Temporal and spatial variation in phytoplankton community structure and their relationship with environmental factors in Sanggou Bay

Abstract:

In order to better understand the temporal and spatial variation in characteristics of phytoplankton community structure and their relationship with environmental factors in Sanggou Bay, four seasonal cruises were carried out at 21 sites in April (spring), July (summer) and November (autumn) 2017 and in January 2018 (winter). Analysis identified 51 species from 31 phytoplankton genera in the surveyed area. Among these, 43 species were from 24 genera of diatoms, 4 species from 3 genera of dinoflagellates, 2 species from 2 genera of Chlorophyta, and 1 species of Cyanophyta. Seasonal analysis showed that there were 22 species in spring, 20 species in summer, 23 species in autumn, and 20 species in winter. The dominance index showed that diatoms comprised the dominant species, and that Paralia sulcata was the dominant species throughout the year, with percentages ranging between 18.6% and 84.9%. The abundance of phytoplankton cells ranged from 0.16×103 cells/L to 12.2×103 cells/L (winter > spring > autumn > summer). The species diversity index (Shannon-Wiener index) varied from 0.69 to 1.35 (autumn > summer > winter > spring). The species evenness index J (Pielou) ranged from 0.42 to 0.70. Phosphate is the main limiting nutrient for phytoplankton growth in Sanggou Bay. The results reveal the spatial and temporal variation characteristics of phytoplankton community in a typical large-scale mariculture bay and provide the basic data for in depth understanding of the structure and function of the mariculture ecosystem.