Cool waters finally return to Northwest coast, but concerns linger
Seattle Times staff reporter
Upwellings of nutrient-rich cold water have finally arrived off the Pacific Northwest coast, purging the ocean of warmer surface temperatures that earlier in the year disrupted the food chain for seabirds, salmon and other maritime life.
Surface temperatures on the Pacific recently have dropped as much as 11 degrees Fahrenheit, which is expected to help produce a rich buffet of zooplankton, tiny creatures that are a staple diet to a host of sea animals.
But scientists say it may have come too late for many species, such as murres and coho salmon, that depend on heavy feeding in spring and early summer.
Researchers are still trying to better understand what happened this spring, when a lack of northerly winds apparently prevented the upsurges of cold water that usually bring nutrients up from decaying sea life on the ocean bottom. That ocean cycle sparks an explosion of plankton and other zooplankton that feeds many species.
Spring upwellings have been weak in some past years when the El Niño warm current spread north from the equator to the Northwest coastal waters. But this wasn't an El Niño year.
Scientists say it could have been an aberration, but they worry it may have signaled a new ocean pattern that might be connected with global warming.
"This one caught us completely by surprise," said Julia Parrish, an associate professor at the University of Washington's School of Marine Affairs.
In May and June, the Coastal Observation and Seabird Survey team, a volunteer group that works with the University of Washington, assessed more than 45 coastal sites in Oregon and Washington and found seabird carcasses at up to10 times the average mortality rates compared to the past six years.
The seabird die-offs continued into July, when 181 murre carcasses were tallied along one stretch of Oregon beach near Newport, shattering the previous record of 125 found in 1983, an El Niño year, according to Roy Lowe, manager of the Oregon Coast National Wildlife Refuge. Autopsies indicated that the murres probably starved.
Spring also is a crucial time for young salmon, because they emerge from rivers to the ocean and need to fatten up for their first winter at sea.
"There is a growing recognition that the lack of food during the early marine period has an impact during the winter," said Richard Beamish, a senior scientist for Fisheries and Ocean Canada. "The harsher conditions basically can kill them."
Spring surveys off Oregon found the lowest amount of young salmon since 1998, according to Bill Peterson, a NOAA Fisheries scientist in Newport. That could mean another downturn in some of the region's struggling salmon runs because fewer fish will be returning in future runs to spawn.
Scientists are hopeful that the recent surge of cold water will continue through the winter, setting the stage for a fertile spring next year. That would boost the confidence of marine scientists who have predicted that ocean conditions will be favorable for at least a decade.
But some scientists remain uneasy that global warming could short-circuit weather patterns that create the cold-water upwellings. The concern is heightened by other recent unusual ocean events.
Some Canadian scientists say that abnormal weather in British Columbia last year, as well as general warming on land, spread warm water offshore, and in some cases sent ocean temperatures to record highs.
This year in the Bering Sea and the Gulf of Alaska, ocean-surface temperatures have been above average, said John Piatt, a federal wildlife biologist.
That warming has invited unusual fish to the waters, including a 300-pound sunfish that was netted by a Kodiak-based trawler. Such a fish would normally stay off the coast of California. And some seabirds are having trouble, with several species failing to produce young in the northern and western Gulf of Alaska.
In the Atlantic, surface waters also have been abnormally warm, contributing to an unusual series of summer storms, according to Parrish.
"As scientists, we don't want to be Chicken Little and say the sky is falling," Parrish said.
"But this is weird stuff."
Hal Bernton: 206-464-2581
Copyright © 2005 The Seattle Times Company