Evaluating physiological responses of microalgae towards environmentally coexisting microplastics: A meta-analysis

Area of Science:

• Environmental Science
• Ecotoxicology
• Marine Biology

Background:

• Microplastics (MPs) are ubiquitous in aquatic ecosystems, leading to unavoidable interactions with phytoplankton.
• Existing research on MP effects on microalgae at environmentally relevant concentrations is controversial and varied.

Purpose of the Study:

• To synthesize findings from 52 studies to clarify the impact of MPs on microalgae at environmentally relevant concentrations.
• To investigate how MP characteristics and algal type influence the observed effects.

Main Methods:

• Meta-analysis of 52 existing studies on microplastic-microalgae interactions.
• Comparative analysis of effects on different algal groups (Cyanobacteria vs. Chlorophyta).
• Evaluation of MP size, condition (pristine vs. aged), and their influence on biological responses.

Main Results:

• Microplastics generally inhibit microalgal growth and photosynthesis, inducing oxidative stress, but recovery is possible.
• Cyanobacteria are more susceptible to MP impacts than Chlorophyta.
• MP size relative to algal cells and MP condition (pristine vs. aged) significantly alter impact mechanisms and outcomes, including extracellular polymeric substances (EPS) and microcystin (MC) production.

Conclusions:

• Microplastics pose a significant threat to aquatic microalgae, affecting key physiological processes.
• Algal type and microplastic properties are critical determinants of ecotoxicological outcomes.
• Further research is needed to fully elucidate the complex interactions and long-term consequences in aquatic environments.