The concentrations and wet depositions fluxes of inorganic ions in oceanic precipitation——Study on precipitation over the China Sea and Northwest Pacific Ocean
LIN Jiu-ren;QI Jian-hua;XIE Dan-dan;MENG Xiang-bin;Key Laboratory of Marine Environment and Ecology,Ministry of Education,Ocean University of China;
The precipitation samples were collected in the Yellow Sea, the East China Sea, the South China Sea and the Northwest Pacific Ocean during two-period of cruise in spring and summer of 2016. The concentrations of Cl~-, NO_3~-, SO_4~(2-), PO_4~(3-), Na~+, NH_4~+, K~+, Mg~(2+) and Ca~(2+) were measured by ion chromatograph, and the wet deposition fluxes of these ions, as well as their impact on marine primary productivity, were estimated. Considering the common features such as high concentration of sea salt ions and comparable major ions among the East China Sea, the South China Sea and the Northwest Pacific Ocean, the precipitation over the wide ocean was likely dominated by the localized ocean effect. The major ions in the precipitation were Cl~-, Na+, SO_4~(2-)and Mg2+ over the Northwest Pacific Ocean, NO_3~-, SO_4~(2-), Ca~(2+) and Cl~-over the Yellow Sea and Cl~-, Na~+, NO_3~-and SO_4~(2-)over the East China Sea and South China Sea. The magnitude of the mean concentration(mmol/L) of total ions in precipitation among the four sampling regions was in the order of the Northwest Pacific Ocean(1.27) the South China Sea(0.53) the East China Sea(0.40) the Yellow Sea(0.31). Inorganic nitrogen mainly existed in the form of nitrate and the contribution of nitrate to total inorganic nitrogen continues to increase during the air mass transport from the land to ocean. The wet deposition fluxes[mg/(m~2·h)]of Cl~-, NO_3~-, SO_4~(2-), PO_4~(3-), Na~+, NH_4~+, K~+, Mg~(2+) and Ca~(2+) were in range of 3.47~451.43, 0.60~49.36, 1.13~124.02, 0.0015~0.094, 1.21~383.37, 0.06~7.57, 0.25~28.86, 0.17~47.39 and 0.37~27.24, respectively. In regions near the emission source and abundance of precipitation, the wet deposition flux of major ions was relatively high. The inorganic nitrogen and phosphorus in precipitation was able to provide new productivity, approximately accounting for 0.13‰~32.08% of the primary productivity per hour on average.
【CateGory Index】： X51
【CateGory Index】： X51