LEXEN: Microbial Diversity and Energy Flow in Barren, High Elevation Talus

9809348施密特高海拔生态系统对生命来说是极其恶劣的环境。 不稳定的岩屑坡和长时间的积雪排除了植物的建立和土壤的发育。 在这个LExEn项目中，Steven施密特和Mark威廉姆斯将继续进行初步研究，表明岩屑坡的微生物群落由贫营养细菌组成，但初级生产由化能自养生物主导。 PI预测，岩石风化产生的铁和硫的还原形式，以及大气沉积产生的氮，是岩屑堆中生命的主要能量来源。 他们将测量这些因素，以及微生物群落的有机和光能输入。 他们还将跟踪功能组的生物地球化学活动和种群动态，并测试孤立生物的生理生态极限。 这种综合的方法是促进在选定的研究地点（上游的绿色湖谷在科罗拉多前线范围），其附近的高海拔实验室，允许频繁的样品收集和即时的样品处理。

9809348SchmidtHigh altitude ecosystems are extremely harsh environments for life. Unstable talus slopes and prolonged snow cover exclude plant establishment and soil development. Almost nothing is known about the microbial life in these sites.In this LExEn project, Steven Schmidt and Mark Williams will follow on from preliminary studies indicating that the microbial communities of talus slopes are composed of oligotrophic bacteria, but primary production is dominated by chemoautotrophs. The PIs predict that reduced forms of iron and sulfur from rock weathering, and nitrogen from atmospheric deposition, to be the principal sources of energy for life in talus. They will measure these factors, as well as organic and light energy inputs to the microbial communities. They will also track the biogeochemical activity and population dynamics of functional groups, and test the ecophysiological limits of isolated organisms. This integrative approach is facilitated at the chosen research site (upper reaches of Green Lakes Valley in the Colorado Front Range) by its proximity to nearby high altitude laboratories that allow frequent sample collecting and immediate sample processing.