陆源物质输送对赤潮高发区的影响-以铝为例

近年来长江口附近海域富营养化问题日趋严重，赤潮爆发次数增多，而富含营养物质的长江水的输入可能是海内富营养化的主要物质来源．Al在海洋中停留时间较短且不易受到人为活动的影响，常用Al作为陆源输入及不同水团运动的有效示踪元素．结果表明。研究海域中溶解态Al的浓度秋季高于夏季，且与水体的盐度和悬浮颗粒物浓度表现出一定的关系．赤潮高发区内溶解态Al的浓度一般大于0．04pmol.L-1，明显表现出受到陆源输入的影响．赤潮发生时由于其自身的絮凝及赤潮生物颗粒物表面的吸附作用使水体中的溶解态Al含量平均下降约40％，而在赤潮发生过程中溶解态Al形态变化及机理尚需进一步深入研究．

Effects of terrestrial input on the harmful algal bloom area-with aluminum as an example

In recent years, eutrophication and frequently occurred harmful algal blooms (HAB) become serious in the coastal area near Changjiang River estuary, and the nutrients came from Changjiang River may be the main sources for them. Aluminum could be used as a useful tracer for the terrestrial input and the movement of different water mass, since it enters into the natural water with the erosion products of soil and rock, and its residence time in the ocean is short and uneasy to be disturbed by the activities of human being. Based on our results, the concentration of dissolved Al was higher in Autumn than in Summer, and showed some relationships with the salinity and suspended particulate matter (SPM). The concentration of Al in the HAB area was higher than 0.04 mumol.L-1, which showed the significant influence from the terrestrial input. The concentration of dissolved Al decreased nearly 40% after the occurrence of HAB, and the flocculation of dissolved Al and its absorption onto the surfaces of biogenic particles might be the main reasons. There still need further study about the variation of Al forms and its mechanism during the occurrence of HAB.