Oceans Acidifying at an Alarming Pace

According to a study published recently in the Journal Science,  researchers from Columbia University analyzed 300 million years of ocean fossil records to try to understand the likely outcomes of the increasing acidification of our oceans.  What they found isn’t pretty.

 The scientists found surging levels of carbon dioxide in the atmosphere forced down the pH of the ocean by 0.1 unit in the last century, 10 times faster than the closest historical comparison from 56 million years ago, New York’s Columbia University, which led the research, said yesterday in a statement. The seas absorb CO2 from the atmosphere, forming carbonic acid. The lower the pH level in the seas, the more acidic they are.

The National Oceanic and Atmospheric Administration (NOAA) has a nice explanation of what Ocean acidification means.  The bottom line is that as more Carbon Dioxide (Co2) gets absorbed into the ocean, the more carbonic acid is formed, and the less calcium carbonate is avalable.

Now you might ask why you should care about the levels of calcium carbonate.  – Shellfish and Coral Reefs.  – In order for coral or shells to form, the ocean needs to be supersaturated with calcium carbonate.  As the acidity of the ocean increases, and the saturation levels of calcium carbonate decreases, we corals and shells are unable to form, and an entire strand of the ocean food chain can become undone.

To a large extent, CO2 absorbed into the ocean us used by phytoplankton to support photosynthesis.  In fact,  some people believe that the excess CO2 will simply mean more photosynthesis and more food.  The only problem with this is that phytoplankton has been in precipitous decline for several decades due to overfishing and the removal of fixed nitrogen from the oceans.

So,  how bad is the situation?  In the past 100 years, the pH level of the oceans has dropped 0.1, that is a rate 10 times faster than the nearest  equivalent (almost 56Million years ago) when a dramatic increase in CO2 resulted in a .45 unit lowering of pH (increase in acidity) and a huge extinction wave hit the ocean.

What is scary today is not the absolute level of acidity, but the rate of change.

In the last hundred years, atmospheric CO2 has risen about 30 percent, to 393 parts per million, and ocean pH has fallen by 0.1 unit, to 8.1–an acidification rate at least 10 times faster than 56 million years ago, says Hönisch. The Intergovernmental Panel on Climate Change predicts that pH may fall another 0.3 units by the end of the century,to 7.8, raising the possibility that we may soon see ocean changes similar to those observed during the PETM. (56 Million years ago)

We need healthy, food producing oceans to survive.  Our rapid production of CO2 emmissions has the potential of doing irreparable harm to the food chains in our ocean.   We need to act.

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