Cycle of life in ocean spinning into extremes
Models suggest climate change is causing strange disruptions among organisms off the coast
Sunday, July 02, 2006
MICHAEL MILSTEIN
The Oregonian http://www.oregonlive.com/news/oregonian/index.ssf?/base/news/1151733444141130.xml
The ocean is behaving strangely along the west coast in the latest of a string of unusual years, with scientists reporting crashing bird populations off California for the second consecutive year and hiccups in the nutrients that feed marine life off Oregon.
It has researchers wondering more openly whether global warming is driving unpredictable shifts with repercussions for familiar species such as seabirds and salmon.
"The evidence is accumulating that climate change is likely disrupting the atmospheric and oceanic processes that drive our ocean system," said Jane Lubchenco, a professor of marine biology at Oregon State University.
Although the ocean's behavior is always changing, "we're seeing more variability in some new and bizarre ways," she said.
Usually summer along the west coast brings a shift in wind patterns where breezes begin blowing from the north. The winds push water offshore, making way for cold water rich in nutrients to well up, conveyor-like, from the deep ocean.
The nutrients carried by the upwelling of deep water are an essential ingredient in the rich marine life along the Oregon Coast. They nurture tiny plants known as phytoplankton, which in turn feed a chain of sea life including salmon and other fish, whales and seabirds.
Upwelling usually shows up first along California by April, said Frank Schwing, director of the Environmental Research Division of the federal Southwest Fisheries Science Center in Pacific Grove, Calif. But it has not happened this year.
"There's just not enough feeding the food chain," he said.
Many seabirds that usually nest in great numbers on the Farallon Islands near San Francisco abandoned their nests, probably because they could not find enough food, said Jesse Irwin, a biologist at Farallon National Wildlife Refuge.
It's not as grim in Oregon. Winds began bringing nutrients up from the deep ocean about the end of April, said Bill Peterson, an oceanographer at the Northwest Fisheries Science Center in Newport.
But the winds died out for two to three weeks in late May, interrupting the flow, he said. That has set back phytoplankton growth, which remains below normal.
So far, though, it's not as bad in Oregon as it was last year.
Upwelling came roughly two months late last year to most of the west coast, especially Oregon, leaving waters starved of nutrients, plankton scarce and many other species starving. Seabirds washed up dead on beaches in record numbers with nothing in their stomachs and some salmon nearly disappeared from coastal waters.
But when the upwelling finally arrived last year, it did so with a vengeance.
Plankton multiplied so rapidly it died off and sucked oxygen from the water as it decayed, creating an eerie "dead zone" off the coast that further stressed sea life, Lubchenco said.
"We went from no upwelling to very intense upwelling," she said.
Similar dead zones appeared in 2002 and 2004.
The striking shifts match what climate models suggest will happen as greenhouse gases accumulate in the atmosphere, causing global warming, researchers said. For instance, some models suggest that coastal upwelling will begin later each year, Schwing said.
"Certainly there's consistency there that's intriguing," he said.
Research also suggests warming will lead to the kind of unpredictable and extreme swings in conditions the Oregon coast has seen in the last few years, Lubchenco said.
"We're just seeing much greater variability in ways that have consequences at least for some important species," she said. "We have to build into our management of the ecosystem the expectation it's going to be more variable. We need to expect some surprises."
Biologists at national wildlife refuges along the Oregon coast do not have the staff to track the nesting success of birds, so they're not yet sure how Oregon populations have done this year, said Roy Lowe, manager of the refuges.
Few starved seabirds have washed up on beaches so far. But last year they did not begin turning up in large numbers until July.
He said Oregon bird populations need a few productive years to help recover from declines they suffered last year.
Michael Milstein: 503-294-7689; michaelmilstein@news.oregonian.com
©2006 The Oregonian
Informant: binstock
Sunday, July 02, 2006
MICHAEL MILSTEIN
The Oregonian http://www.oregonlive.com/news/oregonian/index.ssf?/base/news/1151733444141130.xml
The ocean is behaving strangely along the west coast in the latest of a string of unusual years, with scientists reporting crashing bird populations off California for the second consecutive year and hiccups in the nutrients that feed marine life off Oregon.
It has researchers wondering more openly whether global warming is driving unpredictable shifts with repercussions for familiar species such as seabirds and salmon.
"The evidence is accumulating that climate change is likely disrupting the atmospheric and oceanic processes that drive our ocean system," said Jane Lubchenco, a professor of marine biology at Oregon State University.
Although the ocean's behavior is always changing, "we're seeing more variability in some new and bizarre ways," she said.
Usually summer along the west coast brings a shift in wind patterns where breezes begin blowing from the north. The winds push water offshore, making way for cold water rich in nutrients to well up, conveyor-like, from the deep ocean.
The nutrients carried by the upwelling of deep water are an essential ingredient in the rich marine life along the Oregon Coast. They nurture tiny plants known as phytoplankton, which in turn feed a chain of sea life including salmon and other fish, whales and seabirds.
Upwelling usually shows up first along California by April, said Frank Schwing, director of the Environmental Research Division of the federal Southwest Fisheries Science Center in Pacific Grove, Calif. But it has not happened this year.
"There's just not enough feeding the food chain," he said.
Many seabirds that usually nest in great numbers on the Farallon Islands near San Francisco abandoned their nests, probably because they could not find enough food, said Jesse Irwin, a biologist at Farallon National Wildlife Refuge.
It's not as grim in Oregon. Winds began bringing nutrients up from the deep ocean about the end of April, said Bill Peterson, an oceanographer at the Northwest Fisheries Science Center in Newport.
But the winds died out for two to three weeks in late May, interrupting the flow, he said. That has set back phytoplankton growth, which remains below normal.
So far, though, it's not as bad in Oregon as it was last year.
Upwelling came roughly two months late last year to most of the west coast, especially Oregon, leaving waters starved of nutrients, plankton scarce and many other species starving. Seabirds washed up dead on beaches in record numbers with nothing in their stomachs and some salmon nearly disappeared from coastal waters.
But when the upwelling finally arrived last year, it did so with a vengeance.
Plankton multiplied so rapidly it died off and sucked oxygen from the water as it decayed, creating an eerie "dead zone" off the coast that further stressed sea life, Lubchenco said.
"We went from no upwelling to very intense upwelling," she said.
Similar dead zones appeared in 2002 and 2004.
The striking shifts match what climate models suggest will happen as greenhouse gases accumulate in the atmosphere, causing global warming, researchers said. For instance, some models suggest that coastal upwelling will begin later each year, Schwing said.
"Certainly there's consistency there that's intriguing," he said.
Research also suggests warming will lead to the kind of unpredictable and extreme swings in conditions the Oregon coast has seen in the last few years, Lubchenco said.
"We're just seeing much greater variability in ways that have consequences at least for some important species," she said. "We have to build into our management of the ecosystem the expectation it's going to be more variable. We need to expect some surprises."
Biologists at national wildlife refuges along the Oregon coast do not have the staff to track the nesting success of birds, so they're not yet sure how Oregon populations have done this year, said Roy Lowe, manager of the refuges.
Few starved seabirds have washed up on beaches so far. But last year they did not begin turning up in large numbers until July.
He said Oregon bird populations need a few productive years to help recover from declines they suffered last year.
Michael Milstein: 503-294-7689; michaelmilstein@news.oregonian.com
©2006 The Oregonian
Informant: binstock
rudkla - 2. Jul, 22:44
