MSA: Dust as an ecosystem driver: determining the ecosystem consequences of cross-system subsidies of nutrients and microorganisms in dusts

点击翻译按钮获取中文摘要

Atmospheric transport of soil (dust) connects distant ecosystems, moving nutrients and organisms across continents and against gravity from lowland areas to mountain wilderness. Dust deposition can influence climate, accelerate snowmelt, affect air and water quality, and have human health consequences. Despite the importance of dusts within the environment, we know very little about the quantity and composition of dusts transported by the atmosphere through time and space. This project will determine where within the western USA dust loading is greatest, examine the composition of collected dusts, and document how nutrients and microorganisms transported in dusts affect aquatic ecosystems in which they are deposited. The results will inform natural resource managers and policymakers on how climate and land-use activities can influence ecosystem services downwind, such as water quality and community diversity. The project will provide research experiences for high school students by directly involving them in the collection and examination of dust samples. Students will be able to compare the properties of collected dusts in their region as it relates to geography, land-use, and climate. This research will examine the role of dust in transporting nutrients and microorganisms in ecologically meaningful quantities to mountain ecosystems. Because dust can contain appreciable concentrations of terrestrial limiting nutrients, it has been hypothesized that increased dust deposition has led to widespread eutrophication of remote waterbodies in the US. Moreover, dust deposition may represent a major mechanism of microbial dispersal across ecosystems, potentially shaping the composition and function of resident microbial communities. The project will test these hypotheses through the capture and analyses of atmospheric dusts across the western and mid-western USA, with direct examination of nutrient bioavailability and microbial community composition through laboratory and field experiments. The research has four main objectives, 1) determine the gravitational deposition rate of dusts in the western US through a coordinated effort with the National Atmospheric Deposition Program (NADP), 2) use controlled laboratory experiments to quantify the microbial composition and the leachable and hydrolysable nutrient fraction from dusts, 3) determine in situ effects of dust additions on aquatic microbial and algal community composition, and 4) provide critical data on best practices for measuring and tracking dust movement. The education plan will engage high school geography, earth science, and ecology students, and cultivate an interest and understanding of the role of climate and human land-use in affecting important biogeochemical cycles, air quality, and environmental conditions.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.