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Lake Superior State celebrating 30 years of salmon releases
The Associated Press (5/29)
In Michigan, the Aquatic Research Laboratory at Lake Superior State University is celebrating three decades of raising and releasing Atlantic salmon in the St. Marys River.

University of Windsor invasive species research centre closes
CBC News (5/27)
The Canadian Aquatic Invasive Species, based at the University of Windsor, is closing because it's run out of federal funding.

Stockbridge HS invention to monitor Great Lakes pest
Lansing State Journal (5/27)
In Michigan, a team of Stockbridge High School students has spent the past year designing an underwater camera to keep tabs on the state’s fight against invasive sea lampreys. Next week their invention will get its first real test.

'Once in a lifetime ' experience: Lighthouse keeper on Lake Superior
CBC News (5/19)
A group is hiring two students to serve as lighthouse keepers this summer on Porphyry Island, about 40 kilometers east of Thunder Bay, Ont.

Superior students set sail for hands-on learning about St. Louis River, Lake Superior
Wisconsin Public Radio (5/16)
Close to 1,500 students from northern Minnesota and Wisconsin set sail for a day on St. Louis River to learn about the Great Lakes, as part of the week-long St. Louis River Quest.

Tree group aims to ‘ReLeaf’ Michigan
WKAR - East Lansing, MI (5/10)
An Ann Arbor-based organization has been planting trees all over Michigan since 1988. ReLeaf Michigan helps property owners learn about trees and how to plant them, citing their numerous benefits.

TEACH Calendar of Events
What's going on in your neighborhood this month? Meet other people and learn together at recreational and educational events! Our new dynamic calendar is updated daily with current educational events.
TEACH Questions & Answers

If the St. Lawrence River connects the Great Lakes to the Atlantic Ocean, why aren't the Great Lakes saltwater instead of freshwater?
from Billie Rae in Summerville, South Carolina, Age 12

Great question!

The St. Lawrence River can be divided into three broad sections: the freshwater river, which extends from Lake Ontario to near the city of Quebec; the St. Lawrence estuary, which extends from Quebec to Anticosti Island; and, the Gulf of St. Lawrence, which leads into the Atlantic Ocean.

View a map of the St. Lawrence river region
View a map of the entire Great Lakes-St. Lawrence River system

Originating from Lake Ontario near the Canadian town of Kingston, the St. Lawrence River is freshwater until near the Canadian town of Donnacona in Quebec. In this section, the river is always freshwater and flowing in the direction of the Gulf, or downstream. There are many tributaries that flow into the river, such as the Ottawa and Chateauguay Rivers. Because the water flow is quite fast in this part of the river, the water from the tributaries is kept from entering the center of the St. Lawrence River; this phenomenon creates two separate water masses that flow beside one another for a long distance before mixing completely.

After Donnacona, the river widens considerably and enters the brackish water zone, the area where freshwater and saltwater meet. In this section, the salinity of the water rises from zero to twenty percent! Tidal influences from the Atlantic start to affect the river, and the river becomes an estuary, with one of its main tributaries being Saguenay River. An estuary is where a freshwater river current meets an ocean tide, and is often abundant in wildlife. The St. Lawrence estuary is over 300 miles long, and is one of the most productive marine ecosystems along the Canadian coast. Over 718,000 seabirds of 19 species, such as the Atlantic puffin, the red-throated loon, and the Artic tern, and several different species of whales, such as finback, minke, Beluga, sperm and blue whales, are found in the St. Lawrence estuary.

The estuary deepens considerably as it heads toward the ocean, with the depth increasing from around 80 feet (25 meters) to 1,145 feet (358 meters). Once the waterway passes by Anticosti Island, the estuary becomes known as the Gulf of St. Lawrence. The Gulf extends 250 miles from the St. Lawrence River estuary to Newfoundland, where it becomes the Atlantic Ocean, and at its greatest width the Gulf is 500 miles (800 km) wide.

St. Lawrence River and Seaway, Encyclopedia Britannica
The Hydrology of the St. Lawrence Basin, Canada's Digital Collections
The Seabirds of the St. Lawrence, Environment Canada

St. Lawrence Region, College of Communication, University of Illinois
St. Lawrence Hydrographic System, Encyclopedia Britannica

Thank you for your question!

Answered on September 1, 2000

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