Radiotracer and Inhibitor Studies of Amino Acid Cycling in Anoxic Marine Sediments

该项目的目标是进一步表征利用缺氧海洋沉积物中溶解的游离氨基酸的生物地球化学过程。这项工作是对之前拨款的更新，以及利用14C标记的氨基酸和特定微生物过程的抑制剂进行的一系列实验，重点是消耗氨基酸时硫酸盐还原和发酵反应之间的关系。这项工作的一个主要重点将是量化缺氧海洋沉积物中氨基酸代谢产生的特定中间体(例如，醋酸盐与丙酸，而不是简单的总挥发性脂肪酸)。为了进行比较，将使用从几个地点收集的沉积物进行实验。以前对这些沉积物中谷氨酸和丙氨酸利用的研究将扩大到包括涉及甘氨酸和赖氨酸的类似研究。这些氨基酸之所以被选中进行研究，是因为它们是主要的氨基酸。这项研究的结果有可能增加我们对缺氧海洋沉积物中氨基酸生成的控制的认识。

The goal of this project is to further characterize the biogeochemical processes utilizing dissolved free amino acids in anoxic marine sediments. This work is a renewal of a previous grant and series of experiments utilizing 14C- labelled amino acids and inhibitors of specific microbial processes, focussing on the relationship between sulfate reduction and fermentation reactions in consuming amino acids. A major emphasis of this work will be to quantify the specific intermediates produced from the metabolism of amino acids in anoxic marine sediments (e.g., acetate vs. propionate as opposed to simply total volatile fatty acids). For comparative purposes experiments will be carried out using sediment collected from several locations. Previous studies of glutamic acid and alanine utilization in these sediments will be expanded to include analogous studies involving glycine and lysine. These amino acids have been chosen for study because they are the dominant amino acids. The results of this study have the potential of increasing our knowledge of the controls on amino acid digenesis in anoxic marine sediments.