Distributions And Biological Production And Consumption Rates Of DMS And DMSP In The Pacific Sector Of The Arctic

Dimethylsulfide(DMS) is one of the major biogenic sources of sulfur to the atmosphere. The atmospheric oxidation products of DMS not only contribute to acid precipitation, but may also influence global climate change.Dimethylsulfoniopropionate(DMSP) is the major precursor of DMS and the biogeochemistry of DMSP can influence the concentration of DMS in the sea water.The biological production and consumption of DMS are considered to be the principal mechanisms controlling the concentration of DMS in the surface ocean and its sea-to-air flux, and play a key role in the global biogeochemical cycle of DMS and DMSP. Therefore studies on the distribution of DMS and factors which can influence DMS and biogeochemical production and consumption offer a unique opportunity to make the assessment of the quantitative contribution of biogenic sources of sulfur to the atmosphere, which will be helpful to understand better the influence of biogenic sulfur to global climate.Changes in the Polar Regions have the instruction and regulation effect on global climate change. Distributions of DMS and DMSP and factors influencing them in the Pacific sector of Arctic were systematically studied during July to August in 2014.Meanwhile, we study on the DMS production and consumption rates and sea-to-air emission for the DMS and the main removal process in the surface water. The main conclusions are drawn as follows:1. The survey in the Pacific sector of Arctic shows that average concentration of DMS was highest in Bering Sea(10.3±8.0 nmol/L), least in the Arctic Ocean(1.4±1.0nmol/L) and middle in Chukchi Sea(6.3±5.8 nmol/L). The concentrations of DMSPd(dissolved) and DMSPp(particulate) were highest in Bering Sea, then in Chkchi Sea and least in the Arctic Ocean. The water temperature and salinity can influence theconcentrations and distributions of DMS and DMSP. In the sea area whose water temperature during 2-7oC indicated that higher temperature was beneficial to the release of the DMS and lower temperature was helpful to the production of the DMSP.The lower salinity was beneficial to the release of the DMSP in the north of the Bering Sea and higher salinity was helpful to the production of the DMSP in Bering Sea and Chukchi Sea. And Chl-a didn’t have a obvious relationship with DMS and DMSPd but with DMSPp.2. In the surface water, the biological production and consumption rates of DMS were highest in Bering Sea, then in Chukchi Sea and lowest in the Arctic Ocean. Compared with DMSPp, DMSPd had a greater influence with biological production and consumption rates of DMS in Bering Sea, but it was completely opposite in Chukchi Sea and the Arctic Ocean. And it was indicated that the way of DMS production was different in Pacific sector of Arctic.3. The biological turnover time in surface layer of Bering Sea(0.29±0.34 d) was similar with it in Chukchi-Arctic Ocean(0.27±0.12 d). The sea-to-air emission of DMS in surface layer was fastest in Bering Sea(1.83±0.82 d), then in Chukchi Sea(2.29±1.36 d) and slowest in the Arctic Ocean(5.31±4.79 d), and the sea-to-air emission of DMS in Bering Sea and Chukchi Sea was about 23μmol/(m2·d). What’s more, it was about ten times more than that in the Arctic Ocean. The sea-to-air turnover time was about 20 times of biological turnover time and the crucial sink of DMS in the surface water was bacterial consumption when compared to the sea-to-air emission.4. Compared with the survey of July to August in 2012 in the Pacific sector of Arctic,the concentrations of DMS and DMSP and the sea-to-air emission of DMS increased by several times and the high area of DMS in Chukchi Sea had the trend of expanding both in the scope and value, which may be caused by the increase of water temperature.