A Bush Administration proposal to mitigate the effects of global warming by capturing carbon dioxide emissions from power plants and injecting it into the deep sea could have disastrous effects on sea life, according to a University of Rhode Island researcher. Brad Seibel, assistant professor of marine biology at URI, said that while the Administration's plan is still in the experimental stage, enough is already known about the biology of marine organisms to say with certainty that the plan will harm the marine environment in significant ways.
Increased CO2 in the oceans would result in decreases in the pH levels of seawater, resulting in dramatic physiological effects on many species, Seibel said. Shallow-living organisms like shelled mollusks and corals are already being affected by the growing levels of CO2 in the atmosphere. As atmospheric CO2 diffuses into the upper layers of the water, it inhibits the ability of shellfish to form shells and causes coral reefs to dissolve.
Deep-sea creatures are even more sensitive to environmental changes, he said. In some species, their metabolism would become suppressed and lead to retarded growth and reproduction, while others would be unable to transport oxygen in their blood.
"CO2 injection would be detrimental to a great many organisms," said the URI biologist. "It would kill everything that can't swim fast enough to get out of the way, because in concentrated form it's highly toxic, even to humans. But the Department of Energy seems willing to sacrifice the animals of the deep sea if it will stop global warming. That's not entirely unreasonable considering that if we keep stalling on taking serious measures to reduce global warming, we won't be able to do anything about it. But I'd still like to see that we're doing everything else possible to reduce emissions before we begin polluting the deep-sea."
The government's "carbon sequestration" plan is designed to collect carbon dioxide emissions that would otherwise be released into the atmosphere and store them in underground geologic formations or deep in the ocean. Energy Secretary Spencer Abraham announced in September the creation of seven regional partnerships to establish the framework needed to develop the necessary technologies and put them into action. In addition, the Bush Administration convened a Carbon Sequestration Leadership Forum last June where energy ministers from 13 countries discussed the potential for CO2 injections around the globe.
In the new book Climate Change and Biodiversity, Seibel and co-author Victoria Fabry wrote: "From the perspective of marine organisms, deep-ocean sequestration means concentrating an otherwise dilute toxin to well above lethal levels, and placing it in an environment where the organisms are less tolerant of environmental fluctuation in general and CO2 in particular. Localized devastation of biological communities at the injection sites is certain."
As seawater becomes acidified, growth rates of calcareous phytoplankton (those with calcium carbonate shells) will be reduced as a result of the effects of CO2 on the process of calcification. Metabolism in some animal species may also be depressed by increased acidity. Furthermore, some fish, squids, and shrimps will have a diminished capacity for oxygen uptake at the gill and transportation through their bloodstream, leading to asphyxiation.
Seibel said that there is typically a natural exchange of CO2 between the sea and the atmosphere, but increases of atmospheric CO2 are already affecting the equilibrium. Intentional injections of CO2 will further disrupt the ecosystem.
"The carbon dioxide-carbonate system is arguably the most important chemical equilibria in the ocean," Seibel and Fabry wrote. "It influences nearly every aspect of marine science, including ecology and, ultimately, the biodiversity of the oceans."
