Development of a microplate-based novel toxicity bioassay using Chlorophyta and Phaeophyceae macroalgae

Area of Science:

• Marine Biology
• Ecotoxicology
• Environmental Science

Background:

• Macroalgae are key marine producers, yet standardized toxicity tests are lacking for water quality monitoring.
• Existing methods often don't cover macroalgae's growth and reproductive effects from chemical exposure.

Purpose of the Study:

• To establish a microplate-based toxicity testing method for macroalgae.
• To evaluate the toxicity of specific chemicals, including herbicides, on selected macroalgae species.
• To assess macroalgae sensitivity to environmental toxicants.

Main Methods:

• Selected reference macroalgae: Ulva aragoënsis (Chlorophyta), Ectocarpus siliculosus (Phaeophyceae), and Undaria pinnatifida.
• Developed a microplate assay to measure growth and reproductive effects (sporangia formation in E. siliculosus).
• Tested toxicity of potassium dichromate, 3,5-dichlorophenol, diuron, and simazine under controlled laboratory conditions.

Main Results:

• Macroalgae growth and reproduction were impaired in a dose-dependent manner by the tested chemicals.
• Macroalgae demonstrated high sensitivity to organic compounds, particularly herbicides, compared to other aquatic species.
• Reliable test conditions were identified: 0-32 PSU for U. aragoënsis and 25-32 PSU for E. siliculosus.

Conclusions:

• The developed microplate method effectively assesses chemical toxicity in macroalgae.
• These tests enhance understanding of chemical risks to aquatic life and can be applied to seawater and brackish water quality management.
• The findings support the use of macroalgae in routine effluent toxicity testing.