Mysterious Changes
Hit Pacific Coast
'The Bottom Has Fallen
Out
Of The Coastal Food Chain'
The Globe and Mail
8-2-5
SAN
FRANCISCO (AP) -- Marine biologists are seeing mysterious and disturbing things
along the Pacific Coast this year: higher water temperatures, plummeting catches
of fish, lots of dead birds on the beaches, and perhaps most worrisome, very little
plankton -- the tiny organisms that are a vital link in the ocean food chain.
Is this just one freak year? Or is this global warming?
Very few scientists
are willing to blame global warming, the theory that carbon dioxide and other
manmade emissions are trapping heat in the Earth's atmosphere and causing a worldwide
rise in temperatures. Yet few are willing to rule it out.
"There
are strange things happening, but we don't really understand how all the pieces
fit together," said Jane Lubchenco, a zoologist and climate change expert
at Oregon State University. "It's hard to say whether any single event is
just an anomaly or a real indication of something serious happening."
Scientists say things could very well swing back to normal next year. But
if the phenomenon proves to be long-lasting, the consequences could be serious
for birds, fish and other wildlife.
This much is known: From California
to British Columbia, unusual weather patterns have disrupted the marine ecosystem.
Normally, in the spring and summer, winds blow south along the Pacific Coast
and push warmer surface waters away from shore. That allows colder, nutrient-rich
water to well up from the bottom of the sea and feed microscopic plants called
phytoplankton.
Phytoplankton are then eaten by zooplankton, tiny marine
animals that include shrimp-like crustaceans called krill. Zooplankton, in turn,
are eaten by seabirds and by fish and marine mammals ranging from sardines to
whales.
But this year, the winds have been unusually weak, failing to
generate much upwelling and reducing the amount of phytoplankton.
Off
Oregon, for example, the waters near the shore are 5 to 7 degrees warmer than
normal and have yielded about one-fourth the usual amount of phytoplankton, said
Bill Peterson, an oceanographer with the National Oceanic and Atmospheric Administration
in Newport, Ore.
"The bottom has fallen out of the coastal food chain,
and there's just not enough food out there," said Julia Parrish, a seabird
ecologist at the University of Washington in Seattle.
Seabirds are clearly
distressed. On the Farallon Islands west of San Francisco, researchers this spring
noted a steep decrease in nesting cormorants and a 90 per cent drop in Cassin's
auklets -- the worst in more than 35 years of monitoring.
On Washington
state's Tatoosh Island, common murres -- a species so sensitive to disruptions
that scientists consider it a harbinger of ecological change -- started breeding
nearly a month late. It was the longest delay in 15 years of monitoring.
Researchers
have also reported a sharp increase in dead birds washing up in California, Oregon
and Washington.
Along Monterey Bay in Central California, there are four
times the usual number of dead seabirds, said Hannah Nevins, a scientist at Moss
Landing Marine Laboratories.
"Basically, they're not finding enough
food, and they use up the energy that's stored in their muscles, liver and body
fat," Dr. Nevins said.
Fish appear to be feeling the effects, too.
NOAA found a 20 per cent to 30 per cent drop in juvenile salmon off the coasts
of Oregon, Washington and British Columbia in June and July, compared with the
average over the previous six years.
And researchers counted the lowest
number of juvenile rockfish in more than 20 years of monitoring in Central and
Northern California. Fewer than 100 were caught between San Luis Obispo and Fort
Bragg this year, compared with several thousand last year.
Scientists
have seen some of these strange happenings before during El Nino years, when higher
water surface temperatures in the equatorial Pacific alter weather patterns worldwide.
But the West Coast has not had El Nino conditions this year.
As for the
possibility that this is being caused by global warming, scientists are not so
sure, since climate change is believed to be a gradual process, and what is happening
this year is relatively sudden.
But "if we did see this next year,
the notion that global warming plays a role in this carries more weight,"
said Nathan Mantua, a climate expert at the University of Washington in Seattle.
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