Ｊ．Ｅｄｍｏｎｄ在中美长江口联合调查中惊呼,长江口硝酸盐含量高达６５ｍｏｌ／Ｌ,并把此归因于水稻田里一种蓝细菌的固氮作用(Ｅｄｍｏｎｄ等１９８３),认为其来源于农业(Ｅｄｍｏｎｄ等１９８５)。顾宏堪等１９８１年指出这一数值比１９６３年高约４倍,认为这与长江流域小 J. Edmond exclaimed in a joint survey of the Yangtze Estuary between China and the United States that the nitrate content in the Yangtze Estuary was as high as 65 mol / L and attributed it to the nitrogen fixation of a cyanobacterium in paddy fields (Edmond et al. 1983) Edmond et al. 1985). Gu Hongkan et al. Pointed out in 1981 that this value was about 4 times higher than in 1963, believing it to be small with the Yangtze River