The large-scale utilization of synthetic organic compounds, such as herbicides, pesticides and plastics, into terrestrial as well as freshwater and marine environments has been posing considerable threats to the diversity and health of lifeforms, which is to some extent due to their recalcitrance in the environments. Pollutants include, among others, halogenated compounds. Long-term research accumulated evidence that a group of microbes, termed Organohalide-respiration bacteria (OHRB), thrives by coupling reductive dehalogenation of organohalogens to energy conservation. Recent reports revealed the distribution of OHRB in pristine marine environments according to the discovery of reductive dehalogenase homologous in marine sediments’ metagenomes, but their dehalogenation potential has yet to be elucidated. Thus, my aim is at first to test the dehalogenation potential of marine sediments and further characterize and isolate the responsible microorganisms, which is supportive for understanding the role of pristine marine environments in promoting the halogen cycle.