Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 27 for “"epilimnion"”.
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Diffuser Operations at Spring Hollow Reservoir
… in two distinct layers, the warmer, less dense epilimnion on top and the colder, denser, hypolimnion on the bottom. The epilimnion remains saturated with dissolved oxygen (DO) from mass transfer with the atmosphere, while the hypolimnion continues to undergo oxygen-depleting processes. During …
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Hydrogen peroxide in the Halls Brook Holding Area, a small meromictic lake
… peroxide concentrations with depth in the epilimnion was observed. Below the pycnocline, HBHA is anoxic. Hydrogen peroxide was not detected below the pycnocline on any date, and hydrogen peroxide that was added to samples below the pycnocline was rapidly destroyed. A decay rate of hydrogen …
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The effects of seasonal change, impoundment, and stratification on trihalomethane precursors
… collected from each lake site-- one from the epilimnion, and the second from the hypolimnion. All of the samples were size fractionated by ultrafiltration and chlorinated for determination ofTHMFP. The differences in THMprecursor characteristics were determined by assessing the differences in …
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The distribution, abundance and ecology of mixotrophic algae in marine and freshwater plankton communities
… in surface waters of the Sargasso Sea and in the epilimnion of one freshwater seepage pond. Mixotrophic nanoplankton abundances in the Sargasso Sea ranged from less than a few cells mi-l to more than 140 cells mi-l, and they were more abundant in surface waters. On two occasions rnixotrophic algae …
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The effects of diel vertical migration of Daphnia on zooplankton-phytoplankton interactions
… assumed that phytoplankton communities in the epilimnion of stratified lakes profit from the presence of DVM. This might be caused by less grazing due to intermittent grazing and/or less grazing due to lower population densities of migrating Daphnia populations (as they migrate into the colder, …
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Holocene sedimentary and aquatic biogeochemical responses reflected in Ordy Pond, Oahʻu, Hawai'i, and, contemporary modeling of submarine groundwater discharge in Kahana Bay, Oahʻu, Hawaiʻi
… was thermally stratified in the spring/summer, epilimnion primary productivity increased dramatically as indicated by dissolved O2, dissolved inorganic carbon, S13CDIC, and particulate production rates. Once the density gradient waned, the anoxic hypolimnion mixed with the epilimnion, organic …
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The biogeochemistry of 210Pb and 210Po in fresh waters and sediments
… 210Pb sediment dating. A mass balance for the epilimnion showed that 210Pb inputs by precipitation were matched by outputs on settling particles, indicating that direct uptake by bottom sediments was inconsequential. Below the epilimnion, vertical eddy diffusion was calculated by the heat flux …
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Transport of perchlorate in the Las Vegas Wash and Lake Mead
… variations in perchlorate levels within the epilimnion, metalimnion and hypolimnion layers of the Lake, and to correlate perchlorate levels with total dissolved solids concentrations. Investigation showed that multiple sources contribute to the perchlorate contamination in the Wash. …
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Environmental Determinants of Stigonematales In A Southeastern Reservoir.
… at three different depths: one surface reading (epilimnion), one reading at 1 meter (metalimnion), and one reading near the bottom (hypolimnion). Relationships between the abundance of Stigonematales and the independent environmental factors were analyzed using generalized linear modeling (GLM) …
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Effects of a surface circulator on temperature, dissolved oxygen, water velocity, and photosynthetic yield in Falling Creek Reservoir
… was only intended to mix and possibly deepen the epilimnion, the entire reservoir became mixed about two weeks after the circulator was put into operation. The reservoir is quite shallow, leading to a weak stratification that is easily disrupted by the operation of the circulator.
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Trophic Level Changes and Alewife Predation on Conesus Lake
… increased significantly (P < 0.022) within the epilimnion in 1988 compared to 1985.
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The phytoplankton of a eutrophic lake : community dynamics and ultrastructural studies
… summer algal populations resemble those in the epilimnion of a stratified eutrophic lake. 32 principal phytoplankton species from seven algal classes are illustrated by light micrographs and their periodicity recorded over two annual cycles; a statistical method is employed to produce graphical …
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Littoral wetlands and lake inflow dynamics
… land borne nutrients and chemicals enter the epilimnion where they can enhance eutrophication and the risk of human exposure. The third and last physical mechanism considered in this thesis is the exchange flows generated between littoral wetlands and lakes. Field experiments show that during …
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The Biogeochemistry of Carbon Isotopes in Local Lakes
… the heaviest carbon can be found in the epilimnion near the surface, where photosynthesis dominates the biogeochemical processes. At greater depths, the DIC carbon becomes lighter as 12C-enriched organic matter decomposes. In the hypolimnion, methane production in the late summer could be …
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The Occurrence of Fish Remains in Modern Lake Systems : A Test of the Stratified-Lake Mode
… in buckets to the bottom of the lake in both the epilimnion (water temperature >15 deg. c. and oxygenated) as well as the hypolimnion (water temperatureanoxic), directly testing the effects of oxygen content, temperature, and pressure on the preservation of fishes. In the warm, oxygenated water …
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OVERLOOKED AND UNDERSTUDIED: A SURVEY OF THE SMALL AND HIDDEN FRESHWATER INVERTEBRATE TAXA (PHYLUM ROTIFERA AND SUBPHYLUM CRUSTACEA)
… rotifers were most abundant in the epilimnion and differences in community composition with depth were minor. Mean epilimnetic rotifer density peaked in August (average 330 L-1) when surface water temperature was highest. Seasonal succession included a spring dominated by Synchaeta …
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Algal nutrients: sources and patterns of flow in the Occoquan Watershed
… that hypolimnetic nutrients do not enter the epilimnion at a rate sufficient to cause algal bloom conditions. Storm events were observed to cause mixing of the reservoir and so provided the nutrient concentration necessary for algal blooms. It is suggested that removal of phosphates from all …
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Stable isotopic insight into pelagic carbon cycling in Loch Lomond: a large, temperate latitude lake.
… Spring / summer peaks in δ13CDIC (-5.1‰ epilimnion maximum) are indicative of photosynthetic incorporation, and vice versa in the autumn / winter (-13‰ hypolimnion minimum) points towards respiratory dominance. δ18ODO is enriched during respiratory utilisation and peaks in the autumn / …
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The vertical distribution and migration of planktonic rotifers in a hypereutrophic tarn
… September, all the rotifers were confined to the epilimnion by the anoxic water of the bottom two metres. F. brachiata, B. calyciflorus, B. angularis and P. vulgaris were concentrated nearer the surface than the other species. K. cochlearis and K. quadrata were aggregated just above the oxycline …
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Better understanding human impacts on river thermal regimes under climate change
… fluxes can only warm a reservoir’s top layer (epilimnion) while the bottom layer (hypolimnion) remains cold. As a result, the cold hypolimnetic releases greatly depress downstream river temperatures. Additionally, reservoir releases during cold seasons can increase downstream river …
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