摘要
全球变暖导致北极地区冻土退化、海冰消融、河流径流增加及海洋动力发生变化,这些因素连同日益增加的人类活动都影响北冰洋中汞的输入和运移。对取自北极东西伯利亚陆架的87个表层沉积物进行了汞含量测试与分析,发现沉积物中汞含量的分布有显著的空间差异性,可分为近岸低汞区(33 ng/g)、陆架中部汞含量中等区(58 ng/g)和北部深水高汞区(84ng/g)。总体来看,从近岸向外海,汞含量随水深的增大而升高。结合沉积物粒度、有机碳和比表面积等指标,发现东西伯利亚陆架沉积物中黏土含量与汞含量呈现正相关,显示了沉积物粒度对汞分布的控制作用。近岸由于受河流输入、海岸侵蚀和环流分选等因素的影响,沉积物粒径较粗,导致汞含量较低,而北部陆架深水区的细粒沉积物则吸附了更多的汞。在楚科奇海和拉普捷夫海,沉积汞含量和总有机碳含量有较强的正相关性,而在东西伯利亚海相关性较弱,这可能是因为东西伯利亚海的沉积有机碳来源相对更为复杂。基于沉积汞的富集因子指标,我们认为北极东西伯利亚陆架沉积汞的污染水平整体较低,受人类活动的影响相对较弱。
Global warming is leading to permafrost degradation, sea-ice melt, increased river runoff, and changes in ocean dynamics in the Arctic region. These factors, plus the increasing human activities, affects the input and transport of mercury in the Arctic Ocean. We analyzed the mercury content in 87 surface sediments(0~2 cm) sampled in the East Siberian Arctic Shelf in the Chukchi Sea, East Siberian Sea, and Laptev Sea during three Sino-Russian Arctic joint expeditions in 2016, 2018, and 2020 at water depth of 9~2 546 m. Results show a significant spatial variability in mercury concentration, which can be divided into the nearshore low-mercury zones(33 ng/g), the middle shelf mediummercury zone(58 ng/g), and the northern deep water high-mercury zone(84 ng/g). In general, the mercury concentration tended to increase with water depth increasing from nearshore toward offshore. Analyses of sediment grain size, total organic carbon, and specific surface area of sediments show that the mercury concentration was positively correlated with the clay content in the surface sediments, indicating the controlling role of sediment grain size in the distribution of mercury. The coarse sediments in the nearshore showed lower mercury concentration due to the influence of river input, coastal erosion, and hydrodynamic sorting, while the fine-grained sediments in the northern shelf are prone to absorb more mercury. There was a strong positive correlation between mercury and total organic carbon in the Chukchi and Laptev Seas, while the correlation was weaker in the East Siberian Sea due probably to more-complexed source of total organic carbon. The enrichment factor of mercury manifests that the overall level of contamination of sedimentary mercury is low at present in the East Siberian Arctic Shelf area,showing relatively weak influence of human activities.
作者
张振虎
姚政权
胡利民
Anatolii Astakhov
邹建军
刘焱光
王昆山
杨刚
陈志华
夏逸
李秋玲
冯晗
石学法
ZHANG Zhenhu;YAO Zhengquan;HU Limin;Anatolii Astakhov;ZOU Jianjun;LIU Yanguang;WANG Kunshan;YANG Gang;CHEN Zhihua;XIA Yi;LI Qiuling;FENG Han;SHI Xuefa(Key laboratory of Marine Geology and Metallogeny,First Institute of Oceanography,Ministry of Natural Resources,Qingdao 266061,China;Laboratory for Marine Geology,Pilot National Oceanography Laboratory for Marine Science and Technology,Qingdao 266237,China;College of Marine Geosciences,Key Laboratory of Submarine Geosciences and Prospecting Technology,Ocean University of China,Qingdao 266100,China;V.I.Il’ichev Pacific Oceanological Institute,Far Eastern Branch of Russian Academy of Sciences,Vladivostok 690041,Russia)
出处
《海洋地质与第四纪地质》
CAS
CSCD
北大核心
2023年第1期49-60,共12页
Marine Geology & Quaternary Geology
基金
国家自然科学基金重点项目“末次冰消期以来北极东西伯利亚陆架对快速气候变化的响应”(42130412)。
关键词
表层沉积物
汞含量
污染水平
北极东西伯利亚陆架
surface sediments
mercury concentrations
pollution levels
Eastern Siberian Arctic Shelf
作者简介
张振虎(1998-),男,硕士研究生,从事海洋沉积与古环境研究,E-mail:zhangzhenhu98@126.com;通讯作者:姚政权(1980-),男,研究员,主要从事海洋沉积与古环境、古气候研究,E-mail:yaozq@fio.org.cn。
