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Showing 1 to 20 of 57 for “"Lake Sediment"”.
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Resolving abrupt palaeoenvironmental changes in a lake sediment sequence from Ioannina, northwest Greece
… responses to Quaternary climate change. Lake Ioannina (NW Greece) is one such archive, with a vegetation record which spans multiple glacial-interglacial cycles. This PhD builds upon earlier work at Ioannina, seeking to characterise last glacial millennial-scale palaeoenvironmental change …
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A late-Quaternary record of environmental variability from lake sediment cores, Wind River Range, Wyoming
1 PDF file (viii, 227 pages)
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Lake Sediment-Based Reconstructions of Late-Holocene Lowland Environments of Dominican Republic and Barbuda, Northern Caribbean
… the analysis of proxy data sources contained in sediment cores. At Laguna Alejandro, a coastal lagoon in the southwestern Dominican Republic, we interpreted, from sediment lithology and stable oxygen isotope data, at least ten storm events over the past 1,000 years, producing the first long …
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Laser-based method for black carbon determination in lake sediment cores and black carbon deposition in Greenland since 300 CE
… study presents a new method for measuring BC in lake sediment cores using a laser-based instrument that has small sample requirements and high sample throughput. The method has low detection limits and is highly reproducible with proper sample preparation. This method is then applied to a lake …
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Holocene environmental change at Groenvlei, Knysna, South Africa : evidence from diatoms
This study demonstrates that diatom analysis of lake sediment can provide very detailed information on long and short term climate change, hampered only by inconsistent sediment accumulation at Groenvlei. Further work may provide insight to periods which were not covered in this study.
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Setting the Holocene clock using varved lake sediments in Sweden
… to study annually laminated (varved) Holocene lake sediment in Sweden, their formation and their potential as chronological and palaeoecological archives. Five lakes with continuous Holocene varved lake sediment sequences in northern (Västerbotten) and west central Sweden (Värmland) were …
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Microbial diversity of a nature reserve: eukaryotic microorganisms of Mere Sands Wood in N.W. England
… with diversity indices. Terrestrial soil and lake sediment microhabitats supported distinct assemblages of testate amoebae and diatom communities which enabled inferences to be made about the potential factors influencing microbial diversity and distribution in terrestrial and aquatic …
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Reconstruction of aspects of Northern New Zealand paleoclimate over the last 200 ka using laminated Auckland maar lake sequences
Continuous lake sediment records spanning two glacial cycles are rarely available from the Southern Hemisphere mid-latitudes, let alone with the requisite resolution and robust chronological control required to optimise paleoenvironmental reconstructions. In this context Onepoto maar paleolake in …
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Assessing Two Centuries of Anthropogenic Impacts on Silver Lake, Summit County, Ohio
… negatively impacts the quality of our waters. Lake sediment often preserves a record of past anthropogenic activities and can be used to assess the impact of humans on the lake system. This study examines Silver Lake, a groundwater-fed kettle lake located in the Village of Silver Lake, Summit …
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A multi-proxy approach to investigating the latest Holocene (~4,500 yrs. BP) vegetational history of Catahoula Lake, Louisiana
<p>A multi-proxy investigation of sediments examined from Catahoula Lake, Louisiana has provided a record of late-Holocene vegetational changes, related to both hydrology and climate. This study integrates data from phytoliths, pollen, stable isotopes, magnetic susceptibility, and core sediment …
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Environmental change recorded in physical and geochemical proxies over the Last Glacial Cycle from two Northland, New Zealand dune lakes: Lake Kanono and Lake Kai Iwi
Lake sediment archives from Southern Hemisphere mid-latitude regions with maritime climates provide invaluable records of late Quaternary environmental change that are essential for the evaluation of inter-annual, decadal, centennial, and millennial-scale trends driven by shifting positions of the …
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Holocene guano influences on eutrophication and lacustrine ecology at Kettle Lake, North Dakota
… avian migration on nitrogen cycling at Kettle Lake, North Dakota throughout the Holocene. I investigate this influence using stable nitrogen isotope values (𝛿15N) from lake sediment organic matter, with particular focus on periods of struvite deposition, a magnesium-ammonium-phosphate mineral …
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Chironomid-based paleotemperature reconstruction of the North Slave Region, Northwest Territories during the Late Holocene
… a chironomid-based inference 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 …
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A comparative study on the effect of acid preparation methodologies on bulk organic materials, and a long-core geochemical palaeoenvironmental reconstruction from South China.
… of palaeoenvironmental change from a lake sediment sequence from south China, using geochemical proxies. To address these aims, a systematic comparative study was developed to examine the three most common acid treatment methods (capsule method; rinse method; fumigation method) and a …
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East African monsoon variability since the last glacial
… a precise evaluation of future climate. From Lake Challa near Mount Kilimanjaro, we report records from a laminated lake sediment core spanning the last 25,000 years. Analyzing a monthly cleared sediment trap confirms the annual origin of the laminations and demonstrates that the …
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Basic studies for the incorporation of uranium in sediments
… on sorption interactions with soil, sediments and rocks are important to understand uranium mobility, in order to correct U/Th dating methods in open systems. Uranium immobilization is possible due to reduction U(VI) to U(IV), adsorption or co-precipitation. Under oxidizing …
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Subarctic ecosystem responses to climate, catchment and permafrost dynamics in the Holocene
… and biogeochemical analyses of one peat and two lake sediment sequences were conducted, including analyses of organic matter and carbonate content, mosses, diatoms, testate amoebae, pigments, carbon and nitrogen and their stable isotopes, near infrared spectroscopy and biogenic silica. Results …
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Environmental Impacts on the Development and Dune Activity of Oxbow Lake along the Southwest Coast of Lake Michigan at Saugatuck, Michigan USA
Coastal dunes of Lake Michigan and corresponding down-wind lakes are studied for links between dune activity and climatic forcing; to date, little is certain about climate control on dune activity. By unveiling relationships between climate variables and dune activity, it becomes possible to …
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A 4700-Year Record of Lake Evolution and Fire History for Laguna Limon, Dominican Republic
… Macroscopic charcoal (>125 "m) deposited into lake sediment is a record of a local fire event, whereas microscopic charcoal indicates fire activity on a broad landscape scale. Patterns of charcoal deposition may shed light on both human activities and climate history over long-time scales. …
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The impact of glaciation and climate change on biogeochemical cycling and landscape development
Lake cores from Dry Lake, California and Crystal Lake, Illinois were analyzed to identify climate variability and characterize landscape response to glacial/deglacial climate transitions. Geochemical analysis of the Dry Lake sediment prior to the 8.2 kyr event revealed average values for percent …
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