Does Arctic warming reduce preservation of organic matter in Barents Sea sediments?
Does Arctic warming reduce preservation of organic matter in Barents Sea sediments?
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DOI：
10.1098/rsta.2019.0364
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发表时间：
2020-10-02
期刊：
影响因子：
5
通讯作者：
Marz, Christian
中科院分区：
文献类型：
--
作者：
Faust, Johan C.;Stevenson, Mark A.;Marz, Christian
在过去的几十年里，巴伦支海经历了大幅变暖，相对温暖的大西洋海水扩大，海冰覆盖面积减少。这种环境变化迫使整个巴伦支海生态系统进行适应和重组，因此，预计在水层-海底耦合、有机物沉积和长期碳固存方面会发生变化。在这里，我们结合联合收割机新的和现有的有机和无机地球化学表层沉积物数据从西巴伦支海和现代生态系统结构，海冰覆盖和有机碳和碳酸钙含量在巴伦支海表层沉积物之间的联系。此外，我们讨论了总铁和活性铁相的来源，并评估了与活性铁结合的有机碳的空间分布。与最近的全球估计一致，我们发现，平均21.08.3%的总有机碳与活性铁（fOC-Fe-R）在巴伦支海表层沉积物。然而，fOC-Fe-R的空间分布似乎与海冰覆盖、大西洋水流入或靠近陆地无关。因此，未来的北极变暖可能既不会增加也不会减少铁相关有机碳的埋藏率。然而，我们的研究结果也意味着，正在进行的海冰减少和相关的垂直碳通量的改变可能会导致伴随着巴伦支海表面沉积有机碳含量的变化，这可能会导致在未来的整体减少碳封存。这篇文章是“变化中的北冰洋：对生物群落、地球化学过程和生态系统功能的影响”主题的一部分。
Over the last few decades, the Barents Sea experienced substantial warming, an expansion of relatively warm Atlantic water and a reduction in sea ice cover. This environmental change forces the entire Barents Sea ecosystem to adapt and restructure and therefore changes in pelagic-benthic coupling, organic matter sedimentation and long-term carbon sequestration are expected. Here we combine new and existing organic and inorganic geochemical surface sediment data from the western Barents Sea and show a clear link between the modern ecosystem structure, sea ice cover and the organic carbon and CaCO3 contents in Barents Sea surface sediments. Furthermore, we discuss the sources of total and reactive iron phases and evaluate the spatial distribution of organic carbon bound to reactive iron. Consistent with a recent global estimate we find that on average 21.08.3 per cent of the total organic carbon is associated to reactive iron (fOC-Fe-R) in Barents Sea surface sediments. The spatial distribution of fOC-Fe-R, however, seems to be unrelated to sea ice cover, Atlantic water inflow or proximity to land. Future Arctic warming might, therefore, neither increase nor decrease the burial rates of iron-associated organic carbon. However, our results also imply that ongoing sea ice reduction and the associated alteration of vertical carbon fluxes might cause accompanied shifts in the Barents Sea surface sedimentary organic carbon content, which might result in overall reduced carbon sequestration in the future. This article is part of the theme issue 'The changing Arctic Ocean: consequences for biological communities, biogeochemical processes and ecosystem functioning'.