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 21 for “"shallow lakes"”.
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Climate impact on phytoplankton blooms in shallow lakes
… by multiple anthropogenic influences on lakes. This thesis contributes to a better understanding of climate impacts on freshwater phytoplankton, which forms the basis of the food chain and decisively influences water quality. The analyses were, for the most part, based on a long-term data …
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Food web regulation under different forcing regimes in shallow lakes
… the food webs. All studies were conducted in shallow lakes, which is worldwide the most abundant type of lakes. The specific morphology of shallow lakes allows that the benthic production contributes substantially to the whole-lake production. Further, as shallow lakes are often small they are …
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Carbon gains, losses, and feedbacks in shallow, eutrophic lakes of phytoplankton and macrophyte dominance
Lakes are increasingly being recognized as an important component of the global carbon cycle, yet anthropogenic activities that alter their community structure may change the way they transport and process carbon. This research focuses on the relationship between carbon cycling and community …
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Chironomid-based paleotemperature reconstruction of the North Slave Region, Northwest Territories during the Late Holocene
… model based on lake sediment collected from two shallow lakes within the North Slave Region, Northwest Territories. No significant shifts were identified in the chironomid species assemblages, which indicated that these lakes experienced very little environmental change over the last …
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Entwicklung eines Langfristgewässergütemodells für flache Standgewässer
… level. Until today, water quality models for lakes and reservoirs have been implemented into catchment scale water quality models only rarely and in strongly reduced form with limited prognostic capabilities. As a particular property of shallow lakes and reservoirs, the vertically well-mixed, …
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Understanding good ecological status: a palaeolimnological approach
… closely adjacent, moderately nutrient-enriched lakes in Carmarthenshire, South Wales. The use of diatoms, Pediastrum and ephippia allows for the analysis of changes in ecosystem dynamics in response to nutrient enrichment, whilst pollen, charcoal analysis and archaeology enables the degree to …
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A Field and Modeling Assessment of Methyl Mercury Accumulation in an Engineered Retention Pond
<p>The accumulation of methyl mercury (MeHg) in lakes during summer stratification has been demonstrated to affect biotic mercury (Hg) accumulation. However, small, shallow polymictic lakes can experience short-term stratification and mixing events that are largely unstudied in their abilities to …
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The Biogeochemistry of Carbon Isotopes in Local Lakes
… processes on carbon isotopes in local lakes. Crystal Lake is a small but deep glacial lake (12.5 acres, 11.9 meters). The study shows that during thermal stratification, the heaviest carbon can be found in the epilimnion near the surface, where photosynthesis dominates the …
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Investigating drivers of cyanobacterial blooms in Aotearoa – New Zealand lakes using sedimentary ancient DNA
… services such as water, food and energy. Lakes can be impacted by natural disturbances, but they are increasingly threatened by human-induced disturbances. Studies have shown that eutrophication and climate change often enhance cyanobacteria over other photosynthetic taxa. As …
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The Weichselian in southern Sweden and southwestern Baltic Sea : glacial stratigraphy, palaeoenvironments and deglaciation chronology
… level. Between 42 and 36 cal. ka BP wetlands and shallow lakes existed on Kriegers Flak (unit B). Macrofossil and pollen from this unit suggest tundra-like, or forest tundra-like vegetation, possibly with birch and pine in sheltered locations. From 28.5 to 26 ka, a thick succession of …
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Depositional environments of a portion of the Bullion Creek Formation (Paleocene), Western Billings County, North Dakota
… sandstone body is believed to represent a broad shallow delta, deposited in to a large swamp or shallow lake. Type E sandstone bodies include all sandstone bodies that are too poorly indurated to be ascribed to one of the other types. </p><p> Mudrocks of both fluvial and lacustrine origin were …
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Ecosystem impacts of the invasive rusty crayfish (Faxonius rusticus) over time
… (Faxonius rusticus) in northern Wisconsin lakes to investigate the impacts of this invader over time. Since it was initially introduced in the 1960s, F. rusticus has reached hyper-abundance relative to native crayfishes and caused declines in fishes, macrophytes, and macroinvertebrates such …
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Palaeoenvironmental change from the Hettangian to Toarcian in Moyeni (Quthing District), southwestern Lesotho
… energy depositional system with small rivers and shallow lakes. The bulk of the Clarens Formation comprises very thick, tabular, fine- to medium-grained, massive to large-scale cross-bedded arenites. However, the lower part of the Clarens also preserves thin-bedded mudstones and theropod tracks. …
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The phytoplankton communities of nine lakes, Waikato, New Zealand: a comparative study of floristics, seasonal dynamics and the influence of herbivory
… of the phytoplankton communities of nine shallow lakes located in relatively close proximity to one another within the Waikato Basin, and of similar age and origin, were studied for one year (July 1983 to July 1984); the lakes were Kainui, Mangahia, Mangakaware, Maratoto, Ngaroto, …
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A water quality model for shallow river-lake systems and its application in river basin management
… mass transport and turnover in rivers and shallow lakes. The simulation tool called 'TRAM' is intended to complement mesoscale eco-hydrological catchment models in studies on river basin management. TRAM aims at describing the water quality of individual water bodies, using problem- and …
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Effects of repeated early season herbicide treatments of curlyleaf pondweed on native macrophyte assemblages in Minnesota Lakes.
… these constraints are exemplified in the small, shallow, lakes of Minnesota. Curlyleaf pondweed (Potamogeton crispus L.) is one of the common occurring and most influential non-native invasive species in Minnesota. Characterized by its early spring growth and early summer senescence, curlyleaf …
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The palaeolimnological record of regime shifts in lakes in response to climate change
… palaeolimnological records of regime shifts in lakes during the Holocene to explore how lake ecosystems responded to climate changes and anthropogenic activities and to identify thresholds or tipping points that produced regime shifts. The thesis includes case studies of two Swedish lakes and a …
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Influence of Resource Pulses Following Stochastic Disturbances on Aquatic Food Webs
… carpio is a highly abundant invasive fish in shallow eutrophic lakes throughout much of the world and is associated with deleterious effects on aquatic ecosystems due in part to nutrient subsidies provided through bioturbation and excretion. Shallow lakes dominated by common carp are often …
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The prospects for stormwater harvesting in Cape Town, South Africa using the Zeekoe Catchment as a case study
… determine the optimal storage required from the shallow lakes (vleis) in the study area i.e. Zeekoevlei and Rondevlei. It was determined that after 4 Mm3 , there was limited increase in demand met and reduction in spill. Stormwater could also be abstracted, fully treated to potable water …
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Constructed treatment wetlands: Tools to attenuate diffuse agricultural pollution and enhance the biodiversity of eutrophic peat lake ecosystems
… and excessive sedimentation of many rivers, lakes, wetlands, and estuaries. In excess, these contaminants cause diverse negative impacts on lake ecosystems such as prolific growth of phytoplankton and aquatic plants, toxic algal blooms and collapse of macrophyte beds, high turbidity and …
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