冯旭文, 金翔龙, 章伟艳, 于晓果, 李宏亮. 长江口外缺氧区柱样沉积物元素的分布及其百年沉积环境效应[J]. 海洋地质与第四纪地质, 2009, 29(2): 25-32. DOI: 10.3724/SP.J.1140.2009.02025
引用本文: 冯旭文, 金翔龙, 章伟艳, 于晓果, 李宏亮. 长江口外缺氧区柱样沉积物元素的分布及其百年沉积环境效应[J]. 海洋地质与第四纪地质, 2009, 29(2): 25-32. DOI: 10.3724/SP.J.1140.2009.02025
FENG Xuwen, JIN Xianglong, ZHANG Weiyan, YU Xiaoguo, LI Hongliang. VARIATION OF ELEMENTS IN SEDIMENTS FROM THE HYPOXIA ZONE OF THE YANGTZE ESTUARY AND ITS RESPONSE TO SEDIMENTARY ENVIRONMENT OVER THE LAST 100 YEARS[J]. Marine Geology & Quaternary Geology, 2009, 29(2): 25-32. DOI: 10.3724/SP.J.1140.2009.02025
Citation: FENG Xuwen, JIN Xianglong, ZHANG Weiyan, YU Xiaoguo, LI Hongliang. VARIATION OF ELEMENTS IN SEDIMENTS FROM THE HYPOXIA ZONE OF THE YANGTZE ESTUARY AND ITS RESPONSE TO SEDIMENTARY ENVIRONMENT OVER THE LAST 100 YEARS[J]. Marine Geology & Quaternary Geology, 2009, 29(2): 25-32. DOI: 10.3724/SP.J.1140.2009.02025

长江口外缺氧区柱样沉积物元素的分布及其百年沉积环境效应

VARIATION OF ELEMENTS IN SEDIMENTS FROM THE HYPOXIA ZONE OF THE YANGTZE ESTUARY AND ITS RESPONSE TO SEDIMENTARY ENVIRONMENT OVER THE LAST 100 YEARS

  • 摘要:210Pb定年的基础上,对取自长江口外缺氧区内外的柱样沉积物开展了10种常量元素、13种微量元素和粒度的测定分析,研究了其物源及分布特征。结果表明,缺氧区外柱样沉积物主要来源于老黄河口海岸泥沙,大部分元素具有"粒度控制"规律。缺氧区内沉积物主要来源于夏季长江陆源的输入和海洋自生生物死亡后的沉降,部分氧化还原敏感元素(RSE)和亲生物元素不受控于"粒控效应",其中Mo、Cd、As等氧化还原敏感元素自20世纪70年代以来明显富集,分别增加了83%、73%和50%,而Mn出现贫化,指示了缺氧区水体富营养化加剧和底层水体季节性缺氧,引起底层水-沉积物界面氧化还原环境变化;亲生物元素Ca、Sr、P含量自20世纪70年代起分别增加了129%、65%和38%,反映了受化肥使用等人类活动影响,近40年来长江口外水体生产力提高和生物量增加。

     

    Abstract: We selected two cores in the Yangtze estuary, one within the region of seasonal hypoxia (named CJ43 core) and the other nearby but outside the hypoxia region (named CJ56 core). The grain size and elements, including ten kinds of major elements and thirteen kinds of trace elements, were determined on the 210Pb-dated sediment cores. The two core sediments had different resources and represented different element distribution characteristics. Major sources of the CJ56 core sediment were from the old Yellow River estuary, and the distribution of most elements was controlled by "grain size effects". The sources of the CJ43 core sediment were mainly from the riverine input of the Yangtze River in summer and the burial fluxes of the dead marine organisms. The distribution of some redox sensitive elements (RSE) and biogenic elements did not conform with "grain size effects". Mo, Cd and As. have been enriched significantly, whose concentrations increased by about 83%, 73% and 50% respectively from 1970s. Conversely, Mn has been depleted since 1970s. The results indicate the redox environment of the bottom water-sediment interface has been changed, which might be caused by the eutrophication and hypoxia in the Yangtze estuary. Concentrations of biogenic elements, as well as Ca, Sr and P, have also increased by about 129%, 65% and 38% respectively since 1970s, which reflected the increasing of productivity and biomass influenced by the anthropogenic activities such as the fertilizer consumption during the last forty years.

     

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