The Role of Reactive Iron in Preservation of Terrestrial Organic Carbon in Marine Environment
The Role of Reactive Iron in Preservation of Terrestrial Organic Carbon in Marine Environment
复制标题
活性铁在海洋环境中陆地有机碳保存中的作用
DOI：
10.1029/2018jg004649
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Zhigang Yu
中科院分区：
文献类型：
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作者：
Bin Zhao;Peng Yao;Thomas S. Bianchi;Michael R. Shields;Xingqian Cui;Xiaowen Zhang;Xinying Huang;Christian Schröder;Jun Zhao;Zhigang Yu
为了更好地了解活性铁（FeR）在河口沉积物有机碳（SOC）保存中的作用，研究了长江口及其邻近陆架表层沉积物的比表面积、粒度组成、总有机碳（TOC）、木质素酚、FeR、FeR-相关有机碳（Fe-OC）和木质素酚（Fe-lignin）以及FeR-相关有机碳的δ 13 C（δ 13 CFe-OC）。在长江口及其邻近陆架中，7.4 ± 3.5%的有机碳与FeR直接结合。在移动的泥浆中，TOC/比表面积负荷和Fe-OC/Fe比值异常低，这表明频繁的物理再加工可能会减少与OC结合的FeR，并选择性地损失海洋OC。在三角洲地区和移动的泥浆中，相对于TOC（13 C bulk）的13 C，13 CFe-OC的消耗更多，表明FeR主要与陆地OC相关，来自广泛的河流OC和Fe输入。与海上样品相比，移动的泥浆中的赤铁矿比例较高，表明铁氧化物可能在长期沉积物搬运过程中进行选择性分选和/或变得成熟。当考虑不同海洋环境中Fe-OC占SOC的百分比和SOC埋藏率时（例如，非三角洲陆棚、缺氧盆地、斜坡和深海），我们的研究结果表明，在全球范围内，约15.6 ± 6.5%的SOC直接与FeRon结合，这低于以前的估计（约21.5%）。这项工作进一步支持了aRusty Sinkwhere的概念，在这种情况下，FeR在海洋环境中陆地OC的保存和潜在迁移中起着重要作用。
To better understand the role of reactive Fe (FeR) in the preservation of sedimentary organic carbon (SOC) in estuarine sediments, we examined specific surface area, grain size composition, total OC (TOC), lignin phenols, FeR, FeR‐associated OC (Fe‐OC) and lignin phenols (Fe‐lignin), and δ13C of FeR‐associated OC (δ13CFe‐OC) in surface sediments of the Changjiang Estuary and adjacent shelf. An estimated 7.4 ± 3.5% of the OC was directly bound with FeRin the Changjiang Estuary and adjacent shelf. Unusually low TOC/specific surface area loadings and Fe‐OC/Fe ratios in mobile muds suggest that frequent physical reworking may reduce FeRbinding with OC, with selective loss of marine OC. More depleted13CFe‐OCrelative to13C of TOC (13Cbulk) in deltaic regions and mobile muds showed that FeRwas largely associated with terrestrial OC, derived from extensive riverine OC and Fe inputs. A higher proportion of hematite in the mobile muds compared to the offshore samples indicated that Fe oxides are likely subjected to selective sorting and/or become mature during long‐term sediment transport. When considering the percentage of Fe‐OC to SOC and SOC burial rates in different marine environments (e.g., nondeltaic shelf, anoxic basins, slope, and deep sea), our findings suggest that about 15.6 ± 6.5% of SOC is directly bound to FeRon a global scale, which is lower than the previous estimation (~21.5%). This work further supports the notion of aRusty Sinkwhere, in this case, FeRplays an important role in the preservation and potential transport of terrestrial OC in the marine environment.