A study of all the oceans of the world has discovered over 5000 new viruses. Some of the viruses help carbon capture:

https://www.science.org/doi/10.1126/science.abn6358

Some of the viruses infect and affect the phytoplankton in the oceans. When the phytoplankton die they carry the carbon within their bodies to the ocean floor where it can be sequestrated for thousands or millions of years, as much as 12 gigatonnes of carbon each year.

The viruses can 'alter the metabolism of their microbial hosts... This ability, which might have evolved to contend with the extremely resource-depleted open ocean, could be another route for RNA viruses to affect the carbon pump.'