Abstract: In order to study the extent of eutrophication in Shenzhen Bay, spatial and temporal distributions of bacterioplankton biomass were seasonally investigated at three sampling stations in Shenzhen Bay in May, June, September, October and December in 2015 and March in 2016. The seasonal bacterioplankton biomass ranged from 4.90×10^-2 μg·mL^-1to 86.90×10^-2 μg·mL^-1, with an annual average of 3.14×10^-1 μg·mL^-1. The bacterioplankton biomass was the greatest in winter (5.98×10^-1 μg·mL^-1), followed by autumn (3.02×10^-1 μg·mL^-1), summer (2.79×10^-1 μg·mL^-1), and spring (7.52×10^-2 μg·mL^-1) in turn, revealing different seasonal patterns in this bay. The bacterioplankton biomass decreased horizontally from the center of the bay to the mouth of the bay and the top of the bay, with a higher biomass at station near the area for cultivation. The bacterioplankton biomass was significantly po sitively relatived to NO^-₂-N and NH⁺₄-N in Shenzhen Bay. The seasonal abundance of bacterioplankton ranged from 2.45×10⁶ ind·mL^-1 to 43.50×10⁶ ind·mL^-1, with an annual average of 1.57×10⁷ ind·mL^-1, implying serious eutrophication in this bay and revealing a decreasing pattern from the center to the mouth and the top of the bay.

Key words: Shenzhen Bay, bacterioplankton, biomass, temporal and spatial variation, affecting factor