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Dissertations / Theses on the topic 'Freshwater plankton'
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1
Del, Giorgio Paul A. "Heterotrophy in lake plankton." Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=41362.
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The overall aim of this thesis was to determine the relative importance of heterotrophy and autotrophy in lake plankton. Empirical analyses using extensive surveys of literature data revealed three specific patterns in metabolism and biomass structure in freshwater plankton. First, the ratio of phytoplankton production to plankton respiration (P/R ratio) tends to be low in unproductive lakes ($<$1), and increases along gradients of enrichment. Second, the contribution of planktonic heterotrophs (bacteria and zooplankton) to community respiration is highest in oligotrophic lakes. Third, planktonic heterotrophs dominate community biomass in oligotrophic lakes, whereas phytoplankton increasingly dominate plankton biomass along gradients of enrichment. These three distinct patterns were then tested simultaneously in a set of lakes that span a wide trophic gradient. Results indicated that the plankton of oligotrophic and mesotrophic lakes were characterized by P/R ratios well below unity, and a high contribution of heterotrophs to both community respiration and biomass. These trends are completely the opposite in the most productive lakes. The plankton communities of oligotrophic temperate lakes are predominantly heterotrophic and extensively utilize external inputs of carbon, and therefore only the plankton of eutrophic lakes conformed to the classical phytoplankton-based food web. In most lakes, excess heterotrophic activity could be supported by inputs of organic matter from the drainage basin. Excess plankton respiration, fueled by allochthonous organic carbon, could represent an important source of CO$ sb2$ to lakes.
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Sanderson, Rory J. "Ecology of freshwater plankton in contrasting hydraulic environments." Thesis, University of Leicester, 1998. http://hdl.handle.net/2381/29785.
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The effects of contrasting water residence time on the planktonic community of three water bodies was studied. The sites were Rutland Water, Covenham reservoir and the River Nene, in order of decreasing retention time. The river was the only site where the residence time was sufficiently short to directly impact upon planktonic populations. The importance of physical mechanisms of control in the river was indicated by the dominance of r-selected phytoplankton, namely diatoms and green algae, and zooplankton, namely rotifers. This pattern was in contrast to that of the reservoirs in which slower-growing cyanobacteria and cladocerans dominated. Riverine rotifers were found to have rapid population turnover, due to a combination of short pre-adult duration and high maximum growth rates. Some species also showed a shift in reproductive behaviour to the constant production of resting eggs. This was assumed to convey benefits in a system where resting stages may be less susceptible than adults to downstream displacements. The total chlorophyll 'a' concentration achieved per unit phosphorus was significantly lower in the river than either of the reservoirs. Algal density was negatively associated with discharge in the Nene, suggesting the importance of physical control. The relationship was not a simple one, however, as periods of increased retention time during the summer were associated with low algal density. The absolute density of rotifers was found to be constrained by discharge. Animals were rare above a threshold flow velocity of 0.08ms-1. Simple models of water flow in open channels were insufficient to account for the continued persistence of a plankton in the Nene given the level of advection. It was assumed that the overall retention time of the system was increased by the presence of dead zones within the channel which 'held' planktonic organisms for sufficient time for populations to develop. This behaviour was important during the spring when population density increased in the main channel.
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Penczykowski, Rachel M. "Interactions between ecosystems and disease in the plankton of freshwater lakes." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50368.
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I investigated effects of environmental change on disease, and effects of disease on ecosystems, using a freshwater zooplankton host and its fungal parasite. This research involved lake surveys, manipulative experiments, and mathematical models. My results indicate that ecosystem characteristics such as habitat structure, nutrient availability, and quality of a host’s resources (here, phytoplankton) can affect the spread of disease. For example, a survey of epidemics in lakes revealed direct and indirect links between habitat structure and epidemic size, where indirect connections were mediated by non-host species. Then, in a mesocosm experiment in a lake, manipulations of habitat structure and nutrient availability interactively affected the spread of disease, and nutrient enrichment increased densities of infected hosts. In a separate laboratory experiment, poor quality resources were shown to decrease parasite transmission rate by altering host foraging behavior. My experimental results also suggest that disease can affect ecosystems through effects on host densities and host traits. In the mesocosm experiment, the parasite indirectly increased abundance of algal resources by decreasing densities of the zooplankton host. Disease in the experimental zooplankton populations also impacted nutrient stoichiometry of algae, which could entail a parasite-mediated shift in food quality for grazers such as the host. Additionally, I showed that infection dramatically reduces host feeding rate, and used a dynamic epidemiological model to illustrate how this parasite-mediated trait change could affect densities of resources and hosts, as well as the spread of disease. I discuss the implications of these ecosystem–disease interactions in light of ongoing changes to habitat and nutrient regimes in freshwater ecosystems.
4
She, Nian. "Chaos in aquatic systems /." Thesis, Connect to this title online; UW restricted, 1995. http://hdl.handle.net/1773/6370.
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Henshaw, Tracey. "Seasonal microbial dynamics in two ultra-oligotrophic Antarctic freshwater lakes." Thesis, University of Nottingham, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368363.
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McKinnon-Newton, Laurie. "Ecology of plankton in a terminal lake Walker Lake, Nevada, USA /." abstract and full text PDF (free order & download UNR users only), 2007. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1446303.
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Thompson, Patrick Lyn. "Regional plankton diversity as a buffer against environmental change in freshwater ecosystems." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/17411.
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Many experiments show that species diversity at small, local scales affects ecosystems;
however, conservation is concerned with extinctions of species across broad
landscapes. The relevance of global or regional diversity to ecosystems therefore
remains in question. I asked whether regional biodiversity in freshwater zooplankton
affects the resilience and resistance of local ecosystems to the multiple stressors of
warming and salinization. I hypothesised that dispersal of species from the regional
community should buffer ecosystems against environmental change by providing
species with traits adapted to the novel conditions. I subjected freshwater zooplankton
communities in mesocosms that were either connected to or isolated from the larger
regional species pool to a factorial manipulation of experimental warming and increased
salinity. Dispersal introduced heat-tolerant regional taxa that were able to compensate
for reductions in local taxa under warmed conditions. Dispersal also dampened the
effects of warming on net primary productivity, suggesting that regional diversity can
provide stability against some aspects of climate change. However, other measures of
ecosystem performance like decomposition and sedimentation were affected by
warming and salinity but not dispersal. The results indicate that regional biodiversity
provides important insurance that can stabilize ecosystems in a dynamic environment.
However, compensation by the regional biota could not buffer all ecosystem rates
against all sources of stress. My results show that the connectivity of habitats to
regional biodiversity introduces species with broad ranges of traits that can maintain
some local ecosystem function in the face of environmental changes.
8
Thompson, Lisa C. "The influence of hydraulic retention time on planktonic biomass in lakes and reservoirs /." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=56754.
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Hydraulic retention time (HRT) might contribute to the substantial variation in phosphorus-chlorphyll and chlorophyll-zooplankton models because rapid flushing might depress plankton development. However, for a world-wide data set. HRT was not correlated with chlorophyll. Total phosphorus had no effect on chlorphyll when hypereutrophic sites were considered separately, but chlorophyll was negatively related to HRT. Short term HRT, averaged over periods up to one month, was not correlated with chlorophyll, or zooplankton biomass, in seven impoundments on the St. Lawrence and Ottawa Rivers. The size distribution of algae was not affected by HRT. The proportion of rotifer to total zooplankton biomass was positively related to HRT, but this trend disappeared when nauplius biomass was removed from the total. These results indicate that rapid flushing does not necessarily reduce planktonic biomass and that short term HRT is not useful for the prediction and management of planktonic biomass in these systems.
9
Huang, Hui Doyle Robert D. "Spatial and temporal patterns of planktonic and community metabolism along the riverine-lacustrine gradient in Texas reservoirs." Waco, Tex. : Baylor University, 2006. http://hdl.handle.net/2104/4958.
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Tewes, Miriam [Verfasser], and Hans-Curt [Akademischer Betreuer] Flemming. "Association of hygienically relevant microorganisms with freshwater plankton / Miriam Tewes ; Betreuer: Hans-Curt Flemming." Duisburg, 2020. http://d-nb.info/1213910552/34.
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Arenovski, Andrea Lynn. "The distribution, abundance and ecology of mixotrophic algae in marine and freshwater plankton communities." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/33523.
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Briland, Ruth. "Evaluating the causes and consequences of ecosystem change in Lake Erie: From plankton to fish." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1532076326598788.
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Katechakis, Alexis. "Selected interactions between phytoplankton, zooplankton and the microbial food web: Microcosm experiments in marine and limnic habitats." Diss., Connect to this title online, 2006. http://edoc.ub.uni-muenchen.de/archive/00005047/.
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Thesis (doctoral)--Ludwig-Maximilians-Universität München, 2006.Title from PDF t.p. (viewed on May 14, 2006). Includes reprints of papers co-authored with others. Vita. Includes bibliographical references.
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Reaugh, Matthew L. "The effects of freshwater flow and grazing on the plankton community structure of Chesapeake Bay tributaries." College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/2537.
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Thesis (M.S.) -- University of Maryland, College Park, 2005.Thesis research directed by: Marine, Estuarine, Environmental Sciences Graduate Program. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
15
Beckwith, Matthew. "Coupling of autotrophic and heterotrophic plankton food web components in the tidal-freshwater James River, USA." VCU Scholars Compass, 2009. http://scholarscompass.vcu.edu/etd/1706.
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Empirical studies have shown that algal- and detrital-based food web components are coupled in many pelagic systems as algal carbon enhances bacterioplankton production and growth efficiencies. Such phyto-bacterioplankton coupling impacts carbon flow through plankton food webs, yet the extent of coupling is poorly understood in systems receiving large amounts of allochthonous carbon. To investigate this issue, bacterioplankton abundance (BA) and community composition were compared to chlorophyll a concentrations and phytoplankton production in the tidal-freshwater James River (VA). BA averaged 107 cells mL-1 and was significantly related to chlorophyll a, phytoplankton production, and DOC concentrations. Analysis of DOC quality using fluorescence spectroscopy revealed that the fulvic DOC fraction was dominated by allochthonous compounds. However, estimates of DOC C:N and DOC turnover rates indicated that DOC was more labile in the lower part of the study reach where BA was highest. T-RFLP analysis of 16s rDNA showed that bacterioplankton community composition significantly varied between the upper and lower portions of the sampling reach. These findings suggest that coupling of food web components is an important pathway affecting carbon cycling within the tidal-fresh water James River.
16
Ahrens, M. (Martin). "The size distribution of the limnoplankton /." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=75985.
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The hypothesis that aquatic biomass is uniformly distributed over logarithmic size classes was evaluated with samples from epilimnetic plankton communities. Although the hypothesis is true for oligotrophic lakes, biomass increases between successive size classes in mesotrophic and eutrophic lakes. The abundance of organisms in logarithmic size intervals is strongly negatively correlated with size. The relationship between organism size and physiological performance in mixed communities was examined by testing the hypothesis that limnoplankton respiration rates are predictable functions of mean body size. The equation governing this relationship was found to be similar to those obtained with laboratory cultures. The total epilimnetic phosphorus concentration is correlated with both biovolume and respiration rate. Many limnological relationships, including those established in this thesis, are based on linear regressions between log-transformed variables. The rules for the correct use of backtransformed predictions are elucidated. A theorem is proven, which sets limits to the relationship between the coefficients of determination on the original and transformed scales. Simulated data and empirical results are used to illustrate the applications and limitations of the theoretical results.
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Tewes, Miriam [Verfasser], Hans-Curt [Akademischer Betreuer] Flemming, and Bernd [Akademischer Betreuer] Sures. "Association of hygienically relevant microorganisms with freshwater plankton / Miriam Tewes. Gutachter: Bernd Sures. Betreuer: Hans-Curt Flemming." Duisburg, 2013. http://d-nb.info/1031879668/34.
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Kerrison, P. "Effects of low concentrations of heavy metals on plankton community dynamics in a small, fertile, freshwater lake." Thesis, University of East Anglia, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372349.
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Harlin, Hugo. "2D Modelling of Phytoplankton Dynamics in Freshwater Lakes." Thesis, Uppsala universitet, Avdelningen för beräkningsvetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-388868.
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Phytoplankton are single celled organisms capable of phytosynthesis, and are present in all the major oceans and lakes in the world. Phytoplankton contribute to 50% of the total primary production on Earth, and are the dominating primary producer in most aquatic ecosystems. This thesis is based on the 1D deterministic model by Jäger et. al. (2010) which models phytoplankton dynamics in freshwater lakes, where phytoplankton growth is limited by the availability of light and phosphorus. The original model is here extended to two dimensions to include a horizontal dimension as well as a vertical dimension, in order to simulate phytoplankton dynamics under varying lake bottom topographies. The model was solved numerically using a grid transform and a finite volume method in MATLAB. Using the same parameter settings as the 1D case studied by Jäger et. al. (2010), an initial study of plankton dynamics was done by varying the horizontal and vertical diffusion coefficients independently.
20
Carpenter, Kurt Davis. "Indicators of Nutrient Limited Plankton Growth in Lakes Near Mount Saint Helens, Washington." PDXScholar, 1994. https://pdxscholar.library.pdx.edu/open_access_etds/4874.
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Several lakes located in the blast zone of the 1980 eruption of Mount St. Helens were studied to determine if the plankton in the lakes were limited in their growth by nitrogen or phosphorus availability. Long term nutrient enrichment experiments were performed on lake water from five lakes and measures of chlorophyll-a, carbon fixation, and nutrient uptake were used to evaluate the extent of limitation. Nutrient concentrations, ratios, and uptake from 14 lakes provided additional evidence for limitation by nitrogen and/or phosphorus. The physical, chemical, and biological characteristics of the lakes were also examined to monitor the return of these lakes to pre-eruption conditions. Lakes heavily impacted by the 1980 eruption (Ryan, Fawn, and Hanaford Lakes) and newly formed Castle Lake produced positive responses to nitrogen additions, reflecting the continuing importance of nitrogen in these lakes. Evidence for colimitation by phosphorous was apparent in some of the lakes. Venus Lake, located near the fringe of the blast zone received less organic debris and responded only with phosphorus additions. Evaluations of nutrient depletion from the photic zones of these lakes during the growing season supported the results from the bioassays. Two measures of growth (chlorophyll-a and carbon fixation) often responded differently to enrichment, suggesting active algal and bacterial communities in some of the lakes. Qualitative measures of alkaline phosphatase activity normalized to chlorophyll-a indicated that those lakes which contained the highest dissolved organic carbon and bacterial counts following the eruption had higher alkaline phosphatase activities than less impacted lakes, suggesting bacterial enzyme production. Alkaline phosphatase activity confirmed that phosphorus limitation was more severe in lakes having less soluble reactive phosphorus. Most of the lakes appear to be similar to other Cascade Mountain lakes, although many have reduced dissolved oxygen concentrations in the bottom waters during stratification. Incomplete mixing of these lakes during periods of circulation may regulate the decomposition of the organic material and hence, full recovery of these lakes.
21
Kane, Douglas D. "The development of a planktonic index of biotic integrity for Lake Erie." Connect to this title online, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1092242571.
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Thesis (Ph. D.)--Ohio State University, 2004.Title from first page of PDF file. Document formatted into pages; contains xxii, 277 p.; also includes graphics. Includes bibliographical references (p. 252-277). Available online via OhioLINK's ETD Center.
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Weissbach, Astrid. "The role of allelopathy in microbial food webs." Doctoral thesis, Linnéuniversitetet, Institutionen för naturvetenskap, NV, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-11375.
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Phytoplankton produce allelochemicals; excreted chemical substances that are affecting other microorganisms in their direct environment. In my thesis, I investigated strain specific variability in the expression of allelochemicals of the harmful flagellate Prymnesium parvum, that is euryhaline but mainly bloom forming in brackish water. I found a large variation among strains, but further showed that all strains of P. parvum were more allelopathic in brackish water compared to marine water. In a marine microbial community, allelochemicals can affect prey, competitors and grazers both, directly and indirectly. For instance, in a food web where grazing controls prey abundance, the negative direct effect of allelochemicals on grazers will positive affect their prey. During my thesis, I investigated how marine microbial communities respond to the addition of allelochemicals. I performed field experiments with microbial communities from seawater collected from different places over Europe, and tested how this communities respond to the addition of allelochemicals from the dinoflagellate Alexandrium tamarense. Before I incubated the microbial communities for several days with A. tamarense algal filtrate, I evaluated the allelopathic efficiency of the algal filtrates with an algal monoculture of Rhodomonas spp. This allowed me to compare the effect of A. tamarense filtrate between the different microbial communities. In general, bacteria reached higher abundances when allelochemicals were present. As allelochemicals also inhibited nanoflagellates and ciliates, we concluded, that allelochemicals indirectly benefit bacteria by reducing grazing pressure. In microbial food webs with many heterotrophic grazers, allelochemicals further benefitted other phytoplankton by inhibiting grazers. It was also shown that bioavailable DOM is released from a microbial community when allelochemicals are present. As most DOM was released from the seawater fraction > 60 μm, we concluded, that larger microorganisms are more affected by allelochemicals than smaller microorganisms. The results can be explained by the surface to volume ratio of microorganisms: Larger organisms provide more contact surface for allelochemicals, and therefore, are probably more vulnerable towards allelochemicals. In conclusion, the effect of allelochemicals on a microbial community depends among others on the structure of the microbial food web, the amount of available DOM, the particle density in the seawater and the composition of the phytoplankton community.
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Cescon, Cinzia Tatiana. "The 1996 population dynamics of microcrustacean zooplankton at Prairie Creek Reservoir in Delaware County, Indiana." Virtual Press, 1997. http://liblink.bsu.edu/uhtbin/catkey/1048368.
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This research was conducted to provide baseline data on the population dynamics of microcrustacean zooplankton at Prairie Creek Reservoir in Delaware County, Indiana from 24 January 1996 to 30 December 1996. This lake is a shallow lake (average depth <8m) used for recreational fishing and water supply for the local community. No published studies of zooplankton have previously been conducted at this location. I intended to test the hypothesis that Prairie Creek Reservoir has the same microcrustacean populations of shallow lakes in this region. The findings were compared to other studies in several North American lakes and reservoirs. Biotic and abiotic factors were considered as related to the population dynamics of zooplankton. Zooplankton serve as a critical forage base for many fish species, including several of economic importance. Increases and changes in species composition of zooplankton organisms associated with eutrophic conditions may also be an indication of deteriorating water quality (Gannon 1972). The data from this research suggest that Prairie Creek Reservoir has the typical zooplankton populations of a shallow, eutrophic North American lake. The presence of relatively high numbers of organisms generally associated with eutrophic environments, such as Bosmina longirostris, Leptodiaptomus siciloides, Acanthocyclops vernalis, and others supports this idea. The data from this study will be helpful to fisheries and environmental managers and will provide a baseline for future studies.Department of Biology
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Ng, Patti A. "Trends in the nearshore zooplankton community in the Indiana waters of Lake Michigan, 1990-1996." Virtual Press, 1997. http://liblink.bsu.edu/uhtbin/catkey/1041923.
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Zooplankton samples collected May through August, 1990 to 1996 at site M, 15 m depth in the Indiana waters of Lake Michigan were examined for microcrustaceans, rotifers, and zebra mussel (Dreissena polymorpha) veligers. Abundance numbers per m3 were combined with Coffman's (1995) data to quantify recent trends in the zooplankton.Rotifers dominated the community, with Polyarthra vulgaris, Colurella, Keratella crassa, and K. cochlearis the most prevalent species. Copepods, primarily nauplii and copepodid forms, were the next most abundant taxa. Except for 1994 and 1995, Cladocera abundance was higher than zebra mussel veliger abundance. The cladoceran assemblage was dominated by Bosmina Iongirostris, with very few Daphnia noted. A precipitous decrease in zebra mussels veligers from 1994 to 1996 warrants further investigation to determine the nature and the extent of the population decline.Regression analysis of zebra mussel veliger abundance against abiotic and biotic factors demonstrated veligers varied directly with rotifer abundance and water column temperature and indirectly with cladoceran and yellow perch (Perca flavescens) abundance. A similar regression model of rotifer abundance revealed direct correlation with calanoid, cladoceran, zebra mussel veliger, and yellow perch abundance.Department of Biology
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Menting, Victor Lee. "The Biogeochemistry of Lakes in the Mount St. Helens Blast Zone." PDXScholar, 1995. https://pdxscholar.library.pdx.edu/open_access_etds/4927.
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Dilution and ash weathering are the most important processes controlling the ion chemistry of lakes in the Mount St. Helens blast zone. Gibbs' models indicated total dissolved solids were decreasing as a result of dilution from high precipitation and runoff and the lakes plot in the rock weathering dominated region. Plots of theoretical dilution curves indicated a decline in ion concentrations as a result of dilution. Ion concentrations followed the exponential decline predicted by the dilution curve, although concentrations were higher than predicted by the curve. Increased concentrations were a result of the rapid weathering of ash in basins and on lake bottoms. Rapid weathering of ash in lake watersheds and on lake bottoms continues to influence the ionic concentrations of the lakes. In general, sodium and potassium have declined at a much faster rate than calcium or magnesium. Slower relative declines in concentrations of calcium and magnesium were a result of more rapid rate of leaching of calcium and magnesium from the ash. Ash in the watersheds will continue to be a major contributor to the overall ion chemistry of the lakes until such time as the watersheds are stabilized by vegetation and a permanent soil layer. Ash on lake bottoms will be unavailable as sources of ionic constituents when it becomes buried within deep sediment layers. Ion concentrations observed in study lakes affected by the eruption were similar to those observed in control lakes with few exceptions. Although ion concentrations in affected lakes have declined to values observed in control lakes, most were at higher concentrations than the regional means. Several functions of the ion chemistry were used to correlate planktonic community structure to lake ion chemistry. The data suggested ion chemistry was not influencing biological community structures as no patterns emerged. Analysis of diatom populations with respect to monovalent:divalent cation ratios showed no correlation.
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Scharnberg, Larry Duane. "Zooplankton Community Structure in Lakes Near Mt. St. Helens, WA." PDXScholar, 1995. https://pdxscholar.library.pdx.edu/open_access_etds/5050.
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Eighteen lakes around Mt. St. Helens (MSH) were sampled for zooplankton from September '92 until September '94. Samples were enumerated and identified to the species level in most cases. Standard deviation and t-tests were performed to determine the precision of enumeration methods and replication of duplicate tows. Palatability indexes based upon predator preferences were developed and coupled with length-frequency analyses as indicators of predation pressure. The weighted means of the summer samples were then subjected to cluster analysis in an attempt to categorize lakes with respect to zooplankton community structure. Lastly, the community compositions and abundances of MSH lakes were compared to those in lakes on Mt. Rainier and Mt. Hood in an attempt to assess recovery of MSH lakes from the 1980 eruption. Results of analyses indicate the presence of three distinct groups of lakes: 1) A group of lakes with heavy predation resulting in simplified zooplankton communities dominated by Keratella, Ke/licottia, and sometimes cyclopoid species. Predation in these instances can be attributed to extremely high fish or Chaoborus abundance. 2) A second group of lakes characterized by great depth, high transparency, significant abundances of Diaptomus kenai, and moderate to light fish predation. These lakes support balanced zooplankton communities with substantial proportions of Daphnid and calanoid specimens attaining large size. Significant indications of size-specific niche differentiation among the cladocerans are notably absent from these first two groups. 3) A third group consists of lakes which appear to be more productive than the other two groups. This group has higher biovolumes of zooplankton in general, coexistence of several different sized cladoceran species, the highest diversity indices of all the lakes sampled, and moderate predation as indicated by length-frequency analysis. Two conclusions are drawn from the data. First, it appears that predation and primary productivity are both significant factors affecting the abundance and composition of MSH zooplankton communities. Additionally, these data document a significant overlap in zooplankton species in lakes near Mt. Rainier and Mt. Hood, suggesting that the zooplankton communities in lakes around MSH have recovered from the effects of the 1980 eruption.
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Meilander, Tracey Trzebuckowski. "The Role of Bacterioplankton in Lake Erie Ecosystem Processes: Phosphorus Dynamics and Bacterial Bioenergetics." [Kent, Ohio] : Kent State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=kent1163880480.
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Thesis (Ph.D.)--Kent State University, 2006.Title from PDF t.p. (viewed Mar. 5, 2009). Advisor: Robert T Heath. Keywords: bacterioplankton, phosphorus dynamics, bacterial bioenergetics, labile dissolved organic carbon, bacterial productivity, bacterial respiration, bacterial growth efficiency, Lake Erie, hypoxia. Includes bibliographical references (p. 357-397).
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OCK, Giyoung. "PARTICULATE ORGANIC MATTER DYNAMICS IN THE DOWNSTREAM OF DAM RESERVOIRS: ROLES OF CHANNEL GEOMORPHOLOGY AND RESPONSES OF BENTHOS COMMUNITIES." 京都大学 (Kyoto University), 2010. http://hdl.handle.net/2433/120804.
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Ersoy, Zeynep. "Biotic and environmental factors shaping body size distributions in freshwater planktonic food webs." Doctoral thesis, Universitat de Vic - Universitat Central de Catalunya, 2018. http://hdl.handle.net/10803/665387.
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Les interaccions basades en la mida individual dels organismes tenen un paper important en la dinàmica de la comunitat i en els processos dels ecosistemes aquàtics, ja que la mida d’un individu és un tret clau dels organismes molt vinculat a la seva taxa metabòlica. El canvi climàtic i les pertorbacions afecten a les xarxes tròfiques planctòniques d'aigua dolça, debilitant les interaccions basades en la mida dels individus.
En aquesta tesi es van desenvolupar quatre estudis relacionats però independents per obtenir una comprensió més profunda de les interaccions tròfiques basades en la mida individual dels organismes. L’objectiu era demostrar com els factors biòtics i ambientals afecten les interaccions basades en la mida dels individus de xarxes tròfiques planctòniques utilitzant aproximacions observacionals i experimentals en diferents localitats a Europa.
Generalitzant, les nostres troballes clau d'aquesta tesi ressalten la importància d’integrar les relacions basades en la mida dels organismes i la resiliència de les comunitats amb la variació intraespecífica dels organismes a l’hora d’estudiar les interaccions tròfiques entre els organismes d’un ecosistema aquàtic. La comprensió d'aquestes interaccions ens permetrà gestionar i restaurar millor els ecosistemes aquàtics davant el canvi climàtic i altres pertorbacions induïdes per l'home.Individual size-based interactions play a significant role in the community dynamics and ecosystem processes of aquatic ecosystems, because body size is a key trait of organisms that is highly linked to metabolic rates. Climate change and disturbances influence freshwater planktonic food webs, weakening the strength of size-based interactions. In this thesis, we conducted four related but independent studies to obtain a deeper understanding of the size-based trophic interactions. We aimed to demonstrate biotic and environmental factors influencing size-based interactions in planktonic food webs using observational and experimental approaches at different locations in Europe. Overall, our key findings from this thesis suggest that integrating size-based relationships and resilience of communities together with intraspecific variation is important while studying trophic interactions. Understanding these interactions will allow us to better manage and restore aquatic ecosystems in the face of climate change and other human-induced disturbances.
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Brittain, Jeffrey Thomas. "The Response of Zooplankton Communities in Montane Lakes of Different Fish Stocking Histories to Atmospheric Nitrogen Deposition Simulations." PDXScholar, 2015. https://pdxscholar.library.pdx.edu/open_access_etds/2394.
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Freshwater ecosystems are subject to a wide variety of stressors, which can have complex interactions and result in ecological surprises. Non-native fish introductions have drastically reduced the number of naturally fishless lakes and have resulted in cascading food web repercussions in aquatic and terrestrial habitats. Additional anthropogenic influences that result from increases in global airborne emissions also threaten wildlife habitat. Atmospheric nitrogen deposition has been recognized as an anthropogenic contributor to acidification and eutrophication of wilderness ecosystems. Planktonic communities have shown declines in response to predation and shifts in composition as a result of nutrient inputs and acidification, both of which are potential fates of nitrogen deposition. This study identified the response of zooplankton communities from two lakes (fish present vs. absent) in Mount Rainier National Park to manipulations simulating an episodic disturbance event in mesocosms. The experiment used a 2 x 2 factorial design with acid and nitrogen treatments. Treatments resulted in significantly elevated nitrogen and decreased pH conditions from control mesocosms over 42 days, indicating that the treatment effects were achieved. Results indicate that zooplankton communities from lakes with different food web structure respond differently to the singular effects of acid and nitrogen addition. Surprisingly, the interaction of the two stressors was related to increases in community metrics (e.g., abundance, biomass, body size, richness, and Shannon-Weiner diversity) for both lake types. This work can aid management decisions as agencies look to restore more aquatic montane habitats to their historic fishless states, and assess their abilities to recover and afford resistance to atmospheric pollution.
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Perriss, Stephen James. "The physiological ecology of photosynthetic ciliated protozoa and their trophic roles in freshwater and brackish planktonic microbial food webs." Thesis, Lancaster University, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334069.
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Reboul, Guillaume. "Metabarcoding and metagenomic approaches to decipher microbial communities in suboxic environments Microbial eukaryotes in the suboxic chemosyn- thetic ecosystem of Movile Cave, Romania Hyper- diverse archaea near life limits at the polyextreme geothermal Dallol area Performance of the melting seawater-ice elution method on the metabarcoding characterization of benthic protist communities Core microbial communities of lacustrine microbialites sampled along an alkalinity gradient Environmental drivers of plankton protist communities along latitudinal and vertical gradients in the oldest and deepest freshwater lake Ancient Adaptive Lateral Gene Transfers in the Symbiotic Opalina-Blastocystis Stramenopile Lineage Marine signature taxa and microbial community stability along latitudinal and vertical gradients in sediments of the deepest freshwater lake." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASL041.
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L’écologie microbienne concerne l’étude des microorganismes et de leurs interactions biotiques et abiotiques dans un écosystème donné. Ces vingt dernières années, l’avancement des techniques moléculaires pour analyser la diversité microbienne et, notamment, les nouvelles technologies de séquençages (NGS) ont permis de surmonter les limitations associées aux approches traditionnelles basées sur la culture et la microscopie. Ces approches moléculaires ont conduit à une accumulation des données de diversité microbienne et de potentiel métabolique dans des communautés microbiennes des écosystèmes variés.Cependant, ces efforts ont été principalement appliqués sur des environnements facilement accessibles ou liés à l’humain, comme le plancton (marin principalement) et la flore intestinale. Néanmoins, ceci a conduit à une très forte augmentation de données environnementales et au développement de la bioinformatique par le biais de nombreux outils. Parmi les environnements délaissés des études, les environnements faibles en oxygène sont probablement également porteurs de nouveautés phylogénique ou métaboliques.Afin de palier à cela, nous avons choisi d’explorer deux environnements suboxiques relativement peu étudiés : la cave Movile (Roumanie) et les sédiments du lac Baikal (Sibérie, Russie). Notre but étant de montrer les diversités phylogénétiques et fonctionnelles des microbes de ces biotopes.Pour cela, j’ai d'abord développé un pipeline d’analyse de données métabarcoding (petite sous-unités ribosomique). Ensuite, j’ai appliqué cet outil sur des données de métabarcoding de protistes provenant d’échantillons d’eau et de tapis microbiens de la cave de Movile, un écosystème chemosynthétique pratiquement fermé. Nous avons montré que la diversité des protistes de la cave s’étendait à quasiment tous les grands groupes eucaryotes et provenait à la fois d’origine d’eaux douces et marines. De plus, la plupart ont été affiliées à des groupes d’organismes typiquement anaérobies, ce qui est concordant avec les paramètres abiotiques de la cave. Écologiquement, ces protistes sont des prédateurs mais aussi vraisemblablement des partenaires symbiotiques avec des espèces procaryotes de la cave.Dans une deuxième étude, j’ai eu l’opportunité d’appliquer ce pipeline de métabarcoding sur des données procaryotes et eucaryotes provenant des couches superficielles des sédiments du lac d’eau douce Baikal. Comme attendu, les communautés microbiennes dans ces sédiments sont particulièrement diverses et relativement enrichis en archées. Nous avons aussi pu mettre en évidence des lignées que l’on pensait exclusivement marines dans ces sédiments. Ces lignées sont probablement planctoniques mais s’accumulent au fond par sédimentation. Enfin, les échantillons ont été prélevés dans le but de tester les influences de la profondeur, du bassin et de la latitude sur les communautés. Aucune d’elles ne s’est révélée significative.Dans une troisième étude, j'ai utilisé une approche métagénomique afin de révéler les acteurs écologiquement majeurs dans les sédiments, leurs rôles et de reconstruire leurs génomes. Cela nous a permis notamment de mettre en évidence le rôle primordial des Thaumarchaeota dans le cycle de l’azote et la production primaire de molécules de carbone. Les chloroflexi et les protéobacteries ont aussi un rôle important dans la surface des sédiments du lac Baikal. Ce travail de thèse participe à la connaissance globale de la diversité microbienne sur la planète en mettant en lumière des environnements peu étudiés. De plus, l’étude de la surface des sédiments du lac Baikal apporte de nouvelles données sur le sujet de la transition eau douces/eau marines des microbes. Enfin, la métagénomique a permis de révéler le cycle des nutriments et les microorganismes y participant dans ces échantillons de sédiment. En résumé, ce travail vient mettre en lumière l’écologie microbienne d’écosystèmes suboxiques, notamment la surface des sédiments du lac BaikalMicrobial ecology is the science of micro-organisms and their biotic and abiotic interactions in a given ecosystem. As technology has advanced, molecular techniques have been widely used to overcome the limitations of classical approaches such as culturing and microscopy. Indeed, the development of Next Generation Sequencing (NGS) technologies in the past twenty years has largely helped to unravel the phylogenetic diversity and functional potential of microbial communities across ecosystems.Nonetheless, most of the environments studied through these techniques concentrated on relatively easily accessible, tractable and host-related ecosystems such as plankton (especially in marine ecosystems), soils and gut microbiomes. This has contributed to the rapid accumulation of a wealth of environmental diversity and metagenomic data along with advances in bioinformatics leading to the development of myriads of tools. Oxygen-depleted environments and especially their microbial eukaryote components are less studied and may lead to future phylogenetic and metabolic discoveries.In order to address this, we conducted analyses on two poorly studied suboxic ecosystems: Movile Cave (Romania) and lake Baikal sediments (Siberia, Russia). In this task, we aimed at unveiling the taxonomic and functional diversity of microorganims in these environments.To do so, I first evaluated the available bioinformatics tools and implemented a bioinformatics pipeline for 16S/18S rRNA gene-based metabarcoding analysis, making reasoned methodological choices. Then, as a case study, I carried out metabarcoding analyses of the water and floating microbial mats found in Movile Cave in order to investigate its protist diversity. Our study showed that Movile Cave, a sealed off chemosynthetic ecosystem, harbored a substantial protist diversity with species spanning most of the major eukaryotic super groups. The majority if these protists were related to species of freshwater and marine origins. Most of them were putatively anaerobic, in line with the cave environment, and suggesting that in addition to their predatory role, they might participate in prokaryote-protist symbioses.In a second study, I applied my metabarcoding pipeline to explore unique and relatively unexplored environment of Lake Baikal sediments. I first applied a metabarcoding approach using 16S and 18S rRNA genes to describe prokaryotic as well as protist diversity. Overall, the communities within these ecosystems were very diverse and enriched in ammonia-oxidizing Thaumarchaeota. We also identified several typical marine taxa which are likely planktonic but accumulate in sediments. Finally, our sampling plan allowed us to test whether differences across depth, basin or latitude affected microbial community structure. Our results showed that the composition of sediment microbial communities remained relatively stable across the samples regardless of depth or latitude.In a third study, we applied metagenomics to study the metabolic potential of communities associated to Baikal sediments and to reconstruct metagenome-assembled genomes (MAGs) of dominant organisms. This revealed the considerable ecological importance of Thaumarchaeota lineages in lake Baikal sediments, which were found to be the major autotrophic phyla and also very implicated in the nitrogen cycle. Chloroflexi and Proteobacteria-related species also appeared ecologically important.This PhD thesis reveals the taxonomic diversity of poorly studied suboxic ecosystems and therefore contributes to our knowledge of microbial diversity on Earth. Additionally, the analyses of surface sediment samples in lake Baikal adds new light on freshwater-marine transitions. The metagenomic analyses reported here allowed us to postulate a model of nutrient cycle carried out by microorganismsin these sediments. Overall, this work sheds light on the microbial ecology of oxygen-depleted environments, and most notably lake Baikal surface sediments
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Marvalin, Olivier. "ABONDANCEcr, BIOMASSE, ACTIVITE ET RELATIONS TROPHIQUES DES COMMUNAUTES BACTERIENNES HETEROTROPHES DU LAC D'AYDAT (PUY DE DOME) : contribution a l'etude du fonctionnement des systemes aquatiques." Clermont-Ferrand 2, 1988. http://www.theses.fr/1988CLF21086.
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Mraz, Alexis Layman. "Forecasting in the Unseeable: A Mixed Methods Model of Planktonic and Biofilm-Bound Legionella pneumophila in Building Water Systems." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu154350645678355.
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Vail, Timothy L. "Morphometric and isozyme analysis of the planktonic cladoceran Holopedium gibberum (zaddach) /." Diss., 2000. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:9982859.
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Lai, Chao-Chen, and 賴昭成. "Temperature effects on plankton community respiration in a subtropical freshwater ecosystem." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/sf6cc5.
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博士國立臺灣大學
海洋研究所
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With a ten-year weekly to biweekly data set taken from a P-limited subtropical reservoir, this study intends to explore the potential mechanisms in controlling the temporal variation of plankton community respiration rate (CR) and bacterial respiration rate (BR). Summer not only had high CR and BR value, but also high variation. The results showed that CR, BR, specific plankton community respiration (SCR), and specific bacterial respiration (SBR) all correlated with temperature significantly (p < 0.05). Activation energy, Ea, of CR is 0.80±0.04, SCR is 0.34±0.06, BR is 0.93±0.06, and SBR is 0.39±0.06. The results also indicated that temperature might be the major controlling factor for CR and BR. We also found that Ea-BR is high than Ea-CR, which indicate that BR was more sensitive to temperature than CR. Temperature manipulation experiment provide a situation to estimate temperature effect in wilder range. However, the most common characteristic of temperature response, activation energy (Ea), might be more variation. Our result combined two years temperature manipulation, the result proved that BR is more sensitive than CR either short-term temperature change (CR:0.69 and BR: 1.07) or long-term seasonal variation(CR: 0.67 ± 0.05 and BR:0.94 ± 0.08). Temperature change would increase system unstability. Two years result comparison showed that environmental condition would affect result warming.
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Rusak, James A. "Variability in the zooplankton of north-temperate lakes its estimation, spatial and temporal extent, synchrony, and the influence of environmental change /." 2000. http://wwwlib.umi.com/cr/yorku/fullcit?pNQ56267.
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Thesis (Ph. D.)--York University, 2000.Typescript. Includes bibliographical references. Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pNQ56267.
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Beckwith, Matthew J. "Coupling of autotrophic and heterotrophic plankton food web components in the tidal-freshwater James River, USA: /." 2009. http://hdl.handle.net/10156/2397.
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Brepohl, Daniela Christine [Verfasser]. "Fatty acids distribution in marine, brackish and freshwater plankton during mesocosm experiments / vorgelegt von Daniela Christine Brepohl." 2005. http://d-nb.info/975488422/34.
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Seaman, M. T. "A zooplankton study of Hartbeespoort Dam." Thesis, 2014. http://hdl.handle.net/10210/11141.
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Grünwald, Herbert M. [Verfasser]. "Effects of a pesticide mixture on plankton in freshwater mesocosms - from single substance studies to combination impacts / Herbert M. Grünwald." 2004. http://d-nb.info/970274114/34.
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Mnisi, Peral. "A taxonomic study of the planktonic freshwater free-living copepods in Turfloop Dam, Limpopo Province." Thesis, 2021. http://hdl.handle.net/10386/3489.
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Thesis (M.Sc. (Zoology)) -- University of Limpopo, 2021Representatives of the subclass Copepoda are the most abundant aquatic crustaceans found in most water bodies including fresh, estuarine and marine waters. Planktonic copepods contribute a major portion to the aquatic productivity and biomass in these ecosystems. Most are generally omnivorous which make them important in the energy transfer of aquatic environments. Copepods also serve as a food source for aquatic organisms including fish. Currently there are 11 137 species worldwide belonging to 10 orders. Most free-living species reported from freshwater bodies of South Africa belong to the orders Calanoida (Family Diaptomidae) and Cyclopoida (Family Cyclopidae). The copepod life cycle starts with the hatching of the eggs into nauplii (6 stages) which then molt into copepodids (5 stages), followed by the molting into the adult male and female. These copepods have high morphological diversity and as a result identification is mostly done using the morphological characteristics of the adult stage, specifically the length and shape of the antennules, the structure of the fifth legs and the relative size of the metasoma and urosome. However, identification based on morphological analyses is a cumbersome process and requires specific skills, thus molecular techniques are applied in order to expedite the identification of these numerous organisms. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is one of the molecular-based identification approaches with a high capacity for fast and accurate identification of species without the need for a highly-skilled expert in taxonomy. Zooplankton were collected from Turfloop Dam using a plankton net and fixed and preserved in 70% ethanol. Copepods were then isolated and studied under stereo- and light microscopes, using the wooden slide technique. A total of 17 633 calanoids and 2 577 cyclopoids were collected during the sampling period of one year. Selected specimens were dissected and morphological features drawn, using drawing tubes, for identification. The examined specimens were identified as species of Lovenula, Metadiaptomus, Paradiaptomus, Mesocyclops, Thermocyclops and Microcyclops. Full descriptions and illustrations were done of the eight collected species, i.e. Lovenula falcifera, Metadiaptomus colonialis, Paradiaptomus schultzei, Mesocyclops major, Thermocyclops inopinus, Thermocyclops crassus, Thermocyclops oblongatus and Microcyclops raynerae (male). Full descriptions and illustrations were also done for the three copepodid stages (CoIII, CoIV and CoV) of ii Lovenula falcifera, Metadiaptomus colonialis and Mesocyclops major as well as copepodid stages three and five (CoIII and CoV) of Thermocyclops oblongatus. The identification of different stages are mostly based on the development of the antennules, the number of segments of the first to the fourth pairs of legs and the development stage of the fifth pair of legs. The descriptions of these copepodids are compared with those of the described copepodids of other species from the families Diaptomidae and Cyclopidae. One hundred fifty specimens of each collected species were individually prepared for protein extraction using alpha-cyano-4-hydroxycinnamic acid (CHCA) matrix solution and loaded for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF). Protein mass spectra peaks were successfully generated for L. falcifera (6 females, 4 males and 5 female CoV), M. colonialis (24 females and 17 males), P. schultzei (8 females), M. major (15 females) and T. inopinus (19 females and 7 males). The generated data set was analysed using the Mass-Up software in an attempt to identify potential biomarkers for species identification and to perform a cluster analysis of protein peak values. From the total of 603 protein peak values generated for calanoid samples, only 164 peaks can possibly be used as potential biomarkers because they have a q-value of less than 0.05. Of the total of 585 peak values generated for all cyclopoid samples only 46 peak values can be used as potential biomarkers. The clustering analyses, based on the presence or absence of the peak values and visualized as dendrograms, displayed no clear clustering of calanoids and cyclopoids species studied. This study constitutes the second report of freshwater free-living copepods from the Limpopo Province. Full descriptions and illustrations are provided of all the adults of the collected species which improve the current knowledge regarding their morphology. Included is the first description of the male M. raynerae. Additionally, this is also the first description of the copepodid stages of some of the collected species. Thus, the study contributes towards increasing the limited knowledge of freshwater free-living copepods occurring in water bodies of the Limpopo province, but also the biodiversity of these organisms in South Africa.
National Research Foundation (NRF)
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GRUJČIĆ, Vesna. "Differential freshwater flagellate community response to bacterial prey with a focus on planktonic \kur{Betaproteobacteria}." Doctoral thesis, 2018. http://www.nusl.cz/ntk/nusl-375267.
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Gilpin, Cheryl. "Diel Temperature and Dissolved Oxygen Patterns in Sites with and without Planktonic Life Stage of Thompsodinium intermedium in Comal Springs, TX." Thesis, 2012. http://hdl.handle.net/1969.1/ETD-TAMU-2012-05-11222.
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Between July 2009 and October 2011, a new habitat was found for a rarely reported freshwater dinoflagellate species, Thompsodinium intermedium - Comal Springs (Comal County), Texas. In 2011, diel in-situ monitoring in monospecific blooms of this species revealed previously undetected negative impacts on endangered species habitat availability associated with conditions of low flow levels, recorded at the U.S. Geological Survey gage # 08169000 on Texas Commission on Environmental Quality river segment 1811 station 12655. During a period of low springflow in the summer of 2011, late afternoon and early morning measurements of dissolved oxygen and temperature and presence of dinoflagellate blooms were monitored at six sites. Significant differences in diel fluctuations were found in all of these parameters among sites with and without the planktonic blooms. These fluctuations increased risk of hypoxia and hyperthermia conditions at sites of planktonic bloom events. Arrays of in-situ continuous monitoring temperature/light probes were used inside and outside of blooms. Wildlife and human health implications are that hypoxia and hyperthermia are known to promote conditions favorable to harmful microbes which may be transported from springs to coastal bays. In-situ data demonstrated that T. intermedium blooms, hypoxia, and hyperthermia occurred in the upper Comal headwaters. These natural environmental stressors may be avoidable if adequate springflows are maintained to buffer against these impacts.