氨基酸指示海洋中有机物降解行为的研究进展

氨基酸是海洋中重要的生源有机质，它在有机碳和有机氮的生物地球化学循环中起着非常重要的作用。氨基酸作为海洋有机物中的活性组分，在有机物降解过程中会被异养细菌选择性的去除，是指示海洋中有机物降解程度的灵敏指示因子。本论文首先介绍了海水中氨基酸的分类，总结了溶解游离氨基酸（DFAA）、溶解结合氨基酸（DCAA）、颗粒氨基酸（PAA）和细菌标志物D-型氨基酸的来源及生物学活性。同时归纳了有机物降解过程中氨基酸变化可归结为选择性保存、产生或者富集细菌源的物质和细菌的转化三种机理。最后本文综述了基于氨基酸的6种降解因子:溶解态氨基酸（THAA）对有机碳或有机氮贡献率（THAA-C%或THAA-N%）、降解因子（degradation index）、活性因子（reactivity index）、个体氨基酸的D/L比值、天门冬氨酸/β-丙氨酸或谷氨酸/γ-氨基丁酸比值（Asp/β-Ala或Glu/γ-Aba）以及细菌源有机物的贡献率，它们各自的特点、适用的降解阶段以及具体的应用。

Review of study on amino acids as indicators of the degradation of marine organic matter

Amino acids are important biogenic organic matter and play a critical role in biogeochemical cycling of organic carbon and organic nitrogen in the ocean.As one of the most labile fraction of marine organic matter, amino acids can be selectively removed by heterotrophic bacteria during the organic matter degradation, and be considered as a sensitive indicator for the degradation of organic matter.In this paper, the classification of amino acids in seawater is introduced, and the reactivity of dissolved free amino acids (DFAA), dissolved combined amino acids (DCAA), particulate amino acid (PAA) as well as the source of the D-amino acids are summarized.The changes of amino acids in the degradation process of organic matter can be ascribed to three mechanisms including selective preservation, production or enrichment of bacterial organic matter and transformation by the bacteria.Finally, comparisons of the characteristics, suitable degradation stages and specific applications of the six degradation indices including carbon-and nitrogen-normalized yields of total hydrolyzable amino acid (THAA-C% and THAA-N%), degradation index (DI), reactivity index (RI), the D/L-amino acid ratio, aspartic acid/β-alanine and glutamic acid/γ-aminobutyric acid ratios (Asp/β-Ala or Glu/γ-Aba) and bacterial contributions are summarized.