DISSERTATION RESEARCH: Understanding the influence of eolian dust on soils in the San Juan Mountains, CO

在过去的200年里，科罗拉多州西南部的圣胡安山脉的尘埃沉降量增加了500%。沙尘的增加在高寒湖泊沉积物的化学成分中是明显的，但是尚不清楚这些沙尘的增加是否影响了该地区的土壤化学。本研究的目的是量化粉尘沉积对土壤基本元素库的作用，相对于圣胡安山脉当地基岩的风化。这项研究将利用粉尘和当地基岩之间锶同位素化学的差异，以量化这些元素来源对土壤的贡献。此外，本研究中使用的同位素方法允许对植物和微生物吸收的粉尘来源元素的有效性进行评估。这项研究不仅可以量化土壤中粉尘的积累，还可以评估粉尘对土壤中植物和微生物生产力的贡献。此外，这项工作将深入了解灰尘在长时间尺度上对土壤形成和风化通量的重要性。这也将有助于了解该地区土地利用和气候变化在沙尘沉积中的作用。该项目还将为调查人员提供机会，为科罗拉多州西南部传统上在此类活动中服务不足的人群提供教育和外展服务。

Dust deposition has increased by as much as 500% over the past 200 years in the San Juan Mountains for southwestern Colorado. This increase in dust is evident in alpine lake sediment chemical composition, however it is unclear if these increases in dust have influenced soil chemistry in this region. The purpose of this research is to quantify the role of dust deposition to soil essential element pools relative to the weathering of local bedrock in the San Juan Mountains. This study will exploit the difference in strontium isotope chemistry between dust and local bedrock in order to quantify the contribution of these sources of elements to soils. Furthermore, the isotopic methods used in this study allow for an assessment of the availability of the dust-derived elements for plant and microbial uptake. This research will not only quantify the accumulation of dust in soils, it will also serve to assess the contribution of dust to productivity of plants and microbes in these soils. In addition, this work will provide insight into the importance of dust for soil formation and weathering fluxes over long time-scales. This will also lend perspective to the role of changing land-use and climate in dust deposition in this region. This project will also provide the opportunity for the investigators to serve in education and outreach programs based in southwestern Colorado for populations that are traditionally underserved in such activities.