Ocean acidification, which occurs as seawater takes up CO2 from the atmosphere, could threaten around 70% of cold-water coral living below 1,500 metres in the North Atlantic Ocean by 2050, the research finds.
Acidified waters that accumulate in the North Atlantic could then be circulated to the global seas via a system of ocean currents, the lead author tells Carbon Brief, which could have consequences for reefs across the world.
The findings reiterate how many coral reefs could “dissolve” and “crumble” as the world continues to warm, another scientist tells Carbon Brief.
Cool corals
Cold-water corals are found in deep, dark parts of the world’s oceans in both the northern and southern hemisphere. They can thrive at depths of up to 2,000 metres and in water temperatures as low as 4C.
Unlike tropical corals, cold-water corals do not rely on colourful algae for their food. Instead, cold-water coral feed on floating plankton.
This means they are unaffected by coral bleaching, a process which is heightened by climate change and poses a great threat to the survival of tropical reefs, such as the Great Barrier Reef.
However, both tropical and cold-water coral species are threatened by a process known as “ocean acidification”, which occurs as seawater absorbs CO2 from the atmosphere.
The oceans have absorbed around 30% (pdf) of the CO2 released by human activity since the industrial revolution. This has caused oceans, which are alkaline, to become more acidic over time. The overall pH of seawater has fallen from around 8.2 to 8.1from pre-industrial times to the present day.
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