EAGER: Land use and climatic controls on dust deposition

大气尘埃是地球表面物理、化学和生物过程的重要组成部分。灰尘是侵蚀的一个重要结果，并导致重要的植物营养素和其他化学品在其他地方的远程沉积。人类在粉尘生成中的相对作用是一个由很少的实际数据支持的大量猜测的主题。来自湖泊沉积物记录的初步数据显示，对于美国西部的一个山脉，自世纪中期以来的时间段内的灰尘沉积比过去几千年的平均速度高出5到7倍。这一增长与19世纪后期铁路建设和牲畜引进后西部各州土地使用的快速变化相吻合。这种明显的增加导致了营养物质如钙和磷沉积到顺风高海拔地区的数倍增加，对源和汇生态系统都有潜在的深远影响。 该项目将导致一个新的区域重建西部粉尘沉积的高海拔湖泊沉积物芯分析的基础上。岩芯中的硅藻成分将有助于更全面地了解粉尘沉积变化的生物反应。灰尘问题不仅仅是学术问题。这些结果对美国各地区的化学遥相关，了解落基山脉高山积雪反射率和融化率变化背后的机制，以及了解区域空气质量趋势和与土地利用变化的联系等都有影响。该项目将包括培养一名博士后研究员、一名研究生和两名本科生。在科罗拉多的部分工作将在一个新开发的科学教育和推广工作的主持下进行，该工作名为圣胡安合作实验室，旨在为科罗拉多西南部的农村地区提供科学信息和教育机会。

Atmospheric dust is an important component of physical, chemical, and biological processes occurring on the surface of the Earth. Dust is an important result of erosion and results in the remote deposition elsewhere of essential plant nutrients and other chemicals. The relative role of humans in dust generation is the subject of much conjecture supported by very little actual data. Preliminary data from lake sediment records show that for a mountain range in the western United States, dust deposition in the time period since the mid 19th century is five to seven times higher than average rates over the past several thousand years. This increase coincides with the rapid land use change of the western states that occurred after the construction of railroads and introduction of livestock in the late 1800s. This apparent increase results in many fold increases in the deposition of nutrients such as calcium and phosphorus to downwind high elevation areas, with potentially profound implications for both the source and sink ecosystems. This project will lead to a new regional reconstruction of western dust deposition based on analyses of high elevation lake sediment cores. Diatom composition in the cores will help establish more complete understanding of biological responses to changes in dust deposition. The issue of dust is not just academic. The results have implications for everything from chemical teleconnections across regions of the United States, to understanding the mechanisms behind changes in reflectivity and melting rates of alpine snow in the Rockies, and understanding trends in regional air quality and connections to changes in land use. The project will include the training of a postdoctoral researcher, one graduate student, and two undergraduate students. The portion of the work in Colorado will be carried out under the auspices of a newly developed science education and outreach effort titled the San Juan Collaboratory, designed to provide scientific information and educational opportunities to rural southwestern Colorado.