Microbial Mediation of Organic Carbon Transformations in An Emergent Macrophyte-Dominated Habitat of the Okefenokee Swamp Ecosystem

&gt；&gt；分解将在佐治亚州东南部Okefenokee沼泽生态系统中以大型植物为主的紧急栖息地进行研究。在这个以碎屑为基础的生态系统中，来自新兴大型植物&gt；Carex&gt；&gt；walteriana&gt；的木质纤维素是最丰富的碳来源。由于木质纤维素在很大程度上不能被动物消化，它们不能利用它的碳(能量)，直到它被微生物降解。因此，了解木质纤维物质的微生物转化和控制其分解速度的因素是了解奥克菲诺基和其他湿地生态系统如何工作的关键。研究将分为三个部分：详细的过程研究、综合系统、水平测量和模型综合。详细的过程研究将重点放在野外和实验室的分解上，旨在阐明转化、命运和控制分解的时间和空间方面，不仅是木质纤维素，而且是非木质纤维素碳。这些研究中使用的技术包括：用1.4C放射性标记底物来确定分解物质的命运；用ı标记细菌。用胸腺嘧啶核苷测定颗粒掺入效率。系统水平测量旨在将分解研究放在网站整体碳预算的背景下进行。系统水平的研究将使用标准方法，包括流过代谢室和1.4摄氏度的“尖峰”光。在这项研究中，建模将作为一个综合工具发挥作用。现有的微生物降解木质纤维素的模型将扩展到：1)考虑与碎屑输入有关的腐烂的空间和时间方面；以及2)包括对腐烂速率的更明确和更详细的控制，包括N、P和S的影响。最后，将对修改后的模型进行详细的流动和敏感性分析。这项研究的意义在于，它将帮助我们了解湿地作为一种主要的生态系统类型，在世界范围内是如何发挥作用的。这项研究将为合理管理这一重要地貌提供科学依据。霍德森博士、维格特博士和霍普金森博士都是非常有能力的科学家，有着良好的研究记录。为他们提供的机构支持是极好的。

>> Decomposition will be studied in an emergent macrophyte.dominated habitat of the Okefenokee Swamp ecosystem in southeastern Georgia. In this detritus.based ecosystem, lignocellulose from the emergent Macrophyte >Carex> >walteriana> is the most abundant source of carbon. Since lignocellulose is largely indigestible to animals they cannot use its carbon (energy) until it is degraded by microorganisms. Thus, having an understanding of microbial transformations of lignocellulosic material and the factors controlling rates of its breakdown are key to understanding how the Okefenokee and other wetland ecosystems work. The research will be divided into three parts; detailed process studies, integrative system.level measurements, and modeling syntheses. The detailed process studies will focus on decomposition in field and laboratory efforts designed to clarify the temporal and spatial aspects of transformations, fate, and controls on decomposition not only of lignocellulosic, but also of non.lignocellulosic carbon. Techniques to be used in these studies include: the radiolabeling of substrates with .1.4C to determine the fate of the decomposed material; and the labeling of bacteria with ı.3H! thymidine to determine the efficiency of particle incorporation. The system.level measurements are designed to put the decomposition studies in context of the site's overall carbon budget. Standard methods including flow.through metabolic chambers and .1.4C "spiked" light.dark bottles will be used in the system level studies. Modeling will function as a synthesis tool in this research. Extant models of microbial degradation of lignocellulose will be expanded to: 1) consider spatial and temporal aspects of decay related to detrital inputs; and 2) incorporate more explicit and detailed controls on rates of decay including the influence of N, P and S. Finally, detailed flow and sensitivity analyses will be made of the modified models. The significance of this research is that it will help us to understand how wetlands, a major ecosystem type, worldwide, function. This research should provide a scientific basis for wise management of this important landform. Drs. Hodson, Wiegert and Hopkinson are very capable scientists with strong research records. The institutional support available to them is excellent.