西北冰洋总碱度与溶解无机碳的分布

2008年7～9月，中国进行了第三次北极科学考察。本研究即利用此次宝贵的科学考察机会，在西北冰洋现场采集大量的海水样品，进行二氧化碳体系（主要包括总碱度(TA)，和溶解无机碳(DIC)等）研究。得到了西北冰洋二氧化碳体系参数的分布，并对其控制因素进行了讨论。夏季西北冰洋表层海水总碱度（TA）、盐度归一化总碱度（nTA，nTA =TA*35/S）、溶解无机碳（DIC）和盐度标准化溶解无机碳（nDIC，nDIC=DIC*35/S）的范围分别为1757～2229μmol kg-1，2383～2722μmol kg-1，1681～2034μmol kg-1，2119～2600μmol kg-1。由于受到河水和海冰融化水的稀释，表层DIC和TA的浓度都比较低。78°N以南西北冰洋上层水柱中TA与盐度有良好的正相关关系，比较保守，在盐度大于30时，主要是海水端元与河水端元混合，在盐度小于30时主要是海水端元与海冰融化水端元的混合。在楚科奇海，DIC分布主要受到有机质生产或降解的主控，而加拿大海盆无冰区混合层DIC分布的主控因素是海水与海冰融化水的保守混合。

DISTRIBUTIONS OF DISSOLVE INORGANIC CARBON AND TOTAL ALKALINITY IN THE WESTERN ARCTIC OCEAN

The 3rd Chinese National Arctic Research Expedition(CHINARE 2008) was carried out from July to September in 2008.During survey,a considerable number of seawater samples were taken for CO2 parameters measurements(including total alkalinity(TA),total dissolved inorganic carbon(DIC)).The distributions of CO2 parameters in the Western Arctic Ocean were determined,and the according controlling factors were discussed.The ranges of summertime TA,nTA(nTA =TA×35/S),DIC and nDIC(nDIC=DIC×35/S) in the Western Arctic Ocean surface water were 1 757—2 229 μmol·kg-1,2 383—2 722 μmol·kg-1,1 681—2 034 μmol·kg-1,2 119—2 600 μmol·kg-1,respectively.As a result of dilution from ice-melt water,the surface TA and DIC concentrations were rather low.TA from the upper 100m in the south of 78°N in the Western Arctic Ocean had a good correlation with salinity,showing a conservative behavior,and the distribution followed seawater-river mixing line at salinity>30,then followed the mixing line of seawater(diluted by river water to salinity=30) with the icemelt water.The distribution of DIC in the Chukchi Sea was dominated by biological production or respiration of organic matter,whereas the conservative mixing dominated the distribution of TA of mixed layer in the ice-free Canada Basin.