There is much research that needs to be done about the biological implications of ocean acidification, Hales said. We now have a fairly good idea of how the chemistry works.
Increasing levels of carbon dioxide in the atmosphere are a product of the industrial revolution and consumption of fossil fuels. Fifty years ago, atmospheric CO2 levels were roughly 310 parts per million the highest level to that point that the Earth has experienced in the last million years, according to analyses of gas trapped in ice cores and other research.
During the past 50 years, atmospheric CO2 levels have gradually increased to a level of about 380 parts per million.
These atmospheric CO2 levels form the beginning baseline for carbon levels in ocean water. As water moves away from the surface toward upwelling areas, respiration increases the CO2 and nutrient levels of the water. As that nutrient-rich water is upwelled, it triggers additional phytoplankton blooms that continue the process.
There is a strong correlation between recent hypoxia events off the Northwest coast and increasing acidification, Hales said.
The hypoxia is caused by persistent upwelling that produces an over-abundance of phytoplankton, Hales pointed out. When the system works, the upwelling winds subside for a day or two every couple of weeks in what we call a relaxation event that allows that buildup of decomposing organic matter to be washed out to the deep ocean.
But in recent years, especially in 2002 and 2006, there were few if any of these relaxation breaks in the upwelling and the phytoplankton blooms were enormous, Hales added. When the material produced by these blooms decomposes, it puts more CO2 into the system and increases the acidification.
The research team used OSUs R/V Wecoma to sample water off the coast from British Columbia to Mexico. The researchers found that the 50-year-o
|Contact: Burke Hales|
Oregon State University