The latest from the group of researchers studying ocean acidification is out–Craig Welch wrote a good article for the Seattle Times on this subject the other day. I’ve previously discussed work done in Hood Canal by this same group of researchers, but this current paper is the first work to directly link oyster larval mortality to low pH ocean waters.
In a very brief nutshell (or oyster shell, if you will), increasing CO2 concentrations in the atmosphere lead to an increase in dissolved CO2 in ocean water–as the amount of CO2 increases in ocean water, that carbon dioxide forms carbonic acid in those waters, and carbonic acid reduces the amount of available carbonate (CO3) ions in those ocean waters. This is important because carbonate ions are the building blocks of things like oyster shells–when you strip away all the thermodynamics and aquatic chemistry, what this all comes down to is that increasing CO2 levels in the atmosphere make it much harder (or impossible) for organisms with carbonate-based shells or skeletons to build those shells or skeletons. A more detailed description of the chemistry involved is available over at Crosscut, penned by Eric Scigliano.
This latest work by Alan Barton, Burke Hales, George Waldbusser, Chris Langdon and Richard Feely demonstrates how the ocean acidification dynamic is impacting the oyster hatchery at Whiskey Creek in Netarts Bay, Oregon. The researchers did a nice job of compiling existing data the hatchery had been collecting and analyzing that data.
I’m a big fan of these types of creative, real-world studies, and this new paper is a good read for science geeks. What they demonstrated is a correlation between oyster larvae mortality and upwelling events that brought lower pH waters to the surface along the Oregon coast. One of the interesting parts of this correlation is that oyster larvae would still start growing once spawning was complete and up to about 120 micrometers in size, but larvae spawned in low pH conditions would take longer to grow from 120 to 150 micrometers in size. Also, lower pH waters were correlated with less production of oyster larvae at the hatchery. The paper also details how the hatchery has adapted to these conditions by modifying its operations in creative ways (drawing water in at different times of the day, and paying attention to upwelling conditions).
The reality is that such adaptations are probably the only way to respond on a local or regional scale to this issue. As I detailed earlier, the low pH issue in Hood Canal seems to be partially attributed to local inputs of nutrients, but those inputs are from sources that are hard to control. Carbon emissions are a global issue, and even with reductions in carbon emissions now, there will be a significant lag in atmospheric and oceanic responses. The shellfish industry may be a relatively low-profile industry because it operates in rural areas, but it nonetheless is important to the west coast’s economy, generating more than $200 million a year in the form of jobs and revenue.
Washington has been gearing up its regulatory and policy response to this issue, partnering with federal agencies in an intitative aimed at growing Washington’s shellfish industry. Part of that initiative’s efforts is a task force looking specifically at this ocean acidification issue. From a science and policy standpoint, these efforts are a great example of how you can bring together academia, government, and industry to address emerging issues that threaten jobs and economic growth in very real ways. The task force will meet over the course of the next few months, and I’ll try and attend those meetings and report back here on their progress.