Copepod population-specific response to a toxic diatom diet

Area of Science:

• Marine Biology
• Ecotoxicology
• Phytoplankton Ecology

Background:

• Diatoms are crucial primary producers in aquatic ecosystems.
• Some diatoms produce oxylipins, secondary metabolites toxic to grazers like copepods.
• Copepod populations may exhibit differential tolerance to these diatom-derived toxins.

Purpose of the Study:

• To investigate population-specific gene expression in Calanus helgolandicus exposed to oxylipin-producing diatoms.
• To compare the responses of North Sea, Atlantic, and Mediterranean copepod populations to Skeletonema marinoi.
• To elucidate cellular mechanisms underlying copepod susceptibility to diatom toxins.

Main Methods:

• Comparative gene expression analysis of selected genes in three Calanus helgolandicus populations.
• Exposure of copepods to Skeletonema marinoi (toxic diet) and Rhodomonas baltica (control diet).
• Analysis of detoxification enzymes, stress proteins, apoptosis, and cell cycle regulatory proteins at 24 and 48 hours.

Main Results:

• Significant differences in gene expression were observed among the three copepod populations.
• The Mediterranean population of C. helgolandicus exhibited higher susceptibility to the toxic diatom diet.
• Gene expression patterns indicated varying cellular stress and detoxification responses.

Conclusions:

• Copepod populations display distinct responses to diatom-produced oxylipins.
• Mediterranean copepods are more vulnerable to toxic diatom diets, suggesting population-specific adaptive strategies.
• This research provides insights into the cellular basis of copepod toxicity during diatom blooms.