Mixed blessings from super ships

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On my walk to work, I cross Duluth’s iconic Aerial Lift Bridge. During the shipping season, my commute can be seriously disrupted by traffic…shipping traffic that is. The span of the bridge is nearly as long as a city block, and when a boat comes off of Lake Superior, the entire span raises up about 200 feet to get out of the way. Out of any given five days of work, there’s at least one day when I have to wait five, ten, even fifteen minutes to continue to work.

On the flip side, I get to walk down to the edge of the ship canal and experience the boats up close. They are stunning to watch and hear.

Just as these ships are a mixed blessing for my walk to work, they are a mixed blessing for the harbor ecosystem.

These ships are critical to the economy of Duluth and Northeastern Minnesota. Followers of the progressive think tank Minnesota 2020 may have read their detailed report Safe, Clean and Efficient: Moving Minnesota to Market by Water, which does a great job explaining the economic benefits to Minnesota taxpayers.

These ships carry taconite, coal and grains out. That’s where the money is. They also carry ballast water in. That’s the problem. Ballast water can contain exotic species, invaders from foreign ports. Aquatic invaders such as zebra mussels and the spiny waterflea arrived in the Duluth-Superior harbor in the hulls of these same ships. These invasive species have dramatically affected the food chain in Duluth and other harbors around the Great Lakes. Annual costs of dealing with these invaders run up to $200 million per year in the Great Lakes basin.

Those concerned about Minnesota’s economy and Minnesota’s environment can and should support Great Lakes shipping. But the economic and ecologic impact of exotics species needs to be part of the discussion.  In coming months, the federal government will take major steps forward in protecting our harbors from these invaders. The Environmental Protection Agency has a draft permit for marine vessels, requiring them to treat ballast water before releasing it. The Republican-controlled House of Representatives has passed a bill with similar provisions. Another mixed blessing: many environmental groups think both proposals, though a step in the right direction,  are too weak to prevent further aquatic invasions.

Minnesota will always move to market by water; now we can ensure that water stays healthy.


(This article initially appeared in Hindsight, the Minnesota 2020 blog)

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