by Rud Istvan
Is ocean acidification the new global warming?
A recent Climate Etc. post on the 2C target asked what might be next. The IPCC target is increasingly problematic, since lower climate sensitivity (the pause plus) means the world may come close without doing anything. The CAGW/IPCC apparatus will need other raisons d’etre. Extreme weather isn’t cooperating. Sea level rise is too slow. About the only direct CO2 emissions linkage left is ocean acidification. Expect an orchestrated crescendo of the usual stuff from the usual suspects about ‘the lesser known twin of climate change’ (to quote the Seattle Times). Following is a little overture.
Seattle loves oysters. Its most valuable is the Pacific oyster. The Seattle Times followed up earlier alarming oyster stories with 10/18/12 headlines:
Oysters in deep trouble: Is Pacific Ocean’s chemistry killing sea life? Oyster larvae have been dying by the billions. Scientists suspect it’s a sign that carbon dioxide is dramatically affecting the ocean — and if they’re right, it could push Washington into the center of the debate about the future of the seas.
This was the latest in a series of articles about Pacific oyster problems in Washington’s commercial shellfish industry. The reporting is based on peer reviewed research by NOAA’s Pacific Marine Environmental Lab (PMEL) and Northwest Fisheries Science Center (NFSC), partly joint with OSU. These NOAA labs are using federal dollars to broadcast their alarm: An Upwelling Crisis: Ocean Acidification.
Of course this was picked up by other MSM, eventually including Yahoo News and NBC News. A ‘quality’ example is Maria Dolan’s 2/18/2013 Slate headline:
ARE OYSTERS DOOMED? Don’t believe in climate change? Talk to a clam digger.
Seattle’s Center for Biological Diversity announced on 7/23/13 that it was suing the EPA for failing to curb CO2 emissions in order to halt Pacific acidification:
Lawsuit Launched Targeting Large-scale Oyster Deaths in Oregon, Washington Driven by Ocean Acidification
The Center may be well intentioned, but has a few things to learn about futility. The EPA may try to affect U.S. CO2 emissions, but it won’t China’s.
There are certainly AGW related ocean facts beyond reasonable scientific doubt. Henry’s law requires that the partial pressures of atmospheric and dissolved ocean CO2 equilibrate. Increasing dissolved CO2 lowers pH by increasing carbonic acid. NOAA PMEL has documented this in the central Pacific off Mauna Loa. Station Aloha surface pH has declined from 8.12 to 8.08 since 1991 as dissolved pCO2 increased from about 325 to 360μatm, while atmospheric CO2 increased from about 350 to 395 ppm. That is Δ0.04 pH in 20 years. Caution is due about simple linear extrapolation. This is just a portion of a PDO cycle, and ocean pH is not a linear system driven only by Henry’s law.
Ocean pH is not uniform. It varies diurnally and seasonally with ecosystem biorhythms. At the deep ocean PMEL site north of tropical Hawaii, seasonal surface variation is only Δ0.1 pH because that ocean is relatively ‘barren’. Southern ocean surface seasonality is Δ0.5 pH. Seasonal variation is as high as Δ1.43 pH depending on where in the Pacific its 8 general ecosystems are evaluated.
How marine organisms do under experimental aquarium conditions of significantly increased CO2 (with food, light, and temperature held constant) depends on species. Crustaceans, temperate urchins, calcifying (coralline) algae, limpets, and mussels do well. Oysters, conch, bay scallops, and some tropical corals do not. Aquariums probably do not reflect the important interplay of other ecosystem factors affecting these creatures. As an example, Florida Bay conchs thrive amidst complex interactions between season and salinity that drive extreme pH swings. The Everglades mangrove fringe has winter pH 5.8, while out toward Key West (the ‘Conch Republic’) pH peaks as high as 9.8 during sunny summer days with elevated (from evaporation) salinity.[i] The extreme alkalinity comes from Thallassia sea grass photosynthesis consuming dissolved CO2, plus high salinity (>50ppt) driven calcium carbonate precipitation above pH 8.3. There is a lot of uncertainty about, and potential resilience in, marine biodiversity. Together with pH buffering mechanisms and other possible CO2 driven processes, the oceans will adapt naturally to some inevitable acidification.
The Pacific oyster, the Miyagi, is an estuarine species from Japan where it has been cultivated for hundreds of years. It thrives from tidal flats to depths of about 40 meters. It is now grown all over the world since it is fecund, fast growing, and environmentally tolerant of large temperature and salinity swings. One 100g oyster can produce 80 million eggs in a single spawn, and will spawn every year when the water warms sufficiently (over 20°C). (BTW, for the MSM this means anyone eating a dozen oysters destroys at least a billion spawn.) It is the most valuable commercial oyster, introduced to Washington around 1920.
In 2005, the natural Pacific oyster spawn failed at Willapa Bay in Washington. The problem was traced to a bacterial infection (Vibrio tubiashii) that is particularly virulent to Pacific oyster larvae. It failed again in 2006, and 2007, and 2008. The solution was to put out artificially spawned spat from (among others) the Whiskey Creek Hatchery (WCH) on Netarts Bay in northern Oregon. There, brood oysters are cultivated at 18°C. They are induced to spawn by raising water temperature to 22°C, with the ensuing eggs and larvae held at 25°C until the spat sets. In 2008, 80% of the WCH spawn failed to set spat. This was quickly traced to V. tubiashii infection; concentrations were 100 times normal. So WCH installed expensive ultraviolet sanitizing systems on its seawater intakes. But in 2009 a portion of the spawn still failed. WCH noticed those failures were associated with intake of seasonal upwelling seawater. Subsequent experiments showed this lower pH seawater was the new culprit at WCH. NOAA PMEL was quoted in a Seattle Times ocean acidification story on 4/11/12 about the new OSU/PMEL paper concerning near term ocean acidification alarm: “This is the smoking gun for oyster larvae”
This is climate change smoke and mirrors, not an ocean acidification smoking gun. The situation is contrived and the facts are misrepresented. Lets put the foregoing information together again in a way that removes the smoke.
Pacific oysters are estuarine. NOAA’s ocean education website explains why estuary pH is always seasonally variable. In the warmer months, heighted phytoplankton, algal, and sea grass photosynthesis consumes CO2, producing bottom food chain food (e.g. for oysters) and raising pH just like in Florida Bay. The Fraser River estuary north of Seattle at Vancouver BC annual pH variation is 7.3 to 8.3.[ii] The famous Elkhorn Slough on Monterey Bay in northern California variation is 7.4 to 8.4.[iii] Estuarine oysters naturally spawn when pH is elevated during the warm water months when food is plentiful for larvae and spat.
Netarts Bay is not estuarine. Most of its annual pH variation from 7.7 to 8.2 comes from seasonal upwelling rather than biological activity. NOAA provides the simple explanation. Seasonal shoreline winds create Ekman transport currents that cause coastal upwelling, something known since 1902.
Temperature contrasts between normal surface water and upwelling water are large (≈8°C), and monitored by NASA satellites.
Upwelling water from below the euphotic (light penetrating photosynthetic) zone (100-200 meters depth depending on location and season) is nutrient rich. This causes phytoplankton to bloom, in turn providing a banquet for the entire food chain. NASA satellites can see the chlorophyll increase using natural as well as enhanced imaging. The sea literally becomes greener and more turbid.
Seasonal upwelling is crucial for the sardine, salmon, Dungeness crab, and tuna fisheries, which is why it is studied by NFSC and PMEL.
Water below the euphotic zone has naturally lower pH than surface water. Again, the reasons are simple. Henry’s law is temperature dependent; colder water holds more CO2. More important, the ‘rain’ of organic detritus from the euphotic zone begins decomposing, which lowers pH (the Great Dismal Swamp’s seasonal pH 3.5-4.0 is a more extreme terrestrial example). This biological ‘recycling’ enriches the water with nutrients. Upwelling surface pH is lower than ‘normal’ until phytoplankton raise it by photosynthesizing dissolved CO2 and nutrients back into marine food. PMEL’s sampled California/Oregon border pH profile shows natural upwelling changes surface water pH from 8.1 to 7.7.
Coastal fisheries thrive. Pacific oyster larvae at WCH don’t. By now, the reason should be obvious. The hatchery was taking in ‘winter’ pH water, then warming it to ‘summer’ temperatures to induce artificial spawn without also raising it to estuarine summer pH. Of course the spawn failed to set spat even through brood oysters were unaffected. The WCH problem has nothing to do with ocean acidification. Neither does naturally upwelling ΔpH 0.4 compared to possible AGW acidification ΔpH 0.04—despite official NOAA ‘Upwelling crisis: ocean acidification’ PR. Pacific oyster spawning depends on estuarine seasonal pH. WCH must be managed like an estuary where these oysters naturally live.
So what was the real purpose of the highly touted peer-reviewed research that, instead of merely confirming centuries old biology, goes on extensively about alarming implications for near term ocean acidification?
The study authors from Oregon State University and NOAA PMEL and NFSC knew or should have known the WCH problem was just Oysters 101. It has nothing to do with near term ocean acidification, unlike their study title, MSM quotes, and their US government websites. The Seattle Times could have figured WCH out with an hour of Oysters 101 research, rather than amplifying a misleading message that Feely has been promoting since 2008.
The shell game is an ancient street confidence game. It is portrayed in medieval paintings. It spawned the aphorism “watch the pea”. ‘Shell men’ never worry about which of three shells hides the pea, because they palmed it. Here, the pea is estuarine pH biorhythm. ‘Shell men’ often use accomplices as shills to goose betting on which shell the pea is under; here the Seattle Times and NOAA shill. The betting here concerns a misled public demanding that PMEL and OSU get more research funding.
The pea was palmed in this climate change version of the shell game.
[i] NOAA/National Park Service Joint Report: NOAA Technical Memorandum NOS NCCOS CCMA154, same as NPS Special Report 01-02. Page 64.
[ii] Canadian Council of Ministries of the Environment, Marine pH water quality guidelines (1999). Page 1
[iii] Hofmann et. al., High-frequency dynamics of ocean pH: a multi ecosystem comparison, PLoS One 6: e28983 (2011). Table 2
JC note: This guest post was submitted via email, in response to my request in the comments for something on ocean acidification. As with all guest posts, please keep your comments relevant and civil.