The potential impacts of plastic on the marine carbon cycle

Increasing plastic waste has triggered global concerns for the potential detrimental effects on marine ecosystems. The impact of plastic reaches beyond the immediate harm to marine life to encompass the marine biogeochemical cycle and the global carbon budget. We investigate these effects by integrating an oceanic plastic simulation with a marine ecosystem model. We find that oceanic plastic could disturb the marine carbon cycle through three pathways: the plastic carbon buried in sediments, the release of dissolved organic carbon from water-column plastic and the toxicity effect on marine phytoplankton. Our scenario analysis suggests that there are 0.70 (0.13-3.8) Tg of plastics entering the ocean every year, however, the overall impact of oceanic plastics on decreasing ocean carbon uptake could reach 12.1 TgC yr-1. Our model predicts that the global plastic released into the ocean could result in up to 1.6 PgC of lost ocean carbon uptake and storage by 2050, given the foreseeable growth of plastic production and its long-lasting impacts. We urge comprehensive control policies to mitigate the losses caused by marine plastics both in ecosystem integrity and addressing climate change.