Thursday, May 10, 2012

Oyster Farm Failure Due to Ocean Acidification - The Future Is Already Here

 Hannah-Barbara credit
I can remember when I looked forward to the future.  Think about it, someday we would all get George Jetson flying cars - how cool would that be! Of course, if you looked closely at the cartoon, George's life did not seem all that wonderful - not sure I want to trade really. And the car, ever notice that it made little putt-putt noises and seemed to have exhaust coming out the back - makes you wonder. Which brings me to today's topic, the future is here and I'm not sure I like it.

Harvesting Oysters - NOAA credit
A few years back oyster farms in the Pacific Northwest started having problems with their oyster beds: young oysters were not recruiting successfully. This was happening in the hatcheries and with wild stocks as well. Some worried that maybe ocean acidification was already here and that a slight change in ocean water acidity was affecting the young oyster's ability to start their shells. If this were true, this was very scary.

Several years ago when the Whiskey Creek Oyster Hatchery in Oregon noted declines in oyster seed production they proceeded to eliminate several possible factors, including low oxygen and bacterial issues. This left pH as a probable cause, but pH changes are hard to document. PH levels routinely fluctuate widely in estuary waters, from day to night, from tide to tide, seasonally and especially if there is an upwelling event bringing up old cold corrosive waters.

Ultimately, Alan Barton from the Whiskey Creek Hatchery and a group of state and federal researchers were able to show that pH issues were driving the oyster seed declines, despite the various natural fluctuations. In fact, one of the "natural" fluctuations, upwelling water, already had a human signal in it.  Since it is only decades old, it was exposed to human created high CO2 levels when it was at the surface in the 1960's. Water that upwells in coming years will only get worse.

There are ways that the farmers can compensate. By timing oyster spawning to correlate with the best water quality events (in terms of pH), farmers should be able to see better success now that they know what the problem is. But these windows of opportunity are likely to lessen in the coming years, making the current 270+ million dollar industry less and less viable.

Now if this information does not seem perky enough to you, just one month before this study came out, another came out with this comment (as quoted from Science Daily), "The world's oceans may be turning acidic faster today from human carbon emissions than they did during the four major extinctions in the last 300 million years, when natural pulses of carbon sent global temperatures soaring . . ."

So the future is here. It is us. And I am not sure I like what I see.

Oyster farmer and chef at work - NOAA credit
I actually do like oysters (small ones, with a touch of lemon or sometimes just cold). I like what they do for a bay (filtering that is) and although I am not so wild about getting cut on their shells,
a world without oysters  - well - that would just not be my oyster.



References and further reading:

Interested in what pH is? Check out this classic "Acid Rain Explained" site from the EPA (yes acid rain still exists) - see: "Acid Rain Students Site: PH Scale."  or if you want a very cool chemistry site, work your way through a bit of  "Acids and Bases," (Charles Ophardt, Elmhurst College's Virtual Chembook) an excellent site.

"Ocean Acidification Linked to Larval Oyster Failure." ScienceDaily (Apr. 11, 2012).

"Ocean Acidification Rate May Be Unprecedented, Study Says." ScienceDaily (Mar. 1, 2012)

"The Pacific oyster, Crassostrea gigas, shows negative correlation to naturally elevated carbon dioxide levels: Implications for near-term ocean acidification effects." Alan Barton, Burke Hales, George G. Waldbusser, Chris Langdon and Richard A. Feely. Limnol. Oceanogr., 57(3), 2012, 698-710 | DOI: 10.4319/lo.2012.57.3.0698

Note - As always, if any of our volunteers want a look at the original study, let me know. You will need access to the paid subscription.

All sites accessed 05/10/2012.

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