The biochemical composition and fluorescence properties of DOM were assessed in relation to phytoplankton and major aquatic bacterial clades in a regenerative area of the Argentine Shelf. DOM was mainly of autochthonous biological origin, containing humic- and protein-like substances of medium degree of unsaturation and diagenesis. Biochemical-DOM accounted for 25% of total DOC, being dissolved combined amino acids (DCAA) the dominant fraction followed by free carbohydrates. Phytoplankton was the main source of serine, alanine, and valine, and particulate carbohydrates. Gammaproteobacteria abundance correlated negatively with ammonium and positively with DCAA, suggesting a coupling between ammonium consumption and refractory amino acid production. A preferential utilization of alanine, leucine and threonine as nitrogen source was inferred from the distribution of Cytophaga-Flavobacteria-Bacteroidete in relation with dissolved free amino acids (DFAA). Notably, Alpha- and Betaproteobacteria correlated with the large pool (75%) of chemically unidentified DOC and not with DCAA or dissolved combined carbohydrates. Particularly, Alphaproteobacteria (∼40% of EUB total heterotrophic bacteria) either significantly contribute to the production of the “humic”, refractory fraction of marine DOM, or the latter impairs resource control on their abundance. Spatial heterogeneity inherent to coastal-shelf areas drives important regional variability in the biochemical properties of DOM.

DOM的生化组成和荧光性质与浮游植物和阿根廷陆架再生区主要水生细菌进化枝有关。DOM主要来自土生生物，含有中等程度的不饱和度和成岩作用的腐殖质和蛋白质样物质。生化-DOM占总DOC的25％，主要成分是溶解的组合氨基酸（DCAA），其次是游离碳水化合物。浮游植物是丝氨酸，丙氨酸，缬氨酸和碳水化合物的主要来源。γ-变形杆菌丰度与铵含量呈负相关，与DCAA呈正相关，表明铵消耗与难熔氨基酸产量之间存在关联。从细胞吞噬黄杆菌-拟杆菌的分布与游离氨基酸（DFAA）的关系推断出丙氨酸，亮氨酸和苏氨酸作为氮源的优先利用。值得注意的是，α和β变形细菌与大量未化学鉴定的DOC相关（75％），而与DCAA或溶解的合并碳水化合物无关。特别是阿尔法变形杆菌（约占EUB总异养细菌的40％）显着促进了海洋DOM的“腐殖质”，难降解部分的生产，或者后者损害了其丰富度的资源控制。沿海陆架地区固有的空间异质性在DOM的生化特性方面具有重要的区域差异性。