叶君^1,2,,
胡利民^2,3,,,
石学法^1,2,
姚鹏⁴,
夏逸¹,
白亚之^1,2,
张钰莹¹
1. 自然资源部第一海洋研究所, 海洋地质与成矿作用重点实验室, 山东 青岛 266061
2. 青岛海洋科学与技术试点国家实验室, 海洋地质过程与环境功能实验室, 山东 青岛 266237
3. 中国海洋大学海洋地球科学学院, 海底科学与探测技术教育部重点实验室, 山东 青岛 266100
4. 中国海洋大学, 海洋化学理论与工程技术教育部重点实验室, 山东 青岛 266100

基金项目: 国家自然科学基金项目（批准号：41722603和42076074）和山东省"透明海洋"科技创新工程专项项目（批准号：2018SDK0104-3）共同资助


详细信息

作者简介: 叶君, 女, 28岁, 硕士, 海洋有机地球化学, E-mail: 792083520@qq.com

通讯作者: 胡利民, E-mail: hulimin@ouc.edu.cn

中图分类号: P727;P734.5;P593

收稿日期:2020-12-30
修回日期:2021-03-08
刊出日期:2021-05-30

Sources, transport and burial of terrestrial organic carbon in the surface sediments across the East Siberian Arctic shelf, insights from lignin

YE Jun^1,2,,
HU Limin^2,3,,,
SHI Xuefa^1,2,
YAO Peng⁴,
XIA Yi¹,
BAI Yazhi^1,2,
ZHANG Yuying¹
1. Key Laboratory of Marine Geology and Metallogeny, First Institute of Oceanography, Ministry of Natural Resources, Qingdao 266061, Shandong
2. Laboratory for Marine Geology and Environment, Qingdao National Laboratory for Marine Science and Technology(Pilot), Qingdao 266237, Shandong
3. College of Marine Geosciences, Key Laboratory of Submarine Geosciences and Prospecting Technology, Ocean University of China, Qingdao 266100, Shandong
4. Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao 266100, Shandong


More Information

Corresponding author: HU Limin,E-mail:hulimin@ouc.edu.cn

MSC: P727;P734.5;P593

--> Received Date: 30 December 2020
Revised Date: 08 March 2021
Publish Date: 30 May 2021


摘要
摘要:在全球变暖和北极快速变化的背景下，北极陆架陆源有机碳的供应显著增加；受海冰和流域背景条件等因素的制约，前人对北极陆架沉积有机碳的研究主要集中在河口或近岸陆架区。文章基于2016年和2018年中俄北极联合科考航次获得的表层沉积物样品资料，系统分析了东西伯利亚海和楚科奇海表层沉积物的比表面积（SSA）、粒度、有机碳（TOC）含量及其稳定同位素（δ¹³C）和木质素等相关参数，研究了近海河口-陆架不同沉积环境有机碳的来源、输运和埋藏降解情况。研究发现东西伯利亚海东部和楚科奇海的沉积有机质总体以海源为主，东西伯利亚海西部陆架区以陆源输入为主（约60%）；不同区域有机碳的沉积格局具有明显的空间异质性特征。相比之下，本研究中木质素降解参数（Ad/Al）s和（Ad/Al）v受植被组成、降解和浸出/吸附作用等因素综合影响，并未呈现明显的区域差异。受水动力分选、海冰、有机质降解和洋流等因素影响，有机碳的载荷（TOC/SSA）在输运过程中也呈不断下降的趋势。而3，5-Bd/V则呈现近岸低、远岸高的趋势，这说明在输运过程中土壤源有机质的降解程度不断变大；这类陆源有机碳向海输运过程中的"损失"将对于认识和评估变暖背景下北极近海冻土碳的释放与归宿及其气候环境效应具有重要意义。
关键词: 北极/
沉积有机碳/
木质素/
来源/
降解/
输运

Abstract:The East Siberian Arctic Shelf is the widest and shallowest continental margins in the world ocean; it receives particulate organic carbon from both river and coastal erosion, while the ice complex deposit is dominant in the central study region, the East Siberian Sea(ESS) presents two physical and biogeochemical regimes, the western part of the nearshore East Siberian Shelf is dominated by freshwater flux and coastal erosion, whilst the eastern part is influenced by water from the Pacific Ocean entering the region through the Bering Strait.
Application of a variety of specific surface area(SSA), content of elemental(TOC/TN) and its stable isotope(δ¹³C) and lignin analyses of surface sediments(0~1 cm) along the East Siberian Arctic Shelf(67.86°~79.18°N, 147.35°E~169.91°W) yielded information on the sources, degradation status and transport processes of sediments organic carbon in different sedimentary environments. A three end-member mixing model is applied to deduce the relative contributions from top-soil, ice complex deposit and marine sources.
Results indicate that the sources of organic carbon in the East Siberian continental shelf are different, and the distribution of organic carbon presents significant regional differences. East Siberian continental shelf in the western sediments mainly from runoff, coast erosion and Siberian coastal current transport particulate matter, it has lower TOC% values(0.47±0.38%), and the more enriched ¹³C(-25.9±0.7‰), while the Chukchi Sea mainly affected by inflow of the nutrient-rich Pacific waters with high primary productivity, has the high TOC% values(1.66±0.68%), and the most depleted ¹³C(-22.09±0.42‰). The three end-member mixing model results also indicate that around 60% sedimentary organic carbon from terrigenous material(top-soil and ice complex deposit) in the nearshore western Siberia Sea, eastern Siberian Sea and the Chukchi Sea sedimentary organic carbo mainly from marine source. Combined with S/V, C/V and LPVI parameters, the lignin in the study area is a mixed source of gymnosperms and angiosperms.
The fingerprint of lignin such as the(Ad/Al) s and(Ad/Al) v affected by vegetation composition, degradation, leaching/adsorption factors with no obvious regional difference in spatial distribution, By contrast, the 3, 5-Bd/V ratio exhibit a across-shelf trend suggesting either increasing degradation during transport.
Many indicators(δ¹³C, C/N, Λ₈) vary with increasing water depth due to hydrodynamic sorting, sea ice, current and degradation during transport. Loading of organic carbon(TOC/SSA) decreased from 0.65 mg/m² to 0.21 mg/m², index of terrigenous organic matter also showed that lignin loading in the transport process lost about 97%. During the transport process of sediments, due to the influence of hydrodynamic sorting and sea ice, the coarse particles with relatively low loss and rich lignin will be deposited directly near the shore, and only a small number of fine particles will be transported to the central and far-shore deep water areas, and the organic carbon will be degraded to different degrees during the transport process In addition, the Atlantic Ocean water and Beaufort circulation will also transport particulate matter to the central of the deep water area.
Key words:Arctic/
sediment organic carbon/
lignin/
sources/
degradation/
transport



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