The GOS station locations and environmental genomes.

The total numbers of unique genes of each defined LH gene-type identified at each station are shown. Only samples in the size fraction <0.8 µm and from surface (5-m depth) marine stations were used in this analysis; non-marine (such as a hypersaline lagoon) stations were not used. Stations where no LH genes were found are either in the NE Atlantic, and so assumed to be dominated by large eukaryotic phytoplankton species >0.8 µm, or from stations in the equatorial and south Pacific where the size of the sequenced environmental genome is low.