Federal and university scientists engaged in an ocean
acidification study hope to learn by autumn how much impact glacial melt water
is having on the saturation state of carbonate minerals in Alaska’s Prince
William Sound.
“If the saturation state becomes too low, the waters can
become corrosive to shell building organisms,” said Jeremy Mathis, an
oceanographer at NOAA’s Pacific Marine Environmental Laboratory.
Mathis, who is also an affiliate professor at the Institute
of Marine Science, at the University of Alaska Fairbanks, said greater efforts
are needed to slow the release of carbon dioxide into the atmosphere. The glacier
melt itself has some unique chemistry that exacerbates ocean acidification, he
said.
“We need to
understand how the water chemistry is changing in the sound,” Mathis said in an
interview on July 8. “That will provide a foundation for understanding the impact
of ocean acidification on the fisheries in Prince William Sound.”
Meanwhile scientists are thinking about what can be done in
the way of mitigation efforts and strategies, so if they see a decline in
fisheries they can respond, and have some adaptive capabilities in these
fisheries resources.
“The glacial melt
water entering the sound has low concentrations of carbonate ion, which marine
organisms need to build shells and skeletons,” Mathis said. “When increasing amounts of this freshwater
enter the sound, it makes surface water less hospitable for animals that build
shells.”
To learn more, scientists from the Pacific Marine
Environmental Laboratory, the University of Alaska and the Alaska Ocean
Observing System earlier this spring launched two Carbon Wave Gliders and a
Slocum underwater glider into the Gulf of Alaska to collect data for five
months.
The Carbon Wave Gliders, which look and act like
remotely-controlled surfboards, ride at the surface of the ocean, collecting
data on water temperature, salinity, pH, dissolved oxygen and carbon dioxide in
water and air.
The Slocum glider, which resembles a torpedo, and was
conceived by Douglas C. Webb, tracks ocean data down to 200 meters. It travels from a near shore ocean
acidification buoy across the continental shelf and back. Scientists pilot the
Slocum from the federal lab as well. It
provides data showing the downstream effects of melting glaciers and how
freshwater changes the chemistry of the water column.
This is the first time that these types of glides have been
used in the cold waters of Alaska, NOAA officials said.
“Understanding these unique processes will help us determine
which species are at risk, not just in Prince William Sound, but up and down
the coast of the Gulf of Alaska,” Mathis said. “This information can help
Alaskan communities better prepare for and adapt to ecosystem changes that may
affect important fisheries.”
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