Disappearance of plankton causes unprecedented collapse in sea and
bird life off western US coast.
A catastrophic collapse in sea and bird life numbers along America's Northwest
Pacific seaboard is raising fears that global warming is beginning to irreparably
damage the health of the oceans.
Scientists say a dramatic rise in the ocean temperature led to unprecedented
deaths of birds and fish this summer all along the coast from central California
to British Columbia in Canada.
The population of seabirds, such as cormorants, auklets and murres, and fish,
including salmon and rockfish, fell to record lows.
This ecological meltdown mirrors a similar development taking place thousands
of miles away in the North Sea, which The Independent on Sunday first reported
two years ago. Also caused by warming of the water, the increase in temperatures
there has driven the plankton that form the base of the marine food chain hundreds
of miles north, triggering a collapse in the number of sand eels on which many
birds and large fish feed and causing a rapid decline in puffins, razorbills,
kittiwakes and other birds.
The collapses in the Pacific are also down to the disappearance of plankton,
though the immediate cause for this is different. Normally, winds blow south
along the coast in spring and summer, pushing warmer surface waters away from
the shore and allowing colder water that is rich in nutrients to well up from
the sea bottom, feeding the microscopic plants called phytoplankton. These are
eaten by zooplankton, tiny animals that in turn feed fish, seabirds and marine
But this year the winds were extraordinarily weak and the cold water did not
well up in spring as usual. Water temperatures soared to 7C above normal, which
delighted bathers but caused the whole delicate system to collapse. The amount
of phytoplankton crashed to a quarter of its usual level.
"In 50 years this has never happened," said Bill Peterson, an oceanographer
with the US government's National Oceanic and Atmospheric Administration, NOAA,
in Newport, Oregon.
Record numbers of dead seabirds soon washed up on beaches along the coast.
There were up to 80 times more dead Brandt's cormorants, a fishing bird, than
in previous years.
Tests showed the birds died of starvation. "They are not finding enough
food, and so they use up the energy stored in their muscles, liver and body
fat," said Hannah Nevins, who investigated similar mass deaths in Monterey
Many fear the ecological collapse is a portent of things to come, as the world
heats up. A Canadian Government report noted that ocean temperatures off British
Colombia reached record levels last year as well, blaming "general warming
of global lands and oceans". And Professor Ronald Neilson, of Oregon State
University, added: "The oceans are generally warming up and there are all
sorts of signs that something strange is afoot."