Phytoplankton community responses to environmental changes in the Yellow Sea

This research examines phytoplankton dynamics in the Yellow Sea (YS), a highly productive and ecologically significant region currently experiencing rapid environmental changes. Using high-performance liquid chromatography (HPLC), we analyzed phytoplankton pigment composition from samples collected between 2018 and 2020 to assess community responses to environmental factors. Cluster analysis, Redundancy Analysis (RDA), Variance Partitioning Analysis (VPA), and Generalized Additive Models (GAMs) were applied to identify dominant phytoplankton communities and their environmental association. Our analysis identified four distinct phytoplankton communities. Cluster 1 was dominated by diatoms under low temperature and high nutrient condition. Cluster 2 also featured a significant presence of diatoms but included a higher contribution of cryptophytes. Cluster 3 exhibited a mixed community with no single dominant group. Cluster 4 was characterized by high temperatures and low nutrient concentrations, with cyanobacteria and prymnesiophytes being dominant groups. RDA and VPA identified temperature and nutrients as key drivers of community structure in the YS. GAMs indicated that increasing temperatures favor cyanobacteria and prymnesiophytes, while phosphorus limitation reduces diatom dominance. These results suggest that global warming and anthropogenic nutrient inputs could substantially alter the YS phytoplankton community, reducing the prevalence of diatoms and increasing non-diatom groups such as cyanobacteria and prymnesiophytes. Such shifts could have profound implications for the marie food web, productivity, and biogeochemical cycles in the YS.