Spatiotemporal variations of plankton communities in different water bodies of the Yellow River: Structural characteristics, biogeographic patterns, environmental responses, and community assembly

Abstract

Phytoplankton and zooplankton serve as critical indicators of aquatic ecological health, playing vital roles in nutrient cycling in aquatic ecosystems. Nevertheless, their biogeographic patterns and community assembly remain poorly understood, especially in large-scale watersheds. In this study, we collected plankton samples from typical reservoirs and river sections along the Yellow River during spring and summer to investigate their spatiotemporal dynamics, geographic patterns, and community assembly. Our results revealed that the diversity and composition of plankton communities varied with season significantly, showcasing higher diversity and density during summer. Distance-decay relationships highlighted significant correlations between environmental gradients and plankton community heterogeneity in both seasons, whereas spatial factors exerted a more prominent effect on phytoplankton during summer. Water temperature, dissolved oxygen, chemical oxygen demand, and total suspended sediments emerged as the main environmental attributes affecting plankton composition, as illustrated by Mantel’s test. Both ecological niche differentiation and dispersal limitation contributed to plankton community construction, with ecological niche differentiation being more dominant in spring and dispersal limitation more influential on phytoplankton in summer. These findings enhance our understanding of the structural characteristics of plankton communities in the large-scale Yellow River, shedding light on their biogeographic patterns and community construction mechanisms within large river ecosystems.