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

9809348SchmidtHigh海拔生态系统对生命来说是极其恶劣的环境。不稳定的距骨坡和长期的积雪覆盖阻碍了植物的生长和土壤的发育。人们对这些地方的微生物生活几乎一无所知。在这个LExEn项目中，Steven Schmidt和Mark Williams将继续进行初步研究，表明talus斜坡的微生物群落由寡营养细菌组成，但初级生产以化学自养细菌为主。PIs预测，岩石风化过程中还原的铁和硫，以及大气沉积过程中的氮，将成为talus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量输入。他们还将跟踪生物地球化学活动和功能群的种群动态，并测试分离生物体的生态生理极限。这种综合方法在选定的研究地点（科罗拉多前山脉的绿湖谷上游）方便，因为它靠近附近的高海拔实验室，可以频繁采集样本和立即处理样本。

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.