with increasing % forest within the riparian area around the stream segment, decreasing 1-km stream density, and when land-cover within 1 km of sites was dominated by agriculture or woody vegetation. Multi-season occupancy of river otter and mink were assessed in 2 separate analyses that used either land-cover and management variables or prey availability and riparian community composition, respectively. In the first analysis, river otter and mink were present at ≥84 of 103 sites. Naïve occupancy was higher every year for mink (≥88.3%) than for river otter (≥55.3%). Detection of river otter and mink in the first analysis increased as substrate availability increased. Occupancy of river otter during the initial survey period was predicted by large stream size, low % developed area within 250 m of the surveyed segment, and proximity to nearest river otter reintroduction point. Probability of colonization by river otter varied by survey period and was higher at sites with larger streams, higher stream density, lower % developed area, and within a known river otter population area. Site extinction by river otter in the first analysis varied by survey period and was linked to increased organic carbon in the sediment, and decreased road density within 1 km of the surveyed segment. River otter harvest was not found to affect site colonization or extinction. Mink occupancy during the initial period was negatively associated with water availability within 100 m of the survey segment. Site colonization by mink varied by month and increased with increasing developed area within 100 m of the surveyed segment, increasing channel incision, and decreasing rainfall. Probability of site extinction for mink increased as stream size and developed area within 500 m of the surveyed segment increased, and when woody vegetation was the dominant land-cover type within 1 km of the surveyed segment. The second analysis of multi-season occupancy of river otter and mink used 77 sites, 81.8% of which had ≥1 river otter detection in the study and 98.7% of which had ≥1 mink detection. Naïve occupancy differed between years but gradually increased for river otter and remained high (≥93.5%) for mink. Increasing substrate availability increased the probability of river otter detection, whereas mink detection varied by survey period. Occupancy during the initial survey period was higher in sites closer to the reintroduction points for river otter. Probability of colonization of river otter was positively associated with macroinvertebrate IBI and fish species richness, sites with high fish species richness of fish families preferred by river otter also had reduced otter extinction probability. No tested variables predicted initial occupancy for mink, but mink were more likely to colonize sites with increased fish richness and when muskrat were present during the previous period. Mink had decreased probability of extinction in sites with increasing mussel community index. My results indicate that semi-aquatic mammals in Illinois were affected by a riparian habitat, water availability, and stream community variables at both the landscape and local scale. I found high occupancy of mink, beaver, and muskrat across the entire landscape of southern Illinois, and my results suggest that the geographic range of river otter continues to expand. Relationships of occupancy of these semi-aquatic mammals to measurements of urban areas and human disturbance were not consistent across all species. Mink and river otter occupancy were both predicted by aspects of prey availability, indicating the importance of predator-prey relationships in occupancy dynamics of riparian predators. Hypotheses regarding predator pressure and changes in environmental variables were used to test the effects of river otter reintroduction on stream communities. For this objective, I used structural equation models. I compared fish and macroinvertebrate communities from before (1982-1995) and after (2005-2013) reintroduction of river otter, which occurred in 1994–1996. Fish and macroinvertebrate community data for 35 sites located throughout 6 major watersheds in southern Illinois (25,550 km2) were obtained from state agencies. Changes in stream communities were evaluated using 4 metrics (species richness, species dominance, skewness in size distribution of prey, and proportion of individuals in the size class preferred by river otter). Neither the inclusion of river otter site use nor change in stream quality, measured by change in % forest, improved models over the simple model which only included fish and macroinvertebrate communities. Overall, I found no evidence that river otter presence or change in forest cover affected stream fish and macroinvertebrate communities.
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Bruce, Louise Christina. "A study of the interaction between the physical and ecological processes of three aquatic ecosystems /." Connect to this title, 2005. http://theses.library.uwa.edu.au/adt-WU2007.0178.
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Kamara, Sheku. "Physiological responses of aquatic macrophytes to natural organic matter potential for structuring aquatic ecosystems." Berlin Logos-Verl, 2008. http://d-nb.info/992155371/04.
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Halm, Hannah. "Nitrogen assimilation by aquatic prokaryotes." Berlin mbv, Mensch-und-Buch-Verl, 2009. http://d-nb.info/100292491X/04.
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Gill, Stephen. "Phosphorus liberation by aquatic microorganisms /." Electronic version (Microsoft Word), 2006. http://dl.uncw.edu/etd/2006/gills/stephengill.doc.
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Ashton, Alyssa. "Contextualizing Aquatic Rehabilitative Practices in Canada." Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/37708.
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This thesis explored the current context of aquatic rehabilitative practices in Canada. More specifically, three inter-related topics on Aquatic Therapy (AT) and Aquatic Physical Therapy (APT) in Canada were examined: 1) the development of knowledge, training and expertise on APT and AT, 2) recognition and acceptance of cultural and social authority on AT and APT (Starr, 1982), and 3) the practitioners’ perceptions of barriers to practicing and participation in aquatic therapy. Semi-structured qualitative interviews were conducted with seven (7) stakeholders including Ontario aquatic physical therapists, aquatic therapists, instructors on aquatic therapy and members of the College of Physiotherapy of Ontario (CPO) and the Canadian Physiotherapy Association (CPA). Interviews were complimented with open-ended questionnaires sent to Chairs of Physical Therapy programs in seven Canadian Universities.
Our research identified the most common means of acquiring knowledge on aquatic rehabilitative practices was through University Physiotherapy program curriculum; private training courses; and in-house within facilities where aquatic therapists and aquatic physical therapists are employed. This thesis also examined facilitators/barriers to practicing and receiving aquatic therapy and aquatic physical therapy. Through critical analysis, this thesis reflected on the ways in which social and cultural authority (Starr, 1982) are constructed within the field of aquatic therapy (AT) and aquatic physical therapy (APT). Recommendations and areas for future research included specialized training courses by scope of practice, and increased in-pool practicum training within Physiotherapy programs in Canada.
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Bellingan, Terence Andrew. "The diversity of aquatic insects in the Tsitsikamma region, with implications for aquatic ecosystem conservation." Thesis, Rhodes University, 2011. http://hdl.handle.net/10962/d1005348.
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As a result of research carried out within the last decade to assess the diversity of macroinvertebrates of the Salt River in the Western Cape Province, South Africa, surveys of macroinvertebrates of 20 sites on 11 selected rivers from the same mountain range source were undertaken. This was done to make a preliminary assessment of the conservation status of the rivers of this region. Aquatic insects from the orders Ephemeroptera, Odonata, Plecoptera, Megaloptera, Trichoptera and the dipteran family Simuliidae were collected using techniques to maximize the number of taxa found. The insects collected were identified to species level where possible. Water physicochemical parameters were recorded at all sites for each sampling trip to characterize these rivers and to establish a set of baseline data for future comparisons. These parameters included measurements made on site and analysis of the concentrations of all the major ions in water samples in the laboratory. Multivariate analyses including Principle Components Analysis and Canonical Correspondence Analysis were used to reveal patterns within the water physicochemistry and species distributional data. Results include the identification of 123 species from 70 genera and 30 families. A total of 31 species were found to be undescribed, of which 17 were not previously collected and are thus completely new to science. In addition, four of these species could not be placed into any known genus. The analysis of water physicochemistry showed a clear distinction between rivers of Table Mountain sandstone and Bokkeveld shale origin. Downstream effects of anthropogenic influences were discernable too. Distinct macroinvertebrate assemblages were found based upon stream order and water chemistry composition. pH proved to be the most important driver of invertebrate assemblage composition. The high levels of endemism of the macroinvertebrates found within the upper reaches of these rivers and their degree of ecological specialization make these systems a priority for the conservation of aquatic biodiversity on a national and global scale.
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Castro, Rodrigo Martinez [UNESP]. "Estudo comparativo das perdas d'água em mesocosmos colonizados ou não por Aguapé (Eichhornia crassipes (Mart.) Solms-Laubach." Universidade Estadual Paulista (UNESP), 2008. http://hdl.handle.net/11449/86352.
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McNeish, Rachel E. "Terrestrial-Aquatic Connections: Riparian Invasion by Lonicera maackii Drives Shifts in Aquatic Biota and Ecosystem Processes." University of Dayton / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1459941895.
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Núñez, Marcé Mireia. "Emerging organic contaminants in aquatic organisms." Doctoral thesis, Universitat Rovira i Virgili, 2017. http://hdl.handle.net/10803/456825.
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Aquesta Tesi Doctoral se centra en el desenvolupament de nous mètodes analítics per determinar diferents contaminants orgànics emergents, com ara productes farmacèutics de consum generalitzat, els medis iodat de contrast per a raigs-X (un altre grup de productes farmacèutics emprats en la medicina de diagnòstic), i un grup d'edulcorants d'alta intensitat en organismes aquàtics. Dues tècniques d'extracció (extracció mitjançant líquids pressuritzats i QuEChERS) van ser avaluades per extreure els compostos seleccionats i diferents neteges també van ser provades. La determinació es va realitzar mitjançant cromatografia de líquids acoblada a espectrometria de masses.D'altra banda, també es va dur a terme un estudi ecotoxicològic en l'espècie Gammarus pulex, on s' avaluà la toxicitat del triclosan en aquesta espècie i, a més a més, es van estudiar poblacions procedents de diferents ambients amb diferents graus de contaminació per determinar si la seva resistència era similar o no.Esta tesis doctoral se centra en el desarrollo de nuevos métodos analíticos para determinar diferentes contaminantes orgánicos emergentes, como productos farmacéuticos de consumo generalizado, medios yodados de contraste para rayos-X (otro grupo de productos farmacéuticos empleados en medicina de diagnóstico) y un grupo de edulcorantes de alta intensidad en organismos acuáticos. Para ello se evaluaron dos técnicas de extracción (extracción con líquidos presurizados y QuEChERS) para extraer los compuestos seleccionados y también se ensayaron diferentes limpiezas. La determinación se realizó mediante cromatografía de líquidos acoplada a espectrometría de masas. Además, se realizó un estudio ecotoxicológico en la especie Gammarus pulex, donde se evaluó la toxicidad del triclosán para esta especie y, además, se estudiaron poblaciones procedentes de diferentes ambientes con diferentes grados de contaminación para determinar si su resistencia era similar o no.
This Doctoral Thesis focuses on the development of new analytical methods to determine different emerging organic contaminants such as pharmaceuticals of widespread consumption, iodinated X-ray contrast media (another group of pharmaceuticals employed in diagnostic medicine), and a group of high-intensity sweeteners, in aquatic organisms. To do so two extraction techniques (pressurised liquid extraction and QuEChERS) were evaluated to extract the selected compounds and different clean-ups were also tested. The determination was perfomed with liquid chromatography coupled with mass spectrometry. Moreover, another objective is to conduct an ecotoxicological study in the amphipod species Gammarus pulex, where the toxicity of triclosan to this species was evaluated. Moreover, populations that come from different environments with different degrees of pollution were evaluated in order to establish whether their resistance was similar or not.
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Johansson, Håkan. "On Distribution Coefficients in Aquatic Systems." Doctoral thesis, Uppsala University, Department of Earth Sciences, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-1777.
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In this thesis, different types of chemical and physical distribution coefficients are identified, examined and used to describe the fate and transport pathways of substances in aquatic systems.
Observations from field experiments in streams with non-reactive and reactive tracers constituted the basis for development of an advection-dispersion model. Differences in the concentrations in both the water and sediment data for the tracers were due to the particle affinity of the reactive tracer. This difference in behaviour could be described by including an instantanous and a kinetically controlled sorption, which included distribution coefficients, in the water column (Kd) and in the streambed sediment (KB), respectively.
The results presented in this thesis also include a model for the lake characteristic concentration of suspended particulate matter (SPM). The SPM-model can be used to describe mass flows of particles in lakes. The traditional distribution (or partition) coefficient Kd has been found to be unsuitable for interpretations of the particle association of solutes and also for distributing solute mass flows. Instead, the particulate or the dissolved fraction, PF and DF, defined as ratios of the particulate or dissolved concentration to the total concentration respectively, is recommended for mass-balance calculations. A new PF-model for phosphorus has meant that this part is no longer the most sensitive part of predicting concentrations of phosphorus in lakes using a more extensive dynamic model.
New methods have also been developed to describe the shape of lakes. Together with the mixing depth of lakes, the shape of a lake can be transformed into a distribution coefficient that physically determines the portion of a lake that is exposed, both areally and vertically, to continuously mixing.
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Philipson, née Ammenberg Petra. "Environmental Applications of Aquatic Remote Sensing." Doctoral thesis, Uppsala University, Centre for Image Analysis, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3328.
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Many lakes, coastal zones and oceans are directly or indirectly influenced by human activities. Through the outlet of a vast amount of substances in the air and water, we are changing the natural conditions on local and global levels.
Remote sensing sensors, on satellites or airplanes, can collect image data, providing the user with information about the depicted area, object or phenomenon. Three different applications are discussed in this thesis. In the first part, we have used a bio-optical model to derive information about water quality parameters from remote sensing data collected over Swedish lakes. In the second part, remote sensing data have been used to locate and map wastewater plumes from pulp and paper industries along the east coast of Sweden. Finally, in the third part, we have investigated to what extent satellite data can be used to monitor coral reefs and detect coral bleaching.
Regardless of application, it is important to understand the limitations of this technique. The available sensors are different and limited in terms of their spatial, spectral, radiometric and temporal resolution. We are also limited with respect to the objects we are monitoring, as the concentration of some substances is too low or the objects are too small, to be identified from space. However, this technique gives us a possibility to monitor our environment, in this case the aquatic environment, with a superior spatial coverage. Other advantages with remote sensing are the possibility of getting updated information and that the data is collected and distributed in digital form and therefore can be processed using computers.
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Pungkun, Vithit. "Chronic radiation doses to aquatic biota." Thesis, University of Portsmouth, 2012. https://researchportal.port.ac.uk/portal/en/theses/chronic-radiation-doses-to-aquatic-biota(2cf6cd5f-a8d6-4040-ab2e-5bb8c310b059).html.
Full textAbstract:
On 26 April 1986, the worst nuclear accident in the history of the nuclear industry occurred at Unit 4 of the Chernobyl nuclear power plant (ChNPP) in the Ukraine (at that time a Republic of the Soviet Union) resulting a large amount of radioactive nuclides released into the environment in Russia, Ukraine, Belarus and other European countries. The chronic radiation doses from radioactive nuclides released from the accident are still significant in the freshwater aquatic environment of the 30 km Exclusion Zone around Chernobyl. In this study, current methods of estimating radiation doses have been further developed by model inter-comparison and testing against empirical data. This research also supports previous work on the effects of radiation on aquatic biota by accurately measuring the external radiation dose in the littoral zone of Svyatoye and Perstok lakes in Belarus. The testing and critical analysis of five dose assessment models (RESRAD, FASSET, ERICA, R&D128 and the D-Max model) was carried out in order to understand the key factors which influence predictions of both internal and external doses. For the internal dose, studies of the relationship between modelled dose and organism mass showed that mass is a more important factor than organism shape. The predictions of external dose were generally more variable than those for internal dose. The most important factor causing variation in external dose was the assumed habitat of the organism and the occupancy factor. The Monte Carlo method was used to estimate the uncertainty in internal dose rate caused by the variability of fish mass and fish concentration in real environments. It was found that the variability in Cs-137 activity concentration in different fish was the most important factor contributing to the uncertainty of predictions of internal dose rate. Organism size at different life stages also has a large influence on dose. For young, small, fish, the internal dose is lower than the range of internal doses estimated by the different models, whilst the external dose could be greater than that estimated by models, especially in cases where part of the life cycle is spent on the sediment surface. Using measured values of tissue activity concentration, the model predictions of doses in Svyatoye and Perstok lakes, show good agreement with each other. In cases when tissue activity concentration data are not available, these have to be estimated from the tissue-water Concentration Ratio (CR). In this case, the predicted internal dose rates (using radionuclide concentration in the water) are more uncertain because of the variation of CR in the models. The model where CR is estimated depending on water chemistry gives the best prediction in this case. Measurements were made of the beta- and gamma- dose rate in three lakes (Perstok, Svyatoye and Dvorishche) giving profiles of dose as a function of depth. The method for gamma dose rate measurement worked well and a simple model for external gamma dose rate with depth above and below the sediment surface was found to give reasonable agreement with measured values. The beta in situ measurement was not successful and the method would need further investigation. The modelling studies carried out showed that internal dose rates to fish in Svyatoye and Perstok lakes are lower than or close to the 40 μGy hr-1 recommended limit for possible impacts from radiation .The external dose rate to insect larvae and benthic fish is much higher than to pelagic fish because the former live in or on the sediment which has a much higher activity concentration than the water. None of the estimated external dose rates in these lakes was higher than 10 μGy hr-1. It is concluded that the external dose rates to benthic biota and large fish in these closed lakes are still significant at this long time after the Chernobyl accident. But, radiation effects on these organisms may not be clearly seen, since the dose rates are below or close to guideline limits.
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Pohe, Stephen Robert. "Aquatic invertebrate fauna of Matapouri, Northland." Click here to access this resource online, 2008. http://hdl.handle.net/10292/425.
Full textAbstract:
A study of the aquatic invertebrate communities from two locations (Location 1 and Location 2) within the Matapouri catchment in Northland, New Zealand, was conducted to assess community structure in differing local-scale habitats. Four data collection methods were utilised generating 33,058 adult or larval invertebrates. The sampling methods comprised benthic kick-sampling, sticky trapping, light trapping, and emergence trapping. For the sticky trapping and light trapping, sampling was carried out at three different sites (Sites 1–3) within each location. The sites were situated within three habitat types; native forest, native forest-fringe, and raupo wetland. Emergence trapping also commenced within the three sites, at both locations, but was discontinued after two months, due to the equipment being destroyed by consecutive flooding events (method described in Appendix 1). Benthic sampling was carried out within the Forest and Forest-fringe habitats. Benthic sampling, sticky trapping, and light trapping were carried out following a monthly schedule between June and November 2005. Conductivity, pH, and water temperature measurements were taken concurrently with benthic sampling on a monthly basis, while water velocity and substrate measurements were taken once to assist in habitat characterisation. Overall, 71 taxa were recorded by benthic sampling over the six month period, with a mean of approximately 30 taxa per site per month. In comparison with similar studies elsewhere in New Zealand, a figure of around 30 taxa per sample was high. The benthic macroinvertebrate fauna at all sites was dominated by Trichoptera (19 taxa), Diptera (16 taxa) and Ephemeroptera (10 taxa). This pattern of diversity is similar to that reported in other New Zealand studies. However, in contrast to previous studies, the leptophlebiid mayfly genus Deleatidium was not numerically dominant over the rest of the community, and other leptophlebiid genera (Acanthophlebia, Atalophlebioides, Mauiulus and Zephlebia) were equally represented, possibly reflecting niche partitioning between the groups. The genus Nesameletus was not recorded at any site, despite being one of the core mayfly species in New Zealand streams. The rare mayfly Isothraulus abditus was recorded at one of the forest locations. There are no published records of this species from Northland. Although acknowledged as another of the core New Zealand benthic taxa, the hydropsychid caddisfly Aoteapsyche was not recorded during the study. However, another hydropsychid, Orthopsyche, was commonly recorded, and these may be filling a similar niche to the Aoteapsyche genus. In contrast to the Trichoptera, Diptera, and Ephemeroptera, the Plecoptera fauna was relatively depauperate, probably reflecting the warmer climate of the region and lack of temperature-buffered spring-fed streams. Surprisingly, Zelandobius, a core New Zealand genus, was absent but is regularly recorded in Northland. A species of conservation interest, Spaniocercoides watti, currently recognised as a Northland endemic, was recorded in low numbers. There were no apparent trends in diversity or abundance of benthic invertebrates over time. Also, there were no significant differences in species diversity between the two locations. However, in many cases, taxa were more abundant at Location 2. This may have been due to steeper gradients at Location 2, and the consequent effects on substrate size and streambed stability, as all other physical factors appeared similar between locations. Although several significant differences of individual benthic taxa were recorded, no broad effect of habitat (sites) on species diversity was observable. However, at Location 2, abundances were significantly higher at Site 3 (Forest) compared to Site 2 (Forest-fringe). The reasons were uncertain, but may be attributed to higher retention of allochthonous organic materials, trapped by in-stream cover and larger substrates. Investigations of adult stages by sticky traps supported benthic results recording community compositions and abundances dominated by Trichoptera and Diptera. Plecoptera were poorly represented. Location 2 recorded higher abundances of taxa, particularly Ephemeroptera and Plecoptera. Investigations of adult stages by light traps however did not produce any statistically significant differences in abundances between sites, between locations, or between sites across locations, and it is believed to be due to limited sampling replication combined with some biases of light trapping. This study indicates that the aquatic invertebrate community at Matapouri is diverse but also reasonably representative. Several rare or uncommon insects inhabit the catchment. It is therefore important that Iwi and the local Landcare Group, who invited and supported this research, together with the Department of Conservation, continue their efforts in protecting these areas. The resident fauna have the capacity to restock areas downstream, which are intended to be improved and restored through sediment control and riparian management.
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Patullo, Blair. "Sensory biology of aquatic Australian crustaceans." Connect to thesis, 2010. http://repository.unimelb.edu.au/10187/8393.
Full textAbstract:
Sensory biology of animals is studied throughout the world for the insight it provides to understanding ecosystems and improving how we manage species. In this research, I designed experiments to investigate the sensory biology and behaviour of two Australian species of freshwater crayfish from the genus Cherax, the yabby (Cherax destructor) and redclaw crayfish (Cherax quadricarinatus). Experimental apparatus were constructed and tailored to test specific questions on physiology, tactile (touch) sensitivity, observation techniques, aggressive behaviour and responses to electrical fields. The outcomes were:• abdominal muscle mass was positively correlated to the size of the electrical fields produced by swimming crayfish,
• behaviour changed in response to contact with different structures and textures of wall surfaces,
• computer analysis of underwater behaviour was similar to that scored by a human observer,
• the level of aggression in groups of crayfish changed as group size increased, and
• two species of crayfish responded to electrical fields in the water by decreasing their locomotory movement.
These results reveal a way in which physiology relates to behaviour, how crayfish and other crustaceans may sense the invisible and behave in aquaculture ponds, as well as documenting methodology to further investigate these areas in the future.
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Vander, Zanden M. Jake. "Trophic position in aquatic food webs." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ55390.pdf.
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Johansson, Håkan. "On distribution coefficients in aquatic systems /." Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2002. http://publications.uu.se/theses/91-554-5245-0/.
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Philipson, Petra. "Environmental applications of aquatic remote sensing /." Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2003. http://publications.uu.se/theses/91-554-5542-5/.
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Hayward, Eva. "Envisioning invertebrates and other aquatic encounters /." Diss., Digital Dissertations Database. Restricted to UC campuses, 2007. http://uclibs.org/PID/11984.
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Church, Kathleen. "Agonistic interactions between invasive aquatic species." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=86980.
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Species invasions threaten the integrity of biotic communities, as invaders may outcompete and replace resident species. For many aquatic invaders, species replacements are driven by aggression. I explored this phenomenon through a quantitative synthesis and laboratory experiments. A quantitative synthesis of published studies on aggression in aquatic invaders found that body size and prior residency generally mediate the outcome of aggressive encounters, but there is no consistent tradeoff between intra- and interspecific aggression. As the majority of studies on agonistic interactions focus on phylogenetically related species, I investigated such interactions between two unrelated invasive species that occupy a similar niche: the round goby (Neogobius melanostomus) and the spinycheek crayfish (Orconectes limosus), both benthic omnivores that compete for shelter. Laboratory experiments revealed that round gobies were more aggressive than crayfish, regardless of prior residency. Heightened aggression may be a selective advantage for an animal to invade a habitat occupied by another territorial species.Les invasions d'espèces posent une menace à l'intégrité des communautés biologiques, puisque les espèces envahissantes peuvent gagner la compétition contre les espèces résidentes et en conséquence les supplanter. Le remplacement par des espèces envahissantes est souvent dû à leur comportement agressif. J'ai étudié ce phénomène en employant des méthodes de méta analyse et des expériences en laboratoire. Une méta analyse sur les actes d'agression chez les espèces envahissantes a démontré que la taille du corps et le statut de résidence antérieure affectent généralement le résultat des affrontements, mais il n'y a pas de compromis entre les actes d'agression intra et interspécifique. Puisque la plupart des études sur les interactions agonistes se concentrent sur des espèces apparentées taxonomiquement, j'ai examiné une telle interaction entre deux espèces envahissantes éloignées taxonomiquement qui occupent une niche semblable : le gobie à taches noires (Neogobius melanostomus) et l'écrevisse américaine (Orconectes limosus), deux omnivores qui se font compétition pour leur refuge. Les expériences en laboratoire ont démontré que les gobies à taches noires étaient plus agressifs que les écrevisses, indépendamment du statut de résidence antérieure. Le comportement agressif accru peut être un avantage sélectif qui permet à un animal d'envahir un habitat occupé par une autre espèce territoriale.
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Butler, C. "Pesticide induced stresses in aquatic bacteria." Thesis, Cardiff University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374732.
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Tanino, Yukie 1980. "Aquatic gravity currents through emergent vegetation." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/26712.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2004.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (leaves 109-112).
Differential heating and cooling can generate density-driven, lateral exchange flows in aquatic systems. Despite the ubiquity of wetlands and other types of aquatic canopies, few studies have examined the hydrodynamic effects of aquatic vegetation on these currents. This study investigates the dynamics of lock-exchange flows, a particular class of density currents, propagating through rigid emergent vegetation. First, previous mathematical formulation is extended to develop theoretical models of vegetated lock-exchange flows. The regime in which stem drag is inversely proportional to velocity is considered as a special case. Lock-exchange flows were generated in a laboratory flume with rigid cylindrical dowels as model vegetation. Experimental observations were consistent with the theory. Under high stem drag or low stem Reynolds number conditions, the interface deviated from the well-documented block profile associated with unobstructed lock-exchange flows and approached a linear profile. Criteria are developed to categorize all flow conditions as inertial or non-inertial and the interface profile as linear, transitional, or non-linear, respectively, based on (a) the evolution of the velocity of the leading edge of the undercurrent and (b) the interface shape. Finally, the present model is enhanced to account for wind forcing and bed friction to better describe conditions found in nature. The theory highlights the sensitivity of currents to wind forcing.
by Yukie Tanino.
S.M.
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Delannoy, Christian M. J. "Host adaptation of aquatic Streptococcus agalactiae." Thesis, University of Stirling, 2013. http://hdl.handle.net/1893/17259.
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Streptococcus agalactiae is a pathogen of multiple hosts. The bacterium, an aetiological agent of septicaemia and meningo-encephalitis in freshwater and saltwater fish species, is considered a major threat to the aquaculture industry, particularly for tilapia. Cattle and humans are however the main known reservoirs for S. agalactiae. In humans, the bacterium (commonly referred to as Group B Streptococcus or GBS) is a member of the commensal microflora of the intestinal and genito-urinary tracts, but it is also a major cause of neonatal invasive disease and an emerging pathogen in adults. In cattle, S. agalactiae is a well-recognized causative agent of mastitis. Numerous studies focusing on S. agalactiae from human and bovine origins have provided insight into the population structure of the bacterium, as well as the genome content and pathogenic mechanisms through identification of virulence determinants. Concerning S. agalactiae from aquatic origins, scientific information mainly focused on case reporting and/or experimental challenges, with a limited or absence of information in terms of pathogenesis, virulence determinants and genotypes of the strains involved. The objective of this study was to enhance our understanding of the molecular epidemiology, host-adaptation and pathogenicity of S. agalactiae in aquatic species, with particular emphasis on tilapia. Firstly, a collection of 33 piscine, amphibian and sea mammal isolates originating from several countries and continents was assembled, with the aim of exploring the population structure and potential host specificity of aquatic S. agalactiae. Isolates were characterised using pulsed-field gel electrophoresis (PFGE), multi-locus sequence typing (MLST), and a standardised 3-set genotyping system comprising molecular serotypes, surface protein gene profiles and mobile genetic element profiles. Two major subpopulations were identified in fish. The first subpopulation consisted of non-haemolytic isolates that belonged to sequence type (ST) 260 or 261, which are STs that have been reported only from teleosts. These isolates exhibited a low level of genetic diversity by PFGE and clustered with other STs that have been reported only in fish. Another common feature was the absence of all surface protein genes or mobile genetic elements targeted as part of the 3-set genotyping and that are usually found in human or bovine isolates. The second subpopulation consisted of β-haemolytic isolates recovered from fish, frogs and sea mammals, and that exhibited medium to high genetic diversity by PFGE. STs identified among these isolates have previously been identified from strains associated with asymptomatic carriage and invasive disease in humans. The human pathogenic strain ST7 serotype Ia was detected in fish from Asia. Moreover, ST283 serotype III-4 and its novel single locus variant ST491 detected in fish from Southeast Asia shared a 3-set genotype identical to that of an emerging ST283 clone associated with invasive disease of adult humans in Asia. These observations suggested that some strains of aquatic S. agalactiae may present a zoonotic or anthroponotic hazard. STs found among the seal isolates (ST23) have also been reported from humans and numerous other host species, but never from teleosts. This work provided an excellent basis for exploration of the virulence of selected strains in experimental challenges. The virulence of two strains of S. agalactiae was experimentally investigated by intra-peritoneal infection of Nile tilapia (Oreochromis niloticus), using an isolate originally recovered from fish and belonging to ST260, and an isolate originating from a grey seal and belonging to ST23. The clinical signs, the in vivo distribution of viable bacteria and bacterial antigens, and the gross and histopathological lesions that developed during the time course of the infection were investigated. The ST260 strain was highly virulent, whereas no major clinical sign or mortalities occurred in the fish challenged with the ST23 strain. After injection, both strains however gained access to the bloodstream and viable bacteria were recovered from all organs under investigation. During the early stages of infection, bacteria were mostly found within the reticulo-endothelial system of the spleen and kidney. Thereafter, the ST260 demonstrated a particular tropism for the brain and the heart, but granulomatous inflammation and associated necrotic lesions were observed in all organs. ST23 was responsible for a mixed inflammatory response associated with the presence of bacteria in the choroid rete and in the pancreatic tissue only. After 7 days post-challenge and for both strain, the formation or containment of bacteria within granulomata or other encapsulated structures appeared to be a major component of the fish response. However, the load of viable bacteria remained high within organs of fish infected with ST260, suggesting that, unlike ST23, this strain is able to survive within macrophages and/or to evade the immune system of the fish. This work demonstrates that the lack of report of ST23 strains in fish is possibly not due to a lack of exposure but to a lack of virulence in this host. The two strains, which differ in prevalence and virulence in fish, provide an excellent basis to investigate genomic differences underlying the host-association of distinct S. agalactiae subpopulations. The genome of the ST260 strain used in challenge studies was sequenced. We therefore provided the first description for the genome sequence of a non-haemolytic S. agalactiae isolated from tilapia (strain STIR-CD-17) and that belongs by multi-locus sequence typing (MLST) to clonal complex (CC) 552, which corresponds to a presumptive fish-adapted subgroup of S. agalactiae. The genome was compared to 13 S. agalactiae genomes of human (n=7), bovine (n=2), fish (n=3) and unknown (n=1) origins. Phylogenetic analysis based on the core genome identified isolates of CC552 as the most diverged of all S. agalactiae studied. Conversely, genomes from β-haemolytic isolates of CC7 recovered from fish were found to cluster with human isolates of CC7, further supporting the possibility that some strains may represent a zoonotic or anthroponotic hazard. Comparative analysis of the accessory genome enabled the identification of a cluster of genes uniquely shared between CC7 and CC552, which encode proteins that may provide enhanced fitness in specific niches. Other genes identified were specific to STIR-CD-17 or to CC552 based on genomic comparisons; however the extension of this analysis through the PCR screening of a larger population of S. agalactiae suggested that some of these genes may occasionally be present in isolates belonging to CC7. Some of these genes, occurring in clusters, exhibited typical signatures of mobile genetic elements, suggesting their acquisition through horizontal gene transfer. It is not possible to date to determine whether these genes were acquired through intraspecies transfer or through interspecies transfer from the aquatic environment. Finally, general features of STIR-CD-17 highlighted a distinctive genome characterised by an absence of well conserved insertion sequences, an abundance of pseudogenes, a smaller genomic size than normally observed among human or bovine S. agalactiae, and an apparent loss of metabolic functions considered conserved within the bacterial species, indicating that the fish-adapted subgroup of isolates (CC552) has undergone niche restriction. Finally, genes encoding recognised virulence factors in human S. agalactiae were selected and their presence and structural conservation was evaluated within the genome of STIR-CD-17.
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Davis, James. "A Novel Aquatic Sensor and Network." Thesis, Rensselaer Polytechnic Institute, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10243159.
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Water quality monitoring is essential to human health, ecological stability, and scientific research but remains hampered by Large, expensive, inflexible, and sometimes unreliable systems. To address these problems, an open source, flexible, and inexpensive sonde was designed and created capable of meeting research needs, along with a buoy system to support its use. A new optical UV based sensor was created to help measure phosphate ion levels. Together these technologies could further ecological research and help safeguard ecosystems.
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Pinto, Preston Albert. "Novel Bio-inspired Aquatic Flow Sensors." Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/33807.
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Inspired by the roles of hair cells in nature, this study aims to develop and characterize two new sets of novel flow sensors. One set of sensors developed and studied in this work are flow sensors fabricated using carbon nanomaterials. These sensors are made by embedding carbon nanotubes (CNT) and carbon nanohorns (CNH) into a polymeric substrate and then tested by flowing a conductive aqueous solution over the surface of the exposed CNT and CNH. In response, a flow-dependent voltage is generated. The surface coverage and the electrical relationship between the sensor and water is investigated and the voltage measurements of sensors with different levels of resistance were tested in varying fluid velocities. In response to these fluid velocities, the least resistive sensor showed small, but detectable changes in voltages, while higher resistance sensors showed less response. In addition, plasma treatment of the carbon nanomaterial/PDMS films were conducted in order to render the PDMS on the surface hydrophilic and in turn to pull more fluid towards the carbon material. This showed to improve the sensitivity of the flow sensors. This work also builds on previous research by investigating the flow dependent electrical response of a â skinâ -encapsulated artificial hair cell in an aqueous flow. An artificial cell membrane is housed in a flexible polyurethane substrate and serves as the transduction element for the artificial hair cell. Flow experiments are conducted by placing the bio-inspired sensor in a flow chamber and subjecting it to pulse-like flows. This study demonstrates that the encapsulated artificial hair cell flow sensor is capable of sensing changes in flow through a mechanoelectrical response and that its sensing capabilities may be altered by varying its surface morphology. Furthermore, the sensorâ s response and dynamics as a function of its surface morphology and structural properties are investigated through synchronized motion tracking of the hair with a laser vibrometer and current measurements across the artificial cell membrane.Master of Science
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Davies, Iain A. "Effects of antibiotics on aquatic microbes." Thesis, University of York, 2010. http://etheses.whiterose.ac.uk/4099/.
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Antibiotics are designed to inhibit the growth of or kill bacteria. Of the many classes of antibiotics that have been synthesized two particular classes of antibiotic have been frequently detected in the natural environment, namely the tetracyclines and sulfonamides. Following use, these compounds can enter the environment via the application of animal manures or domestic seawage sludge to land as a fertiliser or from wastewater treatment plant effluents. Once in the environment the compounds can persist and, depending on their properties, are distributed around the different environmental media (i.e. surface waters, groundwaters, soils and sediments). Several studies have suggested that tetracyclines and sulfonamides may have significant impacts on microbial function in the natural environment. However most of these studies have used existing standardised test procedures and/or unrealistic exposure conditions. The aim of the current study therefore was to develop a more environmentally realistic test system for assessing the effects of antibiotics on aquatic microbial communities and to apply this to assess the potential impacts of a sulphonamide and a tetracycline antibiotic on aquatic microbial communities. The developed system, which was an aquatic microcosm composed of fresh river water, return line treated sewage and OECD synthetic sewage, was initially used to assess the effects of 3, 5-dichlorophenol, an OECD reference toxicant. Effects of DCP were seen within the concentration range that is considered valid by other standard microbial toxicity tests, such as OECD method 209 (3.2-32 mg/L). Since the developed system was able to quantify effects on aquatic microbial communities, it can be seen as being more environmentally relevant than existing standard tests, which rely on testing single microbial species or sludge communities. The test system was then used to test the effects of chlortetracycline (CTC) and sulfamethoxazole (SMX) on multisubstrate utilization. Following addition of the study antibiotics, effects were observed for both antibiotics on total substrate utilization and on the utilization of specific, ecologically relevant end-points (such as nutrient cycling and polymer degradation) also. Effects were also observed on the structure of microbial communities and on the functional diversity of substrate utilization (especially in the case of SMX exposure) and these effects generally persisted for up to 3 d after addition of the study compounds at a lower concentration of 0.1 mg/L for both compounds. The results indicate that both antibiotics were inhibiting various aspects of substrate utilization, most of which were related to ecologically relevant processes that occur in the aquatic environment. The results also suggest that SMX and CTC exposure result in changes in the community structure of ecologically relevant groups of microbes (such as bacteria involved in the nitrogen and carbon cycle bacteria). Microbial communities that were exposed to CTC and SMX showed a varying degree of recovery, although more long term effects were seen in SMX exposures; functional effects were observed for the duration of the exposure. It was hypothesized that the observed recovery may have been caused by the selection of antibiotic resistance in the exposed communities. Culture based resistance studies showed that there was a significant temporal rise in CTC resistance at all CTC concentrations, but not SMX resistance, across the dose range. In addition, a greater number of distinct microbial morphotypes could be isolated from combined microcosms on day 7 compared with day 1. An increase in CTC and SMX resistance in control exposures was also observed. In addition, distinct resistant morphotypes developed in both dosed and undosed microcosms on day 7 of the study. Furthermore, the results of a series of different culture based experiments suggested that multidrug resistance was present in morphotypes that were isolated from dosed and control microcosms. These data therefore suggest that multidrug resistance was present at the start of the exposure and may also have been co-selected by exposure to CTC and SMX. In general, CTC and SMX show signs that they may pose a risk to the environment and possibly the wider health of humans and animals.
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Johannesen, Asa. "Predator-prey interactions in aquatic environments." Thesis, University of Leeds, 2013. http://etheses.whiterose.ac.uk/7556/.
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In the first half of this thesis, I have focused on predator ability to locate prey using olfaction and how prey aggregation and turbulence affect prey detection. In chapter 2 I investigate the ability of three spined sticklebacks to compensate for loss of visual cues by using olfaction and find that they can use olfactory cues but that these most likely help the fish detect prey rather than locate prey. In chapter 3 I explore the effect of prey aggregation as an anti-predator strategy when avoiding an olfactory predator and find that aggregated prey survive longer than do dispersed prey. In order to further investigate why this may be, I carried out an experiment using Gammarus pulex as the predator where I recorded search time as a function of prey group size. I found that similarly to detection distance, search time relates to the square root of the number of prey. Finally, I investigate the effect that turbulence in flowing water may have on prey group detection using three spined sticklebacks in a y-maze. I find that risk of detection increases with prey group size but that turbulence lowers this risk. This may mean that there are thresholds below which size prey groups can benefit from turbulence as a ‘sensory refuge’ thus avoiding predators. In the second part of my thesis I focus on the interactions between a cleaner fish and a parasite in an aquaculture setting focusing on whether said fish is useful as a cleaner in industry. I carry out experiments to investigate the use of lumpfish as salmon cleaners in terms of cleaning efficiency and behaviour. I find that while some lumpfish do clean salmon, the required circumstances are still unknown and that further work including selective breeding, personality and effects of tanks is necessary.
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Smith, E. C., Phillip R. Scheuerman, and Kurt J. Maier. "Toxicity of Nanomaterials to Aquatic Organisms." Digital Commons @ East Tennessee State University, 2005. https://dc.etsu.edu/etsu-works/2939.
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Domínguez-Caballero, José Antonio. "Digital holographic imaging of aquatic species." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/35655.
Full textAbstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 160-174).
The aim of this thesis is to design, develop and implement a digital holographic imaging (DHI) system, capable of capturing three-dimensional (3D) images of aquatic species. The images produced by this system are used in a non-intrusive manner to characterize the abundance, morphology and 3D location of the aquatic species. The DHI system operates by recording the hologram produced by the interference between a reference wave and the wave scatter by a coherently illuminated object with a charge-couple-device (CCD). The recorded hologram contains information about the amplitude and phase of the optical field as modified by the object. This optical field is retrieved by numerical algorithms, which enable the reconstruction of the field at different distances relative to the detector from a single hologram. The recording of the holograms with the CCD allows the implementation of image post-processing techniques intended to enhance the reconstructed images. A description of the optimization of the reconstruction by means of an auto-scan algorithm and the reconstruction of large holograms are discussed. It is found that the in-line single-beam experimental set-up is the most suitable configuration for underwater imaging of aquatic species.
(cont.) This is experimentally verified by imaging brine shrimp and copepods under various conditions. Small, sub-10um features of the objects were successfully resolved. It is also found that by using configurations with a spherical reference wave, resolutions comparable to those obtained by a conventional optical microscope can be achieved in a "lens-free" approach with larger working distances.
by José Antonio Domínguez-Caballero.
S.M.
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Christman, Van D. "Ecology of benthic macroinvertebrates in experimental ponds." Diss., This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-07282008-134927/.
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Pitelli, Robinson Luiz de Campos Machado [UNESP]. "Abordagens multivariadas no estudo da dinâmica de comunidades de macrófitas aquáticas." Universidade Estadual Paulista (UNESP), 2006. http://hdl.handle.net/11449/99931.
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pitelli_rlcm_dr_fca.pdf: 512956 bytes, checksum: b7f67dd4835b4a602a6198adbffcab0c (MD5)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
The aquatic weeds are essentially important in water bodies under strong antropic influence, especially in hydropower water reservoirs built-up in highly urbanized regions. In the energy generation system of hydropower company Light Serviços de Eletricidade , the Santana reservoir historically has more problems with aquatic weeds. Aiming to solve these problems the company periodically promotes a mechanical harvesting cleaning up the reservoir, but after some time it is completely re-colonized by the macrophytes and the 4 problems are back. Aiming to understand the macrophytes re-colonization dynamics, fields surveys were done monthly, identifying and quantifying the aquatic weed populations in 91 sampling sites. The weeds quantification was done by means of a colonization scale changing from 0 (no plants) to 4 (high colonization, more than 80% of the sampling site). The evolution of colonization area and the geographic distribution pattern were studied for aquatic weed populations, while diversity and equitability coefficients, several similarity index and multivariate analysis were applied to study the macrophyte communities between sampling times. There was a well defined colonization succession process, characterized by variation in the relative size of the different populations and some seral stages could be established, at least for mechanical harvesting planning and some biotic conditions of the macrophyte community. It was not possible to detect a succession of populations, but a succession of colonization conditions since there were no expressive increments or extinctions of species in the reservoir during the year. The exotic species to the reservoir and with early colonization were the predominant ones in the macrophyte community with special attention to Egeria densa and Brachiaria arrecta. For some species, as Eichhornia crassipes and Myriophyllum aquaticum, the biotic pressures of natural enemies probably had decisive effects on.
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Lønborg, Christian. "Bioavailability of dissolved organic matter in coastal waters." Thesis, Available from the University of Aberdeen Library and Historic Collections Digital Resources, 2009. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?application=DIGITOOL-3&owner=resourcediscovery&custom_att_2=simple_viewer&pid=59094.
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Silva, Carolina Vieira da. "Macroinvertebrados associados à macrófitas aquáticas flutuantes : distribuição, estrutura da comunidade e abordagem experimental /." Botucatu, 2015. http://hdl.handle.net/11449/140219.
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Orientador: Raoul HenryBanca: Virgínia Sanches Uieda
Banca: José Francisco Gonçalves Júnior
Banca: Irineu Bianchini Júnior
Banca: Janet Higuti
Resumo: Não disponível
Abstract: Not available
Doutor
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Castilho, Ivana Giovannetti [UNESP]. "Qualidade microbiológica do ambiente e da tilápia-do-Nilo (Oreochromis niloticus) produzida em sistema de tanques-rede no reservatório de Chavantes, SP." Universidade Estadual Paulista (UNESP), 2012. http://hdl.handle.net/11449/87790.
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castilho_ig_me_botib.pdf: 337909 bytes, checksum: 0470c57c1b16f864f2fba4df4a772a2e (MD5)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
A piscicultura é o setor mais popular da aquicultura e o Brasil tem grande potencial para desenvolvimento da atividade devido às características do país e ao aumento no consumo de peixes. O reservatório de Chavantes, no Médio Rio Paranapanema, possui diversas pisciculturas de tanques-rede com criação de tilápias. No entanto, esses sistemas são intensivos com altas densidades de estocagem e de fornecimento de ração, o que pode ser prejudicial para a qualidade da água e saúde dos animais, trazendo conseqüências ecológicas, econômicas e sociais. Aeromonas e Pseudomonas estão entre os principais patógenos de peixes, porém, no ambiente e na produção de uma piscicultura, uma grande variedade de micro-organismos pode ser identificada sem provocar doenças nos animais, mas sendo via de transmissão de agentes patogênicos para o homem, como Salmonella sp e Staphylococcus aureus. A determinação de coliformes termotolerantes também é de grande importância na vigilância da contaminação por patógenos nos sistemas de criação de peixes. Assim, o objetivo do presente estudo foi avaliar a qualidade microbiológica de pescados tilápia-do-Nilo (Oreochromis niloticus) criados em sistema de tanques-rede no reservatório de Chavantes (médio rio Paranapanema, SP), bem como a qualidade da água e da ração nesses sistemas. As análises foram feitas em quatro ciclos de produção, dois de verão e dois e inverno, através da pesquisa de Pseudomonas sp, Salmonella sp, S. aureus e coliformes termotolerantes (CTe) nos pescados, Salmonella sp e CTe na água e Salmonella na ração. No primeiro ciclo de verão, 8% das amostras de peixes estavam contaminadas com Aeromonas, 4% com Pseudomonas sp e 37,3% das amostras com NMP de CTe/g acima de 103. Não foram detectados Salmonella ou S. aureus. O primeiro ciclo...
Fish farming is the most popular modality of aquaculture and Brazil has great potential for this activity due to its characteristics and increased consumption of fish. The Chavantes reservoir, at Middle Paranapanema River has several fish farms using cages to create tilapia. However, these systems are intensive and therefore use high stocking and feeding densities, which can be detrimental to water quality and animal health. Aeromonas and Pseudomonas are among the main pathogens of fish, but a variety of micro-organism can be identified in the environment and in a fish farm without causing disease in animals, but them can act as a route of disease transmission to humans, as those caused by Salmonella and Staphylococcus aureus. The fecal coliforms determination is also important in surveillance of the contamination by pathogens in fish farming systems. Thus, this study aimed to evaluate the microbiological quality of Nile-tilapia fish (Oreochromis niloticus) cultivated in cages in Chavantes reservoir (Middle Paranapanema River, SP) and water and feed quality in these systems. Analyses were done during four production cycles, two in the summer and two in the winter, by researching Aeromonas sp, Pseudomonas sp, Salmonella, S. aureus and thermotolerant coliforms (TC) in fish, Salmonella and TC in water and Salmonella in feed samples. In the first summer cycle, 8% of the fish samples were contaminated with Aeromonas sp, 4% with Pseudomonas sp and 37.3% with over 103 MPN TC/g. There were no samples with Salmonella or S. aureus. The first winter cycle presented 10% of fish samples with Aeromonas sp, 6.1% with Pseudomonas sp, 1.1% with S. aureus, Salmonella in 0.5% and 58.9% above the allowed limit for TC/g. In the second cycle of summer, 10.6% of the samples were contaminated with Aeromonas sp, 8% with... (Complete abstract click electronic access below)
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Bonocchi, Kelly Saito Lopes [UNESP]. "Dinâmica populacional das macrófitas aquáticas emersas Spartina alterniflora Loiseleur, Crinum procerum Carey e Scirpus californicus Steud, na bacia do rio Itanhaém, SP." Universidade Estadual Paulista (UNESP), 2006. http://hdl.handle.net/11449/87861.
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bonocchi_ksl_me_rcla.pdf: 396015 bytes, checksum: 15e08f47db9dc587bf93f862ab35100b (MD5)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O objetivo deste trabalho foi estudar a dinâmica de populações de três espécies de macrófitas aquáticas emersas, Spartina alterniflora, Crinum procerum e Scirpus californicus, tanto em bancos monoespecíficos (localizados no rio Itanhaém, rio Acima e rio Branco, respectivamente) quanto em um banco pluriespecífico (localizado no rio ltanhaém). Foram fixados 5 quadrados de 0,25 m2 em cada banco e, mensalmente (entre agosto/2000 a junho/2001), contados os números de folhas verdes, folhas senescentes, folhas jovens, inflorescências e altura de cada espécie. Paralelamente, foram estudadas algumas variáveis limnológicas da água e do sedimento. Foram observadas variações sazonais em algumas das variáveis, tanto das biológicas quanto das limnólogicas. Nos bancos monoespecíficos, S. alterniflora e C. procerum apresentaram maior número de folhas verdes na primavera e verão (indicando serem estes os períodos favoráveis ao seu desenvolvimento) e maiores quantidades de folhas senescentes durante o outono (indicando ser este o período desfavorável); S. californicus não apresentou variação significativa durante o período estudado. No banco pluriespecífico os valores de todas variáveis biológicas foram menores do que nos monoespecíficos indicando que, provavelmente, ocorreu competição entre as espécies; o padrão sazonal de S. alterniflora e C. procerum pareceu ser inversamente proporcional, o que evitaria a exclusão competitiva das espécies; o padrão sazonal de S. californicus foi concordante com o observado no banco monoespecifico. Provavelmente, as temperaturas mais baixas do inverno limitem o crescimento de S. alterniflora e C. procerum, enquanto que as maiores temperaturas do verão favoreçam seus desenvolvimentos.
The purpose of this research was to study the populational dynamics of three species of emergent aquatic macrophytes, Spartina alterniflora, Crinum procerum and Scirpus californicus, both in singie-species stands (Iocated at ltanhaem River, Acima River and Branco River, respectively) and a rnixedspecies stand (Iocated at ltanhaern River). 5 quadrats of 0,25 m2 were fixed in each stand and, rnonthly (between august, 2000 to june, 2001), counted the number of green leaves, dying leaves, young leaves, flowering and height of each species. In paraliel, some limnological variables of water and sediment were studied. Seasonal variations in some of the variabies were observed, both biologics and iimnologics. In the singie-species stands, S. alterniflora and C. procerum showed higher numbers of green leaves in spring and summer (pointing out to be the favorable seasons to their development) and higher num bers of dying leaves in autumn (pointing out to be the unfavorable season); S. californicus did not show a significant variation on the biometrical data during the studied period. In the mixed-species stand the vaiues of ali biologic variabies were iower, indicating that, probably, there was competition among the species; the seasonai pattern of S. alterniflora and C. procerum apparentiy was inverseiy proportional, which wouid avoid competitive exciusion of the species; the seasonal pattern of S. californicus was the sarne that observed on the singiespecies stand. Probably, the iowest temperatures during winter iimit the growth of S. alterniflora and C. procerum whiie the highest values of temperature in surnmer allow their deveiopment. Due to the mono specific stands frorn these species are located along a salinity gradient, it's suggested the use of those species as bio-indicators of saiinity in the itanhaern River basin.
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Castilho, Ivana Giovannetti. "Qualidade microbiológica do ambiente e da tilápia-do-Nilo (Oreochromis niloticus) produzida em sistema de tanques-rede no reservatório de Chavantes, SP /." Botucatu, 2012. http://hdl.handle.net/11449/87790.
Full textAbstract:
Orientador: Vera Lucia Mores RallBanca: José Paes de Almeida Nogueira Pinto
Banca: Reinaldo José da Silva
Resumo: A piscicultura é o setor mais popular da aquicultura e o Brasil tem grande potencial para desenvolvimento da atividade devido às características do país e ao aumento no consumo de peixes. O reservatório de Chavantes, no Médio Rio Paranapanema, possui diversas pisciculturas de tanques-rede com criação de tilápias. No entanto, esses sistemas são intensivos com altas densidades de estocagem e de fornecimento de ração, o que pode ser prejudicial para a qualidade da água e saúde dos animais, trazendo conseqüências ecológicas, econômicas e sociais. Aeromonas e Pseudomonas estão entre os principais patógenos de peixes, porém, no ambiente e na produção de uma piscicultura, uma grande variedade de micro-organismos pode ser identificada sem provocar doenças nos animais, mas sendo via de transmissão de agentes patogênicos para o homem, como Salmonella sp e Staphylococcus aureus. A determinação de coliformes termotolerantes também é de grande importância na vigilância da contaminação por patógenos nos sistemas de criação de peixes. Assim, o objetivo do presente estudo foi avaliar a qualidade microbiológica de pescados tilápia-do-Nilo (Oreochromis niloticus) criados em sistema de tanques-rede no reservatório de Chavantes (médio rio Paranapanema, SP), bem como a qualidade da água e da ração nesses sistemas. As análises foram feitas em quatro ciclos de produção, dois de verão e dois e inverno, através da pesquisa de Pseudomonas sp, Salmonella sp, S. aureus e coliformes termotolerantes (CTe) nos pescados, Salmonella sp e CTe na água e Salmonella na ração. No primeiro ciclo de verão, 8% das amostras de peixes estavam contaminadas com Aeromonas, 4% com Pseudomonas sp e 37,3% das amostras com NMP de CTe/g acima de 103. Não foram detectados Salmonella ou S. aureus. O primeiro ciclo... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Fish farming is the most popular modality of aquaculture and Brazil has great potential for this activity due to its characteristics and increased consumption of fish. The Chavantes reservoir, at Middle Paranapanema River has several fish farms using cages to create tilapia. However, these systems are intensive and therefore use high stocking and feeding densities, which can be detrimental to water quality and animal health. Aeromonas and Pseudomonas are among the main pathogens of fish, but a variety of micro-organism can be identified in the environment and in a fish farm without causing disease in animals, but them can act as a route of disease transmission to humans, as those caused by Salmonella and Staphylococcus aureus. The fecal coliforms determination is also important in surveillance of the contamination by pathogens in fish farming systems. Thus, this study aimed to evaluate the microbiological quality of Nile-tilapia fish (Oreochromis niloticus) cultivated in cages in Chavantes reservoir (Middle Paranapanema River, SP) and water and feed quality in these systems. Analyses were done during four production cycles, two in the summer and two in the winter, by researching Aeromonas sp, Pseudomonas sp, Salmonella, S. aureus and thermotolerant coliforms (TC) in fish, Salmonella and TC in water and Salmonella in feed samples. In the first summer cycle, 8% of the fish samples were contaminated with Aeromonas sp, 4% with Pseudomonas sp and 37.3% with over 103 MPN TC/g. There were no samples with Salmonella or S. aureus. The first winter cycle presented 10% of fish samples with Aeromonas sp, 6.1% with Pseudomonas sp, 1.1% with S. aureus, Salmonella in 0.5% and 58.9% above the allowed limit for TC/g. In the second cycle of summer, 10.6% of the samples were contaminated with Aeromonas sp, 8% with... (Complete abstract click electronic access below)
Mestre
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Chi, Siu-chung. "Eco-toxicity of antibiotics on aquatic organism." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B43783600.
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Ros, i. Sala Àlex. "Effects of aquatic vegetation on sediment transport." Doctoral thesis, Universitat de Girona, 2016. http://hdl.handle.net/10803/401629.
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In the margins of continents there are the coastal zones, regions of remarkable biological productivity. Coastal zones include, among others, wetlands, that are land areas inundated permanently o seasonally, characterized by the presence of aquatic vegetation adapted to the hydric soil. Therefore it is necessary to consider the effect of aquatic canopies in wetlands investigations. These areas are governed by physical forces originated from tidal currents, waves, winds, night convection and floods. The aim of this thesis is to study the sediment transport in wetlands in which fluid is dominated by a) progressive waves, b) nearly isotropic turbulence and c) extreme flooding eventsAls marges dels continents hi ha les zones costaneres, regions d’altra productivitat biològica. Les zones costaneres inclouen, entre d’altres, els aiguamolls, que són zones terrestres inundades permanentment o estacionalment, caracteritzades per la presència de vegetació aquàtica adaptada a sols hídrics. És per tant necessari considerar l’efecte de les praderies aquàtiques en les investigacions en aiguamolls. Aquestes àrees estan governades per forces físiques originades per corrents de marees, ones, vent, conveccions nocturnes i inundacions. L’objectiu d’aquesta tesi és estudiar el transport de sediments en aiguamolls on el fluid és dominat per a) ones progressives, b) turbulència gairebé isòtropa i c) inundacions extremes
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Körberg, Turhagen Frida. "Urban building i kvarteret Domherren : Life aquatic." Thesis, KTH, Arkitektur, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-95552.
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Rowe, Will. "Antimicrobial resistance gene monitoring in aquatic environments." Thesis, University of Cambridge, 2016. https://www.repository.cam.ac.uk/handle/1810/253755.
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This dissertation documents the development of an environmental framework for monitoring antimicrobial resistance gene (ARG) dissemination in the aquatic environment. The work opens with a review of the relevant literature and outlines the importance of an environmental framework for monitoring ARG dissemination as part of antimicrobial resistance risk assessments. The ability to interrogate sequencing data quickly and easily for the presence of ARGs is crucial in order to facilitate their monitoring in the environment. As current laboratory methods for the detection and surveillance of antimicrobial resistant bacteria in the environment were limited in their effectiveness and scope, the dissertation begins by describing the design and implementation of a Search Engine for Antimicrobial Resistance (SEAR), a pipeline and web interface for detection of horizontally-acquired ARGs in raw sequencing data. The suitability of metagenomic methods for monitoring the ARG content of effluents from faecal sources was then assessed via a pilot study of a river catchment. Novel metagenomes generated from effluents entering the catchment were interrogated for ARGs. The relative abundance of ARGs in effluents were determined to be higher relative to the background environment, as were sequences relating to human and animal pathogens and mobile genetic elements. Thus, effluents were implicated in the dissemination of ARGs throughout the aquatic environment. To determine if ARGs were potentially in use in the environment, the expression of ARGs within effluents was then evaluated across a series of longitudinal samples through the use of metatranscriptomics, and the presence of potential environmental antimicrobial selection pressures was examined. This demonstrated that the abundance of ARGs, as well as antimicrobial usage at the effluent source, was correlated with the transcription of ARGs in aquatic environments. The work described in this dissertation has also found that horizontally transmitted ARGs were present in pathogenic endospore-forming bacteria commonly found across the aquatic environment, potentially providing a mechanism for ARG persistence in the environment. Finally, these findings were integrated into a universal framework for monitoring ARG dissemination in aquatic environments and used to highlight the developments required to incorporate this framework into future environmental ARG research and to facilitate antimicrobial resistance risk assessments.