夏季东海生源硫的分布、通量及其对非海盐硫酸盐的贡献

摘要

对2012年6月东海表层海水中二甲基硫(DMS)、二甲巯基丙酸内盐(DMSP)和二甲亚砜(DMSO)的浓度分布特征及其影响因素进行了研究,并估算了 DMS 的海-气通量及其对大气气溶胶中非海盐硫酸盐(nss-SO42-)的贡献率.结果表明,DMS、溶解态 DMSP(DMSPd)、颗粒态 DMSP(DMSPp)、溶解态 DMSO(DMSOd)和颗粒态 DMSO(DMSOp)的浓度平均值±标准偏差为(5.71±5.23),(5.94±3.68),(23.84±14.15),(9.14±10.52)和(11.01±5.81) nmol/L.DMS、DMSP和DMSOp浓度均在28oN~29oN,122oE~123.5oE海域呈现高值中心,沿中心向外扩散降低,并且与叶绿素a(Chl-a)的分布趋势基本一致.除DMSOd外,3种二甲基硫化物与Chl-a表现出显著的相关性,表明浮游植物生物量是影响东海生源有机硫化物生产分布的关键因素.此外,夏季东海DMS海-气通量介于(0.93~101.02)µmol/(m2⋅d),平均值±标准偏差为(18.13±21.42)µmol/(m2⋅d).夏季东海生源硫释放对nss-SO42-的贡献率仅为2.2%,表明人为排放是东海大气气溶胶中nss-SO42-的主要来源.%The spatial distributions of dimethylsulfide (DMS), dimethylsulfoniopropionate (DMSP), dimethylsulfoxide (DMSO) as well as their control factors were studied in the East China Sea during June 2012. The sea-to-air flux of DMS and its contribution to non-sea-salt sulfate (nss-SO42-) in atmospheric sulphate aerosol were also estimated. The average concentrations of DMS, dissolved DMSP (DMSPd), particulate DMSP (DMSPp), dissolved DMSO (DMSOd) and particulate DMSO (DMSOp) in the surface seawater were (5.71 ± 5.23), (5.94 ± 3.68), (23.84 ± 14.15), (9.14 ± 10.52) and (11.01 ± 5.81) nmol/L, respectively. Concentrations of DMS, DMSP and DMSOp formed high values center in the region of 28°N~29°N and 122°E~123.5°E and declined around this region diffusively, exhibiting similar distribution patterns to chlorophyll a (Chl-a). Concentrations of DMS, DMSPd, DMSPp and DMSOp were significantly correlated with the levels of Chl-a, suggesting that phytoplankton biomass might play an important role in controlling the production and distributions of biogenic sulfur compounds in the East China Sea. The sea-to-air fluxes of DMS in the study area varied from 0.93 to 101.02 µmol/(m2⋅d), with an average of (18.13 ± 21.42) µmol/(m2⋅d). The contribution of biogenic nss-SO42-to the total nss-SO42- in the atmospheric aerosol was only 2.2%, indicating that anthropogenic emission was the major source of atmospheric sulfur over the East China Sea in summer.