Passive sampling for grazer cues incorporates top-down effects in harmful algal bloom monitoring and toxin prediction.

Copepodamides measured via passive sampling improve HAB prediction accuracy and lead time for Pseudo-nitzschia and domoic acid in Monterey Bay.

• Why it matters: Current HAB monitoring overlooks top-down influences like copepod cues, limiting prediction accuracy and early warning capabilities for harmful algal blooms and toxin risks.
• What they did: Researchers used solid phase adsorption toxin tracking (SPATT) over 28 months to measure copepodamides and incorporated these data into models predicting Pseudo-nitzschia abundance and domoic acid levels, supported by field and lab experiments.
• The result: Inclusion of copepodamide data enhanced prediction accuracy and provided earlier warnings, suggesting that integrating top-down biological cues can significantly improve HAB monitoring and toxin risk assessment.