guardian assays lake
Scientific findings vital to Ontario's health
By Corydon Ireland
The Democrat and Chronicle
ABOARD THE LAKE GUARDIAN - From two miles out in Lake
Ontario, Charlotte looks like a thin gray stripe painted
between wide water and big sky.
But for the scientists aboard this federal research vessel
- the largest one plying the Great Lakes - miles out in
the lake is the place to be.
The Environmental Protection Agency by Friday will wrap
up an 8-day "analysis cruise" of Lake Ontario,
the last in the chain of five Great Lakes, the smallest
and, by some measures, the most polluted.
The cruise is the third of four scheduled this year for
Canadian and American vessels in April, August, September
and October. The U.S. trips, all on the Lake Guardian,
will cost about $500,000, and are part of a twice-a-decade,
binational intensive study of Lake Ontario. The EPA does
annual reviews of each lake - available for review by
scientists and policymakers - but the last large-scale
one for Ontario was in 1998.
Since then, "we have no idea how things have changed,"
said Steve Lozano, a research scientist with the National
Oceanic and Atmospheric Administration in Ann Arbor, Mich.
So researchers from the EPA’s Manhattan-based Region
2, along with university and Canadian scientists, are
evaluating changes in the lake’s lower food web and its
ability to support fish populations. The project is called
the Lake Ontario Lower Aquatic Foodweb Assessment, or
At about 30 sites across the lake, scientists on this
month’s cruise are grabbing samples of water, bottom mud
and the microscopic plants and animals that live in both.
This deep-lake world is populated by the plant and animal
micro-organisms that sustain the life of larger fish.
In the past 10 years, the lake has been under a lot of
pressure from invading exotic species like zebra mussels.
The effects on the food chain are little understood.
In the past 100 years, Lake Ontario and other Great Lakes
have felt the heavy impact of well-known environmental
pressures, including toxic sediments, industrial air pollution
and the decline of shoreline habitats.
But in those terms, improvements have been dramatic.
On lake bottoms, where higher species dine, the problems
have been hidden and are just beginning to be studied
Ten years ago, said EPA researcher Fred Luckey, 80 percent
of the biomass on the bottom of Lake Ontario - about 25
million metric tons - was diporeia. This microscopic creature
was the chief food of white fish and other catchable lake
varieties. There was so much diporeia that there were
about 3,000 organisms in each cubic meter of mud.
Today diporeia have virtually vanished, except in remote
Lake Superior, pushed aside by invading zebra and quagga
mussels. These creatures, imported accidentally in the
bilge of international ships, filter and consume the same
rain of nutrients, falling from the surface of the lake,
that used to feed diporeia.
The mussels "are impossible to control," said
Luckey, who is the EPA’s chief regional environmental
scientist. "We don’t understand what the long-term
effects will be."
At risk, he said, is Lake Ontario’s commercial and recreational
fishing industry, worth about $2.5 billion a year. Bigger
fish depend on the lake-bottom food sources now being
disrupted by nonnative mussels.
Taking telltale samples is a science. Aboard the Lake
Guardian, researchers use a cluster of metal tubes called
a rosette to draw in water samples from selected depths.
Phosphorus in the water indicates nutrient levels. Silica
measures the health of microscopic algae called diatoms,
which use silica in their cell walls. And levels of chlorophyll
indicate how much plankton (plant food) is present.
Researchers also use a box core, a device winched to
the lake bottom to collect undisturbed cores of mud, which
are frozen and analyzed. A single core can be a snapshot
of 50 years of telltale microscopic life in vital sediments.
Data assembled from this year’s four research cruises
- available soon to Canadian and U.S. scientists on a
proprietary Web site - will take a while to digest and
analyze, said Lozano. But it’s bound to lead to management
decisions. "The question is: How can we stop the
next wave of (species) invasions from coming in?"
In the struggle to turn back invasive species, Great
Lakes scientists have at least one success story to point
to. In the last 50 years, sea lampreys, an exotic species,
have preyed on catchable fish. But their numbers were
decimated in the 1970s, with the introduction of chemicals
that killed lamprey larvae.
Another team of scientists aboard the Lake Guardian uses
radar and telescopes to count birds, the first attempt
to quantify birds over the open waters of Lake Ontario.
On board the 180-foot-long Guardian with the federal
scientists were students and professors from Clarkson
University and researchers from Canada and Brazil. Many
of them labored below decks in four laboratory "modules."
"We’re seeing the results of short-term thinking,"
said Catherine Masson, a water researcher at York University
in Toronto. She was helping measure phosphorus levels
in the lake, a legacy of land-based fertilizers and other
"This is the next generation of Great Lakes scientists
we’re teaching here," said Michael R. Twiss, an assistant
professor of biology at Clarkson. Each day, he said, there
are 10 hours of lab or classroom work, including a mandatory
two-hour seminar after dinner.
"I couldn’t ask for a better education," said
Masson, who’s studying "water ethics" in a master’s
Twiss and other Great Lakes scientists treasure their
time on board the Lake Guardian. It’s one of four research
vessels over 80 feet long on the Great Lakes, including
the Limnos, a Canadian Coast Guard ship.
The scientists would like to see more big ships, with
the stable power sources, range and roominess that scientific
expeditions require. Most universities and research centers
can only support small boats used for daylong research
trips. A ship the size of the Lake Guardian costs about
$1 million a year to operate, crew and maintain.
On the U.S. side of the lakes, the EPA has two large
vessels. The National Science Foundation operates a third,
based in Duluth, Minn.
"We’d like to see things change," said Steven
W. Wilhelm, a microbiologist at the University of Tennessee-Knoxville,
on board to study toxic lake bacteria. "Aquatic research
in the United States is very focused on marine (saltwater)
systems - even though (the Great Lakes has) 20 percent
of the world’s fresh water."