Factors regulating the phytoplankton and tintinnid microzooplankton communities in the East China Sea

Abstract

To investigate the effect of bottom-up factors (resource, hydrography, and environmental factors) on the phytoplankton and tintinnid microzooplankton communities, the research voyage was conducted in September 2017 at the East China Sea. An aggregate of 273 taxa of phytoplankton and 65 taxa of tintinnids were identified. Diatoms and dinoflagellates were the major groups of phytoplankton observed while the chain-forming diatoms were the most dominant group present in the study area. The coastal water and Kuroshio water influenced the concentration of dissolved inorganic nutrients as well as phytoplankton abundance. The concentration of dissolved inorganic nutrients increased vertically with the water depth while the phytoplankton and tintinnid abundance diminished. Redundancy analysis (RDA) and Pearson correlation analysis were conducted to analyze the relationship between the planktonic community and the ecological components. The RDA analysis between phytoplankton abundance and nutrients concentration showed that phytoplankton abundance increased with the increase in concentration of ammonium while a negative relationship was observed between phytoplankton abundance and nitrate, phosphate, and silicate. There was a significant positive correlation between the tintinnid microzooplankton and nanophytoplankton abundance as well as in their species richness which indicated that the tintinnid community depended upon nanophytoplankton for their feeding habit and growth rather than nutrients.