What is the commonest living thing on Earth?
Pelagibacter ubique is the most successful member of a group of bacteria called SAR11, that jointly constitute about a third of the single-celled organisms in the ocean. But this is not P. ubique’s only claim to fame, for unlike almost every other known cellular creature, it and its relatives have seemed to be untroubled by viruses. But four viruses that parasitise P. ubique have now neen found, and one called HTVC010P was the commonest. It thus displaces its host as the likely winner of the most-common-living-thing prize.
Abundant SAR11 viruses in the ocean. (2013) Nature. doi: 10.1038/nature11921 http://goo.gl/iXVyF