Viruses Infect Massive Algal Blooms: Implications for Carbon Capture and Climate

Algae blooms can impact our world's oceans and our climate. They can help create dead zones, but can also suck up climate-warming carbon dioxide from the atmosphere. Now, scientists have found out that viruses infecting these algae may be driving the life-and-death dynamics of algae blooms, which could have major implications for our climate.

A single North Atlantic algal bloom of about 30 kilometers in radius converted 24,000 tons of carbon dioxide from the atmosphere into organic carbon. Two-thirds of that carbon turned over within just a week as the bloom grew and then died. Now, scientists have taken a closer look and have found that high levels of viruses infected the algae's cells.

"This is, of course, only one patch out of numerous co-occurring patches in other parts of the Atlantic Ocean," said Ilan Koren, one of the researchers, in a news release. "While the impact that viruses have on the entire ecosystem was previously estimated to be very large, we provide the first approach to quantify their immense impact on open ocean blooms."

That said, questions still remain about the ultimate fate of the carbon taken in by algal blooms. Much of it is probably recycled back into the atmosphere by bacteria. Yet it's also possible that virus-infected algae release sticky sugars and lipids that cause their cells and the carbon within them to sink to the ocean floor.

"If the latter scenario is true, it will have a profound impact [on] the efficiency of carbon dioxide 'pumping' from the atmosphere to the deep ocean," said Assaf Vardi, one of the researchers. "This carbon will then have a better chance [of being] buried in the ocean sediment."

The findings reveal that algae blooms could be a good way to employ carbon capture. This, in turn, could affect the way we approach the rising levels of carbon dioxide in our atmosphere.

The findings are published in the journal Current Biology.