Dead zone expected to form in
CLEVELAND (AP) A dead zone,
an oxygen-deprived area devoid of life, is expected to
form again this summer on Lake Erie and scientists plan
to find out why.
The worst dead zone since the early
1980s formed offshore between Ohio and Ontario, Canada,
last summer, a sign that the lake's environmental progress
is shifting into reverse.
With a larger dead zone expected
to form this summer in the central basin, ships loaded
with scientists and monitoring equipment will try to determine
what is threatening to undo years of environmental improvement.
"I don't want to sound alarmist,
but we have no idea, really, what is going on," Murray
Charlton, a scientist at Canada's National Water Research
Institute told The Cleveland Plain Dealer.
Already this spring, an Environmental
Protection Agency boat has found water samples heavily
clouded with algae and other forms of floating plant life.
Too much algae is a sign that nutrients
such as phosphorus and nitrogen are overabundant
a combination that eventually creates a barren region
beneath the surface. In effect, the nutrients enrich the
lake to death.
A lake can die when its bottom becomes
covered with too much decomposing plant matter, which
consumes more and more oxygen as it rots. When the oxygen
is gone, the suffocating swath becomes lifeless.
Gerald Matisoff, a Case Western Reserve
University geo-chemist heading the U.S. side of the Lake
Erie investigation, said an eight-boat flotilla of research
vessels will crisscross the central basin in search of
Scientists will gather thousands
of water samples to more precisely measure the dead zone's
boundaries, depths and development in June, July and August.
By midsummer, the United States and Canada will have about
40 researchers from 17 universities studying the area,
The Plain Dealer reported Friday.
"Back in the 1960s and 1970s, the
lake had the same problems. We thought they were solved,
and for the last 10 years we've been patting ourselves
on the back," Matisoff said. "All of a sudden we've got
a disturbing trend of degrading water quality. The question
is: How come?"
Many scientists suspect that zebra
mussels and other exotic species such as round gobies
are starting to reshape Lake Erie's ecosystem in ways
that scientists have yet to fathom, Matisoff said. Others
theorize that the lake may be suffering from the effects
of climate changes linked to global warming.
Another theory is that sewage treatment
plants could be dumping excess wastes, Charlton said.
The lake should not be in decline
after nearly $8 billion was spent on new sewage treatment
plants since the 1970s. Laws were passed to restrict the
use of phosphate laundry detergents. Farmers even changed
tillage practices to reduce fertilizer runoff.
Those moves cut the flow of phosphates
into the lake by more than half from 24,000 tons
a year to less than 11,000 tons.
By all prior calculations, Lake Erie
should still be growing cleaner, Charlton said.