Nutrient loading in high alpine lakes of the Sierra Nevada: Sources of elevated phosphorus

3^rd International Conference on Hydrology & Meteorology

September 15-16, 2014 Hyderabad International Convention Centre, India

Blodwyn M McIntyre

Accepted Abstracts: Hydrol Current Res

Abstract :

Phosphorus loading to Sierra Nevada lakes has been identified as a prevalent and increasingly detrimental problem. As a key limiting nutrient for primary productivity, small increases in phosphorus loads boost the occurrence of algal blooms which over time can result in eutrophication. Instances of excessive phosphorus enrichment are commonly associated with agricultural and urban runoff, however, given the remoteness of most Sierra lakes, recent studies have identified other sources as potential explanations for the increased phosphorus; these sources include non-native stocked fish, atmospheric deposition, and wetlands. The introduction of salmonoid fishes into historically fishless lakes of the Sierra Nevada is a common practice to enhance recreational fishing. Recent scientific studies have shown that these stocking programs can drastically alter phosphorus recycling within naturally fishless ecosystems. Significant phosphorus contributions can be transported from the atmosphere to lake ecosystems via wet or dry deposition. Organophosphate pesticides can be an important source of atmospherically transported nutrients to Sierra lakes. Adjacent wetlands may also be contributing to phosphorus loading in Sierra lakes. The dynamics of nutrient release from wetlands is relatively complex given the ecosystems? ability to also act as a nutrient sink for solutes discharged from upstream environments. Hydrologic condition and biological activity are major determinants of whether a wetland functions as a nutrient sink or source. In this study three Sierra lakes were sampled and analyzed for phosphorus content. Seasonal and between-lake trends are presented. Atmospheric samples and those collected near a development on one lake contained significantly higher phosphorus concentrations.

Biography :

Blodwyn M McIntyre completed her PhD at the University of Virginia in Environmental Science. She is the Chair of Environmental Studies at the University of Redlands. Her previous work includes being the manager of a Mountain Cloud Chemistry Project in the Shenandoah National Park and studying Common Raven predation on the Threatened Desert Tortoise in the Mojave Desert. She received her Master?s degree in Forestry from Duke University and her Bachelor?s degree from Colorado College.