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||p.404 top paragraph:"The picocyanobacteria Prochlorococcus and marine Synechococcus are the most abundant oxygenic photosynthesizing organisms in the majority of the oligotrophic ocean [ref 1], together contributing 32% to 80% of oceanic primary productivity [primary sources]. Their ability to live in regions of low nutrient concentrations gives rise to the prediction that their global distribution will expand in the future with the expected increase in stratification of the world’s oceans due to rising sea temperatures [refs 7–9]. Differences in the distributions of marine Synechococcus and Prochlorococcus, both throughout the globe and throughout the water column, allow these two genera to numerically dominate the majority of the marine environment [ref 10]. Specifically, marine Synechococcus live mostly in coastal regions in the upper euphotic zone but can also be found in regions of open ocean, where they are outnumbered by Prochlorococcus [refs 1,11]. Prochlorococcus resides mainly in the oligotrophic open ocean down to the entirety of the euphotic zone [ref 1]."