“…This presumed advantage led to the hypothesis that one type of photoheterotroph, aerobic anoxygenic phototrophic (AAP) bacteria, would be most abundant in oligotrophic systems (Kolber et al, 2000), but subsequent work demonstrated that AAP bacteria are abundant in eutrophic estuaries and coastal waters when compared with the open oceans Jiao et al, 2007;Lami et al, 2007;Waidner and Kirchman, 2007;Ritchie and Johnson, 2012). Light has been shown to positively affect the growth rate and other aspects of AAP bacterial activity in laboratory experiments (Shiba, 1984;Okamura et al, 1986;Holert et al, 2011;Tomasch et al, 2011;Hauruseu and Koblížek, 2012), but it has complex effects on natural microbial communities which include photoheterotrophic microbes Straza and Kirchman, 2011;Ruiz-González et al, 2012a;Ruiz-González et al, 2012b). Data on growth-related activity in natural communities would help elucidate the advantages of photoheterotrophy and whether photoheterotrophic microbes change models of carbon cycling (Karl, 2002).…”