Turbulent Ballast Waters
The strong currents in Lake Superior can be affected by
seasonal changes in temperature and winds, especially in the fall and
spring.
“They’re very sensitive to wind, wind direction,” says Sarah
Green, chair of the chemistry department at Michigan Technological
University, Houghton, and a leader in lake current research. “Sometimes
the currents around the Keweenaw reverse direction. … They can be
speeded up if the wind is pushing them or they can be slowed down if
the wind is against them. … The temperature, the stratification of the
lake, has an effect on currents as well.”
The Keweenaw Current, centered around the Keweenaw Peninsula
in Michigan, carries three times the water of the Mississippi from the
west to the east on the lake each year. This “river” runs near the
surface, and “10 to 20 percent of the whole volume of the lake passes
by Eagle Harbor every year,” she says.
General currents are indicated on the map at top.
Lake Notes
 The
U.S. Coast Guard may have an acceptable alternative to its
controversial live-fire training on the Great Lakes. Tests were being
done of the Multiple Integrated Laser Engagement System to see if this
laser alternative gave the Guardsmen the necessary security training
without using live ammunition.
A
federal judge upheld Michigan’s law requiring salt-water vessels
entering ports in the state to obtain permits regarding ballast water
discharge. The law was challenged by a coalition of nine U.S. and
Canadian shipping companies.
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