Hadal zones – located 6-11 km below the ocean surface – represent the deepest regions on Earth. Limited data suggest that hadal sediments are important repositories for legacy hydrophobic persistent organic pollutants (POPs). The importance of hadal zones as sinks for contaminants with more diverse properties, however, is poorly understood. At the same time, emerging evidence suggests that hadal microbial communities may be adapted to degrade halogenated pollutants. In this project, entitled “Small but efficient – can hadal sediment microbes degrade persistent chemicals? (Hadal-Degrade)”, we will investigate the occurrence of a diverse suite of contaminants in sediments from deep-sea trenches from the northern and southern hemisphere using state-of-the-art mass spectrometric methods.

Further, we will use lab-based biodegradation experiments in high pressure chambers to test hypotheses on the influence of hadal microbial diversity on chemical persistence. In addition to improving fundamental knowledge on the role of hadal trenches in global contaminant cycling, this work has the potential to open pathways into sustainable bioremediation technologies for contaminated environments on the Earth’s surface.