MEPS 289:1-4 (2005)  -  doi:10.3354/meps289001

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 ~60 l of liquid CO₂ onto the seafloor at 3250 m depth and sampled ~2 and ~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.

KEY WORDS:· Global warming · CO₂ sequestration · Deep sea · Benthic infauna · Harpacticoid copepods · Diversity