1. The Great Lakes
Michael W. Rowan, Ph.D.

2. The Great Lakes Began to form ~500,000 years ago
Took present shape ~10,000 years ago
Watershed area = 196,000 sq. miles
34 million people (27.5 million U.S., 6.4 million Canada)
Water surface area = 94,700 sq. miles
U.S. Great Lakes shoreline > U.S. east coast shoreline

3. Unique ecosystem, and unique resources
Largest surface freshwater system on earth
Contains 84% of North America’s surface freshwater
Contains 21% of the world’s surface freshwater

4. Characteristic
Superior
Michigan
Huron
Erie
Ontario
Length (miles)
350
307
206
241
193
Width (miles)
160
118
183 57 53
Depth, Average & Max. (feet)
489 / 1,333
279 / 923
195 / 750
62 / 210
283/802
Volume (cubic miles)
2,935
1,180
849
116
393
Surface Area (sq. miles)
31,700
22,300
23,000
9,910
7,340
Drainage Basin Area (sq.miles)
49,300
45,600
50,700
22,700
23,400
Shoreline (miles)
2,730
1,640
3,830
871
712
Elevation (feet)
601
577
569
243
Outlets
St. Mary's River
Mackinac Straits
St. Clair River
Niagara Falls
St. Lawrence River
Chicago River
Welland Canal
Water Replacement Time (yrs)
173 62 21
2.7 6
Human Population
672,116
12,052,743
2,960,359
12,532,977
5,692,178
Source:   Sea Grant and MSU Extension, 2000

6. Great Lakes Environmental Issues
Invasive species
Nonpoint source pollution
Urban sprawl
Mercury in fish
Contaminated sediments (dredging?)
Nutrient loading
Water diversion
Climate change
Endocrine disrupters
Atmospheric deposition

7. Erie – Our Great Lake
Smallest in volume, depth, retention time, watershed area
Largest human population
Warmest, most nutrient-rich, and most productive
Fishery is more productive than the fisheries of other four Great Lakes combined
Largest percentage of land in agriculture

11. Cuyahoga River Fire
November 1952

12. Brown Bullhead (Ameiurus nebulosus)
Ubiquitous benthic catfish distributed throughout the great lakes
Vulnerable to many hydrophobic contaminants (PAHs)
Sediment PAHs linked to high tumor rates and changes in blood variables
2. Its constant association with the sediment renders it vulnerable to

13. BROWN BULLHEAD (Ameiurus nebulosus) noticeyellow/brown color
Smooth, long barbels (a form of chemical sensory)
Tri-C Eastern Campus BIO Environmental Science for Educators: Promoting Watershed Stewardship July 2007

14. Tri-C Eastern Campus BIO Environmental Science for Educators: Promoting Watershed Stewardship July 2008

15. Something Fishy
34 species of Lake Erie Fish are rare, threatened, or endangered
Blue pike – extinct
Lake sturgeon, brook trout, lake trout, . . .
Fish consumption advisories due to mercury and PCBs

16. CREDITS
Thanks to Michael Rowan, PhD from Tri-C East who donated his Power Point slides so graciously.
Course: “Promoting Watershed Stewardship” for Environmental Science Educators

17. Educator Resources Great Lakes Environmental Atlas - USEPA
Great Lakes science activities – OSU/Ohio Sea Grant
NASA - Visible Earth – satellite images of the Great Lakes
Animation: lake effect snow
Great Lakes Commission
International Joint Commisison
Great Lakes Information Network
Lake Erie: Beyond the Surface -Channel 3