Analysis of Microbial Community Structure and Function Alonga Detrital Particle Size Gradient

在大多数溪流中，群落生产是通过分解进口植物枯枝落叶来维持的。植物凋落物分解的早期阶段得到了很多研究，但很少有人关注细有机颗粒(FPOM)的命运，细有机颗粒是大多数颗粒碎屑在河流生态系统中移动的形式。利用最近开发的生化技术，我建议在两个同时进行的野外实验中调查与FPOM相关的微生物群落的结构和活性。第一个目的是在广泛的条件下评估关于微生物生产、胞外酶活性和群落结构的一系列基本假设。第二个重点是关于FPOM降解率和木质纤维素降解酶活性之间的关系。%这项工作将有助于我们对附着微生物群落的运作有基本的了解，这是一个广泛感兴趣的话题。此外，这可能导致建立模型，将目前难以现场测定的FPOM质量损失与木质纤维素降解酶的活性联系起来，这是一种容易量化的衡量标准。这样一种模式将使人们能够对最低有机污染物的降解率进行常规监测，这一应用可能有助于今后对生态系统过程和管理的研究。

In most streams, community production is sustained by the decomposition of imported plant litter. The early stages of plant litter decomposition have received much study; but little work has focused on the fate of fine organic particles (FPOM), the form in which most particulate detritus moves through stream ecosystems. Utilizing recently developed biochemical techniques, I propose to investigate the structure and activity of FPOM- associated microbial communities in two concurrent field experiments. The first is intended to evaluate a series of basic hypotheses about microbial production, extracellular enzyme activity and community structure over a broad range of conditions. The second is focused specifically on the relationship between FPOM degradation rates and the activity of lignocellulose-degrading enzymes. %%% This work will contribute to our basic understanding of the operation of attached microbial communities, a topic of broad interest. In addition, it may lead to the formulation of models that relate FPOM mass loss, currently difficult to determine in situ, to the activity of lignocellulose-degrading enzymes, a readily quantified measure. Such a model would permit routine monitoring of FPOM degradation rates, an application that could contribute to future studies of ecosystem processes and management.