Projected pH reductions by 2100 might put deep North Atlantic biodiversity at risk
Other literature type
Jones, D. O. B.
Doney, S. C.
Dunne, J. P.
Orr, J. C.
(issn: 1726-4189, eissn: 1726-4189)
This study aims to evaluate the potential for impacts of ocean acidification
on North Atlantic deep-sea ecosystems in response to IPCC AR5 Representative
Concentration Pathways (RCPs). Deep-sea biota is likely highly vulnerable to
changes in seawater chemistry and sensitive to moderate excursions in pH.
Here we show, from seven fully coupled Earth system models, that for three
out of four RCPs over 17% of the seafloor area below 500 m depth in the
North Atlantic sector will experience pH reductions exceeding −0.2 units by
2100. Increased stratification in response to climate change partially
alleviates the impact of ocean acidification on deep benthic environments. We
report on major pH reductions over the deep North Atlantic seafloor (depth
>500 m) and at important deep-sea features, such as seamounts and
canyons. By 2100, and under the high CO<sub>2</sub> scenario RCP8.5, pH reductions
exceeding −0.2 (−0.3) units are projected in close to
23% (~15%) of North Atlantic deep-sea canyons and
~8% (3%) of seamounts – including seamounts proposed as
sites of marine protected areas. The spatial pattern of impacts reflects the
depth of the pH perturbation and does not scale linearly with atmospheric
CO<sub>2</sub> concentration. Impacts may cause negative changes of the same
magnitude or exceeding the current target of 10% of preservation of
marine biomes set by the convention on biological diversity, implying that
ocean acidification may offset benefits from conservation/management
strategies relying on the regulation of resource exploitation.