[Vision2020] Scientists Find Rising Carbon Dioxide and ‘Acidified’ Waters in Puget Sound

[Ted Moffett]

http://www.noaanews.noaa.gov/stories2010/20100712_pugetsound.html
 Scientists Find Rising Carbon Dioxide and ‘Acidified’ Waters in Puget Sound

July 12, 2010

Scientists have discovered that the water chemistry in the Hood Canal and
the Puget Sound main basin is becoming more “acidified,” or corrosive, as
the ocean absorbs more carbon dioxide from the atmosphere. These changes
could have considerable impacts on the region’s shellfish industry over the
next several decades.

The study, co-sponsored by NOAA, the University of Washington Applied
Physics Laboratory and School of Oceanography (UW), the Washington State
Department of Ecology and the U.S. Environmental Protection Agency, was
conducted in the winter and summer of 2008 to determine the combined effects
of ocean acidification and other natural and human-contributed processes on
Puget Sound waters. Annual survey support is typically provided by UW’s
Puget Sound Regional Synthesis Model Program (PRISM), while EPA provided the
ocean survey vessel *Bold* for the summer survey.

“We observed unusually low pH values in the deep waters of southern Hood
Canal,” said Richard Feely, Ph.D., director of the Ocean Acidification
Program at NOAA’s Pacific Marine Environmental Laboratory. “Our calculations
suggest that ocean acidification can account for a significant part of the
pH decrease in this region.”

“This is the first time that the combined impacts of ocean acidification and
other natural and human-induced processes have been studied in a large
estuary like Puget Sound,” says Jan Newton, Ph.D., University of Washington
co-author on the study and chief scientist for the winter cruise. “We are
concerned that ocean acidification may be contributing to the recent loss of
oyster larvae reported by oyster hatcheries in the Pacific Northwest
including within Puget Sound.”

The research team estimated that ocean acidification accounts for 24–49
percent of the pH decrease in the deep waters of the Hood Canal sub-basin of
Puget Sound relative to estimated pre-industrial (before 1850) values. The
remaining change in pH between when seawater enters the Sound and when it
reaches this deep basin results from the decomposition of organic matter.

Over time, the relative impact of ocean acidification could increase
significantly, accounting for 49–82 percent of the pH decrease in Puget
Sound subsurface waters (depths greater than 40 meters) for a doubling of
atmospheric carbon dioxide, according to the study.

To better understand the effects of ocean acidification on shellfish within
Puget Sound, the Puget Sound Partnership, with funds from EPA, has partnered
with the Puget Sound Restoration Fund to support UW, NOAA, Pacific Shellfish
Institute, Washington Department of Ecology, Taylor Shellfish and Baywater,
Inc., to conduct collaborative studies investigating whether or not
corrosive seawater is affecting shellfish populations.

The work monitors both water conditions and shellfish larvae, providing
high-resolution oceanographic data along with measurements on ocean
acidification and larval settlement from two locations where shellfish are
growing, Dabob Bay and Totten Inlet.

As part of this study, UW moved one of the existing Oceanic Remote
Chemical-optical Analyzer (ORCA) marine monitoring buoys from Hood Canal to
Dabob Bay and added surface water carbon dioxide measurements with a NOAA
sensor to the existing suite of measurements.

“We simply need more data near the shellfish growing sites in order to
evaluate causal relationships,” said Allan Devol, Ph.D., UW, an
oceanographer and the designer of the ORCA buoy.

The findings, which are online now, are scheduled to appear in the August
issue of *Estuarine, Coastal, and Shelf Science*.

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

Vision2020 Post: Ted Moffett
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mailman.fsr.com/pipermail/vision2020/attachments/20100714/126de98d/attachment-0001.html