A study on Emission Mechanism of Biogenic Sulfur from the Ocean by using Remoto Sensing and its influence to Global Climate Change

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Marine biogenic sulfur compounds, DMS (CHィイD23ィエD2SCHィイD23ィエD2), and MeSH(CHィイD23ィエD2SH), are emitted from the sea and oxidized to sulfate aerosol. It is considered to act as CCN (Cloud Condensation Nuclei). Therefore, DMS and MeSH have influence on the global climate change. COS is also a main source of sulfur aerosol in the stratosphere. These sulfur compounds relate to DMSP ((CHィイD23ィエD2)ィイD22ィエD2SィイD1+ィエD1CHィイD22ィエD2CHィイD22ィエD2COOィイD1-ィエD1) and DMSO (CHィイD23ィエD2SOCHィイD23ィエD2) in the ocean and react with radicals to be oxidized to sulfate in the atmosphere. In this study, two subjects shown in the following were investigated to understand the biogenic sulfur cycle. 1) Development of automatical monitoring system for sulfur compounds in the environment, 2) Understanding of behavior of biogenic sulfur compounds in the marine environment from the results of field measurement.Our monitoring system consists of two parts; cold trap (0.5g of Chromosorb 107 was packed in glass tube) and gas … More chromatograph with flame photometric detector. Sulfur compounds in the seawater and air were concentrated into the cold trap, and then they were injected into GC and determined by FPD. As all analytical processes were controlled by a sequencer, this system can successively analyze sulfur compounds both in the seawater and marine air at one hour interval. By using our monitoring system, field measurements were carried out in many oceanic areas; Mikawa Bay (Saku Island, 1992-1999), Pacific 0cean, Indian Ocean, Equatorial Ocean, Arctic (Research vessel "HAKUHO-MARU",1992, 1993, 1994, 1996, 1997, "Mirai" 1999) and so on. From the field measurements, many significant information about sulfur compounds in the marine environment was obtained. The mean DMS, COS, MeSH concentration in the seawater were 511ng/L(n=1014), 88ng/L(n=1053), 150ng/L(n=193) for the coastal area and 69ng/L(n=1146), 19ng/L(n=519), 15ng/L(n=15) for the open sea, respectively. Each concentration of sulfur compounds in the seawater was highly correlated with the marine primary productivity. Less