There are a lot of viruses in the Arctic ice – and they can show us where carbon is sinking.

Science News has a novel way to map out potential climate change – by tracking where new viruses are showing up in the ocean:

Water samples taken during a three-year expedition around the world’s oceans identified around 200,000 virus species, roughly 12 times the number found in a previous smaller survey. And 42 percent of those viruses were found exclusively in the Arctic, researchers report April 25 in Cell.

The results come from the Tara Oceans global oceanographic research expedition. From 2009 to 2013, researchers dropped tanks off of an aluminum sailboat called Tara to collect 145 water samples from dozens of sites worldwide, at water depths from 0 to 4,000 meters. Scientists collected everything ranging in size from fish eggs down to viruses. Filtering isolated the viruses, which were then genetically compared.

The researchers identified 195,728 virus species parsed into five global regions that are home to distinct viral communities. The most diversity was found in shallow, temperate and tropical waters, followed closely by Arctic waters.

Almost all of the viruses were bacteriophages, which attack bacteria — not people.

Bacteriophages and other viruses are credited with killing roughly 20 percent of bacteria in the ocean every day. That process stops carbon in the bacteria from passing up the food chain, and instead releases the carbon back into the ocean for other microorganisms — some of which also consume carbon dioxide. These microbes eventually produce a form of carbon that can’t be recycled and stays stored in the ocean.

Viruses may serve an important role in counteracting human-induced climate change by indirectly stashing away carbon in this way, though viruses have rarely been included in climate simulations.