Oceanic plankton have largely disappeared from the waters off Northern California, Oregon and Washington, mystifying scientists, stressing fisheries and causing widespread seabird mortality.
The phenomenon could have long-term implications if it continues: a general decline in near-shore oceanic life, with far fewer fish, birds and marine mammals. No one is certain how long the condition will last. But even a short duration could severely affect seabird populations because of drastically reduced nesting success, scientists say.
The plankton disappearance is caused by a slackening of what is known as "upwelling:" the seasonal movement of cold, nutrient-rich offshore water into areas near shore.
This cold water sustains vast quantities of phytoplankton and zooplankton, which are the basis of the marine food web. During periods of vigorous upwelling and consequent plankton "blooms," everything from salmon to blue whales fattens and thrives on the continental shelf of the West Coast.
The larger fish and baleen whales eat mostly krill: free-floating, shrimp- like crustaceans ranging from one to two inches, the upper size limit of the zooplankton realm.
When the water is cold, krill swarm off the Northern California coast by the tens of thousands of tons. Now that they are largely absent, fisheries and wildlife are feeling the effects.
In perhaps the most ominous development, seabird nesting has dropped significantly on the Farallon Islands off San Francisco, the largest Pacific Coast seabird rookery south of Alaska.
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In fact, say scientists, krill are the keystone forage species for almost everything that swims off Northern California.
"It's the krill that drive the food web dynamics off this coast," said Ellie Cohen, the executive director of the Point Reyes Bird Observatory. "Their absence has tremendous implications for everything out there, right up to the humpback and blue whales. We don't know if this is a result of global warming or some natural cycling, but without the krill, you could be looking at a food web collapse."
I would be very surprised if this phenomenon were not the result of global warming. It's obviously the result of some kind of warming. What is it going to take to get the folks in power to wake up to what is happening to the earth?
Maybe we are like frogs. Here is a quote from a book by David Suzuki: "The frog has a fatal flaw....Having no evolutionary experience with boiling water, he is unable to perceive it as dangerous. Throughout their biological evolution, frogs have lived in a medium that does not vary greatly in temperature, so they haven't needed to develop sophisticated thermal detectors in their skin. The frog in the pot is unaware of the threat and sits complacently until he boils."
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