The rain forests are pretty and important and all, but let's give some credit to these tiny creatures as well! It is actually estimated that about 70% of the oxygen in the atmosphere is produced in the oceans, thanks to the photosynthetic activity of phytoplankton.
...it does so by breaking down the fatty layer around the virus cell wall and basically ripping it open, killing it. I think I read somewhere it takes just 22 seconds.
Virus literally translated means poison.