Risk Assessment of Algal Blooms in the Qiantang River Basin, Zhejiang Province, China: Integrating Biomass, Community Dynamics, and Bloom-Associated Functional Traits
Year: 2025
Type: article
Abstract: Understanding mechanisms governing phytoplankton succession under nutrient fluctuations is essential for algal bloom prevention. Using the Qiantang River Basin as a model system encompassing mesotrophic to mid-eutrophic conditions, we investigated phytoplankton assemblage shifts, bloom-forming traits, and main regulatory mechanisms behind nutrient-driven phytoplankton dynamics. We identified 268 phytoplankton with abundance and biomass ranging from 2.71 × 104 to 9.42 × 106 ind L−1 and 0.025–4.49 mg L−1, respectively. Phytoplankton diversity and biomass increased with nutrient levels, and eutrophication caused taxonomic shifts: Cyanophyta abundance increased significantly while Bacillariophyta declined. Network analysis revealed that nutrient-rich waters supported stronger phytoplankton–zooplankton interactions, highlighting a zooplankton-mediated top-down regulatory mechanism that could constrain phytoplankton biomass accumulation through intensified grazing pressure. Specific nutrient forms (e.g., ammonium [NH4-N], nitrite [NO2-N], phosphate [PO4-P], and dissolved total phosphorus) were primary environmental drivers shaping phytoplankton composition, accounting for 56% of community variation, while zooplankton contributed 25.6%. Mid-eutrophic sites supported more bloom-forming taxa with motility (37.1–73.6%), toxicity (11.4–43.0%), and nitrogen fixation (7.8–24.6%) traits. Mechanistically, bottom-up nutrient supply and top-down zooplankton grazing were both significant regulators of phytoplankton dynamics. These results emphasize the importance of nutrient species, ecological feedback, and functional trait dynamics in modulating algal bloom risks under eutrophication.
Source: Figshare
Authors: Xue, Xue, Fan, Yingchun, Dong, Jiahui, Chen, Yongjin, Liang, Yidong, Zhou, Yanfeng
Language: English
Subfield: Environmental Chemistry
Field: Environmental Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7084050716
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