海洋颗粒物/沉积物中的氨基酸及其对有机质降解的指示作用

Amino acids in marine particulate matters and sediments and their role as indicators for organic matter degradation

氨基酸是海洋有机质尤其是有机氮的重要组分,其地球化学行为活跃,在海洋有机质生物地球化学循环过程中起着重要作用.氨基酸的含量、组成和分布等信息可有效指示有机质的降解状态.本研究系统总结了海洋颗粒物/沉积物中氨基酸的分布特征及影响因素,以及氨基酸对有机质降解程度的指示作用.海洋颗粒物/沉积物氨基酸的主要成分为甘氨酸(Gly)、谷氨酸(Glu)、丙氨酸(Ala)和天冬氨酸(Asp),其含量从近岸到大洋逐渐降低,并随深度增加呈下降趋势组.氨基酸的碳、氮归一化产率()越低,表明有机质%AA-C/TOC,%AA-N/TN)以及基于氨基酸成的降解因子(DI的降解程度越高.基于非蛋白质氨基酸以及)D型氨基酸含量与组成的活性因子(RI)和D型氨基酸与L型氨基酸比值(D/L等指标可以根据细菌对氨基酸的转化作用来指示有机质的降解程度,其中RI值越接近于0,D/L值越高,蛋白质与非蛋白质氨基酸的比值的高Asp/β-Ala和Glu/γ-Aba(氨基丁酸)越小,均表明有机质受到微生物降解和转化程度越.颗粒物/沉积物中氨基酸的迁移转化过程主要受到溶解氧、营养盐水平、有机质来源、沉积环境以及微生物转化等因素的影响.今后应加强颗粒物和沉积物之间的协同效应以及微生物对氨基酸的影响与具体调控机理研究.

As important components of marine organic matters especially of organic nitrogen, amino acids play an important role in organic matter cycles owing to their lability. The concentration, composition, and distribution of amino acids have been widely used to indicate the degradation state of organic matters in particulates and sediments of marine. Here, the distribution, influencing factors of amino acids and their role in indicating degradation of organic matters were system atically summarized. Gly, Glu, Ala, and Asp were the major components of amino acids in marine particulates and sediments. The contents of amino acids in the particles and sediments showed a decreasing tendency from the coastal waters to the open sea, and adecreased with the water depth. The lower value of %AA-C/TOC, %AA-N/TN and degradation index（DI） based on changes in the composition of aminoacids indicated the higher degradation degrees of organic matters. The reactivity index（ RI） and ratios of D-AA and L-AA（D/L） based on non-protein amino acids and D-AA were used to indicate the degradation of organic matter according to the bacterial transformation of amino acids, in which RI value closer to 0, higher D/L, and lower ratios of protein amino acids to non-protein amino acids （Asp/β-Ala and Glu/γ-Aba） indicated the higher degree of degradation in organic matters. The migration and transformation of amino acid were mainly affected by dissolved oxygen, nutrient concentrations, sources of organic matter, depositional environments and microbial activities. Further studies should focus on the synergistic effects of particles and sediments, and also the effects and the specific regulatory roles of microorganisms on amino acids.