中文摘要：

2007年夏季航次对南海越南上升流区的三个站位进行现场采样,利用微电极技术测定了沉积物间隙水中的溶解氧（DO溶解氧分子）、锰（Mn2＋）、铁（Fe2＋）的浓度和氧化还原电位,估算了DO的通量、消耗速率和有机碳的消耗速率。在沉积物间隙水中DO浓度随深度的增加而迅速降低,渗透深度为9—48mm。在沉积物深处还检测到Mn2＋和Fe2＋。采用元素分析仪测定了沉积物中总有机碳（TOC）含量和总氮（TN）含量,三个站位沉积物中的TOC含量为0.7%—1.03%,TN含量为0.052%—0.10%,C/N为10.5—16.0。从C/N可以看出,该研究区域沉积物中的有机物有部分来源于陆源输入,其中一个站位位于湄公河冲淡水区域,其C/N最大。从氧化还原电位来看,三个站位的沉积环境都属于还原性环境。此研究首次测量了南海越南上升流区沉积物的氧化还原化学成分,对于认识该海区海底生物地球化学具有重要意义。

英文摘要：

Sediments were sampled at three sites in the Vietnam upwelling zone of the South China Sea during a summer cruise in 2007.Microelectrodes were applied to measure the concentrations of dissolved oxygen molecules（DO）,Mn2＋,Fe2＋,and redox potentials in the pore water of the sediments.The fluxes and consumption rates of DO and the consumption rates of total organic carbon（TOC） were estimated.It was found that DO concentration decreased with increasing depth in the sediments and that its penetration depths were between 9 to 48 mm.Mn2＋ and Fe2＋ were also detected in the sediments.TOC and total nitrogen（TN） were measured by an elemental analyzer.TOC values at the three sites were between 0.7%—1.03%,TN values were between 0.052%—0.10%,and C/N ratios were between 10.5—16.0.From the C/N ratios,it can be seen that the sediments in the region had terrestrial origins.The sampling site located at the freshwater plume of the Mekong River had maximum C/N ratios.The redox potentials indicated that all sediments belonged to reducing environments.This study measured the redox chemical species in sediments from the Vietnam upwelling zone of the South China Sea for the first time and provided vital clues to the biogeochemistry of the sediments in the region.