Chemoreception drives plastic consumption in a hard coral.

Area of Science:

• Marine Biology
• Ecotoxicology
• Environmental Science

Background:

• Microplastic pollution is a growing global concern.
• The drivers of microplastic consumption by marine animals remain unclear.
• Impacts on foundational species like corals are poorly understood.

Purpose of the Study:

• To investigate the factors influencing microplastic ingestion by scleractinian corals.
• To determine if corals use chemosensory cues to identify and consume microplastics.
• To assess the retention and potential consequences of microplastic ingestion in corals.

Main Methods:

• Corals were exposed to various types of microplastics (weathered, unfouled, biofouled, pre-production) and control (sand).
• Ingestion rates were measured, comparing plastics with and without microbial biofilms.
• Plastic retention and physical presence within corals were observed over 24 hours.

Main Results:

• Corals ingested multiple types of microplastics, indicating the presence of phagostimulatory chemicals.
• Unfouled microplastics were ingested more readily than biofouled ones.
• Approximately 8% of ingested microplastics were retained by corals for over 24 hours, appearing lodged within tissues.

Conclusions:

• Chemosensory cues likely drive microplastic consumption in corals.
• Microbial biofilms may reduce the attractiveness of microplastics to corals.
• Retained microplastics pose risks including energetic costs, toxicity, and trophic transfer, highlighting conservation concerns.