A Planet of Viruses

by Carl Zimmer

Proctor’s figure far exceeded previous estimates. But when other scientists followed up on her work and carried out their own surveys, they ended up with similar figures. They found viruses lurking in deep-sea trenches and locked in Arctic sea ice. They came to agree there are somewhere in the neighborhood of 10,000,000,000,000,000,000,000,000,000,000 viruses in the ocean. It is hard to find a point of comparison to make sense of such a huge number. There are 100 billion times more viruses in the oceans than the grains of sand on all the world’s beaches. If you put the viruses of the oceans together on a scale, they would equal the weight of 75 million blue whales (there are less than 10,000 blue whales on the entire planet). And if you lined up all the viruses in the ocean end to end, they would stretch out 42 million light-years.