Temperature responsive sustained-release microsphere for harmful algal bloom control: preparation, algicidal activity...

Area of Science:

• Environmental Science
• Aquatic Ecology
• Materials Science

Background:

• Cyanobacterial harmful algal blooms (CHABs) are significantly influenced by water temperature.
• Current algicide strategies often overlook temperature-dependent algal growth dynamics.
• A need exists for intelligent algicide delivery systems that respond to environmental conditions.

Purpose of the Study:

• To design and evaluate novel temperature-responsive sustained-release microspheres (T-SRMs) for controlling CHABs.
• To investigate the temperature-dependent release of 5,4'-dihydroxyflavone (DHF) from T-SRMs.
• To assess the efficacy and environmental safety of T-SRMs against key aquatic organisms.

Main Methods:

• Development of T-SRMs using n-heptadecane as a temperature-responsive material for controlled DHF release.
• Evaluation of DHF release rates and anti-algal activity of T-SRMs at various temperatures (15-25 °C).
• Toxicity assessments of T-SRMs on non-target organisms: Chlorella vulgaris, Daphnia magna, and Danio rerio.

Main Results:

• T-SRMs demonstrated enhanced inhibition rates and sustained activity against Microcystis aeruginosa compared to direct DHF application.
• The phase transition of n-heptadecane at 22 °C significantly modulated DHF release, enabling temperature-responsive delivery.
• T-SRMs exhibited no significant toxicity to tested non-target species and maintained efficacy across different salinities.

Conclusions:

• Temperature-responsive sustained-release microspheres offer a promising strategy for intelligent and efficient CHABs management.
• The developed T-SRMs provide extended control duration and can be adapted for various aquatic environments.
• This technology represents a significant advancement towards accurate and environmentally conscious control of harmful algal blooms.