根据2009年4~5月对黄东海大面积调查的资料,分析研究了黄东海颗粒有机碳(particulate organic carbon,POC)的浓度和时空分布特征,并结合叶绿素(Chlorophyll a,Chl-a)和C/N摩尔比值探讨了POC的主要来源.结果表明,春季黄东海POC的浓度范围是24.33~2 817.29μg/L,平均值为230.76μg/L.POC整体上呈现近岸浓度高、远岸浓度低的特点.在苏北近岸、长江口外以及闽浙沿岸均存在POC高值区,尤其是苏北近岸,表层和底层POC浓度非常高,最高浓度达到2 817.29μg/L,这主要是受沉积物再悬浮的影响.垂直分布上,近岸浅水区POC浓度高,水体上下分布均匀,POC的主要来源是陆源输入和再悬浮作用;远岸深水区,POC浓度小于75μg/L,并随着水深的增加而逐渐降低,呈现出大洋海水的性质,POC的来源是海洋自生.周日变化上,东海中部海域,除底层外,各层POC浓度整体上表现出半日周期变化,在午后和深夜出现高值,傍晚出现低值,这主要是受现场生物活动的影响.
Based on the data from cruises that carried out in the Yellow Sea and East China Sea from April to May,2009,the temporal and spatial distributions of the particulate organic carbon(POC) were analyzed.And the sources of POC were further discussed according to the chlorophyll a(Chl-a) and C/N.The results showed that the concentration of POC in the Yellow Sea and East China Sea ranged from 24.33 μg/L to 2 817.29 μg/L in spring and the average content was 230.76 μg/L.In horizontal distribution,the highest POC content is in the coastal zones and it tends to decrease toward the far shore on the whole.The highest concentration of POC appears at the northern of Jiangsu Province coastal waters both in surface layer and bottom layer in particular,which is mainly affected by resuspension of sediments.And there is also a second highest concentration in the vicinity of the Yangtze River estuary,indicating the primary influence in the Yangtze River is by diluted water.The concentration of POC in shallow sea area is the highest and distributed uniformly and it is primarily from terrestrial inputs and resuspension.Moreover,the resuspension is relatively stronger than terrestrial inputs.However,the POC concentration in far coast deep water area is under 75 μg/L and it reduces gradually with the increase of water depth,which shows ocean water characteristics.And the POC is mainly from the ocean.The diurnal change of POC concentration in the middle of East Sea shows half-cycle variation,as a whole,the concentration value is high both in the afternoon and midnight,while it is relatively low at dusk,which is mainly under the influence of biological activity at the scene.