Different sources and degradation state of dissolved, particulate, and sedimentary organic matter along the Eurasian Arctic coastal margin
Different sources and degradation state of dissolved, particulate, and sedimentary organic matter along the Eurasian Arctic coastal margin
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DOI：
10.1002/2015gb005307
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发表时间：
2016-06-01
影响因子：
5.2
通讯作者：
Gustafsson, Orjan
中科院分区：
文献类型：
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作者：
Karlsson, Emma;Gelting, Johan;Gustafsson, Orjan
融化北极永久冻土导致大量的河流和侵蚀释放溶解和颗粒有机碳（DOC和POC）的沿海沃茨。在这里，我们调查了不同的来源和降解的再活化陆地碳可能会影响大规模的碳循环，通过比较分子和双同位素组成的水性高分子量DOC（> 1 kD，又名胶体OC），POC，和沉积OC（SOC）在东西伯利亚北极陆架。木质素酚指纹显示了陆地源对沿海有机碳相对贡献的纵向趋势。在胶体有机碳（COC）中没有检测到蜡脂和切割蛋白，与POC和SOC相反，这表明不同的陆地碳库划分为不同的水生载体阶段。碳-14信号表明绝大多数COC的当代来源，而POC和SOC主要由来自冰复合物存款（ICD）永久冻土的老C。蒙特卡罗源解析（C-13，C-14）限制，COC占主导地位的陆地有机碳从表土永久冻土（65%）和海洋浮游生物（25%）的贡献较小的ICD和其他老冻土股票（9%）。这种分布可能是固有的组成基质差异的结果，可能是由有机矿物协会。发现悬浮在地表水中的现代有机碳可能更容易降解，而较老的有机碳则优先沉降到海底，在那里它可能会在较长的时间尺度上降解。不同来源的DOC、POC和SOC在欧亚北极海岸边缘的命运沿着有很大的不同，可能在不同的时间尺度上对气候变化的响应。
Thawing Arctic permafrost causes massive fluvial and erosional releases of dissolved and particulate organic carbon (DOC and POC) to coastal waters. Here we investigate how different sources and degradation of remobilized terrestrial carbon may affect large-scale carbon cycling, by comparing molecular and dual-isotope composition of waterborne high molecular weight DOC (>1kD, aka colloidal OC), POC, and sedimentary OC (SOC) across the East Siberian Arctic Shelves. Lignin phenol fingerprints demonstrate a longitudinal trend in relative contribution of terrestrial sources to coastal OC. Wax lipids and cutins were not detected in colloidal organic carbon (COC), in contrast to POC and SOC, suggesting that different terrestrial carbon pools partition into different aquatic carrier phases. The C-14 signal suggests overwhelmingly contemporary sources for COC, while POC and SOC are dominated by old C from Ice Complex Deposit (ICD) permafrost. Monte Carlo source apportionment (C-13, C-14) constrained that COC was dominated by terrestrial OC from topsoil permafrost (65%) and marine plankton (25%) with smaller contribution ICD and other older permafrost stocks (9%). This distribution is likely a result of inherent compositional matrix differences, possibly driven by organomineral associations. Modern OC found suspended in the surface water may be more exposed to degradation, in contrast to older OC that preferentially settles to the seafloor where it may be degraded on a longer timescale. The different sources which partition into DOC, POC, and SOC appear to have vastly different fates along the Eurasian Arctic coastal margin and may possibly respond on different timescales to climate change.