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| 氨基糖对中国东部边缘海表层沉积物中有机质来源和降解的指示作用 |
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郑天昊1, 袁华茂1, 宋金明1, 贺志鹏2, 段丽琴1, 李学刚1
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1.中国科学院海洋研究所 青岛海洋科技中心海洋生态与环境科学功能实验室 中国科学院大学 中国科学院海洋大科学中心;2.山东省淡水渔业研究院
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| 摘要: |
| 边缘海是全球有机质埋藏的热点区域,以不足10%的面积承载了全球约80%的有机碳埋藏,而表层沉积物中有机质的活性直接决定了有机质的埋藏效率。中国东部边缘海存在复杂的水动力过程和人为干扰,导致有机质埋藏的不确定性。本文研究了南黄海与长江口及其邻近海域表层沉积物中总有机碳(TOC)、总氮(TN)、稳定碳、氮同位素(δ13C、δ15N)以及氨基糖(AS)的含量和组成,评估了两个海域沉积物中有机质的来源与活性。结果显示,海源自生有机质约占研究海域沉积物总有机质的70%,且随离岸距离增加而增加。研究海域表层沉积物中葡萄糖胺与半乳糖胺之比(GlcN/GalN)小于3,表明其中的有机质经历了深度的异养改造,活性相对较低。相较于长江口及其邻近海域(1.76±0.72),南黄海(1.83±0.66)表层沉积物中的GlcN/GalN更高,表明其有机质降解程度相对较低且活性较高。利用细菌特有的氨基糖生物标志物胞壁酸(MurA)估算了沉积物中有机质的细菌贡献,发现南黄海表层沉积物中有机质的细菌贡献(20.24±7.45%)略高于长江口及其邻近海域(14.95±5.22%),表明南黄海在中国东部边缘海细菌有机碳长期封存中可能发挥更重要的作用。长江口及其邻近海域沉积物中有机质受人类活动影响易发生更深层次的降解,而南黄海泥质区等远端泥质区受人类活动干扰程度更小,将成为有机碳长期埋藏的热点区域。 |
| 关键词: 氨基糖 南黄海 长江口及邻近海域 有机碳来源 有机碳降解 |
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| 基金项目:国家自然科学基金项目（面上项目，重点项目，重大项目） |
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| Indication of amino sugars for sources and degradation of sedimentary organic matter in the Eastern China marginal Sea |
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ZHENG Tian-hao1, YUAN Hua-mao1, SONG Jin-ming1, HE Zhi-peng2, DUAN Li-qin1, LI Xue-gang1
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1.Institute of Oceanology Chinese Academy of Sciences, Laboratory for Marine Ecology and Environmental Science, Qingdao Marine Science and Technology Center ,University of Chinese Academy of Sciences,Center for Ocean Mega-Science, Chinese Academy of Sciences;2.Shandong Freshwater Fisheries Research Institute
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| Abstract: |
| The marginal sea is a global hotspot for organic matter burial, carrying about 80% of global organic carbon burial in less than 10% of its area, and the activity of organic matter in surface sediments directly determines the efficiency of organic matter burial. Complex hydrodynamic processes and anthropogenic disturbances exist in the Eastern China Marginal Sea, leading to uncertainties in the burial of organic matter. In this paper, we investigated the content and composition of total organic carbon (TOC), total nitrogen (TN), stable carbon, nitrogen isotopes (δ13C, δ15N), and amino sugars (AS) in surface sediments from the South Yellow Sea and the Yangtze River estuary and its adjacent seas, and assessed the sources and activities of organic matter in sediments from the two seas. The results showed that marine-derived biogenic organic matter accounted for about 70% of the total organic matter in the sediments of the study sea area and increased with increasing distance from shore. The ratio of glucosamine to galactosamine (GlcN/GalN) in the surface sediments of the study waters was less than 3, suggesting that the organic matter therein had undergone deep heterotrophic modification with relatively low activity. Compared with the Yangtze River Estuary and the adjacent area (1.76±0.72), GlcN/GalN was higher in the surface sediments of the South Yellow Sea (1.83±0.66), suggesting that the degradation of organic matter in it was low and the activity was high. The bacterial contribution of organic matter in sediments was estimated by using the bacterial biomarker muriatic acid (MurA), which is a unique aminoglycan biomarker, and it was found that the bacterial contribution of organic matter in the surface sediments of the South Yellow Sea (20.24±7.45%) was slightly higher than that of the Yangtze River estuary and its neighbouring sea areas (14.95±5.22%), suggesting that the South Yellow Sea may play a more important role in the long-term sequestration of bacterial organic carbon in the Eastern China Marginal Sea. The organic matter in the sediments of the Yangtze River Estuary and the adjacent area is susceptible to deeper degradation due to human activities, whereas distal muddy areas, such as the South Yellow Sea muddy area, are less disturbed by human activities and will become a potential hotspot for the long-term sequestration of organic carbon. |
| Key words: amino sugar South Yellow Sea Yangtze River Estuary and adjacent seas organic carbon sources organic carbon degradation |
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