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

Abstract

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 CO 2 partial pressure (Pa) measured in the summer during the expedition fell between 352 and 370 (×10 -6 CO 2 ·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 CO 2 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 of Pw was 242, which is 116 lower than that of the corresponding P a . In addition, the distribution of Pw 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 CO 2 was indicated. Most sea areas of the region were sinks or strong sinks of atmospheric CO 2 . However, the magnitudes in the fluxes were different. The average values varied from 6.57 (Liss method) to 26.32 mg×CO 2 ·m -2 ·h -1 ( 14 C 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 coefficient calculation were 2.38 times as great as those obtained by them.