Plastisphere Microbes Pack More Survival Genes Than Plankton
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- Helmholtz researchers published a study in Environmental Pollution analyzing ~340 key functional genes in bacterial metagenomes from plastic particles collected in 2019 expeditions to the North Pacific and North Atlantic Garbage Patches aboard the research vessels SONNE and POSEIDON.
- Plastisphere microbes were found to have considerably larger genomes and more gene copies than naturally occurring marine plankton, enabling them to absorb nutrients, break down carbon sources, and repair UV-induced genome damage.
- Lead author Dr. Stefan Lips (UFZ) noted the microbes can also use alternative energy sources such as anoxygenic photosynthesis, which does not produce oxygen — a survival strategy absent in surrounding plankton.
- Marine plankton have shrunk their genomes over evolutionary time to adapt to nutrient-poor environments, but plastisphere microbes benefit from shared metabolic processes on plastic particles and haven't faced the same pressure.
- The biofilms contained relatively high concentrations of chlorophyll a compared to plankton, indicating potential for greater biomass production and the creation of eutrophic niches in otherwise barren subtropical gyres (per co-author Dr. Mechthild Schmitt-Jansen).
- Co-author Dr. Erik Borchert (GEOMAR) cautioned that the microbes use plastic as habitat rather than a nutrient source, making it 'unlikely that they will help to remove plastic from the oceans.'
Why it matters: The findings underscore that plastic pollution is reshaping open-ocean microbial communities in measurable ways, with plastisphere microbes now outcompeting native plankton functionally and creating localized nutrient-rich pockets in nutrient-poor gyres. For policymakers negotiating the global plastic treaty, the research reinforces the urgency of cutting plastic production — because the microbial answer to plastic pollution is colonization, not cleanup.
