MOSS LANDING, California-- Deep-sea animals may be highly sensitive to environmental changes in carbon dioxide concentration and pH, the predicted consequences of deep-sea carbon sequestration. A study by researchers, reported in the 12 October 2001 issue of Science, exposes the need for more research on the biological impacts of CO2 injection in the ocean.
In a survey of the relevant literature, Monterey Bay Aquarium Research Institute (MBARI) marine ecologist Brad Seibel and his colleague Patrick Walsh of the University of Miami's Rosenstiel School of Marine and Atmospheric Science summarize how deep-sea animals respond to the physiological stress caused by increased carbon dioxide in their environment.
"We set out to synthesize and disseminate what is known about deep-sea life physiology in the context of the environmental changes that are likely to result from carbon sequestration," said Seibel. "Increasing CO2 causes a decrease in seawater pH, creating an acidic environment that must be compensated for by physiological responses in living organisms."
Decreased pH can result in metabolic suppression which can inhibit growth and reproduction. Previous studies have established that deep-sea fish and invertebrates have low metabolic rates. Consequently, they lack the metabolic machinery required to compensate body fluid pH changes. Seibel and Walsh describe how even small changes in pH can impact these organisms.
International agencies are investigating deep-sea carbon sequestration as one possible mitigation technique for emissions of carbon dioxide, one of the primary greenhouse gases involved in global warming. MBARI chemists have conducted some of the first experiments aimed at understanding the chemistry and physics of CO2 in the deep ocean. New biological studies are now underway to investigate the ecological effects of CO2 sequestration.
"Many deep-sea organisms are extremely sensitive to environmental change. We need more studies to characterize the extent and method of CO2 injection to predict the broader consequences on deep-sea ecosystems and the global biogeochemical cycles dependent on them," said Seibel.