Ocean Acidification Part 1: What's Happening to our Oceans and Why

Contents

Mommy, What Happened to All the Crustaceans? Ok, so maybe a young child wouldn't know what a crustacean is, and the way the climate is getting all mucked up, future children may never have the chance to learn about them, except from books about extinct animals.

Maybe I am being a bit alarmist, but then I am not the only one  ...

Remember that "rubber egg" science experiment that kids did with the egg and vinegar?  The egg would sit in the vinegar for a few days and the shell would turn to rubber, or so it seemed.  What happened was that the shell was slowly dissolved by the acidic vinegar.

And soon that could be happening in the oceans.

Ocean acidification. If you haven't heard of it before, get to know it now. Just when you are thinking to yourself that we humans have really dropped the ball on taking care of the ecosystem, here's another dangerous sign of our collective irresponsibility.

Since the dawn of the Industrial Revolution, the pH of the world's oceans has dropped about 0.1 from 8.2pH. That may not seem that extreme, but the Intergovernmental Panel on Climate Change   (otherwise known as the Nobel prize-winning IPCC) warns that this number ofpotential Hydrogen may further decrease by another 0.14 to 0.35 by 2100. That move toward the acidic could have some devastating effects on marine creatures that make shells or use shells or eat other creatures that make or live in shells or the animals that eat the fish that eat the creatures that make or live in shells. Hello, that is us.

"Users of the mineral aragonite-a very soluble type of calcium carbonate-are especially vulnerable. They include tiny pteropod snails, which help feed commercially vital fish like salmon. Computer models predict that polar waters will turn hostile for pteropods within 50 years (cold water holds the most CO2, so it is already less shell-friendly). By 2100, habitat for many shelled species could shrink drastically, with impacts up the food chain." - National Geographic 

Recently, a team of scientists have started studying Life around carbon dioxide vents in the Mediterranean, just to get an idea of how high levels of carbon may affect marine organisms living in the more acidic waters. The findings are scary, to say the least.

"Around the vents, it fell as low as 7.4 in some places. But even at 7.8 to 7.9, the number of species present was 30% down compared with neighbouring areas.

Coral was absent, and species of algae that use calcium carbonate were displaced in favour of species that do not use it.

Snails were seen with their shells dissolving. There were no snails at all in zones with a pH of 7.4.

Meanwhile, seagrasses thrived, perhaps because they benefit from the extra carbon in the water.

These observations confirm that some of the processes seen in laboratory experiments and some of the predictions made by computer models of ocean ecosystems do also happen in the real world."  - BBC News 8 June 2008  

Obviously, the snails living by these vents could simply move away, but what happens when the problem of acidity moves beyond the immediate areas around the vents?

And what exactly does a lower pH mean for marine organisms, you ask, and how does this acidification occur? Well, carbon dioxide becomes dissolved into water, and the CO2 binds with the H20 that is water, and voila, you get H2CO3. Simple stoichiometry.  Two Hydrogen atoms, one Carbon atom, and three Oxygen atoms and Carbonic Acid you have.

If you have ever used Coca Cola to clean a penny, you have seen carbonic acid at work.  It will eat through that penny if given long enough, and guess what, that same carbonic acid will also eat through a snail shell or a coral colony. At the same time, increased carbon dioxide also makes it difficult for organisms to even build that shell out of the building blocks calcium carbonate and aragonite. It's the aragonite that carbonic acid corrodes.

It's true that carbon dioxide naturally occurs within the world's oceans. If not, there would be little plant life. The problem that may be (is) on the horizon is an overabundance of carbon in the water. Huh, kind of sounds like the atmosphere and the oceans are somehow connected...

Using the oceans as "carbon sinks"   has been viewed as a possible solution to the threat of global warming due to increasingly high concentrations of carbon dioxide in our atmosphere, but now, the effects of carbon on our oceans is starting to catch the attention of scientists (and reporters).  Efforts are being made to further study the problem of ocean acidification, including the European Project on Ocean Acidification (EPOCA).  The EPOCA, inaugurated just this past June, will attempt to bring together the work of over one hundred scientists studying the effects of increased ocean acidity. The U.S. National Science Foundation has its ownChemical Oceanography Program to fund more studies on the problem that "'is leading to the most dramatic changes in marine chemistry in at least the past 650,000 years,' says Richard Feely, one of the authors [of the 2006 report, Impacts of Ocean Acidification on Coral Reefs and Other Marine Calcifers] and an oceanographer at NOAA's Pacific Marine Environmental Laboratory (PMEL) in Seattle." (National Science Foundation press release July 5, 2006  )

If I haven't given you a reason to worry just yet, earlier this summer, a research team from Oregon State University found that larger amounts of acidic waters are surfacing off the U.S. West Coast. Interestingly, the waters that are "upwelling" have been deeply buried at sea for the last fifty years, and that means that these waters have the carbon levels of a world fifty years ago.The research team used OSU's R/V Wecoma to sample water off the coast from British Columbia to Mexico. The researchers found that the 50-year-old upwelled water had CO₂ levels of 900 to 1,000 parts per million, making it "right on the edge of solubility" for calcium carbonate-shelled aragonites, [OSU's Burke] Hales said.

 "If we're right on the edge now based on a starting point of 310 parts per million," Hales said, "we may have to assume that CO₂ levels will gradually increase through the next half century as the water that originally was exposed to increasing levels of atmospheric carbon dioxide is cycled through the system. Whether those elevated levels of carbon dioxide tip the scale for aragonites remains to be seen.

"But if we somehow got our atmospheric CO₂ level to immediately quit increasing," Hales added, "we'd still have increasingly acidified ocean water to contend with over the next 50 years." -Science Daily May 23 2008  

Forgive me for being a Negative Nelly, but this may get a lot worse before it gets better.