Multiscale impacts of harmful algal blooms and toxins on aquatic ecosystem structure and function: a systematic review

Abstract

Harmful algal blooms (HABs) are ecological phenomena that release toxins or produce excessive biomass, threatening aquatic ecosystems and human health. The global occurrence of HABs is intensifying due to climate change and anthropogenic eutrophication. This paper systematically reviews the multi-scale impacts of HABs and their toxins on the structure and function of aquatic ecosystems. As essential background, the chemical properties, degradation, and transformation of algal toxins are outlined. At the community level, the multi-level impacts and the underlying mechanisms of HABs and toxins on plankton, benthic fauna, aquatic plants, and fish are summarized. At the ecosystem scale, the alterations to food web structure induced by HAB disturbances are further synthesized. By integrating these multi-scale perspectives, this review aims to systematically reveal the composite ecological risks of HABs and provide a theoretical basis and decision-making references for the scientific early warning, ecological risk assessment, and adaptive management of HABs.