Benthic Fauna Enhance Biodegradation of Microplastics in Riparian Sediments: Reactive Oxygen, Keystone Microbes, and...

Area of Science:

• Environmental Science
• Microbiology
• Ecotoxicology

Background:

• Microplastics (MPs) persist in riparian sediments due to slow biodegradation.
• Benthic fauna are proposed as a novel method to enhance MP degradation.

Purpose of the Study:

• To investigate the role of benthic fauna (Branchiura sowerbyi) in enhancing microplastic biodegradation in sediments.
• To elucidate the mechanisms by which bioturbation affects MP degradation and associated microbial communities.

Main Methods:

• Sediment microcosms with and without Branchiura sowerbyi were used to assess MP degradation.
• Weight loss of polystyrene (PS), polypropylene (PP), and polylactic acid (PLA) was measured.
• Metabolomics and microbial community analysis were performed to understand degradation pathways and microbial roles.

Main Results:

• Bioturbation by Branchiura sowerbyi significantly enhanced MP degradation (P < 0.05).
• Weight loss increased by 2.08x for PS, 2.19x for PP, and 1.68x for PLA due to bioturbation.
• Bioturbation promoted hydroxyl radical generation, increased MP aging, and altered plastisphere microbial communities.

Conclusions:

• Benthic fauna bioturbation is an effective strategy for enhancing microplastic biodegradation in sediments.
• Microbial communities, potentially including ammonia-oxidizing archaea and bacteria, play a key role in MP degradation pathways.
• This approach offers potential for the remediation of microplastic pollution in riparian environments.