International Research Fellowship Program: The Impact of Adaptive Strategies of Below Ground Water and Biogeochemical Cycling and Their Thermody Namic Implications

[90055 . 56]该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。国际研究奖学金项目使美国科学家和工程师能够在国外进行9至24个月的研究。该计划的奖励为联合研究提供了机会，并利用独特或互补的设施、专业知识和国外的实验条件。该奖项将支持达伦·t·德鲁里博士与德国耶拿马克斯·普朗克生物地球化学研究所阿克塞尔·克莱顿博士开展为期18个月的研究。地下过程在陆地水文和碳循环中起着至关重要的作用。植物的根系可以深入土壤数十米，以获取水分和养分，控制植物生长和与大气的能量交换。观察到的水分在干湿土层之间通过根系被动再分配可能在水分限制条件下提供适应性优势。与根功能紧密耦合的是生物地球化学过程，特别是微生物将碳和氮从有机凋落物转化为无机矿物质，这是包括光合作用在内的各种植物功能所必需的。植被地下生物地球化学功能的改造可以影响植被自身的长期适应度和竞争优势。由于需要提高最先进的地球系统模型的预测能力，目前正在将控制生态系统功能和进化的几个关键生态水文和生物地球化学过程纳入现有的动态全球植被模型。植被模型能够在一个模拟像元内反映植被形态和功能的多样性。这使得以根过程的作用及其与全球植被动态和生物多样性的生物地球化学循环的相互作用为中心的假设可以在十年或世纪的时间尺度上进行测试。通过与模拟全球大气流量和成分的大气环流模式耦合，可以分析大气环流型和降水时空分布等关键变量的敏感性。这里进行的研究对植被地表如何调节全球水文和生物地球化学循环以及全球气候等基本问题具有广泛的意义。这项工作将对理解人为和自然景观改变对全球气候变化的影响具有实际意义。

0900556DrewryThis award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support an eighteen-month research fellowship by Dr. Darren T. Drewry to work with Dr. Axel Kleidon at Max Planck Institute for Biogeochemistry in Jena, Germany.Belowground processes play a critical role in hydrologic and carbon cycling on land. Root systems of vegetation have been shown to extend tens of meters into the soil to forage for moisture and nutrients that control plant growth and energy exchange with the atmosphere. The observed passive redistribution of moisture between dry and wet soil layers by root systems may provide an adaptive advantage under water-limited conditions. Tightly coupled to root function are biogeochemical processes, particularly microbial transformations of carbon and nitrogen from organic litter to inorganic minerals that are necessary for a variety of plant functions including photosynthesis. Vegetation modification of below-ground biogeochemical function can thus impact the long-term fitness and competitive advantage of the vegetation itself. Motivated by the need to enhance the predictive capabilities of state-of-the-art Earth-system models, several key ecohydrological and biogeochemical processes that govern ecosystem function and evolution are being incorporated into an existing dynamic global vegetation model. The vegetation model is capable of accounting for diversity in vegetation form and function within a simulation pixel. This allows for hypotheses centered on the role of root processes and their interactions with biogeochemical cycles on global vegetation dynamics and biodiversity to be tested over decadal or century timescales. Through coupling to a general circulation model, which simulates the global atmospheric flow and composition, an analysis of the sensitivity of atmospheric circulation patterns, and key variables such as the temporal and spatial distribution of precipitation, can be performed. The research conducted here has broad implications for fundamental questions about how vegetated land surfaces modulate the global hydrological and biogeochemical cycles, and hence global climate. This work will have practical implications for understanding the impacts of anthropogenic and natural landscape modification on global climate change.