FIG 7.

Schematic model summarizing the putative ecological features of Thalassospira in aromatic hydrocarbon-exposed marine environments. Thalassospira occupied niches that utilize single-ring aromatic acids (CBA, phthalic acid, and protocatechuic acid) that are released from complex, hydrophobic aromatic hydrocarbon pollutants. In PAH-exposed environments, Thalassospira likely grew through metabolic dependencies on the pioneering members that possessed specialized enzymes for PAH degradation and thus were responsible for upstream biotransformations. Acquisition of the ability to utilize CBA in Thalassospira may have advantaged them to become abundant in PAH-exposed communities, by allowing them to scavenge the relatively less hydrophobic aromatic acids (CBA and phthalic acid) right after becoming available from the more hydrophobic aromatic hydrocarbon sources that originated from ocean oil spill or plastic waste pollution.