Departamento de Química-Física, INMAR, Universidad de Cádiz, Puerto Real, España.
Ecología Funcional de Sistemas Acuáticos, Centro Universitario Regional Este, Universidad de La República, Rocha, Uruguay.
Sci Rep. 2021 Feb 5;11(1):3200. doi: 10.1038/s41598-021-82632-3.
Seafloor structures related to the emission of different fluids, such as submarine mud volcanoes (MVs), have been recently reported to largely contribute with dissolved organic matter (DOM) into the oceans. Submarine MVs are common structures in the Gulf of Cádiz. However, little is known about the biogeochemical processes that occur in these peculiar environments, especially those involving DOM. Here, we report DOM characterization in the sediment pore water of three MVs of the Gulf of Cádiz. Estimated benthic fluxes of dissolved organic carbon (DOC) and chromophoric DOM (CDOM) were higher than in other marine sediments with an average of 0.11 ± 0.04 mmol m d for DOC and ranging between 0.11 and 2.86 m L m d, for CDOM. Protein-like components represented ~ 70% of the total fluorescent DOM (FDOM). We found that deep fluids migration from MVs (cold seeps) and anaerobic production via sulfate-reducing bacteria represent a source of DOC and FDOM to the overlying water column. Our results also indicate that fluorescent components can have many diverse sources not captured by common classifications. Overall, MVs act as a source of DOC, CDOM, and FDOM to the deep waters of the Gulf of Cádiz, providing energy to the microbial communities living there.
与不同流体排放有关的海底结构，如海底泥火山（MVs），最近被报道大量将溶解有机物质（DOM）注入海洋。海底 MVs 是加的斯湾的常见结构。然而，对于这些特殊环境中发生的生物地球化学过程，特别是涉及 DOM 的过程，人们知之甚少。在这里，我们报告了加的斯湾三个 MVs 沉积物孔隙水中 DOM 的特征。估计的底栖溶解有机碳（DOC）和色源 DOM（CDOM）通量高于其他海洋沉积物，平均为 0.11 ± 0.04 mmol m d 用于 DOC，范围在 0.11 和 2.86 m L m d 之间，用于 CDOM。蛋白样成分占总荧光 DOM（FDOM）的约 70%。我们发现，MVs（冷泉）深部流体的迁移和硫酸盐还原细菌的厌氧产生是 DOC 和 FDOM 进入上覆水柱的来源。我们的结果还表明，荧光成分可能有许多不同的来源，无法用常见的分类法捕捉到。总体而言，MVs 是加的斯湾深部水 DOC、CDOM 和 FDOM 的来源，为那里的微生物群落提供了能量。
