南黄海冷水团海域及西部近岸区表层沉积物中碳、氮、磷的分布特征及其生态学指示意义

Distributions of carbon,nitrogen and phosphorus in the surface sediments and their ecological implications in the areas of Cold Water Mass and off the western coast of the Southern Yellow Sea

基于南黄海西部沉积化学及相关环境因子的调查资料,重点分析和探讨了冷水团海域及近岸区表层沉积物中TOC、TN、TP的分布特征及其生态学指示意义.结果显示,冷水团海域沉积物比近岸区沉积物具有较高的含水率、TOC、TN、TP含量及N/P比.沉积物类型(粒径)、物质来源和沉积环境显著影响着TOC含量,TOC高值主要分布在泥质沉积区.表层沉积物TN与TOC含量在冷水团海域呈显著正相关关系,表明两者的同源性较好,但整个调查海域中TP与TOC、TN无显著相关性,说明其来源较复杂.南黄海冷水团海域和西部近岸浅水区沉积物理化特性之间的显著差异反映了它们受控因素的迥异,冷水团海域沉积物TOC和TN含量受水柱中生物活动的影响较大,上层水体中产生的有机碎屑是其重要的海生物质来源,而浅水区沉积物TN和TP含量受水柱中生物活动的影响相对较小.底层水年平均DO含量对沉积物TOC、TN分布也具有一定影响.

Based on the data of sediment chemistry and other environmental factors,distributions of carbon,nitrogen and phosphorus in the surface sediments and the ecological implications were analyzed and discussed in the areas of Cold Water Mass and off the western coast of the Southern Yellow Sea.The results showed that the contents of moisture,TOC,TN,TP and N/P ratio in the surface sediments of the Cold Water Mass were higher than those off the western coast.TOC concentrations were significantly affected by the sediment type（grain size）,material sources and sedimentary environment,and high TOC values occurred mainly in the muddy sediments.TN contents were significantly positively correlated with TOC contents in the surface sediments,indicating the similarity of TN and TOC sources.In contrast,TP contents were not significantly correlated with the contents of TN or TOC,reflecting the complex sources of TP.The significant differences of the sediment biogeochemical characteristics in the Cold Water Mass and the coastal areas indicated the different controlling factors for sediment chemistry.TOC and TN contents in the surface sediments of the Cold Water Mass were largely influenced by biological activities in the water column,whereas TN and TP in the surface sediments off the western coast was slightly impacted by the biological activities in the water column.The annual average DO concentrations posed some impacts on TOC and TN distributions in the surface sediments.