By Stephen Messenger
January 22, 2012
Earth's oceans may be an inconceivably vast ecosystem home to countless species yet unknown to science, but a new study reaffirms that they too are susceptible to the damaging impact of carbon emissions released by humans. According to researchers from the University of Hawaii, ocean acidity levels in some regions have spiked more quickly in the last 200 years than in the preceding 21 thousand years -- threatening the future existence of some of the planet's most important marine life.
While airborne CO2 emissions are already considered a key factor to climate change on the planet's surface, researchers say that nearly a third of all emissions released by humans actually wind up absorbed into the oceans -- and that the resulting acidification could have devastating effects on aquatic organisms.
To measure rises in acidification, researchers examined the levels of a calcium carbonate called aragonite, an element essential for the construction of corral reefs and the shells of mollusks. As acidity levels rise, the levels of aragonite drop, warn University of Hawaii scientists -- and its rate of decline seems to parallel human's creation of CO2 emissions:
Today's levels of aragonite saturation in these locations have already dropped five times below the pre-industrial range of natural variability. For example, if the yearly cycle in aragonite saturation varied between 4.7 and 4.8, it varies now between 4.2 and 4.3, which – based on another recent study – may translate into a decrease in overall calcification rates of corals and other aragonite shell-forming organisms by 15%. Given the continued human use of fossil fuels, the saturation levels will drop further, potentially reducing calcification rates of some marine organisms by more than 40% of their pre-industrial values within the next 90 years.
"In some regions, the man-made rate of change in ocean acidity since the Industrial Revolution is hundred times greater than the natural rate of change between the Last Glacial Maximum and pre-industrial times," says the study's lead author, Tobias Friedrich.
Although our spewing of more and more CO2 emissions in the atmosphere has already begun to alter our planet's climate patterns, that may be just one of the harmful impacts threatening our sustainable future. So much life on land, including a majority humans, depend on a healthy and fruitful ocean for their food and livelihoods -- but it's held in a delicate balance that current trends are threatening to tip in the wrong direction.
