| 摘要: |
| 根据2013-2016年春季（5月）长江口及其邻近海域4个航次环境综合调查数据，探讨春季长江口水体颗粒有机碳（POC）时空分布特征及其环境影响因素。结果显示：2013-2016年春季长江口POC浓度范围为0.22~16.99 mg/L，均值为1.80 mg/L，总水域POC年际间变化显著，底层浓度高于表层。从口门区、近岸区和近海区三个子水域来看，除近岸底层POC浓度处于高值，年际差异不显著之外，其余水域的表、底层均存在空间变异和年际差异。POC浓度在口门附近偏南部水域达到高值，后沿长江冲淡水（CDW）方向降低，低值区位于近海底层，但表层POC在近海水域123°E附近出现次高值。POC浓度与盐度之间具有显著负相关关系，且相关性逐年递减；POC浓度与总悬浮物浓度（TSM）呈显著正相关，底层相关性高于表层；近海区表层POC与叶绿素a正相关关系极显著，二者高值区均分布在123°E附近。入海径流量与长江口春季POC浓度呈现出截然相反的年际变化趋势，径流对有机碳的稀释作用高于其输入作用。长江口春季POC主要以碎屑源为主，其分布与有机碳源、海水的稀释作用、悬浮物运动等多种因素有关，高浊水体中悬浮物影响显著，陆源有机碳对POC的影响在长江口近海水域有所弱化，而浮游植物对POC的贡献凸显。 |
| 关键词: 长江口 颗粒有机碳(POC) 时空分布 影响因素 春季 |
| DOI：10.11759/hykx20200612001 |
| 分类号:P734 |
| 基金项目:国家自然科学基金资助项目（31872568） |
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| Interannual distribution of particulate organic carbon and its influencing factors in the Yangtze River Estuary in spring |
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LI Qian1,2, ZHANG Shan-shan1, XIAN Wei-wei1,3
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1.The Key Laboratory of Marine Ecology and Environment Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China;2.University of Chinese Academy of Sciences, Beijing 100049, China;3.Laboratory of Marine Ecology and Environmental Science, Qingdao National laboratory for Marine Science and Technology, Qingdao 266071, China
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| Abstract: |
| Based on a comprehensive survey of surface and bottom water samples from four spring voyages from 2013 to 2016, in this paper, we discuss the temporal and spatial distribution characteristics of particulate organic carbon (POC) in the Yangtze River Estuary and its adjacent waters and analyze its environmental impact factors. The results show that from 2013 to 2016 in spring, the POC concentration in the Yangtze River Estuary ranged from 0.22 to 16.99 mg/L, with an average of 1.80 mg/L, and it had a significant overall annual variation and a higher bottom layer concentration than surface layer concentration. Spatial variability and interannual differences were observed between different waters (entrance area, nearshore area, and offshore area) except for the bottom layer of the nearshore area with a high POC concentration. The POC concentration was high in the southern waters near the entrance area, and then decreased in the direction of the Changjiang Diluted Water (CDW), with the second highest surface POC concentration in the offshore waters near 123°E. POC and salinity were found to be negatively correlated and decreased each year. There is a significant positive correlation between POC and total suspended matter (TSM), which is higher in the bottom layer than in the surface layer. In addition, there is a highly significant positive correlation between surface POC and chlorophyll a in offshore areas, with their high-value areas coinciding around 123°E. In contrast to autumn, the interannual variation between the runoff and POC concentration into the Yangtze River Estuary presents a diametrically opposite trend, which indicates that the dilution effect of runoff on organic carbon is higher than the effect of its input. The POC of the Yangtze River estuary in spring was determined to be derived from detrital sources, with its distribution in spring mainly affected by factors such as the organic carbon sources, seawater dilution, and movement of suspended matter. Highly concentrated suspended matter has a particularly significant influence on the POC concentration. As the impact of terrestrial input on POC was found to gradually weaken from the mouth of the estuary to the adjacent waters, the contribution of phytoplankton became prominent in the offshore area. |
| Key words: Yangtze River Estuary particulate organic carbon (POC) interannual distribution influencing factors spring |
