Soap was the answer all along. Well, lye...the active ingredient that makes soap. It looks like scientists may have found a powerful and, just as importantly, RELATIVELY CHEAP way to kill things in ballast water.
Most invasive species in the Great Lakes were introduced by dumped ballast water from ocean-faring ships. That's how the zebra mussels got here.
Those little bastards. The annual estimated costs of invasive species to Great Lakes communities totals about 200 million dollars per year...I've found some sources that claim much higher numbers (nearly 6 BILLION per year)but those sources don't give much detail).
The ships chug across the ocean, with ballast water from their home port halfway across the world and all the critters that live there...like a huge floating aquarium. Then they enter the Great Lakes through the St. Lawrence Seaway and go to their destination and load up on grain and find they need to lighten up and get rid of some ballast water. So they dump the water and and alllll the critters that came with them spill out into a new ecosystem: the Great Lakes.
Of course...the monitoring and control of ballast water dumping has been fairly lax and tough to enforce. Plus, the pumps can't always get everything out before the ship enters the Great Lakes so there's always something squirming around in there. Short of shutting down the St. Lawrence Seaway, the only viable way to fix the problem and slow the spread of invasive species is to kill everything in the tank, so that it doesn't matter if the ballast water is dumped.
But shipping companies resisted ballast water purification on the grounds that it's prohibitively expensive.
Enter the Scientists. After three years of research, scientists believe they may have a cheap, fairly easy solution.
Dump in a bunch of lye, let it kill the beasties (up to 99% of them). Then neutralize the lye with carbon dioxide. Both are wonderfully cheap. Wonderfully, wonderfully cheap.