南黄海及长江口邻近海域夏季溶解有机碳的分布特征及其影响因素

【目的】海水中溶解有机碳(DOC)的研究对于碳的生物地球化学循环具有重要意义。通过对南黄海及长江口邻近海域夏季溶解有机碳的分布特征及其影响因素的研究,为进一步丰富我国陆架边缘海碳循环的研究提供数据支持和参考依据。【方法】利用高温燃烧氧化法对2013年夏季南黄海及长江口邻近海域水体中的DOC进行测定,初步分析夏季南黄海DOC的分布特征,并结合水文、化学、生物同步观测参数,探讨影响DOC分布的主要因素。【结果】2013年夏季南黄海及长江口邻近海域DOC的含量为0.24~2.37mg/L,平均值为(1.34±0.42)mg/L。整体而言,调查海区平面分布呈现北部浓度高,向南部逐渐降低,近岸浓度高远岸浓度低的分布趋势。DOC的垂直分布呈现表层高,逐渐向底层减小,在底层又有所增加的趋势。【结论】研究海区DOC的分布受水团物理混合控制作用十分明显,近岸DOC高值区的分布主要受鲁北沿岸流和陆源输入影响,南部的低值区主要受黑潮表层水及台湾暖流的稀释作用影响,而生物作用对DOC的分布影响较弱。

Distribution and Impact Factors of Dissolved Organic Carbon in the Southern Yellow Sea and the Changjiang Estuary in Summer

Objective] Dissolved organic carbon (DOC) is the biggest organic carbon reservoir in the ocean,and is a extremely important component in oceanic carbon cycling.Methods] The DOC concentrations were determined by high-temperature combustion with a TOC Analyzer. The physical,chemical and biological parameters such as salinity,chlorophyll a and dissolved oxygen were also determined to find their effects on the DOC distribution.Results] Results suggested that DOC concentrations ranged from 0.24 to 2.37 mg/L with the average value of (1.34±0.42) mg/L.DOC concentrations in the north area and coastal waters were relative higher than those in the south area and open sea of the central area. In the vertical profile,the concentrations of DOC were higher in surface layer and decreased with the depth but slightly increased in the bottom layer.Conclusion] The distribution of dissolved organic carbon were obviously affected by the hydrological water mixing and partly by the terrigenous resources while the effect biological production on the distribution of DOC was comparatively insignificant.