A group of researchers participated in the first global survey of the ecological diversity of viruses in the global oceans while on an expedition on a sailboat, the Tara. In their survey, the team identified almost 200,000 marine viruses, vastly surpassing the 15,000 known from previous expeditions.
The findings of the team were published in the journal Cell on April 25, and will help understand different viral bodies that evolve in the ocean and how, for example, climate change affects them. The knowledge about them will help scientists recreate a picture about our planet.
“Viruses are these tiny things that you can’t even see, but because they’re present in such huge numbers, they really matter,” senior author Matthew Sullivan, a microbiologist at the Ohio State University said in a statement. “We’ve developed a distribution map that is foundational for anyone who wants to study how viruses manipulate the ecosystem. There were many things that surprised us about our findings.”
For the scientists, one of the many surprises that came with the expedition was the fact that they found such a vast amount of viruses – nearly 200,000 marine viruses. Scientists collected the viral samples on the Tara which is part of the Tara Oceans project. The viruses were collected between 2009 and 2013.
Scientists didn’t only study the water for viruses, but they also learned about other microbes as well as living creatures that live in the oceans. Researchers were also fairly surprised that the project discovered a great number of samples in the Arctic, which wasn’t as much a focus in previous expeditions.
“In the last 20 years or so, we’ve learned that half of the oxygen that we breathe comes from marine organisms,” Sullivan said about the 200,000 marine viruses. “Additionally, the oceans soak up half of the carbon dioxide from the atmosphere.”
“Because of complex chemistry, increased levels of carbon dioxide at the surface acidify the oceans,” Sullivan said. “However, if carbon dioxide instead is converted to organic carbon and biomass, then it can become particulate and sink into the deep oceans. That’s a good result for helping mitigate human-induced climate change—and we’re learning that viruses can help facilitate this sinking. Having a new map of where these viruses are located can help us understand this ocean carbon “pump” and, more broadly, biogeochemistry that impacts the planet.”
The researchers believe that having a greater picture of viral distribution across the global oceans helps researchers decide which viruses they should focus on in the future. Also, this map provides essential information for collection studies which are planned for the future.
“Previous ocean ecosystem models have commonly ignored microbes, and rarely included viruses, but we now know they are a vital component to include,” Sullivan concludes.