Organic matter burial and deposition conditions in the northern part of Chukchi Shelf, Arctic Ocean, since the Little Ice Age

Xiaoguo, Yu and Liming, Ye and Weiyan, Zhang and Rong, Wang and Yeping, Bian and Xiaobing, Jin and Xuying, Yao and Jingxin, Qian (2025) Organic matter burial and deposition conditions in the northern part of Chukchi Shelf, Arctic Ocean, since the Little Ice Age. Advances in Polar Science, 36 (3). pp. 179-190.

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Abstract

Understanding the sediment record during the Little Ice Age (LIA) can help elucidate natural sea ice fluctuation and carbon cycle variability. This study analyzed the grain size composition (including ice-rafted debris), total organic carbon (TOC), total nitrogen (TN) content, and stable isotopic composition (δ13C and δ15N) of the sediment record (approximately 490 a) of core ARC7-R11 in the northern part of the Chukchi Shelf. The sediment grains comprise mostly (>90%) silt and clay components. The grain size composition suggests generally low-energy hydrodynamic conditions across the region, yet reveals a trend of enhancement in hydrodynamics from the bottom to top layers of the sediment core, particularly after the 1940s. It also shows occurrences of seasonal sea ice and retreat of the perennial sea ice margin during warmer periods of the LIA and the post-LIA period. The organic matter content is high throughout the core, with heavier δ13C values and moderate TOC/TN ratios indicating primarily marine origin; the terrestrial input is <37.5% according to the endmember model. The variation trend of marine-derived organic carbon (OC) content is similar to that of summer temperature anomalies; while variation trend of terrestrially derived OC shows significant correlation with that of the number of ice-free days in the southern shelf region, except for the period from approximately 1700s to the 1870s. During the LIA, the TOC content fluctuated and decreased, and the relative contribution of terrestrial OC was higher than during the modern warm period. The amount of OC buried in the sediment has increased with climate warming, especially after the 1940s, reflecting the enhanced ability of sediment to sequester carbon during warmer periods.

Item Type:	Article
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Keywords:	grain size composition, ice-rafted debris, organic matter, northern Chukchi Shelf, Little Ice Age
Subjects:	Natural Environment > Cryosphere Natural Environment > Oceans Natural Resources and Industry > Mining
Organizations:	Advances in Polar Science (APS)
Date Deposited:	19 Nov 2025 10:06
URI:	https://library.arcticportal.org/id/eprint/2903

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