Investigations on distributions and fluxes of sea-air CO2 of the expedition areas in the Arctic Ocean

The distributions and fluxes of sea-air carbon dioxide were investigated the first time based on the firsthand data collected during the First Chinese National Arctic Research Expedition. The results revealed that values of atmospheric CO2 partial pressure (Pa) measured in the sum-mer during the expedition fell between 352 and 370 (x10−6 CO2·Air−1, same unit below) with an average value of 358. Particularly, Pa appeared high in the northern sea areas of Poitlay. However, the values of CO2 partial pressure at the surface layer of seawater (Pw) ranged from 98 to 580 with the difference between the low and high being 472. The average value ofPw was 242, which is 116 lower than that of the correspondingPa. In addition, the distribution ofPw was roughly low in the west and north, but high in the east and south. These phenomena were closely related to plankton, ice, water temperature and circulation of the region. The estimation in carbon fluxes showed that the patterns in distribution were similar through different calculating methods with an exception in eastern sea areas of the region where a weak source of atmospheric CO2 was indi-cated. Most sea areas of the region were sinks or strong sinks of atmospheric CO2. However, the magnitudes in the fluxes were different. The average values varied from 6.57 (Liss method) to 26.32 mg.CO2·m−2·h−1 (14C method) with a difference of about 4 times between the low and high, which is 2 to 10 times as high as the global average. Compared with the fluxes in the same region obtained using model of Takahashi, Feely et al., the values determined based on Wanninkhof coef-ficient calculation were 2.38 times as great as those obtained by them.