Ocean warming alters biological processes in deep-sea ecosystems in ways that affect deep-sea habitat, biodiversity and material processing. Enhancement of microbial respiration by warming attenuates sinking POC, which has been associated with the globally projected declines in total seafloor biomass of -9.8 and -13.0% by 2081-2100 relative to 1995-2014 under SSP1-2.6 and SSP5-8.5, respectively  . Additionally, climate-change-driven oxygen loss  and geographic shifts in predator distributions  are anticipated to affect deep-sea biodiversity  . Complex responses of some bathyal crustacean assemblages to environmental change suggest an increase in phylogenetic diversity but limited decreases in abundances with temperature . Acute mortality of some reef-forming cold-water corals to laboratory-simulated warming  suggests that both long-term warming and the increase of MHWs in intermediate and deep waters  could pose significant risk to associated ecosystems . Thermal tolerance thresholds  of scleractinians in laboratory settings depend on their geographic position and capacity for thermal adaptation, as well as other factors including food, oxygen and pH  .
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report