Physiology of deep-sea animals:
Implications for CO2 sequestration

Brad Seibel, Ph.D.
MBARI

Wednesday, June 11, 2003
3:00 p.m. – Pacific Forum

A recent proposal to store anthropogenic carbon dioxide in the deep ocean is assessed here with regard to the impacts on deep-living fauna. The stability of the deep sea has allowed the evolution of species ill equipped to withstand rapid environmental changes. Low metabolic rates of most deep-sea species are correlated with low capacities for pH buffering and low concentrations of ion-transport proteins. Changes in seawater carbon dioxide partial pressure may thus lead to large cellular CO₂ and pH changes. Oxygen transport proteins of deep-sea animals are also highly sensitive to changes in pH. Acidosis leads to metabolic suppression, reduced protein synthesis, respiratory stress, reduced metabolic scope and, ultimately, death. Deep-sea CO2 injection as a means of controlling atmospheric CO2 levels should be assessed with careful consideration of potential biological impacts.