Predicting microplastic dynamics in coral reefs: presence, distribution, and bioavailability through field data and...

Area of Science:

• Marine Ecology
• Environmental Science
• Oceanography

Background:

• Microplastic pollution poses a significant threat to marine ecosystems, necessitating ecological risk assessments (ERA).
• Understanding microplastic distribution and bioavailability is crucial for effective mitigation strategies.

Purpose of the Study:

• To quantify microplastic abundance in various environmental and biological compartments in the Great Barrier Reef.
• To predict microplastic transport and fate within the Lizard Island ecosystem.
• To identify factors influencing microplastic bioavailability in marine organisms.

Main Methods:

• Coupling in situ data collection from Lizard Island with numerical modeling and simulations.
• Analyzing microplastic concentrations in abiotic compartments (water, sediment) and biotic compartments (fish, invertebrates).
• Investigating the influence of microplastic characteristics (size, shape, polymer type, color) on bioavailability.

Main Results:

• Microplastics predominantly originate from beached plastics (75%), with northward dispersal and potential deposition on northern beaches.
• Microplastic concentrations increase significantly with depth, showing distinct profiles in surface and deep waters.
• Fish exhibit higher microplastic contamination than invertebrates, with smaller sizes and fibers being more bioavailable.

Conclusions:

• Beached plastics are a major source of microplastic pollution in the Great Barrier Reef, driving northward dispersal.
• Depth and microplastic characteristics (size, shape) significantly influence distribution and bioavailability.
• Ecological risk assessments must consider species-specific traits and microplastic properties for accurate impact evaluation.