Contrasting composition of terrigenous organic matter in the dissolved, particulate and sedimentary organic carbon pools on the outer East Siberian Arctic Shelf
Contrasting composition of terrigenous organic matter in the dissolved, particulate and sedimentary organic carbon pools on the outer East Siberian Arctic Shelf
复制标题
东西伯利亚北极陆架外侧溶解、颗粒和沉积有机碳库中陆源有机质的组成对比
DOI：
10.5194/bg-13-6121-2016
复制
发表时间：
2016
期刊：
影响因子：
4.9
通讯作者：
Ö. Gustafsson
中科院分区：
文献类型：
--
作者：
J. Salvadó;T. Tesi;M. Sundbom;Emma Karlsson;M. Kruså;I. Semiletov;E. Panova;Ö. Gustafsson
抽象的。以永久冻土为主的东西伯利亚北极地区的河流排放和海岸侵蚀向海洋水域输送了大量的陆源有机碳（Terr-OC）。重新动员的 Terr-OC 的组成和命运需要得到更好的限制，因为它影响气候-碳反馈的潜力。在本研究中，评估了不同海洋池中跨大陆架输出的有机碳（OC）的大量同位素（δ13C和Δ14C）和大分子（木质素衍生的酚）组成。为此，作为 SWERUS-C3 探险（2014 年 7 月至 9 月）的一部分，沿喀拉海、拉普捷夫海和东西伯利亚海的外陆架收集了沉积物有机碳 (SOC) 以及水柱（来自地表和近海底海水）溶解有机碳 (DOC) 和颗粒有机碳 (POC) 样本。结果表明，勒拿河和DOC可能对Terr-OC向外陆架的输送具有优先作用。 DOC 浓度 (740–3600μgL−1) 比 POC (20–360μgL−1) 高 1 个数量级，且勒拿河羽流的浓度更高。三个碳库中的δ13C特征变化范围为SOC中的-23.9±1.9‰、DOC中的-26.1±1.2‰和POC中的-27.1±1.9‰。 Δ14C值范围在-395±83（SOC）、-226±92（DOC）和-113±122‰（POC）之间。拉普捷夫海和东西伯利亚海的这些稳定同位素和放射性碳同位素也不同。勒拿河羽流中的 DOC 和 POC 都呈现出枯竭和年轻化的趋势。此外，太平洋流入和海冰覆盖作为阻止“年轻”DOC和POC输入的障碍，似乎对这些碳库有很大影响，在海冰范围下呈现出更古老和更丰富的δ13C特征。木质素酚在 SOC (0.10–2.34mgg−1OC) 和 DOC (0.08–2.40mgg−1OC) 中表现出比 POC (0.03–1.14mgg−1OC) 更高的 OC 归一化浓度。 DOC 中木质素和 Δ14C 特征之间的良好关系表明，外层架 DOC 的很大一部分来自“年轻”的 Terr-OC。相比之下，POC 中木质素酚和 Δ14C 特征之间的轻微负相关性，以及来自近底层水域的较旧 POC 中的木质素浓度较高，可能反映了 OC 从霞云层中重新动员的永久冻土中的离架运输。丁香基∕香草基和肉桂基∕香草基苯酚比率在 DOC、POC 和 SOC 之间呈现出明显的聚类，这意味着这些池可能携带部分不同来源的不同 Terr-OC。此外，用作成岩指示剂的 3,5-二羟基苯甲酸与香草酚的比率以及对香豆酸与阿魏酸的比率在 POC 和 SOC 中增强，表明这些池内的降解更多。总体而言，最年轻的 DOC 和最古老的 POC 样品中木质素产量增加之间的主要对比反映了陆地 OC 来源和途径的显着脱钩。
Abstract. Fluvial discharge and coastal erosion of the permafrost-dominated East Siberian Arctic delivers large quantities of terrigenous organic carbon (Terr-OC) to marine waters. The composition and fate of the remobilized Terr-OC needs to be better constrained as it impacts the potential for a climate–carbon feedback. In the present study, the bulk isotope (δ13C and Δ14C) and macromolecular (lignin-derived phenols) composition of the cross-shelf exported organic carbon (OC) in different marine pools is evaluated. For this purpose, as part of the SWERUS-C3 expedition (July–September 2014), sediment organic carbon (SOC) as well as water column (from surface and near-bottom seawater) dissolved organic carbon (DOC) and particulate organic carbon (POC) samples were collected along the outer shelves of the Kara Sea, Laptev Sea and East Siberian Sea. The results show that the Lena River and the DOC may have a preferential role in the transport of Terr-OC to the outer shelf. DOC concentrations (740–3600 µg L−1) were 1 order of magnitude higher than POC (20–360 µg L−1), with higher concentrations towards the Lena River plume. The δ13C signatures in the three carbon pools varied from −23.9 ± 1.9 ‰ in the SOC, −26.1 ± 1.2 ‰ in the DOC and −27.1 ± 1.9 ‰ in the POC. The Δ14C values ranged between −395 ± 83 (SOC), −226 ± 92 (DOC) and −113 ± 122 ‰ (POC). These stable and radiocarbon isotopes were also different between the Laptev Sea and the East Siberian Sea. Both DOC and POC showed a depleted and younger trend off the Lena River plume. Further, the Pacific inflow and the sea-ice coverage, which works as a barrier preventing the input of “young” DOC and POC, seem to have a strong influence in these carbon pools, presenting older and more enriched δ13C signatures under the sea-ice extent. Lignin phenols exhibited higher OC-normalized concentrations in the SOC (0.10–2.34 mg g−1 OC) and DOC (0.08–2.40 mg g−1 OC) than in the POC (0.03–1.14 mg g−1 OC). The good relationship between lignin and Δ14C signatures in the DOC suggests that a significant fraction of the outer-shelf DOC comes from “young” Terr-OC. By contrast, the slightly negative correlation between lignin phenols and Δ14C signatures in POC, with higher lignin concentrations in older POC from near-bottom waters, may reflect the off-shelf transport of OC from remobilized permafrost in the nepheloid layer. Syringyl ∕ vanillyl and cinnamyl ∕ vannillyl phenol ratios presented distinct clustering between DOC, POC and SOC, implying that those pools may be carrying different Terr-OC of partially different origin. Moreover, 3,5-dihydroxybenzoic acid to vanillyl phenol ratios and p-coumaric acid to ferulic acid ratios, used as a diagenetic indicators, enhanced in POC and SOC, suggesting more degradation within these pools. Overall, the key contrast between enhanced lignin yields both in the youngest DOC and the oldest POC samples reflects a significant decoupling of terrestrial OC sources and pathways.
影响因子：
3
作者：
A. D. Selver;R. Sparkes;J. Bischoff;H. Talbot;Ö. Gustafsson;I. Semiletov;O. Dudarev;S. Boult;B. Dongen
通讯作者：
A. D. Selver;R. Sparkes;J. Bischoff;H. Talbot;Ö. Gustafsson;I. Semiletov;O. Dudarev;S. Boult;B. Dongen
影响因子：
5.2
作者：
Karlsson, Emma;Gelting, Johan;Gustafsson, Orjan
通讯作者：
Gustafsson, Orjan