A diagram of the ballast-free ship (Photo courtesy of Professor Michael Parsons)
Cargo ships move sea life around the world.
Moving aquatic life from one port to another can cause
environmental havoc. Lester Graham reports there’s a
new idea that could nearly eliminate the problem of
transporting sea life to foreign ports:
Transcript
Cargo ships move sea life around the world.
Moving aquatic life from one port to another can cause
environmental havoc. Lester Graham reports there’s a
new idea that could nearly eliminate the problem of
transporting sea life to foreign ports:
There is an invasion of every major port on the globe.
“Today, the world’s shores are under attack. Armies of aliens are secretly invading our coasts.”
If this video, Invaders from the Sea, from the International Maritime
Organization sounds a little over-dramatic, it’s really not. Invaders from far-flung
corners of the world are brought in by commerce. In their travels, cargo ships pick up the
hitchhikers.
Those hitchhikers can be fish, mussels – aquatic bugs of all kinds. They can become
pests. Out-compete native species for food and space. They can destroy the
native ecosystems and often damage the economic well-being of people.
Here’s how it happens. Ocean-going cargo ships dock at a foreign port. They pump in
water for ballast to keep the ship stable. They also pump in some of the living things in
the water. When they arrive at the destination port, they can pump out that water and
the critters that were sucked up with it.
In the US, ports from Chesapeake Bay to San Francisco have been invaded. But,
the Great Lakes have been hit especially hard by invasive species.
Michael Parsons is a professor of naval architecture at the University of Michigan. He
says when foreign ships were able to come in from the Atlantic and travel as far as
inland as Duluth, Minnesota; they brought a lot of invaders with them.
“With the opening of the St. Lawrence Seaway in the ‘50’s, that led to increased
introduction of non-indigenous species such as the zebra mussel, and the round goby, and
the ruffe, and the various smaller creatures that have been brought in to the Great Lakes.”
Those creatures have damaged the ecosystem of the Great Lakes. And they’ve cost the economy.
By one Environmental Protection Agency estimate about five-billion dollars a year.
Parsons and his colleagues have been working to design a ship that has no need for
ballast. In the lab, a scale model has been tested in a long pool. Instead of pumping
water in and out of the ballasts, the water would flow through big
tubes that run the length of the ship.
“And so, that’ll create a slow flow through these trunks so that they’re always swept
clean of foreign water.”
“A ship like that is just what we need in the Great Lakes.”
Andy Buchsbaum runs the Great Lakes office of the environmental group, the National
Wildlife Federation.
“If you eliminate the need for ballast water altogether, then you’re eliminating the vast
majority of invasive species introductions that come in through the discharge of ballast.”
The ballast-free ship design is creating some excitement. Even the shipping industry is
paying attention because the ship also is more fuel efficient.
If someone decides to actually build the ballast-free cargo ship, it’ll be a while before
the first one is on the high seas.
Allegra Cangelosi has been working on the ballast and invasive species problem for
close to a decade. She’s a policy analyst with the Northeast-Midwest Institute.
“I think it’s a wonderful development. I don’t think there’s going to be any one answer
for all ships plying all waters throughout the globe. However, the more good answers
that are out there to choose from, the better for the environment.”
Some of those choices are filtering ballast water or killing organisms in the ballast with
chemicals. Those systems are expensive. And since fuel isn’t getting any cheaper, that
might make a more fuel-efficient ballast-free ship attractive.
For The Environment Report, this is Lester Graham.
