夏季白令海海水二甲亚砜的分布及影响因素

Spatial Distributions of Dimethylsulfoxide and Influencing Factors in the Bering Sea During Summer

基于中国第7次北极科学考察白令海现场调查资料与数据,分析了2016年夏季白令海海水颗粒态(DMSOp)和溶解态二甲亚砜(DMSOd)浓度的空间变化特征及其影响因素。研究表明,夏季白令海二甲亚砜(DMSO)浓度高于全球多数大洋和近岸海域。夏季白令海DMSOd和DMSOp浓度空间变化相似。表层海水DMSOp浓度为6.47~169.40 nmol/L,平均值为(79.62±56.10)nmol/L;DMSOd浓度的变化范围是20.07~153.70 nmol/L,平均值为(72.67±39.20)nmol/L。平面分布上,白令海表层DMSO浓度由海盆区、中外陆架区至内陆架区依次降低;垂直分布上由表至底随深度增加而降低,表层DMSOd和DMSOp浓度高于55 nmol/L,底层低于25 nmol/L。海盆区DMSOd主要源于DMS氧化和浮游生物直接合成的DMSOp,海盆区深层水团DMSOd浓度主要受控于温度和盐度。中外陆架区表层暖水团DMSO浓度主要受控于温度,陆架冷水团DMSO浓度则受盐度影响较大。内陆架区陆架水团DMSOp浓度和阿拉斯加沿岸水团DMSOd浓度分别受温度和DMS光化学氧化影响。

The horizontal/geographical variations in particulate and dissolved dimethylsulfoxide(DMSOp,DMSOd),as well as the oceanographic parameters influencing DMSO concentrations,were investigated in the Bering Sea from July to August in 2016.The surface concentrations of DMSOd and DMSOp in the Bering Sea were significantly higher than those in the coastal and oceanic surveys.The concentrations of DMSOp and DMSOd ranged from 6.47 to 169.40 nmol/L and from 20.07 to 153.70 nmol/L,respectively,with average values of(79.62±56.10)nmol/L and(72.67±39.20)nmol/L.The spatial distributions of DMSOd concentrations in the surface water of Bering Sea presenteda declining trend from the central basin,the outer-middle continental shelf,to the inner continental shelf,similar to those in DMSOp distributions.DMSOd and DMSOp concentrations were substantially higher within the surface layer(>55 nmol/L)than those in the bottom water(<25 nmol/L).In the central basin,DMSOd in the surface water was produced mainly through the photochemical oxidation of DMS and the diffusion of intracellular DMSOp,whereas DMSOd in the deep water were influenced by temperature and salinity.In the outer-middle continental shelf,temperature and salinity might play a crucial role in controlling the DMSO concentrations in the surface warm water and the cold water.In the inner continental shelf,a positive relationship was observed between DMSOp and temperature in the shelf water,whereas in the Alaska coastal water DMSOd concentrations were positively correlated with photochemical oxidation of DMS.