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Full-Text Articles in Physical Sciences and Mathematics

Geochemical Reconstruction Of Late Holocene Drainage And Mixing In Kluane Lake, Yukon Territory, Janice Brahney, John J. Clague, Brian Menounos, Thomas W. D. Edwards Dec 2007

Geochemical Reconstruction Of Late Holocene Drainage And Mixing In Kluane Lake, Yukon Territory, Janice Brahney, John J. Clague, Brian Menounos, Thomas W. D. Edwards

Watershed Sciences Faculty Publications

The level of Kluane Lake in southwest Yukon Territory, Canada, has fluctuated tens of metres during the late Holocene. Contributions of sediment from different watersheds in the basin over the past 5,000 years were inferred from the elemental geochemistry of Kluane Lake sediment cores. Elements associated with organic material and oxyhydroxides were used to reconstruct redox fluctuations in the hypolimnion of the lake. The data reveal complex relationships between climate and river discharge during the late Holocene. A period of influx of Duke River sediment coincides with a relatively warm climate around 1,300 years BP. Discharge of Slims River into …


Fish Nutrient Cycling, Aquatic Respiration, And Terrestrial Insect Nutrient Subsidies To Lakes, Wayne A. Wurtsbaugh Nov 2007

Fish Nutrient Cycling, Aquatic Respiration, And Terrestrial Insect Nutrient Subsidies To Lakes, Wayne A. Wurtsbaugh

Watershed Sciences Faculty Publications

Mehner et al. (2005) reported that fish feeding on terrestrial insects could be important for nutrient budgets and cycling in lakes. They studied bleak (Alburnus alburnus) that fed largely on terrestrial insects, and they suggested that this contributed 2.1% of the lake's nutrient budget and that the subsequent excretion by the fish was equivalent to 11% of epilimnetic dissolved phosphorus concentrations. They concluded that nutrients delivered to lakes via terrestrial insects and recycled by fish would be most important for small lakes because of the large perimeter-to-area ratio between donor and recipient habitats. Fish may have important impacts …


Eutrophication In Farmington Bay And Its Potential Impacts On Wildlife, Wayne A. Wurtsbaugh Oct 2007

Eutrophication In Farmington Bay And Its Potential Impacts On Wildlife, Wayne A. Wurtsbaugh

Watershed Sciences Faculty Publications

No abstract provided.


Relative Role Of Understory And Overstory In Carbon And Nitrogen Cycling In A Southern Appalachian Spruce-Fir Forest, P. T. Moore, H. Van Miegroet, N. S. Nicholas Jan 2007

Relative Role Of Understory And Overstory In Carbon And Nitrogen Cycling In A Southern Appalachian Spruce-Fir Forest, P. T. Moore, H. Van Miegroet, N. S. Nicholas

Watershed Sciences Faculty Publications

This study investigated aboveground pools and fluxes of biomass, carbon (C), and nitrogen (N) in the overstory and understory of a southern Appalachian red spruce (Picea rubens Sarg.) – Fraser fir (Abies fraseri (Pursh) Poir.) forest, following adelgid-induced fir mortality and spruce windthrow. Using fifty 20 m × 20 m plots, stratified by elevation (1700–1900 m), we estimated standing biomass and fluxes of all growth forms from periodic stand inventories (1998–2003), vegetation surveys, and existing or derived allometric equations. Total C and N pools and fluxes were calculated from plant- and tissue-specific C and N concentrations. Total aboveground biomass attained …


Soil Organic Carbon Dynamics Along A Climatic Gradient In A Southern Appalachian Spruce-Fir Forest, C. E. Tewksbury, H. Van Miegroet Jan 2007

Soil Organic Carbon Dynamics Along A Climatic Gradient In A Southern Appalachian Spruce-Fir Forest, C. E. Tewksbury, H. Van Miegroet

Watershed Sciences Faculty Publications

A field study was conducted in a high-elevation spruce–fir (Picea rubens Sarg. – Abies fraseri (Pursh.) Poir) forest in the Great Smoky Mountains National Park to assess the effect of temperature on soil C storage and dynamics. In eight plots along an elevation gradient (1500–1900 m), we measured soil temperature, forest floor and mineral soil C, litter decomposition, soil respiration, and forest floor mean residence time. Mean annual soil temperature and annual degree-days above 5 °C were inversely correlated with elevation. Total soil C (166–241 Mg·ha–1) showed no trend with elevation, while forest floor C accumulation (16.3–35.9 Mg·ha–1) decreased significantly …