How 'Viral Dark Matter' may help Mitigate Climate Change

By Emily Caldwell

A deep dive into the 5,500 marine RNA virus species scientists recently identified has found that several may help drive carbon absorbed from the atmosphere to permanent storage on the ocean floor.

The analysis also suggests that a small portion of these newly identified species had "stolen" genes from organisms they infected, helping researchers identify their presumed hosts and functions in marine processes.

Beyond mapping a fount of foundational ecological data, the research is leading to a fuller understanding of the outsize role these tiny particles play in the ocean ecosystem.

"The findings are important for model development and predicting what is happening with carbon in the correct direction and at the correct magnitude," said Ahmed Zayed, a research scientist in microbiology at The Ohio State University and co-first author of the study.

The question of magnitude is a serious consideration when taking into account the vastness of the ocean.

Lead author Matthew Sullivan, professor of microbiology at Ohio State, envisions identifying viruses that, when engineered on a massive scale, could function as controllable "knobs" on a biological pump that affects how carbon in the ocean is stored.

"As humans put more carbon into the atmosphere, we're dependent on the massive buffering capacity of the ocean to slow climate change. We're growing more and more aware that we might need to tune the pump at the scale of the ocean," Sullivan said.

"We'd be interested in viruses that could tune toward a more digestible carbon, which allows the system to grow, produce bigger and bigger cells, and sink. And if it sinks, we gain another few hundred or a thousand years from the worst effects of climate change.

"I think society is basically counting on that kind of technological fix, but it's a complex foundational science problem to tease apart."

The study appears online today in Science.

These RNA viruses were detected in plankton samples collected by the Tara Oceans Consortium, an ongoing global study onboard the schooner Tara of the impact of climate change on the ocean. The international effort aims to reliably predict how the ocean will respond to climate change by getting acquainted with the mysterious organisms that live there and do most of the work of absorbing half the human-generated carbon in the atmosphere and producing half of the oxygen we breathe.