LINKING META'OMICS TO THE BIOGEOCHEMISTRY OF OXYGEN MINIMUM ZONES

Oxygen minimum zones (OMZ) are regions in the ocean water column with reduced oxygen levels, resulting from aerobic respiration of organic matter precipitating from the upper layers. The biogeochemistry of OMZs is driven by prokaryotic life that utilizes alternative electron acceptors to oxygen for the oxidation of reduced nitrogen, sulfur and carbon compounds. OMZs strongly influence the global marine nitrogen cycle, while their potential role as inorganic carbon sinks and sources of potent greenhouse gases is still poorly understood.

Recent advances in molecular environmental profiling offer an unprecedented insight into the microbial composition and activity in ecosystems such as OMZs. We present a spatiotemporal biogeochemical model for the OMZ in Saanich Inlet, a well studied fjord off the coast of Vancouver Island. The model focuses on key biogeochemical processes and the genes that mediate them, allowing its calibration and validation against available chemical profiles as well as metagenomic, metatranscriptomic and metaproteomic data. Our work demonstrates how meta'omics can be mechanistically linked to environmental redox conditions and biogeochemical process rates.