Structure and assembly mechanism of phytoplankton community driven by upwelling in eastern Guangdong sea area

Yuling Chen¹ Tangcheng Li*

Guangdong Provincial Key Laboratory of Marine Disaster Prediction and Prevention, Shantou University, Shantou, 515063, China

Abstract

  Situated at the intersection of tropical and subtropical regions, the Eastern Guangdong Sea area is characterized by complex and diverse oceanic dynamic processes. In summer, the coastal area is influenced by wind-driven upwelling, while in winter, it is affected by the Fujian-Zhejiang coastal current. The upwelling phenomenon results in lower temperature and higher salinity in the surface seawater along the Eastern Guangdong coast, concurrently leading to an upward distribution of nutrients and phytoplankton maximum concentrations. This marine area supports various typical ecosystems, including algal fields and coral reefs, and exhibits high biodiversity. In this study, 144 samples were collected from 12 sites in 4 voyages in the upwelling area of eastern Guangdong. We measured marine hydrological factors ( such as water temperature and salinity ), marine meteorology ( such as wind direction and wind speed ), chemical factors ( turbidity and nutrients ) and ecological factors ( such as Planktonic bacteria in water, phytoplankton, etc. ). 16S、18S and ITS2 sequencing will be conducted to investigate the diversity distribution, driving factors and assembly mechanisms of phytoplankton community especially Symbiodiniaceae communities. Symbiodiniaceae dinoflagellates play a crucial role as key primary producers within coral reef ecosystems. While research in this area has been increasing globally, molecular studies focused on the Guangdong Eastern Sea region of the South China Sea remain insufficient. Investigating the genetic diversity and adaptive capacity of these dinoflagellates is essential for predicting the resilience and regulatory mechanisms of corals in the face of future climate change.

Keywords: Upwelling, phytoplankton, Symbiodiniaceae, ITS2, diversity