Plastics affect the ocean's uptake of atmospheric CO₂ across the marine boundary Layer

Microplastics are substrates for microbial activity and biomass production. This has potentially important implications in the sea-surface microlayer, the interface mediating air-sea gas exchange and where biological organic compounds can accumulate. In this study, authors simulated a “high plastic ocean” in the mesocosms at CretaCosmos facility, exploring organic matter dynamics in the sea-surface microlayer in the presence and absence of microplastics in the underlying water. In microplastics-amended mesocosms, biomass production and enrichment of marine gels in the sea-surface microlayer were higher, leading to a ∼3 % lower dissolved CO₂ in the underlying water. By interfering with the composition of the sea-surface microlayer, plastic pollution has direct and indirect impacts on the uptake of CO₂ and the marine carbon cycle.

Reference: Galgani, L., Tzempelikou, E., Kalantzi, I., et al. (2023). Marine plastics alter the organic matter composition of the air-sea boundary layer, with influences on CO₂ exchange: A large-scale analysis method to explore future ocean scenarios. Sci. Total Environ., 857, 159624. https://doi.org/10.1016/j.scitotenv.2022.159624