1. Physical and Ecological Responses
of the Great Lakes to Climate Change
Session organizers:
Nathaniel Ostrom
Department of Zoology and
Biogeochemistry Environmental Research Initiative,
Michigan State University
Steve Colman
Large Lakes Observatory
University of Minnesota-Duluth
Sponsors:

2. The Great Lakes ecosystem:
a legacy of change, a future of uncertainty
Nathaniel Ostrom
Department of Zoology and
Biogeochemistry Environmental Research Initiative,
Michigan State University

3. Predicted Climate Trends in the Great Lakes Environment
Region will become warmer and drier
By 2100:
Winters warmer by 3-7 oC
Summers warmer by 3-11 oC
Kling, G.W., K. Hayhoe, L.B. Johnson, J.J. Magnuson, S. Polasky, S.K. Robinson, B.J. Shuter, M.M. Wander, D.J. Wuebbles, D.R. Zak, R.L. Lindroth, S.C. Moser, and M.L. Wilson (2003). Confronting Climate Change in the Great Lakes Region: Impacts on our Communities and Ecosystems. Union of Concerned Scientists, Cambridge, Massachusetts, and Ecological Society of America,
Washington, D.C.

4. Predicted Climate Trends in the Great Lakes Environment
Michigan summer will transition to one more like an Arkansas summer
Migration of Climate: Winter and Summer for Michigan and Illinois
Confronting Climate Change in the Great Lakes Region: Impacts on our Communities and Ecosystems. Union of Concerned Scientists,

5. Recent Changes/Threats to Great Lakes
Rising temp in Superior
- approx. 1 oC/decade
Reductions in Ice Cover
MODIS Rapid Response Team, NASA/GSFC

6. Recent Changes/Threats to Great Lakes
Falling Lake Levels
Historical range in Superior is 1.2 m
Current drop of ~ 1 m since 1985
Economic Impacts to Shipping
Transport through locks
A 2 ft drop equates to 6,000 tons of coal for a 1000 ft vessel
U.S. Army Corps of Engineers and MN Sea Grant

7. Recent Changes/Threats to Great Lakes
Example of Ecosystem Change: Lake St. Clair
Up to 1 m drop in lake level by 2050
22,000 ha exposed (shown in green)
28 of 43 known fish spawning sites lost
(red dots)
(Source: Scudder Mackey, ESPP conf 2007)

8. Predicted Climate Trends in the Great Lakes Environment
Impacts to Fishery:
reduction in ice cover likely harmful to whitefish due to reduced protection
from winter storms
cold water fish likely to decline
invasions of warm water fish likely
Confronting Climate Change in the Great Lakes Region: Impacts on our Communities and Ecosystems. Union of Concerned Scientists,

9. Predicted Climate Trends in the Great Lakes Environment
Changes to algal productivity
spring bloom will occur earlier
likely out of phase with zooplankton and fish communities
composition likely to change from palatable diatoms to inedible blue-green algae
enhanced by zebra mussel spread
overall productivity expected to increase (
Diatom: Aulocoseira sp.
Zebra mussel expelling Microcystisas pseudofeces. (

10. Predicted Climate Trends in the Great Lakes Environment
Changes to algal productivity; Will productivity increase?
Ex. Grand Traverse Bay, Lake Metabolism
Shift to net autotrophy in warmer 2001
2000
2001
O2 sat
d18O
R/P

11. Recent Changes/Threats to Great Lakes
Rising Nitrate in Superior and other
Great Lakes
Causes are not clear
Shift in N cycling in coastal ecosystems:
shift in primary production to blue-greens
(N fixers)
decrease in deposition of labile organics
decrease in rates of denitrification
Increase in nitrate export
Great Lakes?
N fixers are increasing
Is this changing the N cycle?
Finlay et al 2007 Ecological Applications, 17(8), 2007, pp. 2323–2332
Lane N. NATURE Vol October

12. Are we prepared?
“… change may be inevitable. But it is not inevitable for society to be surprised or ill-prepared.”
Robert Gagosian, Director and President, WHOI

13. NSF funding rates
Source: NSF (2007) Impact of Proposal and Award Management Mechanisms

14. Trend Toward Large Scale Monitoring Networks:
“The Long Term Ecological Research (LTER) Network is a collaborative effort involving more than 1800 scientists and students investigating ecological processes over long temporal and broad spatial scales” (
No Great Lakes stations

15. Trend Toward Large Scale Monitoring Networks:
Lake Metabolism chosen as the central parameter by the Global
Lakes Ecological Observing Network (GLEON) with funding by NSF
- No Great Lakes Stations

16. Integrated Ocean Observing System
“a system of systems that routinely and continuously provides quality controlled data and information on current and future states of the oceans and Great Lakes from the global scale of ocean basins to local scales of coastal ecosystems” (
Does include the Great Lakes Observing System

17. Integrated Ocean Observing System
$97.7 million contract recently awarded to an academic partnership led by the Woods Hole Oceanographic Institution (WHOI) to lead development of OOI to an eventual level of $331 million
Role of Great Lakes in OOI not yet well delineated
Recent passage of HR 2342 by House of Representatives clearly encompasses the
Great Lakes

18. Summary:
The Great Lakes Ecosystem is changing… quickly
There is a strong need for a cohesive program of funding and large
scale monitoring of ecosystem processes