Where Have You Been? Backtracking Microplastic to Its Source Using the Biomolecular Composition of the Ecocorona

Area of Science:

• Environmental Science
• Marine Biology
• Biogeochemistry

Background:

• Microplastics are pervasive global contaminants originating from diverse sources.
• Understanding microplastic pathways and sinks is crucial for environmental management.
• The ecocorona, a biofilm on submerged materials, may hold environmental information.

Purpose of the Study:

• To investigate the potential of ecocorona composition for backtracking microplastics.
• To analyze the influence of pre-incubation and environmental exposure on ecocorona development.
• To validate microplastic source tracking using metaproteomics and eDNA metabarcoding.

Main Methods:

• Deployment of pristine and pre-incubated microplastics (polyamide, polyethylene terephthalate) in a controlled tank with Penaeus monodon.
• Mass spectrometry analysis to identify proteins within the developed ecocorona.
• 16S eDNA metabarcoding and untargeted metaproteomics for microbial community and protein profiling.
• Orthogonal Partial Least Square (OPLS) modeling for source prediction.

Main Results:

• The ecocorona successfully formed on deployed microplastics, incorporating bovine serum albumin (BSA) and Penaeus monodon proteins.
• BSA pre-incubation altered ecocorona protein diversity and abundance, with pristine plastics showing more enriched proteins.
• Ecocorona protein profiles reflected the surrounding marine environment, indicating environmental signatures.
• Microplastic source tracking achieved high accuracy (69-92% for eDNA, 69-123% for metaproteomics) using OPLS models.
• Specific microbial taxa (Leucothrix, Rugeria) and species (Salmo salar, P. monodon) were identified as source indicators.

Conclusions:

• The ecocorona effectively records environmental signatures and can be used to track microplastics.
• Metaproteomic and eDNA metabarcoding analyses of the ecocorona provide reliable methods for microplastic source attribution.
• This approach offers a promising tool for monitoring diffuse pollution and understanding microplastic fate in aquatic ecosystems.