Wednesday, October 28, 2015

Holding Off, For A Time, The Effects Of Global Warming

The increasing concentration of CO2 in the atmosphere is a serious problem, as I've posted many times before.  But there is another serious problem with CO2, its concentration in the ocean which is acidifying it.  The planet has experienced something like this before, at the Paleocene/Eocene boundary when ocean acidification produced the largest loss of sea life in the history of the planet.  And we are pouring a far larger quantity of CO2 into the oceans.

The effects of the acidification are already being felt here in Washington State.
But the die-offs he witnessed when he came to Whiskey Creek — a family-run hatchery owned by wife and husband duo Sue Cudd and Mark Wiegard — were different.
We had two awful years in a row.” Barton said. “And this is a small business, so that’s almost the end.”
Whiskey Creek might be a small business, but it’s a crucial link in the $270 million Pacific shellfish industry. As the second-largest commercial shellfish hatchery on the West Coast, it provides hundreds of small to medium-sized oyster farms with the microscopic larvae they need to make their operations work.
For two years, Barton fought the invisible foe killing the oyster larvae at Whiskey Creek, but nothing seemed to stem the losses. Then he started seeing papers by Dick Feely, describing how anthropogenic carbon dioxide was adding to the naturally carbon dioxide rich water upwelling off the Pacific Coast, increasing the ocean’s acidity.
About 30 percent of the carbon dioxide that humans release into the atmosphere gets absorbed by the ocean, and when that happens, it reacts with water to form carbonic acid, which is the same thing that gives soda its signature fizz and slightly acidic bite. In the oceans, carbonic acid is not a very stable chemical compound — it tends to split into smaller chemical pieces fairly quickly, forming both a bicarbonate ion and a hydrogen ion. As the concentration of hydrogen ions increases, the pH of the ocean decreases, increasing the acidity of the water. Over the last 250 years, the average pH of upper-ocean has dropped from 8.2 to 8.1 — and while that might look like a relatively small drop, it translates to roughly a 30 percent increase in the concentration of hydrogen ions.
Oyster larvae go from no shell to 80 percent of their body being shell in about four hours, and so there’s this huge bottleneck where they need to be able to make shell easily,” Barton said.
Using Hales’ monitoring techniques, Whiskey Creek started to pull water into the hatcheries only when the concentration of carbonate ions was high. It wasn’t a perfect strategy, but it worked — for the first time in years, Whiskey Creek’s production numbers started to improve.
With the success of Whiskey Creek’s monitoring program, other hatcheries and scientists looked to implement the testing of seawater on a larger scale. In the winter of 2009, the Pacific Coast Shellfish Growers Association submitted a proposal to Sen. Maria Cantwell (D-WA), asking for funding to expand the monitoring program to other critically important areas for the commercial shellfish industry.
In Cantwell, the shellfish industry found its first political champion in the fight against ocean acidification. With $500,000 in federal money, the industry was able to put in place a robust monitoring system up and down the Pacific Northwest coast, from the Lummi Hatchery in Bellingham, Washington down to the Whiskey Creek Shellfish Hatchery in Netarts. Altogether, the Pacific Coast Shellfish Growers Association set up seven monitoring stations at five different sites, giving both industry workers and scientists real-time information about the carbonate chemistry of the water.
With data coming in daily from the monitoring system, hatcheries were able to install buffer systems — tanks that pump sodium carbonate back into the water to manually raise the concentration of carbonate ions.
“That turned things around almost instantaneously for us in the hatcheries,” Bill Dewey of Taylor Shellfish said. “We went from 75 percent mortality to record production almost overnight.”
But this is only a short term fix.  If we keep pouring carbon dioxide into the biosphere, atmosphere and oceans, sea life is ultimately doomed.
“Human beings have a choice to make, and that choice is are we going to do something about this now, and preserve what we have, or are we just going to burn everything and see what happens,” Feely said. “That’s all our choice, and we have to collectively come to that decision.”
If that doesn’t happen, scientists like Feely and Alin worry that oyster larvae might just be the beginning — scientists at NOAA are beginning to look into how ocean acidification might impact other marine organisms, like pteropods, tiny marine butterflies that are the primary source of food for juvenile salmon during their first year. Preliminary studies have shown that increased acidity in ocean waters can literally eat away at a pteropod’s shell, endangering a critical part of the marine food web. Scientists like Alin are also trying to understand how ocean acidification interacts with things like algae blooms and dead zones, and whether acidification or temperature increase could ramp up the toxicity of potentially harmful blooms.