长江口邻近海域营养盐分布特征及其控制过程的初步研究

利用1997年秋季和1998年春季对长江口邻近海域两个航次的调查结果，对该海域营养盐分布、结构特征以及其主要控制过程进行了探讨．结果表明，该海域的营养盐分布及结构具有明显的季节变化，秋季海水中NO3--N、SiO3^2-．SiSiO3^2-,Si及PO4^3--P,DOP、PP均高于春季，平均含量分别为4．97、11．6、0．44、0．26、0．82μmol·L-1，而春季则是NO2--N、NH4+-N、DON、PN含量高，平均含量分别为0．70、2．26、9．88、7．88μmol·L-·PP(54％)和PO4^3--P(51％)分别为秋季和春季磷的主要形态，两个季节氮结构基本一致，均以DON和PN为主．除春季PO4^3--P外，营养盐受长江冲淡水等陆源输入的影响而呈现近岸含量较高，溶解无机氮秋季以NO3^- -N为主而春季则以NH4^+-N为主，秋季PO4^3- -P同时来源于长江冲淡水和台湾暖流．而春季则主要来源于台湾暖流．显示出春季台湾暖流对调查海区的影响程度大于秋季．

Nutrient distribution and its controlling mechanism in the adjacent area of Changjiang River estuary

In this paper, the nutrient distribution, its structural characteristic and controlling mechanism around the Changjiang River estuary during Autumn 1997 and Spring 1998 were discussed, and a clear seasonal variation of nutrient distribution and structure was observed in this area. The concentrations of NO3(-)-N, SiO3(2-)-Si, PO4(3-)-P, DOP, PP and TP in Autumn 1997 were higher than those in Spring 1998, and their average concentrations were 4.97, 11.6, 0.44, 0.26, 0.82 and 1.52 mumol.L-1, respectively. However, the concentrations of NO2(-)-N, NH4(+)-N, DON, PN and TN in Spring 1998 were higher than those in Autumn 1997, with the average concentration of 0.70, 2.26, 9.88, 7.88 and 25.3 mumol.L-1, respectively. The main form of phosphorus in Autumn 1997 was PP, with the percentage about 54%, while PO4(3-)-P was the dominant fraction, with about 51% of phosphorus in Spring 1998. Both DON and PN were the main fractions of nitrogen in Autumn 1997 and Spring 1998 as well. Due to the influences of the Changjiang dilution water, the concentrations of phosphate, nitrate and silicate along the coastal area were higher than those in the outer area, except the phosphate in Spring 1998, which mainly came from Taiwan warm current. It indicated that the distribution of the nutrients in the survey area was mainly controlled by the Changjiang dilution water and the high salinity sea-water from the Taiwan warm current, and the influence of Taiwan warm current on phosphate was larger in Spring than in Autumn.