Deep-ocean, sediment-dwelling animals are sensitive to sequestered carbon dioxide

The burning of fossil fuel is producing the greenhouse gas CO2 at a rate that is causing global warming and threatens to change the global environment adversely. One proposed solution involves sequestering in the deep sea a substantial portion of the excess CO2 produced. Because large areas would be affected and this environment harbors one of the world's largest reservoirs of biodiversity, the approach is controversial. In particular, deep-sea diversity is found largely in the animals that live in the sediment, but the effects of sequestered CO2 on these organisms are not known. We therefore introduced similar to 60 1 of liquid CO2 onto the seafloor at 3250 m depth and sampled similar to 2 and similar to 40 m from the deposition site 30 d later. The pore water in the samples taken near the site was 0.75 pH unit more acidic (pH decreases when CO2 concentration increases) than that in samples taken farther away, Representative infauna had been killed in significantly greater numbers in the former than in the latter location. This demonstration that sequestered CO2 can adversely affect the deep-sea infauna brings CO2 sequestration in the deep sea into potential conflict with the preservation of deep-sea biodiversity.