夏季黄海冷水团海域的丙烯酸分布与海洋环境因子和叶绿素a变化之间的关系

海水中主要含硫化合物β-二甲基巯基丙酸内盐(DMSP)降解可产生丙烯酸(AA)和活性气体二甲基硫(DMS)。2011年8月对黄海冷水团海域的AA及相关参量的分布特征进行了研究。结果表明,该海域表层海水中AA的浓度为0~0.208μmol/L,平均值为(0.081±0.075)μmol/L。AA的高值区出现在海域的东南部,可能是受到长江冲淡水的影响。AA的浓度总体上呈现出由南到北递增的趋势,与Chl-a较为一致,表明该海域的AA主要是由DMSP裂解产生的。表层海水中AA与温度表现出明显的负相关性。AA的垂直分布表现为:中层底层表层,这可能是产生AA的浮游植物与消耗AA的细菌共同作用的结果。海域中AA浓度与DMSP或DMS无明显的相关性。AA浓度远高于DMS,AA/DMS平均为106∶1,初步估算出DMSP降解产生的AA约为66.5%。AA/Chl-a平均为126.6 mmol/g,比DMSP/Chl-a高1个数量级,比DMS/Chl-a高2个数量级。

Relationships Among the Distributions of Acrylic Acid,Marine Environmental Factors and Chlorophyll a in the Yellow Sea Cold Water Mass in Summer

Acrylic acid (AA), together with the major biogenic sulfur compound dimethylsulfide (DMS), is microbially degraded from dimethylsulphoniopropionate (DMSP), which is one of the major sulfur compounds in the marine environment. Distributions of AA concentrations and related parameters in the Yellow Sea Cold Water Mass was studied during August, 2011. The results showed that the concentrations of AA ranged from 0 to 0.208 μmol/L in the surface water, with an average of (0.081±0.075) μmol/L. The high values appeared in the southeast part of this area, which was influenced by the Changjiang diluted water. An increasing trend from the north to the south of AA concentrations was basically consistent with that of chlorophyll a (Chl-a), suggesting that AA in this area was mainly the product of microbial cleavage of DMSP. There was a significant negative relationship between AA concentrations and temperature in the surface water. The vertical profile of AA concentrations were presented as follows: Middle>Bottom>Surface,which could be attributed to the combined effects of AA production from phytoplankton and AA consumption by aquatic bacteria. Concentrations of AA showed no obvious correlation with those of DMSP or DMS during this cruise, and they were far higher than concentrations of DMS. The average ratio of AA/DMS was 106∶ 1, and production of AA from the cleavage of DMSP was about 66.5% according to observed data. The average ratio of AA/Chl-a was found to be 126.6 mmol/g. It was one order of magnitude higher than that of DMSP/Chl-a and two orders of magnitude higher than that of DMS/Chl-a.