Area of Science:

• Marine biology
• Ecology
• Invertebrate zoology

Context:

• The study investigates the ecological adaptability of Enchytraeus albidus, a common marine annelid.
• Understanding the environmental tolerances of marine invertebrates is crucial for predicting their distribution and population dynamics.

Purpose:

• To determine the dietary preferences of Enchytraeus albidus among different marine plant sources.
• To assess the influence of substrate salinity on the survival, emigration, and reproduction of Enchytraeus albidus.
• To analyze the osmoregulatory capabilities of Enchytraeus albidus in response to varying environmental salinities.

Summary:

• Enchytraeus albidus demonstrated a feeding preference for Fucus, green algae, Zostera marina, and Delesseria, in descending order.
• Worm emigration from Fucus substrates increased with putrefaction and fluctuated with salinity, peaking between 15-45‰ and decreasing at 60‰.
• The species tolerates high salinities (60-70‰) for extended periods, with reproduction possible up to 40‰, and optimal cocoon production at 5‰. Incubation periods were shorter at lower salinities (0-15‰).
• Enchytraeus albidus exhibits significant poikilosmosis, tolerating up to 72‰ coelomic fluid concentration and maintaining hyperosmosis at low salinities.

Impact:

• Provides insights into the ecological niche and resilience of Enchytraeus albidus in coastal environments.
• Highlights the critical role of salinity as an environmental factor regulating marine invertebrate populations.
• Contributes to the understanding of osmoregulation strategies in marine annelids adapting to fluctuating salinities.