Posted by: leahbiery | April 10, 2010

The Ocean on Acid

The 'test' or skeleton of a calcifying organism, the sea urchin.

Thanks to everyone who came to our screening of The Cove at Big Arts last night!  It was a huge success and people asked some very timely and thought-provoking questions during the meet and greet with Expedition Director Simon Hutchins.

The crowd listened intently while Simon talked about marine mammal protection, coral reefs, and sustainable seafood issues, but when he briefly mentioned ocean acidification, I could see the proverbial question marks pop up over many attendees’ heads.  Eyes rolled towards the ground and cheeks flushed with embarrassment as Simon asked, “everyone knows what ocean acidification is, right?” Wrong.

Don’t feel naïve if you’ve never heard of ocean acidification. It’s rarely mentioned by the media and has only recently become a hot topic on the environmental radar, but it is a phenomenon worth understanding because it will have immense effects on our oceans and their inhabitants in the near future. Here is a simple explanation of this very complicated concept:

  • The pH scale is from 0-14.
  • When something has a low pH (less than 7), it is acidic. The more Hydrogen ions (H+) in a substance, the more acidic it is.
  • When humans burn fossil fuels, we release carbon dioxide into the atmosphere. Some of this carbon dioxide stays in the atmosphere and traps heat (the cause of global warming), some is used by plants, and some is absorbed by the ocean.
  • Ocean acidification is the decrease in the pH of our oceans, (i.e., the oceans becoming more acidic) which is caused by their absorption of carbon dioxide from the atmosphere.
  • Carbon Dioxide is released by many things into the atmosphere naturally, but the problem is that anthropogenic (generated from human activity) releases are much, much higher than any other source – creating “extra” carbon dioxide that the ocean can’t neutralize through natural processes.
  • When carbon dioxide enters the ocean, it reacts with water in the following way:

CO2 + H2O –> H2CO3 –> H+ +  HCO3– –> H+ + H+ + CO32-

If you’re like me, your brain shuts down when you see a chemical equation, so don’t worry about the chemistry. The important thing to notice is that when carbon dioxide  is combined with sea water, Hydrogen ions (H+)  are formed. Remember that H+ ions are what make substances more acidic? Aha.

  • Since the Industrial Revolution (about 200 years ago), ocean pH has decreased by 0.1 on a scale of 1-14. This may not seem like much, but on the logarithmic pH scale, it means that the concentration of H+ ions has increased by 30% in the past two centuries! That’s fast.

Why does it matter if the ocean becomes more acidic? Many organisms with skeletons made of calcium carbonate are unable to survive and grow without carbonate ions in the water. As ocean pH falls, so does the availabilty of these ions. Creatures like plankton, sea urchins, corals, crustaceans and mollusks will suffer.

These organisms are at the bottom of the food chain. When they go, so does everything else.

So that’s the short (but not very sweet) version of ocean acidification.

What can you do to slow down the process of ocean acidification? Calculate, then find ways to reduce your carbon footprint! You could start by driving less – share rides, combine trips, walk, or ride your bike.


  1. […] Why should we reduce our CO2 output? Read The Ocean on Acid […]

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s


%d bloggers like this: