U.S. Water News Online
NEWPORT, Ore. -- His hand on a toggle switch and his eyes
on a computer screen, Oregon State University graduate student
Anthony Kirincich uses an array of scientific instruments to probe
the vibrant waters of the Pacific.
He is searching for the absence of life.
Standing next to him in the cramped cabin of the research vessel
Elakha, postdoctoral researcher Francis Chan processes water samples,
measuring oxygen and the microscopic plants that are the foundation
of the food chain.
Both are hunting for very low levels of oxygen, a sign of what
scientists call the Dead Zone. Researchers think the appearance of
such an area that cannot sustain life may be a sign of a fundamental
change in the Pacific.
"This is definitely a cat-and-mouse game," because the dead zone
keeps ebbing to and from the shore and changing characteristics, Chan
said. "It really takes us almost daily trips to really pinpoint the
Two years ago when local fishermen started hauling up pots filled
with dead crabs, scientists figured out that a huge mass of
sub-Arctic water with very low levels of oxygen and high levels of
nutrients had welled up from the ocean's depths and settled in for
the summer on the Continental Shelf off central Oregon.
The Dead Zone dissipated that fall, and based on 40 years of ocean
monitoring and local fishing lore, many thought they would never see
it again. This summer, the Dead Zone came back.
"What I think we are seeing is a tipping of the balance of the
ecosystem," said Jack Barth, a professor of oceanography at Oregon
State. "We don't fully understand what the cause of that is. We have
some good ideas that it is related to some fundamental changes in
circulation and the source of water for the Oregon Continental
There are more than 30 man-caused dead zones -- scientists call
them hypoxic or low-oxygen events -- around the world in enclosed
waters, including Hood Canal in Puget Sound, the Mississippi River
delta and Chesapeake Bay.
There, excess fertilizer from farm fields washing down rivers
fuels a surge in microscopic plants called phytoplankton. When they
die, bacteria decompose them, using up the oxygen in the water and
leaving fish, crabs and other sea life to suffocate.
Naturally caused dead zones in open water, like the one off
Oregon, are rare and less well understood. Others have been found off
the coasts of Peru and South Africa.
In this case, a mass of deep ocean water was transported south
from the sub-Arctic region by a shift in the California Current and
came to rest on the Continental Shelf. Already low in oxygen from
being deep in the ocean, it lost even more when abundant
phytoplankton died and decomposed.
Though Oregon's Dead Zone is relatively small, "It might be a
window into possibly important larger scale changes in the Pacific,"
said Jane Lubchenco, professor of marine biology at OSU.
Barth does not think it is related to El Nino, the ocean warming
that periodically hits the Pacific. It might, however, be related to
the Pacific Decadal Oscillation, a cyclic climate condition in the
northern Pacific that controls upwelling events. It is not behaving
as it has in the past -- scientists have noticed unusually warm water
and different wind patterns.
To understand it better, the 54-foot Elakha -- Chinook for sea
otter -- goes out several times a week. On this day, water samples
Chan process from near the surface showed low oxygen, but not Dead
But the readings on water temperature, dissolved oxygen, depth and
salinity coming from the instruments towed behind Elakha told a
different story. About five miles out, at a depth of about 150 feet,
the green line describing dissolved oxygen slid below the threshold
into the Dead Zone.
"This is one of the most productive parts of the coast," said
Chan. "There are deep water fish that do fine with even hypoxic
water. It's the shallow-water fish that we worry about."
The zone generally extends from Newport south to Florence, a
distance of about 50 miles. Elakha found it about five miles offshore
at a depth of about 150 feet. It lies on the bottom, about 120 feet
thick, and extends at least 10 miles out.
"Because we think it is potentially a long-term change, to be
absolutely certain we need many years of observations," Barth said of
the Dead Zone. "We are still at the fundamental research level, but
the impacts could be quite large."
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