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GLERL Major Scientific Accomplishments and Products
Since its inception in 1975, GLERL's research has produced a vast array of new information, scientific studies, and resource management tools which have had major impact, use, or significance for the Great Lakes and/or coastal marine areas of the Nation. Our most significant and lasting accomplishments are summarized here, more or less chronologically starting with the most recent:
- COMPLETED a Nearshore Hydrodynamics Program study
of the harbor and nearshore area of Milwaukee, Wisconsin, to better
understand how nearshore processes contributed to the 1993 contamination
of the Milwaukee drinking water supply by a massive overload of Cryptosporidium,
which caused over 100 deaths, and illness in over 400,000 Milwaukee
residents. In collaboration with scientists at the University of Wisconsin-Milwaukee
and Wisconsin DNR, this research showed that the probability of the
municipal water intake in Lake Michigan being within the plume of outflowing
Milwaukee Harbor water, the source of the 1993 Cryptosporidium
contamination, can be minimized by simply relocating the intake by less
than a mile. As a result, the city is moving their water intake.
- QUANTIFIED the occurrence and causes of high speed bottom currents
that occur in Lake Champlain. These currents cause frequent episodes
of bottom sediment resuspension and transport, making toxic contaminants
attached to the sediment particles repeatedly available to lake water.
This has become an important factor in planning for water quality restoration
in the lake basin.
- CONDUCTED a multi-year study to document the progression and scope
of ecosystem alterations in the Great Lakes caused by the zebra mussel,
including the extirpation of native mussel populations, changes in the
pathways of contaminant cycling and fate, seasonal changes in water
quality that promoted extensive bottom weed regrowth, and the on-set
of toxic algal blooms. GLERL's comprehensive research showed that the
ecosystem in 1990 was based on productivity predominantly occurring
in the water column, i.e., the system functioned via food and energy
transfer through a pelagic food web. Once the zebra mussel became widely
established, the system changed to a benthic (bottom) dominated system
in which most of the productivity occurs in the benthic regime. This
was caused by zebra mussels stripping food resources from the water
column, which were then reintroduced as organic detritus directly to
the benthic area. Details of our major research findings through 1994
may be found in the Journal of Great Lakes
Research, Vol. 21 (No. 4), 411 - 573 (1995). This remains the most
comprehensive examination of the ecological changes brought about by
the North American zebra mussel invasion, and has provided a basis for
understanding changes in local fisheries, nuisance growths of aquatic
weeds, and blooms of algae, some toxic, that are or have affected recreational
uses of the most heavily invaded areas
- PARTICIPATED in planning and conducting NOAA's Nutrient-Enhanced Coastal
Ocean Productivity [NECOP] Program. This research showed definitively
that nutrient loads derived from fertilizer usage in the Mississippi
River drainage basin cause, or at least greatly exacerbate, the well-documented
occurrences of bottom water hypoxia on the Louisiana shelf. Sedimentary
records showed that major ecological changes began in the 1930s and
have continued to the present.
- AN OPERATIONAL prototype Great Lakes Coastal Forecasting
System for Lake Erie was implemented by GLERL and Ohio
State University (OSU) in 1992. Since 1994, the system has produced
daily maps of water surface temperature, water level, and currents for
the lake. It is under continuing development.
- PROVIDED improved hydrologic and water resources forecast
models and lake levels prediction models for the entire Great Lakes
hydrologic system, in support of lake-level regulation responsibilities
of the International Joint Commission and the US Army Corps of Engineers.
- BUILT a world class environmental radiotracer program that has developed
advanced sediment geochronology techniques to assess past environmental
impacts (retrospective analyses, or forensic geochemistry) in aquatic
ecosystems. This technique has been, or is presently being applied to
reconstructing the environmental history at several Great Lakes sites,
and sites in Florida Bay and the Everglades, in Lake Coeur D'Alene (Idaho),
in Terrace Lake (Colorado), and in the 1993 Midwest Flood area of the
Mississippi Basin. In several cases, the information generated and documented
by the techniques developed under this program have been used to demonstrate
the origins of environmental damages caused decades ago.
- TRANSFERRED the Great Lakes Wave Model, a product of our physical
limnology research, to the National Weather service for operational
use in the Great Lakes region. The GLERL model greatly improved the
accuracy of the NWS wave forecasts, and is a primary basis for NWS forecasts
and warnings to boaters of expected dangerous wave conditions on the
lakes.
- DEVELOPED and computerized a trajectory model for use by the NOAA
HazMat Office to make hazardous materials and oil spill trajectory forecasts
in the Great Lakes. This model has also been used by the U.S. Coast
Guard to help direct search and rescue operations on the lakes.
- DOCUMENTED the effects of top-down predation on the Lake Michigan
food chain that influenced fisheries management decisions in the late
1980s and early 1990s. In the early 1980s, alewife abundance declined
due to severe winters and overpredation by salmon. This dramatic decline
in planktivory allowed populations of large bodied zooplankton to increase,
leading to greater predation on phytoplankton and subsequent decreased
phytoplankton abundance and increased water clarity. The increases in
water clarity were among the largest changes observed in Lake Michigan
over the previous forty years. At the same time, these marked top-down
effects on the food chain alerted fisheries management agencies to the
possibility that Lake Michigan could not sustain the high level of salmonid
planting that was occurring. Subsequently, a collapse of the salmonid
fishery occurred and salmonid stocking rates were reduced.
- PIONEERED the use of sediment traps in the Great Lakes. With the introduction
and use of sediment traps, great strides were made in studies to understand
the deposition and cycling of contaminants in the lakes. It was these
studies that showed that lake sediments are major repositories for many
toxic chemicals and that the recycling of these sediments into the water
column, especially during winter, is greatly lengthening the time required
to eliminate key toxics from the water column and food chain.
- CONDUCTED research and developed nutrient models during the late 1970s
that advanced our understanding of nutrient dynamics in the Great Lakes
and led to better nutrient management decisions for the control of phosphorus.
One outcome of the new information and understanding developed through
these models was a decision by the USEPA NOT to proceed with a proposed
lowering of allowable phosphorus levels in sewage effluents, which would
have added an estimated $7 billion to the cost of upgrading sewage treatment
facilities in the Great Lakes basin.
Last updated May 13, 2002 mbl