U.S.-Costa Rica Dissertation Enhancement: Exogenous Versus Endogenous Control of Microbially-mediated Decomposition in Lowland Neotropical Streams

0434503Pringle本美洲项目学位论文增强助学金将支持Marcelo Ardon Sayao先生在佐治亚大学生态研究所C.M.Pringle博士的指导下进行的研究。哥斯达黎加大学的莫妮卡·斯普林格博士将协助这项研究的某些方面，并将帮助协调哥斯达黎加大学本科生的参与。该项目将在哥斯达黎加的La Selva生物站重点研究一个重要的生态系统过程，即热带气候流中有机物的分解。在人类改变到全球营养循环的时代，了解营养对生态系统过程的影响至关重要。这项拟议的研究将提高我们预测河流对养分沉积的反应的能力。具体目标将：1)检查初始叶凋落物化学对新热带低地溪流分解过程的影响，并将结果与另一个热带地点和一个温带地点进行比较；2)评估凋落物碳质量和溶解营养物质之间的相互作用对微生物和无脊椎动物叶凋落物处理的影响；以及3)使用不同碳质量的人工基质来检查微生物对水营养物质的响应。美洲计划的资助将改善这一研究项目，通过对广泛的热带和温带物种进行化学分析，对热带和温带地点进行比较，并帮助开发和增强人造底物技术。这项研究的更广泛影响还包括通过促进两国研究生和本科生的培训来加强哥斯达黎加和美国学术机构之间的关系。

0434503PringleThis Americas Program Dissertation Enhancement Grant will support the research of Mr. Marcelo Ardon Sayao, under the direction of Dr. C.M. Pringle at the Institute of Ecology, University of Georgia. Dr. Monika Springer of the University of Costa Rica will assist with some aspects of the research and will help to coordinate undergraduate student involvement at the U. of Costa Rica. The project will focus on a vital ecosystem process, the decomposition of organic matter in tropical climate streams, at the La Selva Biological Station, in Costa Rica.In an era of human alteration to global nutrient cycles, it is critical to understand the effects of nutrients on ecosystem processes. The proposed research will improve our ability to predict how streams will respond to nutrient deposition. Specific objectives will: 1) examine effects of initial leaf litter chemistry on breakdown processes in a Neotropical lowland stream and compare the results to another tropical site and a temperate site; 2) assess the influence of interactions between litter carbon quality and dissolved nutrients on microbial and invertebrate leaf litter processing; and 3) use artificial substrates of varying carbon quality to examine microbial response to water nutrients. Funding from the Americas Program will improve this research project by allowing comparisons between tropical and temperate sites through chemical analysis of a broad range of tropical and temperate species and help to develop and enhance an artificial substrate technique. Broader impacts of this research also include strengthening relationships between Costa Rican and U.S. academic institutions through the advancement of training of graduate and undergraduate students in both countries.