Escalating impacts of climate change on marine life will further alter biomass of marine animals , the timing of seasonal ecological events  and the geographic ranges of coastal and ocean taxa , disrupting life cycles , food webs  and ecological connectivity throughout the water column . Multiple lines of evidence suggest that climate-change responses are very likely to amplify up marine food webs over large regions of the ocean. Modest projected declines in global phytoplankton biomass translate into larger declines of total animal biomass  ranging from  -5.7 + 4.1% to -15.5 + 8.5% under SSP1-2.6 and SSP5-8.5, respectively . Projected declines in upper-ocean nutrient concentrations, likely associated with increases in stratification, will reduce carbon export flux to the mesopelagic and deep-sea ecosystems . This will lead to a decline in the biomass of abyssal meio- and macrofauna  by -9.8% and -13.0% under SSP1-2.6 and SSP5-8.5, respectively . By 2100, 18.8 + 19.0% to 38.9 + 9.4% of the ocean will very likely undergo a change of more than 20 d  in the start of the phytoplankton growth period under SSP1-2.6 and SSP5- 8.5, respectively . This altered timing increases the risk of temporal mismatches between plankton blooms and fish spawning seasons  and increases the risk of fish- recruitment failure for species with restricted spawning locations, especially in mid-to-high latitudes of the Northern Hemisphere . Projected range shifts among marine species  suggest extirpations and strongly decreasing tropical biodiversity. At higher latitudes, range expansions will drive increased homogenisation of biodiversity. The projected loss of biodiversity ultimately threatens marine ecosystem resilience , with subsequent effects on service provisioning . 
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report