sentence: Furthermore , examples of well ‐ preserved mats and stromatolites from the Mesoproterozoic ( Knoll et al ., 2013 ) , the Jurassic ( Hefter et al ., 1993 ) and Early Triassic ( Heindel et al ., 2015 ) are consistent with the presence of layered mats containing both oxygenic and anoxygenic phototrophs in saline , low ‐ oxygen marine environments thought to be prevalent on early Earth.In addition to stromatolitic structures , biomarkers for cyanobacteria and other phototrophs include lipids , carotenoids and chlorophylls , and the recovery of these fossil hydrocarbons have been used to infer phototrophic community structure ( Brocks et al ., 2005 ) .