Hitchhiking bacteria dissolve essential ballast in “marine snow” particles, which could counteract the ocean’s ability to sequester carbon, according to a new study.

As any diver knows, oceans can be cloudy places. Even on sunny days, snow-like particles drift through the water column, obscuring the aquatic world below.

Scientists have long known that this “marine snow” carries inorganic calcium carbonate – the building block of shells – but couldn’t explain how the mineral dissolves in the upper part of the ocean.

New research from Rutgers University-New Brunswick points to the culprit: bacteria.“Think of marine particles as the megacities of the ocean,” said Benedict Borer, an assistant professor of marine and coastal sciences at the Rutgers School of Environmental and Biological Sciences and lead author of the study published in the journal Proceedings of the National Academy of Sciences. “Within these tiny spaces, there are huge amounts of microbial activity. It’s here where calcium carbonate dissolves.”