Transformation of organic matter in a Barents Sea sediment profile: coupled geochemical and microbiological processes.
Transformation of organic matter in a Barents Sea sediment profile: coupled geochemical and microbiological processes.
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巴伦支海沉积物剖面中有机物的转化：地球化学和微生物过程的耦合。
DOI：
10.1098/rsta.2020.0223
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Stevenson MA
中科院分区：
文献类型：
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作者：
Stevenson MA
北极大陆架沉积物-水界面（SWI）下的有机质转化和成岩作用机理研究是至关重要的，因为这些地区面临着未来变化的最大风险。这在一定程度上是由于与洋流变化和海冰退缩有关的海底-上层耦合的破坏。在这里，我们专注于一套高分辨率、多学科的测量方法，这些测量方法说明了参与有机物降解的微生物过程如何与无机和有机地球化学沉积物特性（测量和建模）以及生物扰动的程度/深度直接相关。我们发现好氧过程、活性有机碳与最上层（0-4.5 cm深度）细菌和古细菌的最高丰度之间存在直接联系，其次是参与硝酸盐/亚硝酸盐和铁/锰还原的微生物在氧-缺氧氧化还原边界（约1.5 cm深度）占主导地位。4.5-10.5 cm深)。硫酸盐还原剂在深层（约）中占主导地位。10.5-33 cm)的缺氧沉积物，与模拟的反应性输运框架一致。重要的是，有机地球化学参数（正烷烃、正烷酸、正烷醇和甾醇）追踪的有机质反应性在SWI及SWI以下与沉积学和生物活性变化最为显著，但在沉积学的深层变化中相对保持不变。本文是主题议题“北冰洋变化：对生物群落、生物地球化学过程和生态系统功能的影响”的一部分。
Process-based, mechanistic investigations of organic matter transformation and diagenesis directly beneath the sediment–water interface (SWI) in Arctic continental shelves are vital as these regions are at greatest risk of future change. This is in part due to disruptions in benthic–pelagic coupling associated with ocean current change and sea ice retreat. Here, we focus on a high-resolution, multi-disciplinary set of measurements that illustrate how microbial processes involved in the degradation of organic matter are directly coupled with inorganic and organic geochemical sediment properties (measured and modelled) as well as the extent/depth of bioturbation. We find direct links between aerobic processes, reactive organic carbon and highest abundances of bacteria and archaea in the uppermost layer (0–4.5 cm depth) followed by dominance of microbes involved in nitrate/nitrite and iron/manganese reduction across the oxic-anoxic redox boundary (approx. 4.5–10.5 cm depth). Sulfate reducers dominate in the deeper (approx. 10.5–33 cm) anoxic sediments which is consistent with the modelled reactive transport framework. Importantly, organic matter reactivity as tracked by organic geochemical parameters (n-alkanes,n-alkanoic acids,n-alkanols and sterols) changes most dramatically at and directly below the SWI together with sedimentology and biological activity but remained relatively unchanged across deeper changes in sedimentology.This article is part of the theme issue ‘The changing Arctic Ocean: consequences for biological communities, biogeochemical processes and ecosystem functioning’.