[Vision2020] April 2012: "The Pacific oyster, Crassostrea gigas: Negative Correlation to Elevated CO2 levels: Implications for Ocean Acidification"

[Ted Moffett]

The dramatic decline in the Arctic, and impacts of ocean acidification (as
the following just published peer reviewed science paper described lower
down, as named in subject heading, indicates), are but two among many
impacts (increasing floods, fires, drought and eventually faster rate of
sea level rise and species extinction) of human sourced CO2 emissions and
other human activities, that will only increase in magnitude if we as a
species do not profoundly alter course in a matter of decades.

Consider that the impacts we are already witnessing are with only about 40%
of the way towards a doubling of atmospheric CO2 level, from about 280 ppm
pre-industrial to the current level measured at the Mauna Loa site, (
http://www.esrl.noaa.gov/gmd/ccgg/trends/  ) 394 ppm, which shows about at
2 ppm increase in the past year.  At this rate, in 83 years, before the end
of this century, humanity will have pushed atmospheric CO2 to about a
doubling over pre-industrial levels, to 560 ppm, and another doubling will
be underway.  The total planetary reserves of fossil fuels will allow us to
go beyond the first doubling of atmospheric CO2 level.

Global average temperatures have increased about .8 C in the GISS
temperature record,
(  http://data.giss.nasa.gov/gistemp/2011/Fig2.gif ) and if this rate of
temperature increase follows the rate of potential atmospheric CO2 increase
in a business as usual scenario, we will reach over 2 C. increase in global
average temperatures by 2100, a level that many climate scientists think
will result in unmanageable global impacts, "tipping points", as they say,
such as meters of sea level rise from Greenland destabilization.  And of
course, with increasing industrialization and demand for energy, it is very
possible that human fossil fuel use and CO2 emissions will increase, thus
rates of atmospheric CO2 increase will increase, especially if carbon sink
reversal increases in magnitude.  Thus it is also within the range of
significant scientific probability that global average temperature increase
will increase in rate, especially given significant positive feedbacks,
reduced albedo from loss of ice cover, especially in the Arctic, among them.

Good luck, kids!  At 60 now, I certainly won't be around in 2100, without
medical breakthroughs.  But some born today will, who will be about 88 in
2100.

But what I find astonishing is the shrug I have witnesses from the well
educated in their middle years (30-50) who are well aware that climate
change is happening, who state that it "won't impact them," but will impact
the next generation.  Wrong!  Climate change is already impacting us,
and in a matter of decades the impacts will significantly increase, so even
for someone 60, let alone 30-50, if they live to 90, not so
incredible, even they will witness increases in impacts, by 2042.
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http://www.aslo.org/lo/toc/vol_57/issue_3/0698.html

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

ABSTRACT: We report results from an oyster hatchery on the Oregon coast,
where intake waters experienced variable carbonate chemistry (aragonite
saturation state < 0.8 to > 3.2; pH < 7.6 to > 8.2) in the early summer of
2009. Both larval production and midstage growth (∼ 120 to ∼ 150 µm) of the
oyster *Crassostrea gigas* were significantly negatively correlated with
the aragonite saturation state of waters in which larval oysters were
spawned and reared for the first 48 h of life. The effects of the initial
spawning conditions did not have a significant effect on early-stage growth
(growth from D-hinge stage to ∼ 120 µm), suggesting a delayed effect of
water chemistry on larval development.

--------------------------------------------

http://www.sciencedaily.com/releases/2012/04/120411132219.htm?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+sciencedaily+%28ScienceDaily%3A+Latest+Science+News%29
Ocean Acidification Linked to Larval Oyster Failure

ScienceDaily (Apr. 11, 2012) — Researchers at Oregon State University have
definitively linked an increase in ocean acidification to the collapse of
oyster seed production at a commercial oyster hatchery in Oregon, where
larval growth had declined to a level considered by the owners to be
"non-economically viable."

A study by the researchers found that elevated seawater carbon dioxide (CO2)
levels, resulting in more corrosive ocean water, inhibited the larval
oysters from developing their shells and growing at a pace that would make
commercial production cost-effective. As atmospheric CO2 levels continue to
rise, this may serve as the proverbial canary in the coal mine for other
ocean acidification impacts on shellfish, the scientists say.

Results of the research have just been published in the journal, *Limnology
and Oceanography.*

"This is one of the first times that we have been able to show how ocean
acidification affects oyster larval development at a critical life stage,"
said Burke Hales, an OSU chemical oceanographer and co-author on the study.
"The predicted rise of atmospheric CO2 in the next two to three decades may
push oyster larval growth past the break-even point in terms of production."

The owners of Whiskey Creek Shellfish Hatchery at Oregon's Netarts Bay
began experiencing a decline in oyster seed production several years ago,
and looked at potential causes including low oxygen and pathogenic
bacteria. Alan Barton, who works at the hatchery and is an author on the
journal article, was able to eliminate those potential causes and shifted
his focus to acidification.

Barton sent samples to OSU and the National Oceanic and Atmospheric
Administration's Pacific Marine Environmental Laboratory for analysis.
Their ensuing study clearly linked the production failures to the
CO2levels in the water in which the larval oysters are spawned and
spend the
first 24 hours of their lives, the critical time when they develop from
fertilized eggs to swimming larvae, and build their initial shells.

"The early growth stage for oysters is particularly sensitive to the
carbonate chemistry of the water," said George Waldbusser, a benthic
ecologist in OSU's College of Earth, Ocean, and Atmospheric Sciences. "As
the water becomes more acidified, it affects the formation of calcium
carbonate, the mineral of which the shell material consists. As the
CO2goes up, the mineral stability goes down, ultimately leading to
reduced
growth or mortality."

Commercial oyster production on the West Coast of North America generates
more than $100 million in gross sales annually, generating economic
activity of some $273 million. The industry has depended since the 1970s on
oyster hatcheries for a steady supply of the seed used by growers. From
2007 to 2010, major hatcheries supplying the seed for West Coast oyster
growers suffered persistent production failures.

The wild stocks of non-hatchery oysters simultaneously showed low
recruitment, putting additional strain on limited seed supply.

Hales said Netarts Bay, where the Whiskey Creek hatchery is located,
experiences a wide range of chemistry fluctuations. The OSU researchers say
hatchery operators may be able to adapt their operations to take advantage
of periods when water quality is at its highest.

"In addition to the impact of seasonal upwelling, the water chemistry
changes with the tidal cycle, and with the time of day," Hales said.
"Afternoon sunlight, for example, promotes photosynthesis in the bay and
that production can absorb some of the carbon dioxide and lower the
corrosiveness of the water."

A previous study co-authored by Hales found the water that is being
upwelled in the Pacific Ocean off the Oregon coast has been kept at depth
away from the surface for about 50 years -- meaning it was last exposed to
the atmosphere a half-century ago, when carbon dioxide levels were much
lower. "Since atmospheric CO2 levels have risen significantly in the past
half-century, it means that the water that will be upwelled in the future
will become increasingly be more corrosive," Hales said.

The OSU researchers also found that larval oysters showed delayed response
to the water chemistry, which may cast new light on other experiments
looking at the impacts of acidification on shellfish. In their study, they
found that larval oysters raised in water that was acidic, but non-lethal,
had significantly less growth in later stages of their life.

"The takeaway message here is that the response to poor water quality isn't
always immediate," said Waldbusser. "In some cases, it took until three
weeks after fertilization for the impact from the acidic water to become
apparent. Short-term experiments of just a few days may not detect the
damage."

The research has been funded by a grant from the National Science
Foundation, and supported by NOAA and the Pacific Coast Shellfish Growers
Association. Other authors on the journal article include Chris Langdon, of
OSU's Hatfield Marine Science Center, and Richard Feely, of NOAA's Pacific
Marine Environmental Laboratories.

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Vision2020 Post: Ted Moffett
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