A virus infecting the phytoplankton species Emiliania huxleyi spreads through the air, leading to widespread die-offs, according to research presented Monday at the AGU Fall Meeting. Credit: PLoS Biology, June 2011

Researchers think they might know one of the reasons why microscopic ocean-dwelling creatures get sick and die: they sneeze, spraying droplets containing a virus into the air.

Algal blooms cover massive swathes of the ocean, converting carbon dioxide into oxygen, and playing an important role in nutrient regulation.

Scientists know that a virus is often responsible for the die-off of a common algal species, a single-celled coccolithophore known as Emiliania huxleyi. But they didn’t know how the infection spread so quickly, triggering the collapse of a bloom covering hundreds of kilometers.

E. huxleyi is a particularly important in carbon regulation because it builds a hard shell that permanently removes carbon from the atmosphere, according to Miri Trainic, an atmospheric scientist at the Weizmann Institute of Science.

Trainic thought the virus—called the E. huxleyi virus— might move the same way a flu virus spreads through human communities— in the air.

Working with a team of fellow Israeli researchers, she cultivated E. huxleyi infected with the virus in a seawater tank using bubbles to mimic currents and generate sea spray. The tank was linked to two tubes. One contained healthy algae susceptive to the virus. The other held algae bred for viral resistance.

When exposed to the virus, the resistant algae population thrived and the vulnerable population collapsed, Trainic said. The experiment showed the virus can be transmitted through the air and that it is also infectious in the air, she said.

“That is amazing, nobody knew, Trainic said.

Trainic presented her research Monday in a poster session at the American Geophysical Union’s Fall Meeting in San Francisco.

The researchers plan to examine how long the viruses remain infectious in the air and how far they spread in the atmosphere, she said.

Trainic said the E. huxleyi virus exudes a gooey substance that helps the shells form sediment  more rapidly, permanently removing carbon from the atmosphere. Although the virus halts photosynthesis, an infection doesn’t stop the algae’s effect on carbon concentrations, Trainic said.

The algal investigation was prompted by an informal lunch between atmospheric scientist Ilan Koren and microbiologist Assaf Vardi, both of the Weizmann Institute of Science, Trainic said.

Researchers from the two labs worked together to decipher the virus’s spread through the atmosphere, she said.

– Becky Bach is a science communication graduate student at UC Santa Cruz