Benthic fauna contribute to microplastic sequestration in coastal sediments

Area of Science:

• Marine Biology
• Environmental Science
• Ecotoxicology

Background:

• Microplastics are pervasive in marine ecosystems.
• Mechanisms of microplastic uptake and burial in seabed habitats are not well understood.

Purpose of the Study:

• Quantify microplastic burial in coastal seabed habitats.
• Assess the role of burrowing fauna in microplastic sequestration.
• Investigate the impact of microplastics on sediment-processing activities of key species.

Main Methods:

• Field studies at three coastal sites to quantify microplastic burial.
• Functional trait diversity analysis of field data to assess faunal contribution.
• Laboratory experiments exposing the brittlestar Amphiura filiformis to microplastic fibers.

Main Results:

• Broad-scale microplastic burial observed across coastal seabeds, consistent across sites and seasons.
• Microplastic sequestration is linked to benthic-pelagic exchange pathways driven by burrowing fauna.
• Brittlestars were observed burying microfibers and modifying their sediment-processing behavior after exposure to nylon fibers.

Conclusions:

• Biodiverse seabed habitats function as significant microplastic sinks.
• Burrowing fauna are key drivers of microplastic burial via benthic-pelagic pathways.
• Microplastic exposure can alter the sediment-processing rates of marine invertebrates.