The role of microbes in the fate of nanoplastics in the marine realm

forthcoming

Nanoplastics (plastic litter fragments <1µm) were only recently discovered in the marine realm. Due to their colloidal nature, nanoplastics may be dispersed throughout the ocean, potentially affecting all marine life. However, their minuscule size has made it virtually impossible to measure their distribution or determine if microbes can degrade nanoplastics, thus influencing their fate in the ocean. Innovative approaches developed by my team have now made this possible for the first time. Using an ultrasensitive mass spectrometry method, our preliminary results revealed substantial concentrations of various nanoplastic types in both surface waters and the deep sea, suggesting that nanoplastics could constitute an important part of the ocean’s plastic budget. Simultaneously, results from a novel stable isotope assay uncovered the previously unknown ability of marine microbes to degrade nanoplastics, indicating that microbes play a crucial role in determining the fate of these particles in the ocean. However, marine microbes and the ecosystem services they support could also be negatively impacted by nanoplastics. Building on my team’s innovative approaches, we will conduct in situ experiments across surface and deep sea environments, complemented by investigations under laboratory conditions. Through the NanoMare project, we will be the first to provide fundamentally new insights into nanoplastic degradation kinetics, nanoplastic-degrading microbes (including degradation pathways and genes), impacts of nanoplastics on the ocean’s microbiome, and the global prevalence and distribution of nanoplastics and their degradation products in the sea. The NanoMare project will profoundly enhance our understanding of ocean microbe-nanoplastic interactions and nanoplastic inventories, with substantial implications for marine microbiology and other ocean science disciplines. Beyond the ocean, the results will also be important for the fields of hydrology and atmospheric physics.