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Woodward, Kenneth Benjamin. „The Storage, Mobilisation and Metabolism of Soil Nutrients and Carbon in an Australian Lowland River“. Thesis, Griffith University, 2015. http://hdl.handle.net/10072/366245.
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More than 45 000 dams, with the capacity to hold 15% of global river runoff, have been constructed on rivers around the world for diverse purposes including water supply, irrigation water and power. The effects of these dams on river flow are diverse and dependent upon the purpose of the dam; some dams stabilise flow to improve transportation, water access and agricultural productivity, while dams such as those for power generation create flow regimes that vary drastically over a period of hours. The benefits of regulating river flow for human needs comes with ecological costs to riverine ecosystems including local extinctions, depletion of ground water, declines in water quality and water availability. The specific ecological costs of flow regulation are dependent on how the new, regulated, flow regime differs from the natural flow regime of a river system. Regulation of flow in Australia’s lowland rivers has been undertaken to suppress the inherent flow variability and dampen flow extremes, largely to improve water access for floodplain based irrigated agriculture. Flow regulation in these systems captures moderate sized flows, releasing this stored water during periods of natural low flow. This stabilising of river flow has resulted in an increase in the abundance of introduced species and a decline in the diversity of native fish, macroinvertebrate, and littoral plant communities along with altering river channel geomorphology and decreasing water quality. These declines may be partly caused by the loss of moderate sized flows reducing lateral hydrological connectivity between terrestrial and aquatic ecosystems. In an attempt to reverse this effect, flow rules that are designed to increase the frequency of small to moderate sized flow pulses, which are mostly contained within the channel, have been introduced in many of Australian’s lowland rivers.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment
Science, Environment, Engineering and Technology
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Chénier, Martin. „Impact of seasonal variations, nutrients, pollutants and dissolved oxygen on the microbial composition and activity of river biofilms“. Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=85144.
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Biofilm communities were cultivated in rotating annular bioreactors using water from the South Saskatchewan River. The impacts of seasonal variations, nutrients, pollutants and dissolved oxygen on the activity and composition of the biofilms were assessed by using a combination of microcosm assays and molecular biology techniques.The seasonal pattern in nitrification, denitrification and hexadecane mineralization, and in the occurrence of nirK in the South Saskatchewan River biofilms was: fall greater than winter, which was equivalent to spring. Hexadecane mineralization was higher in fall 1999 than in fall 2001, denitrification was similar in these two years, and no seasonal pattern of nitrification was observed.
The addition of combined nutrients (C, N, and P) resulted in significant increases in the measured bacterial activities and in the predominance of alkB, nirS and nirK in all seasons and years. The addition of individual nutrients did not stimulate hexadecane mineralization, denitrification, and the PCR amplification of nirS and nirK. In fall 1999, CNP and, to a lesser extent P, stimulated nitrification, whereas in fall 2001, no pattern was observed. The results showed that nutrients, especially P, were limiting for bacterial activities, and that the biofilm activities and composition varied with nutrient availability and time of year.
At the concentration assessed (1 ppb), hexadecane partially inhibited denitrification to similar extents in both years, had a negative impact on nitrification and hexadecane mineralization in fall 1999, and a positive impact on these two latter activities in fall 2001. Nickel (0.5 mg liter-1 ) negatively affected denitrification but had no effect on hexadecane mineralization. The alkB and nirS genes were less predominant and absent, respectively, in biofilms grown in the presence of nickel. DGGE analyses indicated that nickel reduced the biofilm bacterial diversity.
The results presented herein provide much needed information on the microbial ecology of river biofilms, and on the impact and interactive effects of pollutant and nutrient inputs on these biofilms. These results and the techniques used in this project can be applied to monitor environmental effects of anthropogenic activities on aquatic biofilms, and can contribute to establish or revise environmental regulations.
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Koch, Gregory R. „Dynamics of Ecosystem Metabolism and Flocculent Detritus Transport in Estuarine Taylor River“. FIU Digital Commons, 2012. http://digitalcommons.fiu.edu/etd/680.
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Estuaries and estuarine wetlands are ecologically and societally important systems, exhibiting high rates of primary production that fuel offshore secondary production. Hydrological processes play a central role in shaping estuarine ecosystem structure and function by controlling nutrient loading and the relative contributions of marine and terrestrial influences on the estuary. The Comprehensive Everglades Restoration Plan includes plans to restore freshwater delivery to Taylor Slough, a shallow drainage basin in the southern Everglades, ultimately resulting in increased freshwater flow to the downstream Taylor River estuary. The existing seasonal and inter-annual variability of water flow and source in Taylor River affords the opportunity to investigate relationships between ecosystem function and hydrologic forcing.
Estimates of aquatic ecosystem metabolism, derived from free-water, diel changes in dissolved oxygen, were combined with assessments of wetland flocculent detritus quality and transport within the context of seasonal changes in Everglades hydrology. Variation in ecosystem gross primary production and respiration were linked to seasonal changes in estuarine water quality using multiple autoregression models. Furthermore, Taylor River was observed to be net heterotrophic, indicating that an allochthonous source of carbon maintained ecosystem respiration in excess of autochthonous primary production. Wetland-derived detritus appears to be an important vector of energy and nutrients across the Everglades landscape; and in Taylor River, is seasonally flushed into ponded segments of the river where it is then respired. Lastly, seasonal water delivery appears to govern feedbacks regulating water column phosphorus availability in the Taylor River estuary.
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Clinton, Sandra Mae. „Microbial metabolism, enzyme activity and production in the hyporheic zone of a floodplain river /“. Thesis, Connect to this title online; UW restricted, 2001. http://hdl.handle.net/1773/5560.
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Kupilas, Benjamin [Verfasser], und Daniel [Akademischer Betreuer] Hering. „Effects of river restoration on ecosystem metabolism and trophic relationships / Benjamin Kupilas ; Betreuer: Daniel Hering“. Duisburg, 2017. http://d-nb.info/1137466634/34.
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Treadwell, Simon Andrew 1968. „Patterns in community metabolism and biomass of biofilms colonising large woody debris along an Australian lowland river“. Monash University, Dept. of Biological Sciences, 2002. http://arrow.monash.edu.au/hdl/1959.1/5605.
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Hamblen, Jennifer M. „Spatial And Temporal Trends In Sediment Dynamics And Potential Aerobic Microbial Metabolism, Upper San Pedro River, Southeastern Arizona“. Thesis, The University of Arizona, 2003. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_etd_hy0216_sip1_w.pdf&type=application/pdf.
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Melo, Michaela Ladeira de. „O papel ecológico das bactérias planctônicas para a dinâmica da matéria orgânica na zona de confluência dos Rios Negro e Solimões (AM)“. Universidade Federal de Juiz de Fora, 2002. https://repositorio.ufjf.br/jspui/handle/ufjf/73.
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CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico
Com o objeto de avaliar o papel do metabolismo bacteriano para a dinâmica da matéria orgânica (MO) na região de confluência dos rios Negro e Solimões, foram estimadas em escala espacial: o metabolismo bacteriano - produção bacteriana (PB), respiração bacteriana (RB), demanda bacteriana de carbono (DBC) e eficiência de crescimento bacteriana (ECB), além de variáveis físicas e químicas, como nutrientes inorgânicos, carbono orgânico dissolvido (COD), razões estequiométricas dos nutrientes, condutividade elétrica e turbidez. Um experimento foi realizado para estimar a contribuição do metabolismo bacteriano e dos processos de adsorção da MO para o decaimento de COD na região de mistura das águas. As taxas metabólicas apresentaram variabilidade longitudinal e lateral ao longo da região de confluência dos rios Negro e Solimões, entretanto, não foi observado incremento das taxas metabólicas com o aumento da mistura das águas em condições in situ. A PB variou de 0,03 a 0,56 μgC L-1 h-1 e a RB de 38,8 a 78,73 μgC L-1 h-1, refletindo em baixos valores de ECB, em média 0,236%, ou seja, as bactérias heterotróficas alocam a maior parte da MO disponível para os processos catabólicos das células, o que resulta na rápida remineralização de carbono e nutrientes nestes sistemas. De uma maneira geral, os nutrientes e a qualidade e quantidade da MO parecem ter sido os fatores com maior influência sobre o metabolismo bacteriano na região estudada. O metabolismo bacteriano mostrou-se como principal componente para o decaimento de carbono, porém a adsorção da MO é de grande importância no processamento da MO, principalmente na zona de mistura das águas. Os resultados do presente estudo mostraram que as bactérias planctônicas contribuem significativamente para a transformação da MO, sendo que as altas taxas de RB destacam o importante papel das bactérias planctônicas para a remineralização de carbono e nutrientes na zona de confluência dos rios Negro e Solimões.
In order to evaluated the role of bacterial metabolism for the organic matter (OM) dynamics on the confluence zone of Negro and Solimões rivers, it was estimated in spatial scale: bacterial production (BP), bacterial respiration (BR), bacterial carbon demand (BCD), bacterial growth efficiency (BGE), in addition, chemical and physical variables, such as inorganic nutrients, dissolved organic carbon (DOC), stoichiometric ratio of nutrients, conductivity and turbidity. An experiment was conducted to estimate the contribution of bacterial activity and sorption process of OM to the DOC decay on the mixing waters. The metabolic rates showed longitudinal and lateral variability along Negro and Solimões rivers. However, it was observed in the metabolic rates with the increase of mixing waters in situ. The BP ranged between 0,03 and 0,56 μgC L-1 h-1 and the BR between 38,8 and 78,73 μgC L-1 h-1, reflecting in low BGE rates, average 0,236%, which means the heterotrophic bacteria allocated major part of OM available to the cells catabolic process, resulting in a quick remineralization of carbon and nutrients on these systems. In general, the nutrients and the quality and quantity of OM were the factors that most contributed to bacterial metabolism in the studied site. The bacterial metabolism showed as major component to the DOC decay, however, the OM sorption process is very important to the OM processing, mainly on water mixing zone. The results of this study showed that planktonic bacteria significantly contributed to the processing of OM, and high BR rates highlight the important role of planktonic bacteria for the carbon and nutrient remineralization on the confluence zone of the Negro and Solimões rivers.
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Tassone, Spencer. „A comparison of computational methods for estimating estuarine production and respiration from diel open water dissolved oxygen measurements“. VCU Scholars Compass, 2017. http://scholarscompass.vcu.edu/etd/4988.
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Diel dissolved oxygen (DO) data were used to characterize seasonal, inter-annual, and longitudinal variation in production and respiration for the James River Estuary. Two computational methods (Bayesian and bookkeeping) were applied to these data to determine whether inferences regarding DO metabolism are sensitive to methodology. Net metabolism was sensitive to methodology as Bayesian results indicated net heterotrophy (production < respiration) while bookkeeping results indicated net autotrophy (production > respiration). Differences in net metabolism among the methods was due to low seasonal variation in respiration using the Bayesian method, whereas bookkeeping results showed a strong correlation between production and respiration. Bayesian results suggest a dependence on allochthonous organic matter (OM) whereas bookkeeping results suggest that metabolism is dependent on autochthonous OM. This study highlights the importance in considering the method used to derive metabolic estimates as it can impact the assessment of trophic status and sources of OM supporting an estuary.
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Stuart, Anne. „ELEMENTAL COMPOSITION AND NUTRIENT EFFECT ON THE UPTAKE AND METABOLISM OF DISSOLVED ORGANIC CARBON BY BACTERIA FROM A TEMPERATE REGION RIVER“. VCU Scholars Compass, 2009. http://scholarscompass.vcu.edu/etd/11.
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Rivers are arteries that connect land and sea, and provide a conduit and reactor for allochthonous and autochthonous organic carbon sources (OC) delivered to the coastal ocean. In comparison to marine waters, inland waters quantitatively represent only a fraction of the marine system; however, their importance to global C cycling maybe disproportional to its actual size. Inland systems are subject to multiple sources of OC (autochthonous and allochthonous) that vary individually in space and time with respect to their concentration and potential bacterial bioavailability. This study investigates the impact of high and ambient inorganic nutrient concentrations on the bacterial bioavailability of potential exogenous and internal organic C sources to bacterial decomposition in the Chickahominy River using a long term incubation approach. In addition the elemental composition of each organic C substrate is investigated as a predictor of OC source bioavailability. The results of sole source incubations showed that autochthonous SAV sources were the most labile whereas soil derived OC was the least bioavailable, irrespective of nutrients. However, leaf litter sources showed relatively high bioavailability. The C:N ratios of SAV, Peltandra virginica, Botryococcus braunii, leaf litter, and soil (19.6, 12.4, 15, 29.7, 8.4 respectively) oppose historically accepted theory that autochthonous OC sources with low C:N ratios are a more bioavailable substrate for bacteria than allochthonous OC substrates with higher C:N ratios. The results of this study should provide a better of understanding of the interaction between inorganic nutrients and OC decomposition from allochthonous and autochthonous sources as well and potentially allow model prediction of OC lability based on its elemental signature.
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Entezami, Azam A. (Azam Alsadat). „Aquatic Heterotrophic Bacteria Active in the Biotransformation of Anthracene and Pentachlorophenol“. Thesis, North Texas State University, 1985. https://digital.library.unt.edu/ark:/67531/metadc504319/.
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Dominant genera of bacteria were isolated from three river waters during anthracene and pentachlorophenol biotransformation studies. The genera Pseudomonas, Acinetobacter, Micrococcus, Chromobacterium, Alcaligenes, Azomonos, Bacillus, and Flavobacterium were capable of biotransforming one or both of these compounds. These isolates were subjected to further biotransformation tests, including river water and a basal salt medium with and without additional glucose. The results of these experiments were evaluated statistically. It was concluded that only a limited number of the bacteria identified were able to transform these chemicals in river water. The addition of glucose to the growth medium significantly affected the biotransformation of these chemicals. It was also determined that the size of the initial bacterial population is not a factor in determining whether biotransformation of anthracene or pentachlorophenol can occur.
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Collins, Sean E. „Comparing hypotheses proposed by two conceptual models for stream ecology“. University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1396532770.
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Cogo, Michelle Cristine. „O papel dos sedimentos em suspensão no metabolismo de rios de micro e meso-escala no estado de Rondônia“. Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/91/91131/tde-01072005-144028/.
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As águas superficiais da Amazônia, que englobam, dentre outros, rios das mais variadas ordens, desde pequenos igarapés, até o rio Amazonas, um dos maiores do mundo, são um componente importante do funcionamento deste ecossistema de escala continental. Um paradigma acerca dos sistemas fluviais é que estes integram os processos que ocorrem em suas bacias de drenagem e, portanto, alterações na cobertura vegetal e nos usos da terra, podem interferir diretamente nos parâmetros físicos e químicos dos compartimentos aquáticos. Algumas áreas da Amazônia, como o estado de Rondônia, por exemplo, têm sofrido alterações substanciais nas suas bacias de drenagem e as conseqüências destas nos sistemas fluviais ainda são pouco compreendidas. Sabe-se que a conversão de florestas em pastagens, o tipo de alteração mais comum nos ecossistema de Rondônia, resulta na compactação dos solos e no aumento da erosão. Ao mesmo tempo, diversos estudos têm demonstrado que os sedimentos em suspensão, carreados nos rios, podem ser importantes fontes de carbono e outros nutrientes limitantes para o metabolismo aquático. Com base nestas premissas, este estudo visou avaliar a importância dos sedimentos em suspensão grossos (maiores que 63 µm) e finos (menores que 63 µm e maiores 0,1 µm) no metabolismo de alguns rios de Rondônia, sob diversas coberturas e usos da terra. Para tal, as concentrações destes sedimentos foram artificialmente aumentadas em amostras incubadas no escuro, nas quais os consumos de oxigênio indicaram as taxas respiratórias. No caso dos sedimentos em suspensão finos, observaram-se aumentos nas taxas respiratórias em praticamente todos os casos nos quais suas concentrações foram aumentadas. Os sedimentos em suspensão grossos, por outro lado, somente favorecem aumentos nas taxas respiratórias nos períodos de maiores precipitações. Estes resultados relacionam-se com a composição dos sedimentos. Sedimentos em suspensão finos, por sua maior capacidade de adsorver substâncias orgânicas e nutrientes, constituem uma fonte permanente de substrato para o metabolismo aquático. Sedimentos em suspensão grossos, por outro lado, somente carreiam fração substancial de material orgânico durante o período de maiores precipitações, quando os solos são lavados pelas enxurradas. Apesar destas diferenças no papel relativo destas duas frações do material particulado no metabolismo destes rios, fica evidente que o aumento da erosão pode acarretar mudanças significativas no metabolismo dos sistemas fluviais da Amazônia.Amazonian surface waters, encompassing rivers of distinct orders, from small streams to one of the largest of the world, the Amazon, are important components of the functioning of this continental-scale ecosystem. A paradigm about fluvial systems is that they integrate the processes that occur at their watersheds and, therefore, changes in land use/cover may directly interfere on physical and chemical parameters of the aquatic compartments. In some areas of the Amazon, such as in the state of Rondonia, for example, the landscape has been significantly altered, and the consequences of these changes are still poorly understood. It is well know that the conversion of forests into pastures, a common type of land use change in Rondonia, can cause the compactation of soils and increased erosion rates. At the same time, several studies have demonstrated that suspended sediments can be important sources of carbon and other nutrients to river metabolism. Based on those assumptions, this study aimed the evaluation of the importance of coarse (larger than 63 µm) and fine (smaller than 63 µm and larger than 0,1 µm) suspended sediments on the metabolism of some rivers of Rondonia. This assessment was made through incubations in the dark of samples enriched in sediments, in which the consumption of oxygen indicated respiration rates. In the case of fine suspended sediments, most incubated samples showed increased respiration rates as a result of the concentration of these particles. Coarse suspended sediments, on another side, only favor the increase in respiration rates during the high water period. These results are related to the composition of these sediments. Fine suspended sediments constitute a constant substract for the aquatic metabolism, as a result of their larger surface area and capacity for absorving organic substances and nutrients. Coarse sediments, however, only favor respiration during the high water period, when overland flow carries organic debris from land into the water systems. Although these two fractions of suspended sediments have different relative roles in the metabolism of rivers, it becomes evident from this data that increasing the erosion in the Amazon may affect significantly the metabolism of fluvial systems in this region.
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Savergnini, Fernanda. „Impacto e degradação microbiana de efluentes da indústria sucro-alcooleira no baixo rio Paraíba do Sul, RJ./“. Niterói, 2017. https://app.uff.br/riuff/handle/1/4682.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Universidade Federal Fluminense. Instituto de Química. Programa de Pós-Graduação em Geoquímica, Niterói, RJ
drenagem da bacia hidrográfica e de lançamentos pontuais de efluentes do processamento da cana, como o vinhoto. Este efluente consiste em um líquido com alta carga orgânica, demanda de oxigênio e sólidos em suspensão. Para caracterizar a matéria orgânica proveniente do impacto da agroindústria da cana, ferramentas geoquímicas podem ser utilizadas, determinando sua origem e o estado trófico ambiental. Análises microbiológicas também são importantes na medida em que microrganismos degradam a matéria orgânica, estabelecendo o equilíbrio dinâmico do ecossistema. Este trabalho apresentou como objetivo a caracterização do impacto ambiental e degradação microbiana do vinhoto no Baixo Rio Paraíba do Sul. As análises foram realizadas na água e no sedimento ao longo da zona de mistura fluvial no início (Campanhas I – 07/2006 e III – 07/2007) e final da safra (Campanha II – 10/2006). No laboratório, foram realizados bioensaios para se estimar o potencial de biodegradação do vinhoto. As estações se localizaram a montante e a jusante do lançamento do efluente em até cerca de 200 metros de distância, também sendo realizadas coletas na foz do rio como referência. Os sedimentos foram fracionados em finos (<63 μm) e grossos (>63 μm). Na água, valores elevados de temperatura e oxigênio dissolvido juntamente com baixos valores de pH foram bons indicadores da presença de vinhoto e a alta concentração de potássio foi essencial para a identificação de seu lançamento no efluente industrial. No sedimento, as diferenças encontradas entre as concentrações de fósforo orgânico e inorgânico, e as altas concentrações de carbono orgânico, razão C:N e potássio foram eficientes na caracterização do impacto do efluente e da agricultura. Concentrações semelhantes de fósforo orgânico e inorgânico, juntamente com razões C:N em torno de 12 demonstraram que a foz do rio é influenciada pela agricultura de cana, sugerindo que a matéria orgânica sedimentada é tanto de origem fitoplanctônica como de vegetais superiores. A fração fina correlacionou-se significativamente com a maior parte dos parâmetros e se mostrou útil na avaliação do impacto, pois o principal componente do vinhoto, o potássio, se concentrou preferencialmente nos grãos menores que 63 μm. As análises microbiológicas revelaram que a entrada dos efluentes influencia a comunidade bacteriana, aumentando a biomassa e o ganho energético (analisado através da ETSA) na água e no sedimento no início da safra. Entretanto, o acúmulo de carga orgânica no sedimento do final da safra, inibiu a respiração aeróbia e diminuiu a capacidade de auto-depuração ambiental. Os microrganismos isolados do sedimento foram capazes de crescer e utilizar o vinhoto como única fonte de energia nos bioensaios, demonstrando seu possível uso em processos de biorremediação. Observou-se que o número de células por cm3 deve ser no mínimo da ordem de 108 a 109 para uma eficiente remoção de biopolímeros (37%) e percebeu-se que o fosfato é consumido eficientemente (99%) somente quando em concentrações próximas a 3 mg L-1, observando-se uma baixa eficiência de consumo quando em concentrações próximas a 9 mg L-1.. A eficiência de degradação foi alta nos primeiros 6 dias do bioensaio, não sendo observado reduções eficientes nos demais dias de análise.
The pollution in rivers caused by sugar cane agriculture and industry is a result of runoff and point source discharge of sugar cane effluents, mainly vinasse with high organic content, oxygen biological demand and suspended solids. Geochemical tools can be used to characterize the organic matter from effluents, like determining origin and environmental trophic state. Microbiological analyses are also important, as microorganisms degraded organic matter and establish the ecosystem dynamic equilibrium. The aim of this work was to characterize the impact and microbial degradation of vinasse in the Low River Paraíba do Sul. Analyses were performed in water and sediment along the fluvial mixture zone in the beginning (Campaign I -07/2006 e III – 07/2007) and at the end of crop (Campaign III – 10/2006). In laboratory were performed bioassays to estimate the vinasse potential biodegradation. The samples were collected upstream and downstream ranging in 200 m from the effluent discharge source, as well as at the mouth of the river how reference. The sediment samples were fractionated in fine (<63 μm) and coarse (>63 μm). In water, high values of temperature and dissolved oxygen with low values of pH were indicators of vinasse discharge and high concentration of potassium was fundamental to identify the presence of vinasse in the effluent. In sediments, differences were found between organic and inorganic phosphorus concentration, and the high values of organic carbon, C:N ratio and potassium were efficient descriptors of effluent and sugar cane agriculture. Similar concentrations of organic and inorganic phosphorus, and the C:N ratios around 12 demonstrated that the mouth of river was influenced by agriculture, suggested that the sedimentary organic matter originates from phytoplankton and also vacular plants. The fine fraction was significant correlated with the most part of parameters and was useful in the impact evaluation, as the main component of vinasse, the element potassium, was concentrated in grains smaller than 63 μm. The microbiological analyses revealed that the effluent influence in the bacterial community enhancing biomass, energetic gain (analyzed by ETSA) in both water and sediment at beginning of crop. However the organic fraction accumulated in the sediment inhibited aerobic respiration and reduced the capacity of environmental auto-depuration at the end of harvest period. Microorganisms isolated from local sediment were capable to grow and to use vinasse as a single source of energy during bioassays, demonstrating possible uses in bioremediation. It was observed that the number of cells/cm-3 has be in the minimum of the order 108 a 109 to an efficient remove of biopolymers (37%) and realized the fosfate is consumed efficiently (99%) only when in concentrations near of 3 mg L-1 , observing low efficient of consume when concentrations are nearly of 9 mg L-1 . The efficiency of degradation was high in the first 6 days of bioassay, not being observed efficient reductions in the others days of analyses.
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Geißler, Katja. „Lebensstrategien seltener Stromtalpflanzen : autökologische Untersuchung von Cnidium dubium, Gratiola officinalis und Juncus atratus unter besonderer Berücksichtigung ihrer Stressresistenz“. Phd thesis, Universität Potsdam, 2008. http://opus.kobv.de/ubp/volltexte/2008/1746/.
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Die vorliegende Dissertation behandelt die Ökologie von Cnidium dubium (Schkuhr) Thell. (Sumpf-Brenndolde), Gratiola officinalis L. (Gottes-Gnadenkraut) und Juncus atratus Krocker (Schwarze Binse), drei gefährdeten Arten, die als sogenannte Stromtalpflanzen in Mitteleuropa in ihrem Vorkommen eng an die Flussauen gebunden sind.
Die Arbeit basiert auf verschiedenen Simulationsexperimenten und Feldstudien in der Unteren Havelniederung, einem „Feuchtgebiet von internationaler Bedeutung“. Sie behandelt Themenkomplexe wie das Samenbankverhalten, die Samenkeimung, die Stickstofflimitierung, die Konkurrenzkraft, das Verhalten der Pflanzen nach einer Sommertrockenheit und nach einer Winter/Frühjahrsüberflutung. Ferner widmet sie sich der Populationsbiologie der Arten und dem Verhalten der Pflanzen nach besonderen Störungsereignissen wie Mahd, Herbivorie und der Sommerflut 2002.
Der Leser erfährt, wie die Pflanzen in verschiedenen Lebensphasen auf die auentypische Umwelt reagieren und erhält umfassende Einblicke in physiologische Mechanismen, die der Anpassung an die typischen Bedingungen einer mitteleuropäischen Flussaue dienen.
Eine Interpretation der Ergebnisse zeigt auf, welche der spezifischen Eigenschaften zur Gefährdung der drei Stromtalarten beitragen.
Die Arbeit ist für den Arten-, Biotop- und Landschaftsschutz interessant. Darüber hinaus bietet sie zahlreiche Anknüpfungspunkte zur ökophysiologischen Grundlagenforschung. Die verstärkte Nutzung physiologischer Methoden bei der Klärung ökologischer Fragestellungen wird angeregt.The thesis deals with the ecology of three endangered European river corridor angiosperms Cnidium dubium (Schkuhr) Thell., Gratiola officinalis L. und Juncus atratus Krocker. The study is based on different experimental approaches and field surveys in a wetland along the Lower Havel River, a designated German Ramsar-site (Wetland of International Importance). This involves the examination of aspects of seed bank dynamics, germination, nitrogen limitation, competitive ability, and the response of plants to summer drought and/or winter/spring flooding. The thesis continues with a detailed study of the population biology of the species at natural sites and the response of these plants to specific disturbances like mowing, herbivory and the severe summer flooding in 2002. The reader learns about the traits of the three plant species to tolerate the typical conditions their natural sites are exposed to in different phases of their life cycle. He gets a comprehensive look at physiological means by which plants can adapt to the prevailing conditions of European river lowlands. The interpretation of the results is used to reveal specific plant traits, which may contribute to the endangerment of the three river corridor plants. As such, this thesis is interesting for protection of species, biotopes and landscapes. Furthermore, it provides numerous close connections to fundamental research from an ecophysiological perspective. The increased use of physiological methods is recommended in order to be able to adequately resolve ecological problems.
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Hasanyar, Masihullah. „Assimilation de données haute fréquence dans le modèle de qualité de l'eau ProSe-PA : Les facteurs du métabolisme fluvial dans des conditions de faible débit“. Electronic Thesis or Diss., Université Paris sciences et lettres, 2023. http://www.theses.fr/2023UPSLM047.
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Cette recherche vise à améliorer l’évaluation du métabolisme des rivières en assimilant les données de l’oxygène dissousdans le modèle de qualité de l’eau ProSe-PA, en utilisant des études de cas synthétiques et réelles de la Seine. L’étuderepose sur un travail antérieur en introduisant un nouveau schéma de répartition pour le carbone organique et en utilisantun cadre bayésien avec surveillance de l’oxygène dissous. La recherche montre que les incertitudes dans l’apport encarbone organique entraînent des écarts entre les niveaux d’oxygène dissous observés et simulés. L’étude révèle queles paramètres bactériens et de partitionnement du carbone organique sont les plus influents pour déterminer la qualitéde l’eau. La performance du modèle ProSe-PA est évaluée dans des cas réels et synthétiques de la Seine, montrant desaméliorations dans les simulations d’oxygène dissous et la quantification de la biodégradabilité du carbone organique pendant les périodes de faible débitTThe goal of this research is to improve the assessment of river metabolism by assimilating dissolved oxygen data in theProSe-PA water quality model, using synthetic and real case studies of the Seine river. The study builds on previouswork by introducing a new partitioning scheme for organic carbon and using a Bayesian framework with dissolved oxygenmonitoring. The research shows that uncertainties in organic carbon inflow cause discrepancies in observed andsimulated dissolved oxygen levels. The study finds that bacterial parameters and organic carbon partitioning parametersare the most influential in determining water quality. The ProSe-PA model’s performance is evaluated in both real andsynthetic cases of the Seine river, showing improvements in dissolved oxygen simulations and quantification of organiccarbon biodegradability during low flow periods
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Vilmin, Lauriane. „Modélisation du fonctionnement biogéochimique de la Seine de l'agglomération parisienne à l'estuaire à différentes échelles temporelles“. Thesis, Paris, ENMP, 2014. http://www.theses.fr/2014ENMP0055/document.
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Dans le contexte des nouvelles exigences en termes de qualité des eaux du surface, les modèles hydro-écologiques s'avèrent être des outils indispensables pour compléter notre compréhension du fonctionnement du milieu ou prévoir l'impact sur la qualité de l'eau de nouvelles mesures. L'objectif de cette recherche est de tirer parti de l'outil de modélisation ProSe, et de le faire évaluer afin de compléter la compréhension du fonctionnement biogéochimique de la Seine. Dans une première étape, différents processus biogéochimiques sont implémentés, calibrés et validés indépendamment, grâce à des jeux de données disponibles sur un linéaire de 220 km (de Paris jusqu'à l'estuaire), à différents pas de temps, pour la période 2007-2012. Ces améliorations sont réalisées grâce à l'utilisation directe de résultats expérimentaux, à l'extrapolation de résultats de couplage entre expériences de laboratoire et modélisation biogéochimique, ou encore grâce à l'analyse de mesures haute fréquence in-situ. Le modèle ProSe est ensuite utilisé pour établir un bilan du fonctionnement biogéochimique de la Seine dans cette zone fortement anthropisée. L'effet des processus pélagiques et benthiques sur les différents cycles biogéochimiques (carbone, azote, phosphore) est quantifié, pour différentes conditions hydrologiques, en amont et en aval de la plus grosse station d'épuration de l'agglomération parisienne, qui traite les effluents de plus de 5 millions équivalent habitants. La précision spatio-temporelle du modèle est ensuite utilisée pour évaluer l'effet de la fréquence d'échantillonnage sur l'estimation des critères de qualité de l'eau au sens de la Directive Cadre sur l'Eau. Les résultats soulignent l'importance d'une représentation précise des processus physiques (hydrodynamique et processus hydro-sédimentaires) dans les modèles de qualité de l'eau pour parvenir à une simulation fiable des flux biogéochimiques dans le milieu et des échanges entre compartiment benthique et colonne d'eau. Ce travail illustre enfin toute l'utilité des modèles hydro-écologiques pour venir en appui au suivi du milieu dans le cadre des objectifs actuels d'amélioration de la qualité des milieux aquatiquesHydro-ecological models are essential to complete our knowledge of the functioning of aquatic systems. They can moreover be used to forecast the impact of new management strategies on the future water quality. The aim of this thesis is to use the hydro-ecological ProSe model to improve our understanding of the biogeochemical functioning of the Seine River downstream the Paris urban area. Simulated biogeochemical processes are first implemented, calibrated, and validated independently for the 2007-2012 period. For each one of these processes, appropriate methodologies are used. These methodologies include the direct use of experimentally obtained parameters, the upscaling of results from coupled laboratory experiments and stand-alone biogeochemical modelling, or the analysis of high frequency in-situ measurements. Different datasets, which are available at various time steps, allow the validation of these processes along the whole 220 km simulated stretch (from Paris to the entrance of the Seine River estuary). Once validated, the ProSe model is then used to assess the biogeochemical functioning of the Seine River along this highly anthropized stretch. The impact of pelagic and benthic processes on the different biogeochemical cycles (carbon, nitrogen, and phosphorus) is quantified for different hydrological conditions, up- and downstream the major waste water treatment plant of the Paris urban area, which treats the effluents of over 5 million population equivalent. The model is then used to assess the effect of the monitoring frequency on the estimation of the water quality as defined by the European Water Framework Directive. The results highlight the importance of a detailed representation of physical processes in hydro-ecological models for a reliable simulation of in-river biogeochemical fluxes and of exchanges at the sediment-water interface. Having in mind the present targets of the improvement of the quality of water bodies, this work illustrates the importance of hydro-ecological modelling as an essential complement to water quality monitoring strategies
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Olde, Louise. „How do rates of carbon metabolism vary over a geological gradient, and how does this contribute to riverine greenhouse gas emissions?“ Thesis, Queen Mary, University of London, 2017. http://qmro.qmul.ac.uk/xmlui/handle/123456789/25933.
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Rivers and streams are increasingly recognised as important components in the global carbon cycle, and act as net sources of CO2 and CH4 to the atmosphere. However, the origins and controls over the fate of these greenhouse gases are still poorly constrained. This thesis firstly explores the production of CO2 and CH4 in the sediment of several rivers over a geological gradient (chalk, sand and clay), to investigate the magnitude and controls on production. It was found that, whilst there are some general patterns due to geology, variables such as organic carbon content are much better predictors of production of CO2 and CH4 and these can vary widely within a single reach. The response of production to temperature was found to be very constant across rivers and in both summer and winter, suggesting a uniform increase in production of both CO2 and CH4 with projected future climate change. However, production of CH4 was much more responsive to temperature change than was CO2, meaning a greater proportion of carbon is mineralized as CH4 under warmer conditions and indicating a positive feedback with global warming. In addition, the amount of CO2 and CH4 out-gassed from the rivers to the atmosphere was measured. It was found that the amount out-gassed could not be explained by local sediment respiration alone: CO2 out-gassing was consistently higher (and CH4 consistently lower) than that produced by the riverbed. Instead, CO2 out-gassing was under hydrological control, and was correlated with rainfall. The source of this was ingress from the surrounding catchment, with higher out-gassing during periods of high rainfall. This strong hydrological controls on CO2 emissions were however modulated by biological processes, as lower emissions were measured during the day than night; and the difference could be accounted for by local in-stream GPP.
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Vilmin, Lauriane. „Modélisation du fonctionnement biogéochimique de la Seine de l'agglomération parisienne à l'estuaire à différentes échelles temporelles“. Electronic Thesis or Diss., Paris, ENMP, 2014. http://www.theses.fr/2014ENMP0055.
Der volle Inhalt der QuelleAnnotation:
Dans le contexte des nouvelles exigences en termes de qualité des eaux du surface, les modèles hydro-écologiques s'avèrent être des outils indispensables pour compléter notre compréhension du fonctionnement du milieu ou prévoir l'impact sur la qualité de l'eau de nouvelles mesures. L'objectif de cette recherche est de tirer parti de l'outil de modélisation ProSe, et de le faire évaluer afin de compléter la compréhension du fonctionnement biogéochimique de la Seine. Dans une première étape, différents processus biogéochimiques sont implémentés, calibrés et validés indépendamment, grâce à des jeux de données disponibles sur un linéaire de 220 km (de Paris jusqu'à l'estuaire), à différents pas de temps, pour la période 2007-2012. Ces améliorations sont réalisées grâce à l'utilisation directe de résultats expérimentaux, à l'extrapolation de résultats de couplage entre expériences de laboratoire et modélisation biogéochimique, ou encore grâce à l'analyse de mesures haute fréquence in-situ. Le modèle ProSe est ensuite utilisé pour établir un bilan du fonctionnement biogéochimique de la Seine dans cette zone fortement anthropisée. L'effet des processus pélagiques et benthiques sur les différents cycles biogéochimiques (carbone, azote, phosphore) est quantifié, pour différentes conditions hydrologiques, en amont et en aval de la plus grosse station d'épuration de l'agglomération parisienne, qui traite les effluents de plus de 5 millions équivalent habitants. La précision spatio-temporelle du modèle est ensuite utilisée pour évaluer l'effet de la fréquence d'échantillonnage sur l'estimation des critères de qualité de l'eau au sens de la Directive Cadre sur l'Eau. Les résultats soulignent l'importance d'une représentation précise des processus physiques (hydrodynamique et processus hydro-sédimentaires) dans les modèles de qualité de l'eau pour parvenir à une simulation fiable des flux biogéochimiques dans le milieu et des échanges entre compartiment benthique et colonne d'eau. Ce travail illustre enfin toute l'utilité des modèles hydro-écologiques pour venir en appui au suivi du milieu dans le cadre des objectifs actuels d'amélioration de la qualité des milieux aquatiquesHydro-ecological models are essential to complete our knowledge of the functioning of aquatic systems. They can moreover be used to forecast the impact of new management strategies on the future water quality. The aim of this thesis is to use the hydro-ecological ProSe model to improve our understanding of the biogeochemical functioning of the Seine River downstream the Paris urban area. Simulated biogeochemical processes are first implemented, calibrated, and validated independently for the 2007-2012 period. For each one of these processes, appropriate methodologies are used. These methodologies include the direct use of experimentally obtained parameters, the upscaling of results from coupled laboratory experiments and stand-alone biogeochemical modelling, or the analysis of high frequency in-situ measurements. Different datasets, which are available at various time steps, allow the validation of these processes along the whole 220 km simulated stretch (from Paris to the entrance of the Seine River estuary). Once validated, the ProSe model is then used to assess the biogeochemical functioning of the Seine River along this highly anthropized stretch. The impact of pelagic and benthic processes on the different biogeochemical cycles (carbon, nitrogen, and phosphorus) is quantified for different hydrological conditions, up- and downstream the major waste water treatment plant of the Paris urban area, which treats the effluents of over 5 million population equivalent. The model is then used to assess the effect of the monitoring frequency on the estimation of the water quality as defined by the European Water Framework Directive. The results highlight the importance of a detailed representation of physical processes in hydro-ecological models for a reliable simulation of in-river biogeochemical fluxes and of exchanges at the sediment-water interface. Having in mind the present targets of the improvement of the quality of water bodies, this work illustrates the importance of hydro-ecological modelling as an essential complement to water quality monitoring strategies
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Vilalta, Baliellas Elisabet. „Structure and Function in Fluvials Biofilms. Implications in River DOC Dynamics and Nuisance Metabolite Production“. Doctoral thesis, Universitat de Barcelona, 2004. http://hdl.handle.net/10803/1430.
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The role of natural biofilms affecting the water quality in rivers has been the main theme in this study. Firstly, the study developed the capacity of biofilms in retention and/or production of DOC. Secondly, the study also approached the production of the geosmin metabolite by benthic cyanobacterial mats. In the two developed aspects, the structure and function of the biofilms showed their relevance in evaluating the capacity of biofilms on the amelioration of the water quality. The importance of the biofilms on ecological research in running waters has been focus in their capacity of adsorption and transformation of nutrient, and therefore, in the self-purification capacity of streams and rivers. Biofilms are also major sites of carbon cycling in streams and rivers, affecting the water DOC dynamics. Eutrophication of streams and rivers have been also linked with an increase of algal biomass. As a consequence, the massive growth of cyanobacterial mats can cause the production of toxic and nuisance metabolites, like geosmin, a secondary metabolite which causes earthy and musty taste and odor in the water.The first conclusion of this study was that biofilms may play an important role in the retention of water DOC. We elucidated whether biofilms act as sinks or sources of fluvial DOC, depending on their structure and biomass accumulation. Metabolism (extracellular enzymatic activity) and structure (algae, bacteria, C/N content) of light-growth and dark-growth systems were analyzed over a year. Biofilms from the light-growth regime presented monthly variation in DOC uptake/release rates, but the annual average presented higher DOC uptake than dark-growth biofilms. However, the latter had a constant DOC consumption along the year, permitting a maintenance of low water DOC levels. The biofilm structure and the relative contribution of autotrophs and heterotrophs had a relevant implication in the carbon recycling, since metabolic activities were affected by variations in this structure.
Geosmin production was related with the massive growth of benthic cyanobacteria (formed mainly by Oscillatoria limosa) in littoral zones, where water velocity was low, warmer temperatures and high nutrient concentration and low N/P ratio. The masses were further detached and drift downstream, being the responsible for the dispersion of geosmin along the river. The high biomass accumulation per surface unit, may cause a nutrient depletion inside the mat, e.g. nitrogen limitation. Structural and functional differences were found in the different fractions of the cyanobacterial mat (attached vs. free-floating). Free-floating mats presented higher biomass and exoenzymatic activities. Otherwise, the low phosphatase/aminopeptidase ratio found in both compartments indicated a nitrogen limitation inside the mats. Microstructural analyses with oxygen and redox microsensors have been useful to understand the function of the different cyanobacterial patches inside the mat. During the dark, Oscillatoria micro-patches aggregated and accumulated in thick masses where some anoxia conditions were found, giving a very low redox potential. This low diffusion could be associated with resource depletion, limiting the nutrient availability and defining the appropriate conditions for the geosmin production.
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Colls, Lozano Miriam. „Biofilm responses to flow intermittency in Mediterranean rivers“. Doctoral thesis, Universitat de Girona, 2020. http://hdl.handle.net/10803/670845.
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Currently, global change is promoting the spatiotemporal occurrence of temporary streams, altering fluvial ecosystem function and structure, and the ecosystem services they provide. To effectively protect fluvial ecosystems, a detailed understanding of the effects of hydrological regime changes on their biodiversity and functioning is needed. Organisms inhabiting temporary streams are directly affected by their hydrological regime, including the stream biofilm. Biofilms are associations of microorganisms and they are of particular relevance in temporary streams because of their diversity, abundance, and key role in ecosystem processes. Therefore, understanding biofilm response to hydrological regime variability is key to understand the implications of increasing non-flow periods on fluvial ecosystems. The results of this thesis demonstrate the non-flow duration as a key influence on the structure and functioning of river biofilms, the importance of maintaining photoautotrophic stream biodiversity to preserve stream ecosystems functioning and the protective role of canopy cover to protect these communitiesEl canvi global està promovent l’aparició de rius intermitents, alterant funcionament, estructura i serveis ecosistèmics dels sistemes fluvials. Per a protegir efectivament els ecosistemes fluvials, es necessita un coneixement detallat dels efectes del canvi de règim hidrològic sobre la seva biodiversitat i funcionament. Els organismes que habiten els rius temporals estan directament afectats pels canvis hidrològics, inclòs el biofilm. Els biofilms són associacions de microorganismes i particularment rellevants als rius temporals per la seva diversitat, abundància i paper en processos ecosistèmics. Així, entendre la resposta del biofilm a la variabilitat del règim hidrològic és clau per entendre les implicacions del increment del període sec als ecosistemes fluvials. Els resultats d'aquesta tesi demostren la duració del període sec com a vector d'estructura i funcionament del biofilm, la importància de mantenir la biodiversitat fotoautòtrofa per preservar el funcionament ecosistèmic i el paper protector de la coberta vegetal sobre aquestes comunitats
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AMALFITANO, STEFANO. „Structure and function of benthic microbial community in highly variable freshwater systems“. Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2008. http://hdl.handle.net/2108/576.
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In the semi-arid Mediterranean regions, extended reaches of rivers and streams show a recurrent dry phases of varying duration and spatial extent. It is important to study the effects of water stress on riverine ecological processes since freshwater systems are crucial in linking terrestrial and marine environments, My Doctorate thesis research, supported by the European TempQsim project (EVK1-CT2002-00112), was aimed to investigate the dynamics of microbial communities associated to sediments in temporary rivers. In particular, I have been investigating the effects of water stress on the structure and function of benthic bacterial communities and their role in the carbon cycle of rivers characterized by a seasonal hydrologic regime. Bacterial abundance and phylogenetic composition were assessed by molecular techniques, while bacterial activity was estimated by measuring the incorporation rates of radioactive tracers and by immunofluorescence. From a methodological point of view, all applied techniques required a specific optimization phase in order to increase their analytical efficiency. In particular, a detachment procedure to extract and purify bacterial cells from freshwater sediments was optimized by the combined use of different chemical and physical treatments, followed by high-speed density gradient centrifugation using the medium Nycodenz. This procedure was initially applied to analyze the benthic bacterial communities in rivers with stable water flow conditions (Rivers Albegna, Ente, Fiora – Tuscany, Italy; River Cremera – Lazio, Italy). In addition, the efficiency of specific in situ hybridization techniques (Fluorescence In Situ Hybridization with fluorescently monolabeled probes – FISH; Fluorescence In Situ Hybridization with signal amplification by Catalyzed Reporter Deposition – CARD-FISH) was tested with regards to the different physicochemical characteristics of selected sediments (i.e. sediment organic matter and moisture content). In this respect, CARD-FISH protocol was improved to better estimate the occurrence of specific phylogenetic clusters in dry sediments. For the field study, sediments were regularly collected at the river outlet section of the River Mulargia (Sardinia, Italy). A seasonal in-depth study was performed for benthic bacterial composition and activity analyses. Additional tests were performed in artificial microcosms to experimentally describe benthic bacterial responses to drying and rewetting processes, by simulating desiccation and re-inundation of sediments collected from four European temporary rivers (River Mulargia and Tagliamento - Italy; River Krathis - Greece; River Pardiela - Portugal). In a further laboratory experiment, the composition and activity of the bacterial community that primary colonized the water phase was followed in microcosms set up with Mulargia sediments. This study could contribute to better understand the ecological role of those benthic microbes that reside in a state of low-activity in dry sediments and promptly colonize the new incoming water at the end of the dry period. In synthesis, my Doctorate research contributed to a better understanding of the functional role of bacterial community in river sediments. The results could help to elucidate the mechanisms involved in the sediment transformation processes during drought periods, which are attended to increase in length and frequency as a possible effect of climatic changes.
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Moffett, Carol D. „The Impact of Childhood Measures of Glycemia and Insulin Resistance Factors on Follow-Up Glycemic Measures“. Diss., The University of Arizona, 2007. http://hdl.handle.net/10150/194096.
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The purpose of this research was to evaluate the impact of glycemic measures, and changes in identified risk factors (BMI, waist circumference, lipids, blood pressure) on follow-up glycemia, in Pima children at high risk for type two diabetes (type 2 DM).I computed incidence and cumulative incidence of type 2 DM in Pima children 5-19 years of age between 1983 and 2004. Cox proportional hazards rates for development of type 2 DM were calculated by glycemic measure (HbA1C, 20PG, FPG) controlling for confounding factors (age, sex, BMI, blood pressure, and cholesterol). Diabetes was defined by the presence of at least one of four criteria: 1) 20PG of >200 mg/dl, 2) FPG of >126 mg/dl, 3) HbA1C > 8.0%, or 4) hypoglycemic treatment. Linear regression models were computed to identify the impact of changes in risk factors on changes in HbA1C. Only exams performed in non-diabetic children during childhood were included in the regression models.Among 2658 non-diabetic children, 258 cases of diabetes occurred during mean 9.1 years of follow-up (1.5 - 21.7). The age-sex adjusted incident rate of diabetes was 19.0 cases per 1000 person-years, and cumulative incidence was 54% by age 40. Incidence rates increased with increasing baseline values of 20PG, and FPG, but not for HbA1C. For HbA1C the relationship was u-shaped with the lowest and highest quartiles having the highest DM rates. After adjustment for confounding risk factors using Cox proportional hazards analysis, the risk for diabetes increased 2-fold for every 10 mg/dl increase in FPG. Changes in waist circumference best predicted changes in HbA1C (R2 = 0.48, Ï <0.001). However, the ability of waist circumference to predict change is limited due to the powerful effect of regression to the mean, suggesting that these risk factors contribute very little to changes in HbA1C, at least in childhood.Childhood levels of glycemia predict development of type 2 DM later in life. While changes in waist circumference are associated with only moderate changes in HbA1C, this does not refute the significant contribution of adiposity in childhood to the development of type 2 DM.
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Borges, Patrícia de Sena Piacsek. „Índices e modelos biogeoquímicos para definição do estado trófico, suscetibilidade à eutrofização e metabolismo do estuário do rio Paraíba do Sul, RJ“. Niterói, 2016. https://app.uff.br/riuff/handle/1/1585.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Universidade Federal Fluminense. Instituto de Química. Programa de Pós-Graduação em Geociências-Geoquímica. Niterói, RJ
Ao longo das últimas seis décadas foram intensificadas as pressões antrópicas nas regiões costeiras de todo o globo. Alterações no uso do solo, aporte fluvial de efluentes domésticos, industriais e fertilizantes da agricultura são as principais fontes de nutrientes antropogênicas. Os ambientes costeiros são reconhecidamente áreas de interface terra-mar, onde o aporte terrígeno pode alterar significativamente os ecossistemas destas regiões. Este estudo avaliou comparativamente dois índices de estado trófico e dois modelos de eutrofização para a região do delta estuarino do Paraíba do Sul, localizado no norte fluminense, RJ. As premissas dos índices tróficos são baseadas nas concentrações de elementos biogênicos (nitrogênio e fósforo) e a biomassa autotrófica presentes no ambiente. Os indices foram estabelecidos pelos trabalhos de VOLLENWEIDER (1968), RAST & HOLLAND (1978) e O’Boyle (2013), são eles: índice “O’Boyle” e TRIX. Os modelos de eutrofização utilizados foram ASSETS (Assessment of Estuarine Trophic Status; BRICKER et al., 2003; FERREIRA et al., 2007) e LOICZ (Land and Ocean Interactions in the Coastal Zone; GORDON et al., 1996). O Modelo ASSETS avalia os indicadores de pressão, o estado, a resposta e a suscetibilidade do ambiente à eutrofização. O modelo LOICZ estabelece o balanço de massa de elementos conservativos (água e sal) e não-conservativos (elementos biogênicos) e identifica a natureza do metabolismo do sistema, seja do tipo autotrófico ou heterotrófico e se age como uma fonte ou um sumidouro de matéria. Foram utilizados dados pretéritos fornecidos por STERZA (2004), estes foram obtidos entre 2002 e 2003 durante 12 campanhas de coleta ao longo de um transecto constituinte por 9 pontos de amostragem, com 2 profundidades distintas, abrangendo a fonte fluvial, o gradiente estuarino, a pluma costeira e a fonte marinha. O comportamento do sistema foi analisado para três condições: período seco, úmido e anual. O sistema apresentou estratificação parcial em todos os cenários analisados. Os resultados apontaram dinâmica sazonal, com exceção do resultado do ASSETS que não apresentou sensibilidade suficiente para tal. Os dois índices do estado trófico indicaram o sistema estuarino interno como moderado (mesotrófico a eutrófico) durante o período chuvoso. Esta condição é decorrente do aporte continental acrescido do escoamento superficial (runoff), mais intensos para o período. Os índices para sistema estuarino externo indicaram mesotrofia. Notou-se a inversão destes cenários, para os setores interno e externo, durante o período seco. O sistema como um todo, para o ciclo anual, mostrou-se potencialmente eutrofizado. O modelo ASSETS indicou que o sistema apresenta moderada suscetibilidade à eutrofização. Quanto ao balanço de massa, o estuário interno apresentou fluxos característicos de produção de elementos biogênicos (NID e PID), correspondendo a uma fonte. O sistema estuarino externo atua de forma muito parecida, com exceção do NID que não se encontra tão disponível para regiões adjacentes durante o período seco. Todas as metodologias foram validas para o sistema. Os índices obtiveram respostas semelhantes, o modelo ASSETS apresentou menor sensibilidade ao comportamento do sistema e o modelo LOICZ descreveu de forma minuciosa o balanço dos elementos biogênicos e indicou a tendência geral do sistema para o metabolismo heterotrófico
the main sources of anthropogenic nutrients’ to the coastal zone. This study compared two indices of trophic state and two models that assesses the susceptibility of eutrophication and the whole system metabolism for the estuarine region of the Paraíba do Sul river, located in northern Rio de Janeiro state, RJ. The trophic indices are based on the concentrations of biogenic elements (nitrogen and phosphorus), autotrophic biomass (The TRIX Index; VOLLENWEIDER,1968 & 2008; RAST & HOLLAND,1978) and also pH and dissolved oxygen (O'Boyle, 2013). The models were ASSETS (Assessment of Estuarine Trophic Status; BRICKER et al, 2003; Ferreira et al, 2007) and LOICZ (Land and Ocean Interactions in the Coastal Zone; GORDON et al, 1996). The ASSETS model assessed indicators of pressure, state, response and the susceptibility eutrophication of the environment. The LOICZ model establishes the conservative (water and salt) and non-conservative (biogenic elements) mass balance and identifies the state for the metabolism of the system, being either autotrophic or heterotrophic or in equilibrium. The findings also indicated if the system acts as a source or a sink of biogenic matter. The data used in this work was provided by Sterza (2004), which were obtained between 2002 and 2003 during 12 collection’ campaigns along a transect constituted 9 sampling points, with 2 different depths. Along this transect the river source, the estuarine gradient, the coastal plume and the marine source were included. The system behavior was analyzed for the average annual and seazonal conditions (dry and rainy). At all conditions, the system fell into the category of a partially mixed estuary. The two indices of the trophic state indicated the internal estuarine system as being moderate nourished (mesotrophic to eutrophic) during the rainy season. This condition was due to the increase contribution of continental runoff (runoff), naturally intensified in this period. The indexes for the external estuarine compartment (i.e. the river plume) was mesotrophic.. For the annual cycle the system was classified as potentially eutrophic. The ASSETS model indicated that the system shows moderate susceptibility to eutrophication. The mass balance showed that the internal estuary trends to work as a source for nutrients. The only exception was for DIN, during the dry period, behaving as a sink. All methods presented congruent results. Both Trophic State indeces had similar responses, the ASSETS model indicated moderate susceptibility to eutrophication due to the in general strong water flow and dilution potential of the estuarine waters, and the LOICZ model described in details the mass balance and indicated a very slight trend to heterotrophic metabolism
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Huang, Zheng-Hao, und 黃政豪. „Biological community metabolism of spring pits in Jingmei River“. Thesis, 2012. http://ndltd.ncl.edu.tw/handle/42939928051541777735.
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碩士國立中興大學
生命科學系所
100
There are number of springs pits found in Jingmei river and the dissolved oxygen in them is relatively higher than in river water column. This study hypothesized that the high dissolved oxygen detected in spring pits is caused by algal photosynthesis. The maximum saturated gross primary productivity (PBm) of phytoplankton were observed outside of the spring pits in different seasons, and were higher than in the spring pits. The respiration rate observed outside of the spring pits in different season were higher than the spring pits, too. PBm and respiration rate of periphyton inside the spring pits in winter were higher than in the river. Biomass of phytoplankton in the spring pits is higher than outside river. But Biomass of periphyton in winter is outside river higher than spring pits indicating that the high dissolved oxygen in spring pits was not caused by algal photosynthesis. The pH value inside and outside the pits showed no significant difference, indicates that there is no effect of transformation of carbon dioxide to oxygen through algal photosynthesis on the observed dissolved oxygen. In addition, no significant difference was observed in temperature between inside and outside the spring pits, indicated that temperature was not the main reason affecting the dissolved oxygen in spring pits. Besides, diatom species outside the spring pits tends to tolerant heavy pollution species, and diatom diversity in spring pits is higher than outside river. Therefore, relative higher dissolved oxygen in spring pits is not caused by algal photosynthesis.
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Kuntz, Tim. „System and plankton metabolism in the lower Grand River, Ontario“. Thesis, 2008. http://hdl.handle.net/10012/4163.
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Currently our understanding of both system and phytoplankton metabolism in large rivers is somewhat limited. Knowledge of the metabolic balance in such systems is necessary not only for proper management of the river itself, but also for the lakes into which they discharge. The River Continuum Concept proposes that the deep, turbid waters of large rivers have a poor light climate which leads to heterotrophic conditions (respiration > photosynthesis) yet this idea has been challenged. Similarly, it has been predicted that phytoplankton growth in large rivers is limited to areas of unusually favourable light climate and water retention (e.g. margins, backwaters), but the evidence is limited. Through longitudinal and diel measurements of Chl a, nutrient concentrations, dissolved oxygen and stable oxygen isotopes it was shown in this study that the lower Grand River was autotrophic during the two successive summers but either balanced or heterotrophic in other seasons. This implies that large rivers such as the Grand can be a transition zone for nutrients and a phytoplankton source, depending on season.
Experimental incubations to measure oxygen production under varying irradiance demonstrated that phytoplankton could indeed grow (i.e., achieve positive net production) in the main river channel. Comparison of system and plankton metabolic rates further indicated that the phytoplankton were responsible for the major portion of the system production, but much less of the respiration. Sediment oxygen demand probably accounted for much of the additional respiration, but interactions with marginal and upstream habitats was probably an additional influence on both consumption and production of oxygen.
The results further showed that stable oxygen isotope dynamics did not conform to the steady state model commonly used to infer metabolic patterns from environmental isotope data. A non-steady model was more successful and largely supported independent assessments of metabolism.
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Barrett, Melissa S. „Carbon acquisition in variable environments: aquatic plants of the River Murray, Australia“. 2008. http://hdl.handle.net/2440/47987.
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This thesis considers the implications of changes in the supply of resources for photosynthesis, with regard for modes of carbon acquisition employed by aquatic plants of the River Murray. Carbon supplies are inherently more variable for aquatic plants than for those in terrestrial environments, and variations are intensified for plants in semi-arid regions, where water may be limiting. In changeable environments the most successful species are likely to be those with flexible carbon-uptake mechanisms, able to accommodate variations in the supply of resources. Studies were made of plants associated with wetland habitats of the Murray, including Crassula helmsii, Potamogeton tricarinatus, P. crispus and Vallisneria americana. The aim was to elucidate the mechanisms of carbon uptake and assimilation employed, and to determine how flexibility in carbon uptake and/or assimilation physiology affect survival and distribution. Stable carbon isotopes were used to explore the dynamics of carbon uptake and assimilation, and fluorescence was used to identify pathways and photosynthetic capacity. The studies suggest that physiological flexibility is adaptive survival in changeable environments, but probably does not enhance the spread or dominance of these species. V. americana is a known bicarbonate-user, and it is shown here that it uses the Crassulacean Acid Metabolism (CAM) photosynthetic pathway under specific conditions (high light intensity near the leaf tips) concurrently with HCO[subscript]3 - uptake, while leaves deeper in the water continue to use the C[subscript]3 pathway, with CO₂ as the main carbon source. However, V. americana does not use CAM when under stress, such as exposure to high light and temperature. The diversity of carbon uptake and assimilation mechanisms in this species may explain its competitive ability in habitats associated with the Murray. In this way it is able to maximise use of light throughout the water column. In shallow, warm water, where leaves are parallel to the surface, CAM ability is likely to be induced along the length of the leaf, allowing maximal use of carbon and light. The amphibious C. helmsii is shown to use CAM on submergence, even where water levels fluctuate within 24 hours. This allows continued photosynthesis in habitats where level fluctuations prevent access to atmospheric CO₂. It appears that stable conditions are most favourable for growth and dispersal, and that the spread of C. helmsii is mainly by the aerial form. Carbon uptake by P. tricarinatus under field conditions is compared with that of P. crispus to demonstrate differences in productivity associated with aqueous bicarbonate and atmospheric CO₂ use. P. tricarinatus uses HCO[subscript]3 - uptake to promote growth toward the surface, so that CO₂ can be accessed by floating leaves. Atmospheric contact provides access to light and removes the limitation of aqueous diffusive resistance to CO₂, thereby increasing photosynthetic capacity above that provided by submerged leaves.http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1320380
Thesis (Ph.D) -- University of Adelaide, School of Earth and Environmental Sciences, 2008
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Hsieh, LiYung, und 謝莉顒. „Spatial variability of pelagic and benthic community metabolism in the estuary of Tanshui River“. Thesis, 2003. http://ndltd.ncl.edu.tw/handle/25395261849786035694.
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碩士國立中興大學
生命科學系
91
Pelagic and benthic community metabolism were measured in situ in the estuary of Tanshui River. The samples were collected from 4 sites every 3 months on 13 January, 14 April and 12 August at spring tides. The changes in dissolved oxygen concentration were measured in cores with water or with undisturbed sediment to determinate the rates of pelagic and benthic community metabolism. Secondly, this study was conducted to determine whether microalgal biomass, invertebrate abundance, and environmental variables in the water column and sediments affect these metabolic rates. The results showed that variations in oxygen concentration in Tanshui River were affected by the tides. At spring tides, the pelagic community metabolism at 4 sites showed no significant difference. Stepwise multiple regression analyses indicated that 34% of pelagic PB correlated negatively with the NH4+ from the urban sewage. Of 89% of benthic PB was influenced by the DSi and the molar N:Si ratio <1 indicated the Si-limitation. The benthic PB at Waziwei and Guandu was hardly detected. Benthic respiration was influenced by the median size of sediment at 3 sites in Tanshui River. However, that at Chenmei Bridge was influenced by the concnetration of NH4+. Daily primary production were 93~306 mmol O2 m-3 d-1 for phytoplankton, and 0~72 mmol O2 m-2 d-1 for microalgal. Daily respiration were 35~130 mmol O2 m—3 d—1 for pelagic community, and 6~78 mmol O2 m-2 d-1 for benthic community. The 64~100% of daily primary production was produced by phytoplankton. The 54~98% of daily respiration was consumed by pelagic community. Total community metabolism in the estuary was thus dominated by the pelagic system. The P/R ratio showed that in the estuary of Tanshui River , autotrophy dominated in the pelagic system and heterotrophy in the benthic system.
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Chen, Gao. „Ecosystem oxygen metabolism in an impacted temperate river network: Application of the δ18O-DO approach“. Thesis, 2013. http://hdl.handle.net/10012/7412.
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Ecosystem metabolism is an important indicator of aquatic ecosystem function. This thesis concerns ecosystem metabolism as recorded by daily variation in dissolved oxygen (DO) and δ18O-DO in an impacted temperate river network, the Grand River, Ontario, Canada, and specifically addresses the effects of stream size and human disturbance including agriculture, deforestation, and wastewater treatment plants (WWTPs). A suite of 14 sites in the Grand River network was selected with stream sizes varying from 2nd to 7th order.
A transient model of river ecosystem oxygen metabolism, ROM-TM, was developed in order to calculate river ecosystem metabolic rates and reaeration rates from field observation of changes in DO and δ18O-DO. ROM-TM is an inverse modeling approach programmed using MATLAB. Key parameters describing the main metabolic processes, gas exchange, and isotopic fractionation, such as maximum photosynthetic rate (Pm), photosynthetic efficiency (a), respiration rate at 20℃ (R20), gas exchange coefficient (k), respiration isotopic fractionation factor (aR), and photorespiration coefficient (βR), can be obtained by matching of model predictions with field data. Besides being capable of teasing apart metabolic processes and gas exchange to provide daily average estimates of metabolic parameters at the ecosystem level, ROM-TM can be used to address issues related to light including light saturation phenomena at the ecosystem level, the effect of cloud cover on metabolic balance and photorespiration.
Primary production responses to light along a longitudinal gradient in the Grand River network were described by means of P-I curves. Both light-limited and light-saturated conditions were observed. Production parameters Pm and Ik in the Grand River network exhibited an increase with stream order, while a was independent of stream size. However, a did vary among and within sites.
Higher light availability in small and middle-sized streams without riparian trees was associated with high Pm, Ik and Ec, but low a. Ecosystem-level Pm in both small periphyton-dominated streams and large macrophyte-dominated rivers in the Grand River basin were generally less than community-level Pm values from the literature. However, two Grand River sites had comparable Pm to literature-derived Pm due to the prolific growth of macrophytes supported by high nutrient effluents from upstream WWTPs. Ecosystem-level a in my study streams were also less than those at the community level, indicating there was a declining trend of this parameter with scale, from individual, community to ecosystem. Derived parameters (e.g., Ik, Ec, and saturation point) increased from the individual level to the community level, and then to the ecosystem level.
From May to early October, metabolic rates in the Grand River network (gross primary production, GPP = 0.4 to 20 and ecosystem respiration, ER = 2 to 33 g O2 m-2 day-1) were within the broad range of metabolic rates occurring in the temperate region, regardless of stream size. The Grand River network is a net heterotrophic system. The total GPP and ER for whole basin was 3.3e+08 and 4.2e+08 g O2 day-1, respectively.
Reach geomorphology controls the spatial patterns of stream metabolism in the Grand River network, although the spatial patterns may be modified by effects of human disturbance on riparian vegetation, nutrients and other factors. Stream order and channel width, as measures of stream size, are good predictors of metabolic rates and ratios of GPP: ER from small streams to the central Grand River. Ecosystem metabolic rates and ratios generally increase with stream size, but with site-specific variation.
The Grand River network is experiencing effects of human disturbance, mostly downstream of the urban areas and least in small streams with remaining riparian forest. The small and middle-sized streams (2nd to 4th order) without riparian trees in agriculture regions in the Grand River basin did not exhibit significantly different GPP and ER than their counterparts with riparian trees. The stimulative effect of increased light availability due to open canopy on GPP in non-shaded streams may be offset by shading from stream banks and riparian grasses, and unstable sediments resulting from agricultural activities. Large river sites impacted by WWTPs had significantly increased metabolic rates, both GPP and ER, compared to two upstream sites impacted by agriculture only. This result suggests that urban areas cause impacts on the Grand River that are superimposed on the impacts of agriculture.
Three aspects of metabolism of the Grand River differ from the general pattern for the temperate regions: (1) a increase trend of GPP: ER ratios with stream size from 2nd to 7th order; (2) overall, human activities in the Grand River watershed have stronger positive effects on the GPP than on the ER; (3) the middle-sized to large river sites (5th-7th order) had greater influence than small to middle-sized streams (2nd-5th order) in the Grand River on overall GPP and ER.
The general trend of GPP: ER ratio in tropical, subtropical, temperate, and global data approximately conforms to the predictions of the River Continuum Concept (RCC). However, the maximum ratio of GPP: ER in mid-reaches of river networks is not usually >1 as proposed in the RCC. There is a latitude and stream size shift phenomenon regarding where the peak ratio of GPP: ER occurs in each climate zone. The maximum GPP: ER ratio is higher at higher latitudes and occurs at higher order streams.
The study of stream ecosystem metabolism can benefit from the addition of the second oxygen budget, δ18O-DO, in four ways: (1) it is better to use both DO and δ18O-DO budgets, rather than DO only, in sampling protocols with low temporal frequency but high spatial frequency; (2) the δ18O-DO time series data can provide relatively independent constraints on parameter estimation; (3) the addition of δ18O-DO in using two oxygen budgets to quantify metabolic rates provides a way, the cross-plot of δ18O-DO against fraction of DO saturation, to indicate trophic status of an aquatic ecosystem; and (4) the addition of δ18O-DO can provide an estimate of aR at the ecosystem level that can be used to understand factors affecting respiration.
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Chen, Wei-Chung, und 陳渭中. „Effects of flood discharge and sediment release from the Shihmen Reservoir on the ecosystem metabolism of the Danshui River“. Thesis, 2016. http://ndltd.ncl.edu.tw/handle/q8p992.
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碩士國立中興大學
生命科學系所
104
As the number and severity of extreme rainfall events are predicted to increase due to climate change, increasing sediment from upstream may flow into reservoirs during the flood season followed by severe deposition which may decrease the lifespan of reservoirs. If siltation is not controlled, reservoirs would be simply filled. After desilting, sediment flows from reservoirs to downstream may change the downstream morphology and influence its ecological function. To examine the impacts of typhoon and desilting events of Shihmen Reservoir on ecosystem metabolism along the Danshui River, five flood and three non-flood events were sampled between April 2014 and October 2015, in which two of flood events have experienced reservoir desilting disturbance (August and October 2015). Six sites (WZ, GD, TP, HC, HH, CL) were chosen along the Danshui River. Pelagic and benthic metabolisms in terms of oxygen production and consumption were quantified through incubation of surface water and soil in both light and dark cores. The results showed that an increase in water temperature, nutrient inputs, and microalgal biomass, during the flood season without desilting operation, increased both pelagic and benthic production. Conversely, low microalgal biomass and high turbidity, during the flood season with desilting operation, reduced primary production. Our study suggests that the relationship between primary production and river discharge reflects a balance between nutrient and organic matter inputs and advective losses of microalgae associated with high-flow conditions. In summary, system metabolism was autotrophic during moderate rainfall events without reservoir desilting operation ,but was heterotrophic during extreme rainfall evernts with reservoir desilting operation. According to our results and other relevant literature, we recommend reservoir desilting operation should be conducted when extreme rainfall events occur to minimize the ecological impacts of sediment releasing.
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Hunter, Charles H. „Development of a laboratory river model to determine the environmental impacts of key xenobiotic compounds“. Thesis, 1996. http://hdl.handle.net/10413/9141.
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Microorganisms are increasingly used in toxicological studies to determine potential
environmental impacts of xenobiotic compounds. A multi-stage laboratory model was developed
to facilitate the examination of environmental impacts of selected pollutants on fundamental
cycling processes inherent to aquatic ecosystems, namely, the degradation of organic substances
and nitrogen transformations under aerobic conditions. A microbial association representative of
riverine ecosystems was enriched for, isolated and cultured within the model. Characterisation
of the microbial association were undertaken. Scanning electron microscopy and bright field
microscopy revealed that a diverse heterogenous community of microorganisms had established
within the model. Successional metabolic events, namely organic carbon catabolism,
ammonification of organic nitrogen and the process of nitrification were differentiated in time
and space with the microbial association integrity still being retained. The establishment of a
microbial association within the model was primarily dependent on: dilution rates, specific
growth rates and interactions between microorganisms and the prevailing environmental
conditions. Growth-rate independent populations of microorganisms established within the model
and were thought to contribute significantly to the metabolic processes within the model.
Nitrifying activity was identified as a rate-limiting process within the model.
Following separation of metabolic events, the ecotoxicological impacts of phenol and 2,4-dichlorophenol on the association were assessed. The biological oxidation of ammonia through to nitrate (nitrification) was found to be a sensitive indicator of perturbation. The model was
found to be suitable for testing both acute and chronic intoxication by pollutant compounds as
well as for biodegradation testing and the possible evaluation of ecotoxicological impacts of
wastewater treatment plants. The main disadvantages of the model arose from its operational
complexity, its empirical nature and its impracticality for screening large numbers of compounds.
A bioassay based on the inhibition of ammonium oxidation was developed in order to fulfil the
requirements for a simple and rapid test protocol for the initial screening of perturbant
compounds.Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1996.
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Mini, Anne E. „The role of body size in the foraging strategies and management of avian herbivores : a comparison of dusky Canada geese (Branta canadensis occidentalis) and cackling geese (B. hutchinsii minima) wintering in the Willamette Valley of Oregon“. Thesis, 2012. http://hdl.handle.net/1957/35459.
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Body size explains much of the interspecific variation in the physiology, behavior, and morphology of birds, such as metabolic rate, diet selection, intake rate, gut size, and bill size. Based on mass-specific metabolic requirements and relative energetic costs of activities, being a certain body size has both advantages and disadvantages. In particular, avian herbivores such as geese possess a relatively simple digestive system, consume foods with low digestibility and poor nutrient content, and have increased energetic demands compared to other bird taxa; therefore, any effects of body size on foraging strategies should be readily apparent in this foraging guild. The influence of body size on the behavior and management of Canada Geese (Branta canadensis) and Cackling Geese (B. hutchinsii) as avian herbivores has not been well studied.
My dissertation explores the role of body size in comparative foraging behavior, habitat selection, and winter conservation planning for two congeneric geese, the Dusky Canada Goose (B. c. occidentalis; hereafter Duskys) and the Cackling Goose (B. h. minima; hereafter Cacklers). These two taxa share the same over-winter foraging environment (grass seed fields) in the same restricted geographic area (the Willamette Valley) during winter. Duskys and Cacklers differ by more than a factor of two in body size and have different relative bill sizes and social organization. Because of smaller body size, Cacklers have greater relative energy demands and less fasting endurance compared to Duskys; however, Cacklers have comparatively low energetic costs for flight and transport. Duskys, however, have higher total energy requirements than Cacklers. Additionally, Cacklers form large, high-density flocks and have a total over-wintering population size in the study area of about 200,000. Duskys occur in relatively small family groups and have a total over-wintering population size of about 13,000.
My study demonstrated that interspecific differences in body size between Cacklers and Duskys was associated with differences in foraging behavior, movements, and habitat selection. Cacklers foraged a greater percentage of time (30%) in all habitats and across the entire winter compared to Duskys. Cacklers had higher peck rates (up to 100 pecks min⁻¹ greater) than Duskys in all foraging habitats expect pasture. The pecking rate of Cacklers was greatest in fields of young grass (200 pecks min⁻¹), which may indicate that Cacklers had relatively high intake rates in this foraging habitat. Based on differences in foraging behavior among habitats, Cacklers may have the foraging strategy of energy intake maximizers, whereas the foraging strategy of Duskys is more towards time-energy expenditure minimizers, at least for part of the winter. Cacklers moved across the landscape very differently from
Duskys, exhibiting less site fidelity and greater commuting distances to foraging areas. Cacklers showed a preference for young grass during all periods of the winter, reaffirming that Cacklers are specialized grazers on short green forage, whereas Duskys preferred young grass and pasture. Fields of young grass were the preferred foraging habitat of Cacklers, had less standing crop biomass, and may have enabled higher foraging efficiencies, which may have led to higher intake rates.
The ability of the landscape to support wintering geese changed across the winter because total available plant biomass fluctuated with the rate of grass regrowth. The estimated carrying capacity of the landscape for geese decline by almost one-half during mid-winter (mid-December to mid-February) compared to early winter or late winter periods. Although Cacklers have lower individual energy requirements compared to Duskys, due to a much larger target population size, Cacklers required 89% more foraging habitat than Duskys. Forage requirements encountered a bottleneck during mid-winter, when grass regrowth rates were low and day length was short. Commensurate with this pattern of forage availability, goose body condition declined during the mid-winter period. To support Pacific Flyway target populations for geese, approximately 18,000 ha of total grazing habitat in young and mature grass is needed in the Willamette Valley to support a total over-wintering population composed of 340,000 geese belonging to four subspecies.
The role of body size in influencing the foraging behavior and decisions of over-wintering geese has important implications for conservation planning of goose populations. Small-bodied Cacklers are selective in field choice, yet more likely to
redistribute across the landscape. Disturbances (e.g., hunting, hazing, or predation) will have a disproportionate effect on the movements of smaller-bodied geese compared to larger geese. These characteristics of Cacklers will make conservation planning to retain geese on public land more difficult. Coordinated management with private landowners and farming practices that maximize preferred goose foraging habitat on public lands may attract geese to utilize protected areas and minimize conflicts with agriculture in the Willamette Valley. Availability of resources during critical periods in winter is an important factor affecting the distribution of geese, but may affect small and large bodied geese differently. Management could be targeted during these critical time periods. By considering the role of body size in the context of life history characteristics, foraging behavior and habitat selection, appropriate management strategies can be developed and implemented to reduce the effects of agricultural depredation by geese, while promoting the future conservation of wintering geese in the Willamette Valley.Graduation date: 2013
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„Metal contamination and studies of copper-binding proteins from tilapia collected from Shing Mun River“. 2005. http://library.cuhk.edu.hk/record=b5896403.
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Szeto Tsz Kwan Leo.Thesis (M.Phil.)--Chinese University of Hong Kong, 2005.
Includes bibliographical references (leaves 112-120).
Abstracts in English and Chinese.
Abstract --- p.i
摘要 --- p.iii
Acknowledgements --- p.v
Table of Contents --- p.vi
List of Tables --- p.ix
List of Figures --- p.x
Abbreviations --- p.xii
Chapter Chapter 1 --- Introduction --- p.1
Chapter 1.1 --- Heavy metals contaminations in Shing Mun River --- p.1
Chapter 1.1 --- Importance of copper regulation and role of liverin copper metabolism --- p.6
Chapter 1.1.1 --- Role of copper --- p.6
Chapter 1.1.2 --- Toxicity due to unbalanced copper regulation --- p.7
Chapter 1.1.3 --- Function of liver in copper detoxification --- p.9
Chapter 1.2 --- Aims and rationale of this research --- p.11
Chapter Chapter 2 --- Heavy metal concentrations of tilapia samples collected from Shing Mun River --- p.12
Chapter 2.1 --- Introduction --- p.12
Chapter 2.1.1 --- Sampling sites - Fo Tan and Siu Lek Yuen Nullah --- p.12
Chapter 2.1.2 --- Tilapia samples collected from the sites --- p.16
Chapter 2.1.3 --- Tilapia as a study model --- p.18
Chapter 2.1.4 --- Bioavailability of heavy metals in water --- p.19
Chapter 2.1.5 --- Metal content in liver --- p.20
Chapter 2.1.6 --- Aim of this chapter --- p.20
Chapter 2.2 --- Materials and Methods --- p.22
Chapter 2.2.1 --- Collection of control and field samples --- p.22
Chapter 2.2.2 --- Heavy metal concentrations determination --- p.23
Chapter 2.2.3 --- Homogenization of liver cells --- p.24
Chapter 2.2.4 --- Subcellular fractionation --- p.24
Chapter 2.2.5 --- Determination of copper and zinc content in each subcellular fraction --- p.253
Chapter 2.3 --- Results --- p.27
Chapter 2.3.1 --- Physical data --- p.27
Chapter 2.3.2 --- Metal concentrations in liver and muscle --- p.27
Chapter 2.3.3 --- Copper and zinc subcellular distribution in liver cell --- p.33
Chapter 2.4 --- Discussion --- p.36
Chapter 2.4.1 --- Difference in metal concentration between sites --- p.36
Chapter 2.4.2 --- Copper contamination in water and fish organ (muscle and liver) from the Shing Mun River --- p.36
Chapter 2.4.3 --- Comparison of metal content in muscle and liver at Fo Tan site with previous studies --- p.39
Chapter 2.4.4 --- Copper and zinc concentrations in the liver of tilapia --- p.42
Chapter 2.4.5 --- Copper and zinc sebcellular distribution in the liver of tilapia --- p.43
Chapter Chapter 3 --- Column chromatography of hepatic proteins from tilapias --- p.44
Chapter 3.1 --- Transport of metals from circulatory system to liver --- p.44
Chapter 3.1.1 --- Copper transporting plasma proteins in vertebrates --- p.44
Chapter 3.1.2 --- Copper uptake into hepatocytes --- p.45
Chapter 3.1.3 --- Intracellular metabolism of copper --- p.48
Chapter 3.1.4 --- Mechanism of copper toxicity following excess accumulation --- p.49
Chapter 3.1.5 --- Aim of this chapter --- p.50
Chapter 3.2 --- Materials and Methods --- p.51
Chapter 3.2.1 --- Purification of liver cytosolic proteins by gel-filtration column chromatography --- p.51
Chapter 3.2.2 --- Copper content detection in elution --- p.52
Chapter 3.2.3 --- Analysis of peaks from elution profile using tricine gel SDS PAGE --- p.53
Chapter 3.3 --- Results --- p.55
Chapter 3.3.1 --- Gel-filtration liquid chromatography elution profiles --- p.55
Chapter 3.3.2 --- SDS PAGE analysis of peaks in elution profiles --- p.51
Chapter 3.4 --- Discussion --- p.54
Chapter 3.4.1 --- Comparison of gel filtration profiles of sample liver cytosol between sites and sexes --- p.64
Chapter 3.4.2 --- Possible proteins in peaks found in the gel filtration profiles --- p.64
Chapter 3.4.3 --- Common copper-indeced proteins --- p.67
Chapter 3.5 --- Conclusion --- p.70
Chapter Chapter 4 --- Two-dimensional electrophoresis of hepatic cutosol of tilapias caught from Shing Mun River and copper-treated HEPA T1 cell --- p.72
Chapter 4.1 --- Introduction --- p.72
Chapter 4.1.1 --- The need of ´بin vitro' experiment --- p.72
Chapter 4.1.2 --- Choice of cell line --- p.73
Chapter 4.1.3 --- Aim of this chapter --- p.74
Chapter 4.2 --- Materials and Methods --- p.76
Chapter 4.2.1 --- HEPA T1 cell cultivation --- p.76
Chapter 4.2.2 --- Copper exposure of HEPA T1 cell --- p.77
Chapter 4.2.3 --- Subcellular protein extraction of the copper-treated HEPA T1 cells --- p.77
Chapter 4.2.4 --- Bicinchoninic Acidic (BCA) Protein Assay --- p.79
Chapter 4.2.5 --- Two-dimensional gel electrophoresis --- p.79
Chapter 4.3 --- Results --- p.83
Chapter 4.3.1 --- Graphical presentation of spots observed on 2-dimensional gel of field samples and copper-injected samples --- p.33
Chapter 4.3.2 --- Graphical presentation of spots detected on 2-dimensional gel of HEPAT1 cells --- p.84
Chapter 4.3.3 --- Comparison of matched spots on 2-dimensional gels among control and copper-treated HEPAT1 cells --- p.97
Chapter 4.4 --- Discussion --- p.105
Chapter 4.4.1 --- Comparison of the spot patterns between field sample and copperOtreated HEPA T1 cells --- p.105
Chapter 4.5 --- Conclusion --- p.107
Chapter Chapter 5 --- General Discussions --- p.108
Chapter 5.2 --- Research Overview --- p.108
Chapter 5.2 --- Characterization of metal binding proteins from the cytosol of liver of tilapia --- p.109
REFERENCES --- p.112