Effects of coastal upwelling on picophytoplankton distribution off the coast of Zhanjiang in South China Sea

Abstract

Coastal upwelling occurred along the west coast of Guangdong in the northern South China Sea during the summer of 2006. The effects of upwelling on the vertical and horizontal distributions of Prochlorococcus and Synechococcus were investigated. A distinct vertical temperature difference between the surface water and water at a depth of 30 m was observed in the coastal upwelling region. There was a clear spatial variability of temperature, and an increasingly obvious horizontal gradient was created from the coast to offshore waters. Picophytoplankton communities observed from the coast to offshore waters were significantly different. In the coastal upwelling waters, the picophytoplankton community was dominated by Synechococcus within the euphotic zone. Prochlorococcus dominated the * Corresponding author: dongjd@scsio.ac.cn picophytoplankton community in the euphotic zone in the nonupwelling region. This difference in the picophytoplankton community structure was due to different hydrodynamics. The results of canonical correspondence analysis demonstrate that temperature, salinity, and phosphate concentration may be important factors affecting the distribution of Prochlorococcus and Synechococcus.

Seasonal and Spatial Variation of Pelagic Microbial Food Web Structure in a Semi-Enclosed Temperate Bay

“…At mesoscale, microbial community structure was compared inside and outside of mesoscale eddies (Fernandez et al, 2008). At smaller scale, upwelling conditions influenced the picoplankton community structure in oceans south of Australia (Van Dongen-Vogels et al, 2012) and in coastal China Sea (Wu et al, 2014). Stratification (Bouman et al, 2011;Mena et al, 2019) and fronts (Pan et al, 2006) also separated water masses with different Microbial Structure.…”