Distribution of inorganic phosphate and dissolved oxygen and their relationship in the coastal upwelling area off Zhejiang

The change and distribution of inorganic phosphate and dissolved oxygen content in sea water pos-sess a certuin regularity and correlation, which are closely related to the direct influence of biologicalactivities. During the period of phytoplankton bloom, phosphate content may be exhausted and, at thesame time, oxygen content in sea water increases in the euphotic layer. With the decomposition of or-ganic matter, phosphate content increases and oxygen content decreases in the deeper layer. In addi-tion, the upwelling carries the "new" nutrients to the euphotic layer, which provides advantageous