An international team of scientists, led by Daniel Jones of the National Oceanography Center in Southampton, had predicted seafloor-dwelling marine life will decline by as much as 38 per cent in the North Atlantic and more than 5 percent globally in the next century.
The decline will be driven by a reduction in the plants and animals that live at the surface of the oceans that eventually drift down and feed deep-sea communities, they said.
"There has been some speculation about climate change impacts on the seafloor, but we wanted to try and make numerical projections for these changes and estimate specifically where they would occur," Jones said in a release from the oceanography center Friday.
The researchers used the latest climate models to predict changes in food supply throughout the world oceans, and then applied a relationship between food supply and biomass calculated from a huge global database of marine life.
More than 80 per cent of all identified key sea floor habitats -- such as cold-water coral reefs, seamounts and canyons -- will suffer losses in total biomass, they said.
"We were expecting some negative changes around the world, but the extent of changes, particularly in the North Atlantic, were staggering," Jones said. "Globally we are talking about losses of marine life weighing more than every person on the planet put together."
The study has been published in the journal Global Change Biology.