Episodic Events Great Lakes Experiment (EEGLE)
ISSUE
The episodic resuspension and
subsequent transport of surface sediments profoundly influences biogeochemical
processes in coastal ecosystems. In Lake Michigan, resuspension and transport
of the large inventories of nutrients and contaminants deposited over the
past few decades (e.g. P, 137Cs, PCBs, Pb) presently results in
much greater fluxes to the water column than from all external inputs. In
addition, control of biological processes can occur as a result of effects
on light and substrate availability and the introduction of meroplanktonic
species. The magnitude and episodic nature of these processes in the Great
Lakes has been poorly described from a few point measurements or as the residual
term in mass balance models. In 1996, NOAA Great
Lakes Environmental Research Laboratory (GLERL) scientists monitoring
NOAA CoastWatch
satellite images tracked the development of a massive turbidity plume
that ultimately extended over 10 km off shore and 200 km along the southern
coastline of Lake Michigan. These recent satellite observations of suspended
sedimentary material in Lake Michigan illustrated a unique opportunity to
investigate an annually recurrent major episode of nearshore-offshore transport
(Figure 1).
Figure 1. Plume Event (red), Jan. 31, 1998:
NOAA-12/14 AVHRR Reflectance (Channel 1-Channel 2) imagery
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The plume appears to be initiated by a major late winter storm after the
melting of surface ice, and it eventually veers offshore along the eastern
shore of the lake, coincident with the area of highest measured sediment accumulation
in the lake. The inventory of particulate matter in the plume, conducted on
April 2, 1996, was approximately equal to the total annual load of fine sediments
into the southern basin. Preliminary evidence indicates that this episodic
event may be the major mechanism for cross-margin sediment transport in Lake
Michigan. This type of event is believed to be ideal for studying internal
recycling of biogeochemically important materials, ecosystem responses, and
one of the major processes controlling cross-isobath transport in the Great
Lakes.
APPROACH
In August, 1997 the NOAA-Coastal Ocean Program (COP) and National
Science Foundation (NSF)-Coastal
Ocean Processes Program (CoOP) began a jointly funded study of the impact
related to the episodic plume event on sediment and constituent transport
and subsequent ecological effects in Lake Michigan. This program, Episodic
Events-Great Lakes Experiment (EEGLE), is being coordinated by the NOAA
GLERL and is scheduled
to include three field years followed by two years of interpretation and product
development. Program components include a retrospective analysis of satellite
imagery, water intakes, and other data, process and survey cruises, moored
current meters, traps and data acquisition instruments and coupled hydrodynamic-sediment
transport-ecological modeling. The goal of the program is to characterize
the materials in the plume, infer their sources, and assess their potential
impact on the cycling and transport of nutrients and contaminants. Results
will improve understanding of critical processes that affect the ecosystem,
and will support the development of resource management-oriented information
and modeling.
FUNDING
EEGLE presently involves four funding sources (NOAA COP, NSF,
EPA, NOAA GLERL) and approximately seventeen participating research institutions.
COP regional projects are typically funded at approximately a $5 million level
over a 4-6 year project life cycle. EEGLE will be funded at a total of approximately
$10M over a 5-year period with the funding split approximately 50% between
COP and NSF.
Related Websites:
NOAA/OAR/ERL
Great Lakes Environmental Research Laboratory (GLERL)
Episodic Events
- Great Lakes Experiment (EEGLE)
Keweenaw Interdisciplinary
Transport Experiment in Superior (KITES)
Great Lakes
Forecasting System
Great Lakes CoastWatch
Great Lakes Information Network
U.S. EPA Great Lakes National Program
Office
Coastal
Ocean Processes (CoOP) Program
University of Wisconsin
- Milwaukee (UWM) Center for Great Lakes Studies
For
more information, contact:
John Wickham
CSCOR/Coastal Ocean
Program
phone: 301-713-3338
e-mail: coastalocean@noaa.gov
Last Updated:
October 23, 2002