>One study estimated that viruses in the ocean cause a trillion trillion infections every second, destroying some 20 percent of all bacterial cells in the sea daily.
That excerpt really put it into perspective for me. I guess I always thought that viruses didn't have much of an impact, aside from ocasionally causing a pandemic and incorporating themselves into our genome. But the thought of viruses killing a fifth of all bacteria in the sea everyday is staggering.
I saw this quote in Nature last year 
"Viruses outnumber prokaryotes by ten to one and are said to kill half of the world's bacteria every two days"
Maybe these two are locked in some sort of existential battle for Earth while everything else is a side show?
 H. Ledford, "Five big mysteries about CRISPR’s origins", Nature, 12 January 2017. Volume 541 Number 7637
This is a rare example of extreme understatement in a headline. If the figure given in the article is true, about 800 trillion viruses fall to Earth each day per square kilometer.
I guess the layman's followup question (if I may) is, why didn't something like Smallpox spread over to the Americas, if viruses are that prevalent? Why did they need a human host? Is there a specific evolutionary niche to not being infectious via the air?
> (There is a small group of researchers who believe viruses may even have come here from outer space, an idea known as panspermia.)
Fred Hoyle  is one such researcher. He is an astrophysicist who was the first to demonstrate how elements heavier than helium are synthesized by nuclear reactions in stellar cores. He holds a number of non-mainstream scientific beliefs and one involves the source and evolution of life on earth. He discusses it, along with other evidence challenging the neo-darwinian theory of evolution , in "The Intelligent Universe" . I'm reading it now and highly recommend it.
The possibility that viruses can benefit a host or cellular species is interesting. I have wondered whether the common cold virus(es) may impart some benefit to humans? Are we symbiotic with mutualism?
Could they provide some defense or warning against other diseases in the environment? Just speculating.
Having just read this article, how might this virus activity be tracked / measured back in time?
If viruses and bacteria are the forerunners of more complex life, wouldn't this be helpful to know?
Someone should quickly tell the king that the sky is falling down
Why does this feel a little like fear-mongering?
George Carlin on germs, really funny stuff.