Microbial life thrives in virtually every habitat imaginable in the ocean, from the scalding temperatures found at hydrothermal vents, to frigid environments in and under polar sea ice, to high-pressure habitats in the ocean’s deepest trenches. Our understanding of microbial life in many of these ocean habitats, especially in plankton, has advanced remarkably over the past 30 years or so. The recognition of the ubiquity and distribution of photoautotrophic cyanobacteria such as Synechococcus and Prochlorococcus (Johnson and Sieburth, 1979; Waterbury et al., 1979; Chisholm et al., 1988), the isolation of pressure-requiring piezophilic bacteria (Yayanos et al., 1979), the discovery of Pelagibacter (Giovannoni et al., 1990), and recognition of the high abundance of marine phage (Bergh et al., 1989) represent just a few recent milestones in microbial oceanography. Even at a level as fundamental as the distribution of life’s three major domains (Bacteria, Archaea, and Eukarya), it is only recently that a clear picture of “who lives where” in the ocean has emerged.

DeLong, E.F. 2007. Microbial domains in the ocean: A lesson from the archaea. Oceanography 20(2):124–129, https://doi.org/10.5670/oceanog.2007.56.

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