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Full-Text Articles in Physical Sciences and Mathematics
Late Glacial-Holocene Climate Change Recorded In Proglacial Lake Sediment Cores From The Huaguruncho Massif, Central Peruvian Andes, Dane O'Neil
Honors Theses
Alpine glaciers respond rapidly to changes in climate and the growth and decay of alpine glaciers is recorded in sediment cores extracted from lakes immediately downvalley from the margins of former glaciers. These records provide continuous archives of glaciation and climate change that complement the inherently discontinuous records of glaciation preserved by moraines. The aim of this study is to generate a continuous record of glaciation in Jaico cirque from lake sediment cores, which is located on the southeastern side of the quartz-monzonite dominated Huaguruncho Massif (5789 masl) in the eastern Peruvian Andes. The lakes are Laguna Jaico (10.56° S, …
The Impact Of Dams On Nitrogen Cycling In The Messalonskee Stream, Rebecca K. Forgrave
The Impact Of Dams On Nitrogen Cycling In The Messalonskee Stream, Rebecca K. Forgrave
Honors Theses
The Messalonskee Stream in central Maine has five hydroelectric dams on 16.6km. Each dam drastically changes the flow regime of the stream, dividing it into segments with different patterns of sediment settling and organic matter retention. I investigated how these disruptions impact nitrogen cycling, specifically nitrification rates above and below each dam. I expected higher nitrification rates above the dams, where levels of organic matter are higher, and lower rates below the dam where scouring removes organic matter and fine sediment from the streambed. I measured sediment nitrification rates with a nitrapyrin-inhibition assay and potential drivers of nitrification including sediment …