Academic literature on the topic 'Freshwater'

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Journal articles on the topic "Freshwater"

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Dang, Tran, Pham, Khoi, Tran, and Nguyen. "Exploring Freshwater Regimes and Impact Factors in the Coastal Estuaries of the Vietnamese Mekong Delta." Water 11, no. 4 (April 15, 2019): 782. http://dx.doi.org/10.3390/w11040782.

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Freshwater resources make an essential contribution to the livelihoods of millions of local people in the coastal estuaries of the Vietnamese Mekong Delta (VMD). However, coastal freshwaters currently face numerous threats, not least (i) changing tidal dynamics due to sea level rise and (ii) changes in river regimes due to dam construction upstream. This research explores the evolution of freshwater regimes in these coastal estuaries. Using process diagrams, freshwater distributions are mapped and analyzed. Application of statistical methods provides insight into freshwater flow cycles and variations in water regimes upstream at various measurement points within the estuaries. A previously calibrated and validated hydraulic model is used to simulate drought-year scenarios and spatial changes in freshwaters over time. Findings indicate decreasing river discharges in the flood season, but increasing discharges in the dry season, due to the impacts of hydropower dams. In addition, the driest months are shifting earlier. From this data, we derive rules of thumb regarding freshwater distributions in the coastal estuaries of the VMD. These relate to (i) the boundary beyond which freshwater is always found; (ii) the boundary where freshwater appears daily; (iii) the start of the freshwater season; (iii) the boundary where freshwater appears until February and until April; (iv) the end of the flood season; and (v) the number of days without freshwater per year. The trends discerned will help local freshwater users and decision makers formulate forward-looking, flexible strategies for freshwater exploitation, while also providing avenues for further research.
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Alahuhta, Janne, Tibor Erős, Olli-Matti Kärnä, Janne Soininen, Jianjun Wang, and Jani Heino. "Understanding environmental change through the lens of trait-based, functional, and phylogenetic biodiversity in freshwater ecosystems." Environmental Reviews 27, no. 2 (June 2019): 263–73. http://dx.doi.org/10.1139/er-2018-0071.

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In the era of the Anthropocene, environmental change is accelerating biodiversity loss across ecosystems on Earth, among which freshwaters are likely the most threatened. Different biodiversity facets in the freshwater realm suffer from various environmental changes that jeopardize the ecosystem functions and services important for humankind. In this work we examine how environmental changes (e.g., climate change, eutrophication, or invasive species) affect trait-based, functional, and phylogenetic diversity of biological communities. We first developed a simple conceptual model of the possible relationships between environmental change and these three diversity facets in freshwaters and, secondly, systematically reviewed articles where these relationships had been investigated in different freshwater ecosystems. Finally, we highlighted research gaps from the perspectives of organisms, ecosystems, stressors, and geographical locations. Our conceptual model suggested that both natural factors and global change operating at various spatial scales influence freshwater community structure and ecosystem functioning. The relationships between biodiversity and environmental change depend on geographical region, organism group, spatial scale, and environmental change gradient length. The systematic review revealed that environmental change impacts biodiversity patterns in freshwaters, but there is no single type of biodiversity response to the observed global changes. Natural stressors had different, even contradictory, effects (i.e., multiple, negative, and positive) on biodiversity compared with anthropogenic stressors. Anthropogenic stressors more often decreased biodiversity, although eutrophication and climate change affected freshwater ecosystems in a complex, more multi-dimensional way. The research gaps we identified were related, for example, to the low number of community-based biodiversity studies, the lack of information on true phylogenies for all freshwater organism groups, the missing evaluations whether species traits are phylogenetically conserved, and the geographical biases in research (i.e., absence of studies from Africa, Southern Asia, and Russia). We hope that our review will stimulate more research on the less well-known facets and topics of biodiversity loss in highly vulnerable freshwater ecosystems.
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Haryani, GS. "Migratory freshwater fish in Indonesia: Threats and conservation efforts." IOP Conference Series: Earth and Environmental Science 1062, no. 1 (July 1, 2022): 012001. http://dx.doi.org/10.1088/1755-1315/1062/1/012001.

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Abstract The process of fish migration is one of the most important biological aspects of the life of certain fish species, including fish species that live in freshwaters. In Indonesia’s freshwaters, several types of fish migrate to fulfill parts of their life cycle, such as Anguilla spp., Tor spp., and Rasbora spp., which have economic and ecological values. Fish habitats and migration routes can be affected by many cause changes, including dam constructions, other infrastructure constructions, drainage of wetlands, and floodplain disconnection. Other threats to migratory freshwater fish are overfishing and pollution. In Indonesia, most migratory freshwater fish threats were obstructions to free-flowing rivers, such as dams, and the exploitation of adult fish that migrate for spawning. Some management approaches should conserve and sustain the use of migratory freshwater fish.
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Bury, Gwendolynn W., Rebecca Flitcroft, Mark D. Nelson, Ivan Arismendi, and Evan B. Brooks. "Forest-Associated Fishes of the Conterminous United States." Water 13, no. 18 (September 15, 2021): 2528. http://dx.doi.org/10.3390/w13182528.

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Freshwaters are important, interconnected, and imperiled. Aquatic ecosystems, including freshwater fishes, are closely tied to the terrestrial ecosystems they are embedded within, yet available spatially explicit datasets have been underutilized to determine associations between freshwater fishes and forested areas. Here, we determined the spatial co-occurrence between freshwater fish distributions and forests within 2129 watersheds of the conterminous United States. We identified 21% of freshwater fishes as associated with forested areas, and 2% as strictly present only in highly forested areas (75–100% forested). The northern coasts and southeast regions, both heavily forested, showed the largest numbers of forest-associated fishes in highly forested areas and fish species richness. Fish associated with low-forested areas occurred in the southwest and central plains. Imperiled fishes were relatively evenly distributed among percent forest categories, which was distinctly different from patterns for all fishes. The identification of forest-associated fishes provides insights regarding species-specific landscape contexts. Determining these large-scale patterns of freshwater biodiversity is necessary for conservation planning at regional levels, especially in highly impacted freshwater ecosystems.
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Schuler, Matthew S., Miguel Cañedo-Argüelles, William D. Hintz, Brenda Dyack, Sebastian Birk, and Rick A. Relyea. "Regulations are needed to protect freshwater ecosystems from salinization." Philosophical Transactions of the Royal Society B: Biological Sciences 374, no. 1764 (December 3, 2018): 20180019. http://dx.doi.org/10.1098/rstb.2018.0019.

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Anthropogenic activities such as mining, agriculture and industrial wastes have increased the rate of salinization of freshwater ecosystems around the world. Despite the known and probable consequences of freshwater salinization, few consequential regulatory standards and management procedures exist. Current regulations are generally inadequate because they are regionally inconsistent, lack legal consequences and have few ion-specific standards. The lack of ion-specific standards is problematic, because each anthropogenic source of freshwater salinization is associated with a distinct set of ions that can present unique social and economic costs. Additionally, the environmental and toxicological consequences of freshwater salinization are often dependent on the occurrence, concentration and ratios of specific ions. Therefore, to protect fresh waters from continued salinization, discrete, ion-specific management and regulatory strategies should be considered for each source of freshwater salinization, using data from standardized, ion-specific monitoring practices. To develop comprehensive monitoring, regulatory, and management guidelines, we recommend the use of co-adaptive, multi-stakeholder approaches that balance environmental, social, and economic costs and benefits associated with freshwater salinization. This article is part of the theme issue ‘Salt in freshwaters: causes, ecological consequences and future prospects’.
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Kianpoor Kalkhajeh, Yusef, Bahman Jabbarian Amiri, Biao Huang, Azad Henareh Khalyani, Wenyou Hu, Hongjian Gao, and Michael L. Thompson. "Methods for Sample Collection, Storage, and Analysis of Freshwater Phosphorus." Water 11, no. 9 (September 11, 2019): 1889. http://dx.doi.org/10.3390/w11091889.

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Although phosphorus (P) is an essential nutrient for biological productivity, it can cause freshwater degradation when present at fairly low concentrations. Monitoring studies using continuous sampling is crucial for documenting P dynamics in freshwater ecosystems and to reduce the risk of eutrophication. Despite literature updates of developments of the analytical methods for measurement of P species in natural waters, there has been no comprehensive review addressing freshwater sample collection, sample preparation, and sample treatment to fractionate and characterize different forms of P. Therefore, this paper aims to elaborate the different techniques for freshwater sampling and to introduce alternative laboratory methods for sample preservation and P fractionation. The advantages and disadvantages of various sampling techniques, including the traditional manual and the recently developed automatic and passive methods, are presented to highlight the importance of collecting representative freshwater samples. Furthermore, we provide suggestions for sample pretreatment, including filtration, transportation, and storage steps to minimize microbial activity and to maximize the accuracy of measurement of various P fractions. Finally, the most common laboratory methods to measure dissolved and particulate as well as the organic and inorganic freshwater P fractions are efficiently provided. Using this guide, a comprehensive monitoring program of P dynamics in freshwater ecosystems can be developed and applied to improve water quality, particularly of P-rich freshwaters.
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Ekinadose Orose, Edafe Odioko, and Okechukwu Kenneth Wokeh. "Catalogue of Some Saltwater and Freshwater Fish Species of the Niger Delta Region of Nigeria." World Journal of Advanced Research and Reviews 9, no. 3 (March 30, 2021): 056–84. http://dx.doi.org/10.30574/wjarr.2021.9.3.0075.

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The study was done to review some saltwater and freshwater fish species in the Niger Delta region of Nigeria. The Niger Delta is one of the most prominent regions in Nigeria, endowed with several water bodies that are distributed as freshwater like rivers, lakes, streams and creeks. These freshwater ecosystems in the region, are abundantly endowed with fish species such as Clarias gariepinus, Pila ovate, Labeo coubie, Synodontis budgetti and Synodontis eupterus. Apart from the freshwaters, the region also has vast marine ecosystem with abundance of fish species such as Elops lacerta, Mugil cephalus, Thais coronata, Periophthalmus papilio, Tympanotonus fuscatus, and Sardinella maderensis. Unfortunately, many of these fish species are endangered due to constant pollution in the Niger delta regional coastal environment. As a result, it is important to document some available freshwater and marine water fish species which will serve as a reference material for both academics and research institutions, should any of the fish species go into extinction.
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Rachmawati, Farida Nur, and Untung Susilo. "Biochemical composition of tropical eel Anguilla bicolor McClelland,1844 in Freshwater and Estuary." E3S Web of Conferences 322 (2021): 01008. http://dx.doi.org/10.1051/e3sconf/202132201008.

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During migration, Anguilla bicolor will stop its feeding activity and use energy from its body lipid stores. Therefore, information on changes in the body lipid content of eels is essential to know the preparation of spawning migration. Thus, it is interesting to study the body composition of A. bicolor in freshwater and estuaries. This research conducted a survey method. The eel was obtained from the Serayu River (freshwaters) and Segara Anakan (Estuary). The observed variables were water, dry weight, lipid, protein, crude fiber, ash, and BETN of eel. Oneway ANOVA analyzed data. The results show that freshwater eels' average body length and weight were 457.875 cm ± 153.8552 and 224.4375 g ± 165.3735. The body length and weight of the estuary eels were smaller than freshwater eels, which are 372.5714 cm ± 152.6467 and 109.6429 g ± 134.6054, respectively. The body composition of eel, except for lipid content, was similar for both habitats (p>0.05). However, the body lipid content of freshwater eels and the estuarine eel differed (p<0.05), namely 40.15% ± 9.63 and 27.33% ± 9.93, respectively. In conclusion, the lipid body content of freshwater eels was higher than the estuary eel, while another is relatively the same.
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Kociolek, John P., and Sarah A. Spaulding. "Freshwater diatom biogeography." Nova Hedwigia 71, no. 1-2 (September 3, 2000): 223–41. http://dx.doi.org/10.1127/nova/71/2000/223.

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Javornický, Pavel. "Freshwater Rhodomonads (Cryptophyceae)." Algological Studies/Archiv für Hydrobiologie, Supplement Volumes 102 (August 1, 2001): 93–116. http://dx.doi.org/10.1127/algol_stud/102/2001/93.

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Dissertations / Theses on the topic "Freshwater"

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Shynkar, I. V. "Freshwater." Thesis, Sumy State University, 2014. http://essuir.sumdu.edu.ua/handle/123456789/45218.

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Most people don’t actually think about the supply of water. Water is easy to ignore, you can just turn on a tap and water comes out! We still have the same amount of water in our ecosystem but the supply of freshwater faces a three-pronged attack from population growth, climate change and industrialisation. As it currently stands, there’s not enough water to go around. Of the World’s total water supply 97% is seawater and of the remaining only 0.3% is usable unpolluted clean waterthat is readily available to us for our daily water supply.
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Nel, Jeanne Lindsay. "Enhancing the conservation of freshwater biodiversity through improved freshwater conservation planning techniques." Doctoral thesis, University of Cape Town, 2008. http://hdl.handle.net/11427/6145.

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Freshwater ecosystems and biota are among the most endangered in the world. This current situation is even more disturbing when future threats of escalating human demand and global climate change are considered. Urgent measures are therefore needed to conserve freshwater ecosystems and sustain the services they provide. These may take the form of formal protection but also need to include less restrictive mechanisms, such as implementing integrated catchment management and environmental water requirements. Systematic conservation planning provides a strategic and scientifically defensible framework for doing this. Pioneered in the terrestrial realm, uptake of systematic conservation planning for freshwater ecosystems has been slow. While broad principles are applicable, approaches need to be freshwaterspecific. The lack of freshwater-specific frameworks and tools is a key factor hampering the application of systematic conservation planning in the freshwater realm. The aim of this thesis was to address this need by developing a suite of frameworks and practical applications for planning in freshwater settings. The development of a framework for the rapid assessment of river ecosystem endangerment and protection levels provided a common currency for comparing the state of biodiversity across terrestrial and aquatic realms. It showed, for the first time, that the state of river ecosystems in South Africa is dire, far worse than that of terrestrial ecosystems. In addition, river ecosystems have very low levels of representation in protected areas, with many not represented at all. A more optimistic finding was that river systems in protected areas appear to be in a better overall condition than those outside of protected areas, emphasizing the potential of protected areas in conserving freshwater ecosystems. Currently, however, protected area systems worldwide show significant gaps in their conservation of freshwater biodiversity. A framework was therefore developed for locating and designing protected area systems for the benefit of river biodiversity. Conservation objectives were established for improving river biodiversity pattern and processes in both new and existing protected areas. These included representation of river ecosystems and freshwater fish species, representation of large-scale biodiversity processes associated with free-flowing rivers and catchment-estuarine linkages, and improving the persistence of river reaches already contained within protected areas. Data were collated in a Geographic Information System (GIS) and a conservation planning algorithm was used as a means of integrating the multiple objectives in a spatially efficient manner. Realistically, protected areas can only play a partial role in overall efforts to conserve freshwater biodiversity and need to be supplemented with other off-reserve conservation strategies. In addition, conservation strategies that focus only on representation of biodiversity in isolated areas are conceptually flawed, especially given the inherent connectivity of freshwater ecosystems. Such conservation strategies need to be augmented with approaches that address the persistence of freshwater biodiversity. A framework for planning for the persistence of freshwater biodiversity was therefore developed, synthesizing concepts from freshwater ecology and terrestrial conservation planning. When considering issues of persistence, making use of a multiple-use zoning strategy is a practical option because it helps to emphasize that different levels of protection, and hence utilization, can be afforded to different conservation areas. This helps to strengthen the linkages between people and conservation, and aligns more closely with planning categories used by water resource managers and land use planners. Planning for both representation and persistence should be achieved simultaneously to maximize spatial efficiency. Several methods of planning for representation and persistence were explored. An existing conservation planning algorithm (MARXAN) was adapted for use in freshwater settings through the incorporation of directional connectivity considerations. When using a conservation planning algorithm, the manner in which spatial efficiency between persistence and representation is achieved depends on whether or not a multiple-use zoning strategy will be applied during design. Given the practicalities of multiple-use zoning at local levels of planning, it is recommended that zones should be used in the design phase, rather than merely allocated at the end once the design is complete. In summary, research and practice in conservation has tended to focus on terrestrial biodiversity; while water resources management has tended to have a more utilitarian focus. It is high time to elevate freshwater biodiversity concerns on the agendas of both these sectors. By developing common conservation frameworks around which the water and conservation sector can engage and debate, this thesis attempts to enhance the integration of freshwater biodiversity concerns into both these sectors.
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McIvor, Anna Louise. "Freshwater mussels as biofilters." Thesis, University of Cambridge, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.616028.

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Klein, Sascha. "Microplastics in Freshwater Systems." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-200861.

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Synthetic polymers are one of the most significant pollutants in the aquatic environment, because of abilities such as buoyancy and extreme persistency. Serious effects are expected from so-called microplastics (particle size <5 mm) that are reported in rivers, lakes as well as the ocean and that accumulate in sediments worldwide. In this thesis the abundance of microplastics in river shore sediments in the Rhine-Main area of Germany was studied. Therefore, a new method was developed that is based on a sodium chloride density separation with subsequent destruction of natural debris, and identification of the plastic particles by microscopy or Fourier transform infrared spectroscopy (FTIR). Using the improved density separation, microplastics were separated from river shore sediments of 12 sites originating from the river Rhine, the river Main, and the stream Schwarzbach. Large amounts of microplastic particles of up to 1 g kg-1 or up to 4000 particles kg-1 were detected in the shore sediments. The identification by FTIR showed that polyethylene, polypropylene, and polystyrene were the most abundant polymer types in the sediments, covering over 75% of all plastics identified. Transport of microplastics from tributaries to main streams was indicated by the detection of identical pellets in the River Rhine and in the Main mouth. Comparable concentrations detected by sampling one site over a period of two years suggest a constant pollution of the river shore sediments with microplastics. For deeper insights into the sorption process of organic contaminants to synthetic polymers in freshwater systems, batch experiments in synthetic freshwater were conducted to determine sorption kinetics and sorption isotherms for four selected glass state polymers (polycarbonate, poly(methyl methacrylate), polystyrene, and polyvinyl chloride) and six different model substances (carbamazepine, hexachlorocyclohexane (β/γ), 17α-ethynilestradiol, chlorpyrifos, and o,p-dichlorodiphenyltrichlorethane). Sorption to the polymer particles was observed for all contaminants increasing with the KOW values of the contaminants. Because of losses of contaminants in control samples, sorption reaction models could be applied to four out of six contaminants, and isotherms were calculated for three contaminants. Furthermore, influences of the different polymer types used were observed in the experiments. Finally, microplastics separated from sediments were extracted and analyzed by GC/MS and LC-MS/MS using target screening methods and non-target approaches. Different pesticides were identified in the polymer particles, suggesting that microplastics can act as a sink for hydrophobic contaminants. Moreover, several plastic additives such as phthalates or chlorinated flame retardants were identified. For this reason, it is very likely that microplastics act as a direct source for these chemicals in aquatic systems. The results of this thesis stress the urgency for the mitigation of the plastic particles in the aquatic environment.
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Ranghoo, Vijayanti Mala. "Phylogeny of freshwater ascomycetes." Thesis, Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B20793042.

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DeVaul, Sarah Bess. "Mixotrophy in Freshwater Foodwebs." Diss., Temple University Libraries, 2016. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/380959.

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Biology
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Environmental heterogeneity in both space and time has significant repercussions for community structure and ecosystem processes. Dimictic lakes provide examples of vertically structured ecosystems that oscillate between stable and mixed thermal layers on a seasonal basis. Vertical patterns in abiotic conditions vary during both states, but with differing degrees of variation. For example, during summer thermal stratification there is high spatial heterogeneity in temperature, nutrients, dissolved oxygen and photosynthetically active radiation. The breakdown of stratification and subsequent mixing of the water column in fall greatly reduces the stability of the water column to a vertical gradient in light. Nutrients and biomass that were otherwise constrained to the depths are also suspended, leading to a boom in productivity. Freshwater lakes are teeming with microbial diversity that responds to the dynamic environment in a seemingly predictable manner. Although such patterns have been well studied for nanoplanktonic phototrophic and heterotrophic populations, less work has been done to integrate the influence of mixotrophic nutrition to the protistan assemblage. Phagotrophy by phytoplankton increases the complexity of nutrient and energy flow due to their dual functioning as producers and consumers. The role of mixotrophs in freshwater planktonic communities also varies depending on the relative balance between taxon-specific utilization of carbon and energy sources that ranges widely between phototrophy and heterotrophy. Therefore, the role of mixotrophy in the microbial food web is difficult to predict because functional types of mixotrophs along a gradient of nutritional strategies contribute differently to nutrient cycling and carbon sequestration. The overall objective of this work was to advance existing knowledge of the abundance and activity of phagotrophy phytoplankton in lacustrine systems. The incorporation of mixotrophy into the microbial food web requires the complement of physiological studies in culture (as described in chapter 2) and quantification of activity (including abundance and bacterivory) in relation to strict phototrophs and heterotrophs in situ (as described in chapter 3 and 4). Information on the physiological ecology of mixotrophic protists is crucial to understanding their role in planktonic food webs and influence on the dynamic microbial community structure in lake ecosystems. An understanding of the ecological functioning of lakes has ultimate consequences for management of water resources, particularly in the face of global climate change.
Temple University--Theses
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She, Shu-sheng. "Determinants of macroinvertebrate community structure on stone surfaces in Hong Kong streams /." [Hong Kong] : University of Hong Kong, 1993. http://sunzi.lib.hku.hk/hkuto/record.jsp?B1373149X.

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Saunders, Darla L. "Nitrogen retention in freshwater ecosystems." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/mq64444.pdf.

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Kelly, David C. "Dimethylmercury Production in Freshwater Sediments." Wright State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=wright1292547695.

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Pandeirada, Mariana Sofia Oliveira. "Studies on freshwater woloszynskioids (Dinophyceae)." Master's thesis, Universidade de Aveiro, 2013. http://hdl.handle.net/10773/11811.

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Mestrado em Biologia Aplicada - Ecologia, Biodiversidade e Gestão de Ecossistemas
Os dinoflagelados são um grupo de protistas com características intra- e extracelulares invulgares, encontrados tanto em habitats marinhos como de água doce. Estes organismos são tradicionalmente classificados como tecados ou atecados tendo em conta a constituição da sua região externa, conhecida como anfiesma. Esta região compreende uma camada única de vesículas achatadas subjacentes ao plasmalema, as quais podem ser preenchidas com placas celulósicas mais ou menos espessas nos dinoflagelados tecados, ou com placas celulósicas muito finas, ou mesmo não possuírem placas, nos dinoflagelados atecados. Durante o século XX, contudo, foi demonstrado que algumas espécies atecadas do género Gymnodinium tinham um anfiesma constituído por numerosas placas celulósicas finas. Tais espécies foram transferidas para um novo género, Woloszynskia, o qual foi posteriormente objeto de controvérsia, principalmente associada com o estabelecimento da espécie tipo e a possibilidade de compreender outros grupos taxonómicos, sendo portanto polifilético. Recentemente, uma série de estudos confirmaram a última ideia, e vários géneros foram criados para receber espécies de Woloszynskia, conhecidas como woloszynskióides. Esses géneros foram distribuídos por diferentes famílias: Tovellia, Jadwigia, Esoptrodinium e Opisthoaulax na nova família Tovelliaceae; Borghiella e Baldinia na nova família Borghiellaceae; Biecheleria e Biecheleriopsis incluídos na família Suessiaceae. Estas mudanças taxonómicas foram suportadas por dados moleculares e diferenças morfológicas na estrutura do estigma, organização do apex da célula e tipo de quisto de resistência. O conhecimento taxonómico sobre a diversidade e distribuição de dinoflagelados de água doce em Portugal Continental foi reunido pela primeira vez numa "checklist" e aqui apresentado (Capítulo 2). As entradas na lista foram definidas tendo em conta pesquisa filogenética recente, em particular mudanças taxonómicas que afetam os limites a nível genérico dos taxa. Registos publicados de espécies de dinoflagelados de água doce, retirados de 37 referências, formam a base do inventário, aos quais foi adicionada documentação para 12 taxa ainda não referenciados para Portugal (11 espécies e uma forma). Duas novas espécies de woloszynskióides para a ciência, não incluídas nesta "checklist", são aqui apresentadas (Capítulos 3, 4). A morfologia das células e quistos é descrita, bem como a ultraestrutura das células móveis e aspetos particulares do ciclo de vida. Filogenias baseadas em sequências de LSU rDNA confirmam as novas espécies. A primeira espécie pertence à família Tovelliaceae, género Tovellia (Capítulo 3). O epíteto específico escolhido foi aveirensis, o qual constitui uma referência ao nome da universidade, bem como da cidade onde foi encontrada: Campus da Universidade de Aveiro, Aveiro, Portugal. Tovellia aveirensis possui a característica peculiar de produzir um quisto de resistência com paracíngulo e ornamentado com numerosos processos ramificados, que não só difere do quisto bipolar e quase não ornamentado do género, mas também de todos os outros descritos para woloszynskióides. Morfologicamente esta difere de outras espécies de Tovellia principalmente por ter uma linha de pontos posicionada ao nível do limite posterior do cíngulo, rodeando a célula, e por não possuir uma placa antapical distinta, à volta da qual as séries de placas do hipocone poderiam estar dispostas. A segunda espécie de woloszynskióide foi encontrada na área alagada do Ribeiro da Palha, Nariz, Aveiro, Portugal, e num lago de água doce na Escócia (Capítulo 4). Esta pertence à família Borghiellaceae, género Borghiella, e foi nomeada B. andersenii em honra do Prof. Robert A. Andersen, que primeiro estabeleceu cultura da mesma a partir de material colhido na Escócia. Morfologicamente é idêntica à B. dodgei, divergindo desta principalmente por ter um epicone arredondado e um par de vesículas anfiesmais alongadas (PEV) mais curto, com menos pontos e delineado por duas a três placas apicais. B. andersenii é capaz de se reproduzir assexuadamente tanto no estado móvel, por fissão, como no estado imóvel, com produção de quistos de divisão, algo que nunca foi referenciado para Borghiellaceae. Além disso, evidências mais fortes de reprodução sexuada para esta família foram ainda observadas em culturas de B. andersenii, nomeadamente planozigotos e aparentes quistos de resistência. Dois outros woloszynskióides, designados MSP1 e MSP12, são aqui brevemente descritos (Capítulo 5). Estes foram colhidos respetivamente num lago da Gafanha da Boavista, próxima da Vista Alegre, Ílhavo, Aveiro, e no mesmo local, em Portugal, onde B. andersenii foi encontrada. Tanto os resultados morfológicos como filogenéticos sugerem que são duas novas espécies de Tovellia, evolucionariamente próximas de T. aveirensis.
Dinoflagellates are a group of protists with intra- and extracellular unusual features, found in both marine and freshwater habitats. These organisms are traditionally classified as armoured or thecate, and unarmoured or athecate taking into account the constitution of their outer region, known as amphiesma. This region comprises a single layer of flat vesicles underlying the plasmalemma, which can be filled with more or less thick cellulosic plates in the thecate dinoflagellates, or with very thin cellulosic plates or no plates at all in the athecate ones. During the 20th century, however, it was demonstrated that some athecate species of the genus Gymnodinium had an amphiesma constituted by numerous thin cellulosic plates. Such species were transferred to a new genus, Woloszynskia, which has been later object of controversy, mainly associated with the establishment of the type species and the possibility to comprise other taxonomic groups, thus being polyphyletic. Recently, a series of studies have confirmed the latter idea, and several genera have been created to receive Woloszynskia species, known as woloszynskioids. Those genera have been distributed over different families: Tovellia, Jadwigia, Esoptrodinium and Opisthoaulax in the new family Tovelliaceae; Borghiella and Baldinia in the new family Borghiellaceae; Biecheleria and Biecheleriopsis ranged with the family Suessiaceae. These taxonomic changes have been supported by molecular data and by morphological differences in eyespot structure, organization of the cell apex and type of resting cyst. Taxonomic knowledge about the diversity and geographic distribution of freshwater dinoflagellates in continental Portugal were assembled in a checklist for the first time and here presented (Chapter 2). Entries in the list were defined taking into account recent phylogenetic research, particularly the resulting taxonomic changes that affect genus-level limits of taxa. Published reports of freshwater dinoflagellate species, taken from 37 references, form the basis of the inventory, to which it was added documentation for 12 previously unreported taxa (11 species and one form). Two new woloszynskioid species for science, not included in this checklist, are presented here (Chapter 3, 4). The morphology of cells and cysts is described as well as the ultrastructure of motile cells and particular aspects of the life cycle. LSU rDNA-based phylogenies confirm the new species. The first one belongs to the family Tovelliaceae, genus Tovellia (Chapter 3). The species epithet chosen was aveirensis, which constitutes a reference to the name of the university as well as the city where it has been found: University of Aveiro Campus, Aveiro, Portugal. Tovellia aveirensis has the peculiar feature of producing a resting cyst with paracingulum and ornamented by numerous branched processes, which not only differs from the bipolar and almost not ornamented Tovellia cyst, but also from all others described for woloszynskioids. Morphologically, it differs from other species of the genus mainly by having a line of knobs placed at the posterior edge of the cingulum, surrounding the cell, and lacking a distinct antapical plate around which the series of plates on the hypocone could be arranged. The second new woloszynskioid has been found in a flooded area in Ribeiro da Palha stream, Nariz, Aveiro, Portugal, and in a freshwater pond in Scotland (Chapter 4). It belongs to the family Borghiellaceae, genus Borghiella, and was named B. andersenii in honor of Prof. Robert A. Andersen, who first established a culture of this species from material collected in Scotland. Morphologically, it is identical to B. dodgei, diverging from this mainly by having a rounded epicone and a shorter pair of elongate amphiesmal vesicles (PEV) with fewer knobs and lined on each side by two to three apical plates. B. andersenii is able to reproduce asexually both in the motile stage, by fission, and non-motile stage, with production of division cysts, something that has never been reported within Borghiellaceae so far. Furthermore, stronger evidences of sexual reproduction for this family have yet been observed in B. andersenii cultures, namely planozygotes and apparent resting cysts. Two other woloszynskioids, designated as MSP1 and MSP12, are here briefly described (Chapter 5). These have been collected respectively in a farm pond at Gafanha da Boavista, near Vista Alegre, Ílhavo, Aveiro, and in the same place where B. andersenni was found. Both morphologic and phylogenetic results suggest that they are two new Tovellia species, evolutionarily close to T. aveirensis.
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Books on the topic "Freshwater"

1

Emezi, Akwaeke. Freshwater. Lagos, Nigeria: Kachifo Limited, 2018.

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Freshwater feeders: Studying food webs in freshwater. Vero Beach, FL: Rourke Pub., 2009.

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Hedgecott, S. Freshwater quality. London: HMSO, 1992.

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Lindeen, Carol K. Freshwater fishing. Mankato, Minn: Capstone Press, 2010.

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Hopkins, Ellen. Freshwater fishing. Mankato, Minn: Capstone Press, 2008.

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Green, Sara. Freshwater fishing. Minneapolis, MN: Bellwether Media, Inc., 2013.

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Caso, Frank. Freshwater supply. New York, NY: Facts on File, 2010.

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Bellinger, Edward G., and David C. Sigee, eds. Freshwater Algae. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2015. http://dx.doi.org/10.1002/9781118917152.

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New, Michael Bernard, Wagner Cotroni Valenti, James H. Tidwell, Louis R. D'Abramo, and Methil Narayanan Kutty, eds. Freshwater Prawns. Oxford, UK: Wiley-Blackwell, 2009. http://dx.doi.org/10.1002/9781444314649.

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Wagner, Martin, and Scott Lambert, eds. Freshwater Microplastics. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-61615-5.

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Book chapters on the topic "Freshwater"

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Hodda, Mike, and Walter Traunspurger. "Nematodes from extreme and unusual freshwater habitats." In Ecology of freshwater nematodes, 109–50. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789243635.0004.

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Abstract This chapter discusses the ecology and biogeography of nematodes from freshwater environments that are extreme in temperature, chemical composition, variability, or isolation. Described and compared are the compositions of nematode faunas from hot or mineral springs, pools and bogs in polar regions, intermittent lakes or pools or streams, freshwater pools in bromeliads or tree hollows, stemflow, fresh groundwaters, and caves. Comparisons of the nematode faunas from these extreme habitats with those from more typical freshwater environments are also provided. Also discussed are nematodes with evolutionary affinities to freshwaters that are found in estuarine sediments along with nematodes from freshwaters with evolutionary affinities to otherwise marine taxa. The emphasis is on broad ecological patterns rather than on detailed species interactions with the various freshwater environments. Thus, the chapter focuses on genera or higher taxa rather than species.
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Brauman, Kate A. "Freshwater." In Routledge Handbook of Ecosystem Services, 374–82. New York, NY : Routledge, 2016.: Routledge, 2016. http://dx.doi.org/10.4324/9781315775302-32.

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Hammerton, Desmond. "Freshwater." In Air Pollution, Acid Rain and the Environment, 23–36. Dordrecht: Springer Netherlands, 1988. http://dx.doi.org/10.1007/978-94-009-2735-3_3.

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de Freitas, Chris R., and Martin Perry. "Freshwater." In New Environmentalism, 163–86. Dordrecht: Springer Netherlands, 2012. http://dx.doi.org/10.1007/978-1-4020-8254-2_6.

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Archibold, O. W. "Freshwater ecosystems." In Ecology of World Vegetation, 354–87. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-011-0009-0_11.

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Rodgers, Bradley A. "Freshwater Archaeology." In Encyclopedia of Global Archaeology, 4382–91. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-30018-0_584.

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Frost, Thomas M. "Freshwater Sponges." In Tracking Environmental Change Using Lake Sediments, 253–63. Dordrecht: Springer Netherlands, 2002. http://dx.doi.org/10.1007/0-306-47668-1_12.

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Miller, Barry B., and Michael J. S. Tevesz. "Freshwater Molluscs." In Tracking Environmental Change Using Lake Sediments, 153–71. Dordrecht: Springer Netherlands, 2001. http://dx.doi.org/10.1007/0-306-47671-1_8.

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Sandifer, Paul A., and Theodore I. J. Smith. "Freshwater Prawns." In Crustacean and Mollusk Aquaculture in the United States, 63–125. Boston, MA: Springer US, 1985. http://dx.doi.org/10.1007/978-1-4684-1503-2_2.

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Smith, Ian R. "Freshwater Ecosystems." In Hydroclimate, 215–41. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2906-0_8.

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Conference papers on the topic "Freshwater"

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McKinley, J. M., R. Parker, and A. Ruffell. "Freshwater Ground-penetrating Radar." In Near Surface 2009 - 15th EAGE European Meeting of Environmental and Engineering Geophysics. European Association of Geoscientists & Engineers, 2009. http://dx.doi.org/10.3997/2214-4609.20147116.

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Wang, Jiaxin, Liuguo Zhang, Jingyuan Qu, and Guohua Wu. "Discussion of Water Quality Factors Affecting 137Cs Adsorption and the Relationship Between 137Cs-Kd and Flow Rate in Freshwater." In 2020 International Conference on Nuclear Engineering collocated with the ASME 2020 Power Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/icone2020-16248.

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Abstract The discharge water of Inland Nuclear Power Plant (INPP) is freshwater. Freshwater has a lower environment capacity and more complex environmental impacts comparing with the salt water (oceans), which makes the public more sensitive and stricter. 137Cs, with a long half-life of 30.17 years, is likely to exist as particle form in freshwater, which increases the difficulty to be removed and also becomes a long-term potential radiation hazard. The factors affecting the behavior of 137Cs in freshwater could be divided into water quality factors and hydraulic factors. For water quality factors, the paper summarizes factors that have significantly influence on the adsorption of 137Cs: size and concentration of suspended particles, competing cations, pH, concentration of organic matters and another two environmental factors, time and extreme meteorological events such as floods, heavy rain. We describe the qualitative relationship that tells how the factors take effect on adsorption process. In terms of hydraulic factors, this paper focuses on a representative factor, flow rate, and takes the original measured distribution factor (137Cs-Kd) and flow rate data of 9 freshwaters from Asia and Europe for analysis. The study finds that there are two segmented index relationships between 137Cs-Kd and flow rate above the threshold of 1 m3/s, the experiences of other five rivers that had not participated in data fitting verify the accuracy and generic character of the index relationships. The qualitative summary of water quality factors and the quantitative conclusions between 137Cs-Kd and flow rate can provide advice for evaluating the behavior of 137Cs in freshwater, and then help in the site selection process for INPP.
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Sukop, Michael C., Bei Wei, and Santiago Castex. "ANOTHER LOOK AT FRESHWATER LENSES." In GSA Annual Meeting in Indianapolis, Indiana, USA - 2018. Geological Society of America, 2018. http://dx.doi.org/10.1130/abs/2018am-324336.

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Sherif, Mohsen, and Ampar Shetty. "Freshwater Storage in Brackish Aquifers." In World Environmental and Water Resources Congress 2013. Reston, VA: American Society of Civil Engineers, 2013. http://dx.doi.org/10.1061/9780784412947.043.

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Hegna, Thomas. "A FOSSIL AND PHYLOGENETIC PERSPECTIVE ON MARINE-FRESHWATER AND FRESHWATER-MARINE TRANSITIONS IN BRANCHIOPOD CRUSTACEANS." In GSA Connects 2022 meeting in Denver, Colorado. Geological Society of America, 2022. http://dx.doi.org/10.1130/abs/2022am-381913.

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Llamas, R. A., James J. Niemeier, and Anton Kruger. "Curved spiral antennas for freshwater applications." In 2015 IEEE Radio and Wireless Symposium (RWS). IEEE, 2015. http://dx.doi.org/10.1109/rws.2015.7129723.

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"Sensitivity of Freshwater Organisms to Nickel." In International Conference on Biological, Chemical and Environmental Sciences. International Institute of Chemical, Biological & Environmental Engineering, 2014. http://dx.doi.org/10.15242/iicbe.c614022.

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Clark, Gene, Dave Bowman, Jim Sharrow, Chad Scott, and Randall Hicks. "Duluth-Superior Harbor Freshwater Corrosion Update." In 12th Triannual International Conference on Ports. Reston, VA: American Society of Civil Engineers, 2010. http://dx.doi.org/10.1061/41098(368)36.

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Bernhard, Joan M., Luke Fisher, Megan Reilly, Ann Bucklin, Jennifer Questel, Veronique Le Roux, and Pieter Visscher. "CAN FRESHWATER FORAMINIFERA IMPACT STROMATOLITE FABRIC?" In GSA Annual Meeting in Seattle, Washington, USA - 2017. Geological Society of America, 2017. http://dx.doi.org/10.1130/abs/2017am-303002.

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Hasenmueller, Elizabeth, Heather Levin, Teresa Baraza, and Ashleigh Montgomery. "FRESHWATER SALINIZATION IN CARBONATE CRITICAL ZONES." In GSA Connects 2021 in Portland, Oregon. Geological Society of America, 2021. http://dx.doi.org/10.1130/abs/2021am-368451.

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Reports on the topic "Freshwater"

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Bennett, Oliver. Freshwater habitat restoration. Parliamentary Office of Science and Technology, January 2024. http://dx.doi.org/10.58248/pn709.

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Freshwater habitats, such as rivers and wetlands, provide major benefits to society through services such as flood risk reduction and drinking water. However, many of these habitats are in a poor condition. They have been damaged by a range of human activities including physical modification and pollution. For example, an estimated 90% of wetlands have been lost over the last century. Restoration of freshwater habitats can be achieved by addressing the causes of degradation and by enhancing or extending habitats. There is good evidence on the benefits of some forms of restoration. For example, restoration can deliver effective flood defence and restore fish populations. However, certain restoration measures are less well-studied. There are numerous national and international targets for the restoration of freshwater habitats. These include a commitment to improving at least 75% of waters to close to their natural state as soon as practicable by 2042. However, some stakeholders believe that these commitments will not be met under current plans in England. There have been calls for various actions including: increased and long-term funding to deliver larger-scale projects changes to policy and legislation to deliver more joined-up decision making and to include small water bodies and headwaters further prevention of degradation, including better enforcement of existing legislation the removal of barriers to nature-based solutions Policy in this area is devolved. For England, the UK Government published a Plan for Water in 2023 that contained new actions to help improve the condition of freshwater habitats. The Office for Environmental Protection will publish an assessment of the Government’s approach in 2024.
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Kaiper, G. Freshwater Flow Charts - 1995. Office of Scientific and Technical Information (OSTI), November 2003. http://dx.doi.org/10.2172/15009751.

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Roessink, Ivo, Kas Swinkels, Dick Belgers, Sanne van de Berg, and Theo Brock. Freshwater mysids in ecotoxicology : Testing and culturing freshwater mysid species under laboratory conditions. Wageningen: Wageningen Environmental Research, 2021. http://dx.doi.org/10.18174/548183.

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Kenneth P Hotopp, Kenneth P. Hotopp. Discovering Maine's Own Freshwater Snail. Experiment, May 2013. http://dx.doi.org/10.18258/0489.

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Valenzuela, Nicole M. Evolutionary Ecology of Freshwater Turtles. Ames: Iowa State University, Digital Repository, 2007. http://dx.doi.org/10.31274/farmprogressreports-180814-298.

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Warburton, Kev, undefined, and undefined. Freshwater Research News Issue 1May 2009. The Nature Conservancy, May 2009. http://dx.doi.org/10.3411/col.09300027.

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Hemme, Chris, Ye Deng, Qichao Tu, Matthew Fields, Terry Gentry, Liyou Wu, Susannah Tringe, et al. Comparative Metagenomics of Freshwater Microbial Communities. Office of Scientific and Technical Information (OSTI), May 2010. http://dx.doi.org/10.2172/985937.

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Bonsal, B. R., D. L. Peters, F. Seglenieks, A. Rivera, and A. Berg. Changes in freshwater availability across Canada. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2019. http://dx.doi.org/10.4095/314625.

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David Teel. 2007 NWFSC Tidal Freshwater Genetics Results. Office of Scientific and Technical Information (OSTI), March 2008. http://dx.doi.org/10.2172/1030420.

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Warburton, Kev. Freshwater Research News Issue 5 June 2010. The Nature Conservancy, June 2010. http://dx.doi.org/10.3411/col.06170356.

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