'Impacts of Dust Deposition on Lake Water Quality' Plenary Speaker |
Abstract: |
Human activities have significantly altered the chemistry of the atmosphere changing the global mobility of key macronutrients. The deposition of nitrogen and phosphorus is of particular importance because these nutrients are often the most limiting in terrestrial and freshwater ecosystems. Because alpine lakes receive a large fraction of their nutrients from atmospheric deposition, variations in deposition rate and composition has the potential to impart significant changes in aquatic biogeochemistry. Using proxy evidence we examined the recent changes in dust deposition across the western US and evaluated the influence of dust- nutrient deposition on alpine lake ecosystems. We found large increases in dust deposition over broad regions of the western US. Increased dust emissions were tied to significant increases in precipitation alkalinity and to elevated nutrients in downwind lake ecosystems. Spatially we found that the global, regional, and local patterns of nutrient emissions and deposition were reflected in the water chemistry of alpine lakes. Lakes in affected areas have altered species communities, and higher levels of nutrients and heavy metal concentrations. |
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