Copepodamides: Widespread N‑Acyl Taurine Alarm Cues in Marine Plankton

Copepodamides are N-acyl taurines isolated
from
copepodsthe most abundant zooplankton on Earth and the main
link between phytoplankton primary production and higher trophic levels.
They act as interspecific alarm cues in marine plankton, as prey cells
sensing copepodamides respond by launching defensive traits including
toxin production, bioluminescence, and morphological changes to reduce
predation risk, contributing to large-scale processes such as harmful
algal bloom (HAB) formation. Here, we summarize research on copepodamides
since their discovery in 2015 and outline current challenges and future
opportunities. To date, 41 copepodamides have been identified from
marine and freshwater copepods, and 21 marine protist taxaincluding
several abundant HAB-forming specieshave been shown to respond
to these cues. In situ measurements of copepodamides
have been proposed to improve precision and lead time in HAB forecasting
models, and their potential to increase yields of natural products
in bioreactors warrants further investigation. Copepodamides provide
a powerful framework for quantifying the costs and benefits of inducible
defenses in phytoplankton. The widespread occurrence of copepodamides
across aquatic habitats highlights the relevance of copepodamide signaling
in HAB dynamics and marine food web interactions.