Predator lipids induce paralytic shellfish toxins in bloom-forming algae.

Area of Science:

• Marine biology
• Chemical ecology
• Oceanography

Background:

• Marine plankton interactions are crucial for ocean ecosystems.
• Plankton primarily use chemical sensing due to limited vision.
• Key signaling molecules in marine plankton interactions remain largely unidentified.

Purpose of the Study:

• To identify novel signaling molecules involved in marine plankton interactions.
• To investigate the role of these molecules in phytoplankton responses.
• To understand the ecological implications of this signaling system.

Main Methods:

• Analysis of small molecules released by copepods.
• Chemical characterization of identified compounds (copepodamides).
• Assessing the impact of copepodamides on dinoflagellate toxin production.

Main Results:

• Identification of eight novel compounds, copepodamides, released by copepods.
• Copepodamides are polar lipids containing taurine and isoprenoid fatty acids.
• Pico- to nanomolar copepodamide concentrations induced a 20-fold increase in paralytic shellfish toxin production in Alexandrium minutum.
• Distinct copepodamide blends from different copepod species elicited species-specific phytoplankton defenses.

Conclusions:

• A novel chemical signaling system mediated by copepodamides has been discovered.
• This system influences phytoplankton toxin production and defensive strategies.
• Copepodamide signaling has significant implications for marine food webs and harmful algal bloom formation.