Carbon Chemistry in Deep Sea Coral Ecosystems

Deep sea coral reefs are found on bathymetric highs with elevated currents and support highly dynamic ecosystems that may be impacted by ocean acidification (OA), warming, deoxygenation, and circulation changes. Deep sea corals living in the 400-800m depth range are typically situated in oxygen minimum zones of high CO₂ and low pH where aragonite saturation may be near corrosive: rising temperatures and CO₂ concentrations may increase physiological stress on coral communities, resulting in reduced suitable habitats for the corals and the fish and benthic communities they support. However, these ecosystems are located in hydrodynamically active areas that may already experience significant variations in currents, temperature, and carbonate chemistry due to tides, meandering boundary currents, and mesoscale eddies. If these reefs already experience extremes in carbonate chemistry due to such physical characteristics, they may be relatively resilient to chemical changes resulting from OA. Exploration and characterization of these sites is therefore necessary to establish a baseline of biogeochemical conditions and to investigate changes in biogeochemistry and their impacts on biodiversity of deep sea reefs over time.