1. Context

While the millimeter-sized members of plankton have been studied since 1887, it's only since the 1970s that the abundance and diversity of microbes and viruses have come to light. It has since been shown that one liter of seawater can contain up to 109 bacteria. In the 1990s, the first culture-independent techniques for assessing marine bacterial diversity – including genetics – showed that bacteria are diverse, and that the majority of marine groups were unknown. At the same time, the discovery...