Plastic litter is rapidly bioeroded in mangrove forests.

Area of Science:

• Marine biology
• Environmental science
• Ecology

Background:

• Mangrove forests are increasingly recognized for their role in trapping plastic debris.
• Urban mangroves accumulate significantly higher plastic loads compared to natural areas.
• The impact of plastic colonization on mangrove ecosystems and plastic degradation remains largely unknown.

Purpose of the Study:

• To investigate the differential colonization and transformation of plastics by macrobenthic communities in urban versus wild mangrove forests.
• To assess the role of bioerosion in the degradation of various plastic types within these environments.

Main Methods:

• Plastic sheets (LDPE, PP, PET, EPS) were deployed in urban and wild mangroves in the Colombian Caribbean for four months.
• Colonizing macrobenthic organisms and their interactions with plastics were analyzed.
• Bioerosion rates were compared between urban and wild forest settings.

Main Results:

• Nineteen plant and animal taxa were identified engaging in bioerosion activities on plastic sheets.
• Significant differences in macrobenthic community structure and bioeroder functional groups were observed between urban and wild mangroves.
• Expanded polystyrene (EPS) and polypropylene (PP) exhibited faster bioerosion rates in urban mangroves.

Conclusions:

• Bioerosion by macrobenthic communities is a critical pathway influencing the environmental fate of plastic litter in mangroves.
• Urbanization alters the composition of bioeroding organisms, leading to differential plastic degradation rates.
• The biological transformation of plastics can be a rapid process, driven by diverse fauna, not solely microorganisms.