Bacterial Production Modulates the Persistence of Organophosphate Ester Flame Retardants and Plasticizers in the Ocean

The occurrence of organophosphate ester (OPE) flame retardants and plasticizers has been widely reported in the marine environment. However, few studies have assessed the potential of marine microorganisms to degrade them, especially under non-idealized environmental conditions. Here we report the results of six degradation experiments where in situ bacterial communities were challenged to environmentally relevant concentrations of six OPE compounds in the Atlantic and Southern Oceans. After 48 hours of incubation, OPE concentrations were assessed, as well as changes in bacterial communities. The aryl-OPEs TmCP and EHDPP significantly decreased, almost a 60% in the Atlantic Ocean and 25% in the Southern Ocean. However, only Atlantic Ocean experiments reported potential biodegradation, which accounted for 20% of the decrease. The cold temperatures of the Southern Ocean resulted in a slower non-detectable bacterial response further confirmed by bacterial production results. After the incubations, bacterial communities where dominated by the fast-growing opportunistic bacteria Alteromonas macleodii in the Atlantic Ocean experiments, while several psychrophilic heterotrophic bacteria where found in the Southern Ocean experiments. Interestingly, these taxa have been reported as hydrocarbonoclastic bacteria in polar coastal waters. Significant negative correlations between the fold changes in bacterial production and the decreases in TmCP and EHDPP concentrations further suggested that bacterial metabolic processes may be involved in OPE removal.