Interesting article here on how many viruses exist in the oceans.
Here's an interesting quote from the article: "Scientists estimate that there are 1,000,000,000,000,000,000,
000,000,000,000 virus particles in all the world’s seas. They outnumber all cellular life forms by roughly a factor of 10. "
So apparently all we know about "life on earth" is eclipsed by the viruses in the oceans.
We know about 1/10th of the life on earth and nothing about what the rest does (according to the article we knew of 39 types of viruses out of an estimated tens of thousands).
According to the article viruses in the ocean kill bacteria which control how carbon is sequestered in the oceans (or released into the air).