Washington: A scientist has said that the increasing acidity of the world’s oceans and its growing threat to marine species are definitive proof that the atmospheric carbon dioxide (CO2) that is causing climate change is also negatively affecting the marine environment.
The statement has been made by Antarctic marine biologist Jim McClintock, professor in the University of Alabama at Birmingham (UAB) Department of Biology, who has spent more than two decades researching the marine species off the coast of Antarctica.
“The oceans are a sink for the carbon dioxide that is released into the atmosphere. Carbon dioxide is absorbed by oceans, and through a chemical process hydrogen ions are released to make seawater more acidic,” said McClintock.
“Existing data points to consistently increasing oceanic acidity, and that is a direct result of increasing carbon dioxide levels in the atmosphere; it is incontrovertible,” he said.
“The ramifications for many of the organisms that call the water home are profound,” he added.
A substance’s level of acidity is measured by its pH value; the lower the pH value, the more acidic is the substance.
According to McClintock, data collected since the pre-industrial age indicates the mean surface pH of the oceans has declined from 8.2 to 8.1 units with another 0.4 unit decline possible by century’s end.
A single whole pH unit drop would make ocean waters 10 times more acidic, which could rob many marine organisms of their ability to produce protective shells – and tip the balance of marine food chains.
“There is no existing data that I am aware of that can be used to debate the trend of increasing ocean acidification,” said McClintock.
McClintock said that the delicate balance of life in the waters that surround the frozen continent of Antarctica is especially susceptible to the effects of acidification.
“The impact on the marine life in that region will serve as a bellwether for global climate-change effects,” he said.
“The Southern Ocean is a major global sink for carbon dioxide. Moreover, there are a number of unique factors that threaten to reduce the availability of abundant minerals dissolved in polar seawater that are used by marine invertebrates to make their protective shells,” he added.
“In addition, the increased acidity of the seawater itself can literally begin to eat away at the outer surfaces of shells of existing clams, snails and other calcified organisms, which could cause species to die outright or become vulnerable to new predators,” he explained.