Microplastic analysis in the South Funen Archipelago, Baltic Sea, implementing manta trawling and bulk sampling

Area of Science:

• Environmental Science
• Marine Biology
• Ecotoxicology

Background:

• Microplastic pollution is a growing global concern, impacting marine ecosystems.
• Understanding microplastic distribution in diverse aquatic environments is crucial for effective mitigation strategies.

Purpose of the Study:

• To quantify microplastic contamination in the surface waters of the South Funen Archipelago, Denmark.
• To compare the effectiveness of manta trawls versus low-volume bulk sampling for microplastic assessment.
• To identify potential sources and influencing factors of microplastic pollution in the study area.

Main Methods:

• Conducted ten manta trawls to collect surface water samples for microplastic analysis.
• Collected 31 low-volume bulk samples to compare with manta trawl results.
• Analyzed microplastic concentrations and characterized potential contributing factors.

Main Results:

• Microplastic concentration in the South Funen Archipelago was found to be 0.07 ± 0.02 particles/m3, which is relatively low.
• The sheltered location, low adjacent population pressure, and absence of major point sources contributed to the low microplastic levels.
• Harbors, marinas, and associated vessel traffic were identified as the most probable microplastic sources within the archipelago.
• Low-volume bulk samples yielded results not comparable to manta trawl data due to insufficient sample representativeness.

Conclusions:

• The South Funen Archipelago exhibits low microplastic contamination compared to other reported areas.
• Sampling methodology significantly impacts microplastic concentration data, with manta trawls being more representative than small bulk samples.
• Marine management strategies should consider localized sources like harbors and marinas to reduce microplastic input.