Microbial Transformations and Fate of Vascular Plant Detritus in Aquatic Ecosystems

细菌的代谢常常支配能量和营养 水生态系统中的流动，从而对 地球化学循环和食物网。 有许多 潜在的营养来源，促进细菌的新陈代谢， 但在许多河流和河口， 维管植物很可能是非常重要的。 这 研究将确定细菌的生产率， 包括亚马逊河在内的各种系统中的呼吸 以及德克萨斯州南部海岸的几个河口 的来源 有机物促进细菌生长， 该材料的特性将使用稳定的 同位素（C N）组成，固态13 C核磁共振 共振（NMR）和来源特定的生物标志物化合物。 溶解有机物（DOM）被认为是大部分的燃料。 微生物异养生产在这些系统中，它 似乎维管植物对 这条养分流动的通道 在拟议的研究中， DOM的产生、微生物转化和归宿 各种植物材料的形式将在研究期间进行 长期（2- 3年）分解研究。 成岩变化 在化学和稳定同位素组成的两个 将测定颗粒和溶解组分。 该项目团队是合格的。体制 住宿条件很好。 与下列机构的合作与协调 正在进行的其他工作将是富有成效的。

Bacterial metabolism often dominates energy and nutrient flow in aquatic ecosystems and thereby has a major impact on biogeochemical cycles as well as food webs. There are numerous potential sources of nutrients fueling bacterial metabolism, but in many rivers and estuaries detrital material derived from vascular plants is likely to be of major importance. This research will determine rates of bacterial production and respiration in a variety of systems including the Amazon River and several estuaries on the south Texas coast. The sources of organic matter fueling bacterial growth and the chemical identity of this material will be investigated using stable isotope (C & N) compositions, solid-state 13C nuclear magnetic resonance (NMR) and source-specific biomarker compounds. Dissolved organic matter (DOM) is thought to fuel most of the microbial heterotrophic production in these systems, and it appears likely that vascular plants contribute significantly to this pathway of nutrient flow. In the proposed research the production, microbial transformations and fate of DOM derived form avariety of plant materials will be investigated during long-term (2-3yr) decomposition studies. Diagenetic changes in the chemical and stable isotope compositions of both the particulate and dissolved components will be determined. The project team is well qualified. Institutional accommodations are good. Collaboration and coordination with other work in progress will be productive.