this is some serious stuff, folks, and not getting the attention it warrants!
one of the first major casualties of ocean acidification will be salmon, as the pteropodss that young salmon rely on are one of the first trophic levels to crash....
FOR IMMEDIATE RELEASE
Aug. 11, 2009
most productive in the world may also make them the most vulnerable to ocean
acidification. According to new findings by a University of Alaska Fairbanks
scientist, Alaska¹s oceans are becoming increasingly acidic, which could
damage Alaska¹s king crab and salmon fisheries.
This spring, chemical oceanographer Jeremy Mathis returned from a cruise
armed with seawater samples collected from the depths of the Gulf of Alaska.
When he tested the samples¹ acidity in his lab, the results were more acidic
than expected. They show that ocean acidification is likely more severe and
is happening more rapidly in Alaska than in tropical waters. The results
also matched his recent findings in the Chukchi and Bering Seas.
³It seems like everywhere we look in Alaska¹s coastal oceans, we see signs
of increased ocean acidification,² said Mathis.
Often referred to as the ³sister problem to climate change,² ocean
acidification is a term to describe increasing acidity in the world¹s
oceans. The ocean absorbs carbon dioxide from the air. As the ocean absorbs
more carbon dioxide, seawater becomes more acidic. Scientists estimate that
the ocean is 25 percent more acidic today than it was 300 years ago.
³The increasing acidification of Alaska waters could have a destructive
effect on all of our commercial fisheries. This is a problem that we have to
think about in terms of the next decade instead of the next century,² said
The ocean contains minerals that organisms like oysters and crabs use to
build their shells. Ocean acidification makes it more difficult to build
shells, and in some cases the water can become acidic enough to break down
existing shells. Mathis¹ recent research in the Gulf of Alaska uncovered
multiple sites where the concentrations of shell-building minerals were so
low that shellfish and other organisms in the region would be unable to
build strong shells.
³We¹re not saying that crab shells are going to start dissolving, but these
organisms have adapted their physiology to a certain range of acidity. Early
results have shown that when some species of crabs and fish are exposed to
more acidic water, certain stress hormones increase and their metabolism
slows down. If they are spending energy responding to acidity changes, then
that energy is diverted away from growth, foraging and reproduction,² said
Another organism that could be affected by ocean acidification is the tiny
pteropod, also known as a sea butterfly or swimming sea snail. The pteropod
is at the base of the food chain and makes up nearly half of the pink
salmon¹s diet. A 10 percent decrease in the population of pteropods could
mean a 20 percent decrease in an adult salmon¹s body weight.
³This is a case where we see ocean acidification having an indirect effect
on a commercially viable species by reducing its food supply,² said Mathis.
The cold waters and broad, shallow continental shelves around Alaska¹s coast
could be accelerating the process of ocean acidification in the North,
Mathis said. Cold water can hold more gas than warmer water, which means
that the frigid waters off Alaska¹s coasts can absorb more carbon dioxide.
The shallow waters of Alaska¹s continental shelves also retain more carbon
dioxide because there is less mixing of seawater from deeper ocean waters.
Ask any coastal Alaskan and they will tell you that Alaska¹s waters are
teeming with biological life, from tiny plankton to humpback whales. All of
these animals use oxygen and emit carbon dioxide. Mathis and other
scientists call this the ³biological pump.²
³We are blessed with highly productive coastal areas that support vast
commercial fisheries, but this productivity acts like a pump, absorbing more
and more carbon dioxide from the atmosphere,² said Mathis. ³Because of this,
the acidity of Alaska¹s coastal seas will continue to increase, and likely
accelerate, over the next decade.²
Mathis said that it is still unclear what the full range of effects of ocean
acidification will be, but that it is a clear threat to Alaska¹s commercial
fisheries and subsistence communities.
³We need to give our policy makers and industry managers information and
forecasts on ocean acidification in Alaska so they can make decisions that
will keep our fisheries viable,² said Mathis. ³Ecosystems in Alaska are
going to take a hit from ocean acidification. Right now, we don¹t know how
they are going to respond.²
CONTACT: Carin Stephens, public information officer, at 907-322-8730, or via
e-mail at firstname.lastname@example.org. Jeremy Mathis, assistant professor of
oceanography, at 907-474-5926, or via e-mail at email@example.com.
ON THE WEB: www.sfos.uaf.edu/oa