春季东海挥发性有机硫化物(VSCs)分布的研究

Distribution of volatile sulfur compounds in the East China Sea during spring

于2017年3~4月首次对东海表层海水及大气中3种主要挥发性有机硫化物(VSCs)即羰基硫(COS)、二甲基硫(DMS)、二硫化碳(CS2)的浓度分布进行观测,研究了海水中3种主要VSCs的相关性,并估算了3种VSCs的海-气通量.结果表明,东海表层海水COS、DMS和CS2的浓度平均值分别为(1.0±0.4)、(6.8±6.8)和(0.6±0.4)nmol/L,总体来看东海表层水中3种VSCs呈现出近岸高、远海低的分布趋势.相关性分析表明DMS与Chl-a存在显著相关性,表明浮游植物生物量是影响东海海水中DMS分布的主要因素;同时DMS与CS2存在着显著的相关性,表明这2种物质的来源有着一定的共性.大气中COS、DMS和CS2的浓度平均值分别为:(294.7±158.8)、(22.7±18.0)和(108.8±88.1)×10^(-12),分布呈现出近岸高,远海低的趋势,主要受到人为活动等陆源输入的影响.此外春季东海COS、DMS和CS2的海-气通量平均值分别为(4.0±3.4)、(25.8±33.8)和(2.6±2.9)μmol/(m2?d),表明春季东海是大气中3种VSCs重要的源.

The distributions of three main volatile organic sulfur compounds(VSCs)including carbonyl sulfide(COS),dimethyl sulfide(DMS)and carbon disulfide(CS2)were investigated for the first time in the seawater and marine atmosphere of the East China Sea(ECS)during March-April 2017 to study the correlation between the three main VSCs and their sea-to-air fluxes.The results showed that the average concentrations of COS,DMS and CS2 in the surface seawater were(1.0±0.4),(6.8±6.8)and(0.6±0.4)nmol/L,respectively.In general,the distributions of the three VSCs exhibited a decreasing trend from inshore to offshore sites.The concentration of DMS was significantly correlated with that of Chl-a,suggesting that phytoplankton biomass might play a crucial role in dominating the distribution of DMS in the study area.Moreover,a positive correlation between CS2 and DMS was observed,indicating that they might have some similar production patterns.The average concentrations of COS,DMS and CS2 in the atmosphere were(294.7±158.8),(22.7±18.0)and(108.8±88.1)×10-12,respectively.The levels of VSCs in the coastal atmosphere were obviously higher than those over the open sea.The average sea-to-air fluxes of COS,DMS and CS2 were estimated to be(4.0±3.4),(25.8±33.8)and(2.6±2.9)μmol/(m2?d)during this investigation,suggesting that the East China Sea acted as an important source for atmospheric VSCs in spring.