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 μmol ·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.