If the animals involved were larger or more intelligent it could be the plot of a good action movie: A mile below the ocean, where the water can reach 500 degrees because of heated vents, armies of bacteria do battle with armies of viruses.

According to research published in the May 1 edition of the journal Science, the viruses behave like pirates. They do not simply extract the sulfur from the bacteria they encounter. Instead they force the bacteria to burn the sulfur and then use the energy generated to replicate themselves until the bacteria is burned up.

The study indicates that the viruses act as key players in these deep water ecosystems, which include shrimp, mussels, giant clams and tube worms all huddled around the deep water vents to collect valuable nutrients.

While this kind of microscopic “piracy” has been observed before it is the first time it has been observed in a lightless chemosynthetic ecosystem.

“Our findings suggest that viruses in the dark oceans indirectly access vast energy sources in the form of elemental sulfur,” said University of Michigan marine microbiologist and oceanographer Gregory J. Dick in a statement.

Using a submarine from the Woods Hole Oceanographic Institution, Dick and his fellow researchers collected water samples from the Eastern Lau Spreading Center in the Western Pacific and Guaymas Basin in the Gulf of California. Utilizing samples from six hydrothermal vent plumes, the researchers examined viral and bacterial genomes and found the sulfur-consuming bacterium SUP05, as well as previously unknown viruses.

Combined with the results of previous studies, the researchers believe that the viruses force SUP05 bacteria to use viral SUP05-like genes to process stored sulfur. The viruses then use that extra energy to reproduce and spread.

“We hypothesize that the viruses enhance bacterial consumption of this elemental sulfur, to the benefit of the viruses,” said the paper’s co-author Melissa Duhaime, an assistant research scientist in the U-M Department of Ecology and Evolutionary Biology.

The researchers believe that these viruses play a key role in the evolution of ocean bacteria. The hope is that understanding this process better will help scientists to predict how these systems might respond to ongoing climate change.