Air Date: Week of January 11, 2002

Living on Earth’s Cynthia Graber reports on a new, inexpensive technique to remove exotic species from ships’ ballast water.

Transcript

CURWOOD: Just ahead, how demand for fancy cat litter could mean problems for a Native American community in Nevada. First, this Environmental Technology Note from Cynthia Graber.

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GRABER: One important and expensive problem in the shipping industry is rust in ballast tanks caused by salt water. Shipping companies pay hundreds of thousands of dollars each year for special paint to prevent rust. To accomplish the same job, scientists in Japan came up with a new technique. They blew nitrogen bubbles into water to remove oxygen. Oxygen is what causes rust. In studies, the technique worked to prevent tank corrosion.

And as it turns out, it has a side benefit for the environment, too. Scientists in Monterey, California reason that getting oxygen out of ballast water also kills organisms in the water, organisms like invasive species. Exotics often hitch rides from one port to another in ballast water of huge tankers. The California researchers tried the oxygen depleting method on three known invasive species. In each case, the larvae died in the oxygen-poor water after two to three days. Most ship crossings take weeks. The technique wouldn't be 100 percent effective in killing all invasive species, but scientists say this simple, cheap, and environmentally benign technique holds great promise for cutting down the number of ecosystem invaders. That's this weeks Technology Note. I'm Cynthia Graber.

CURWOOD: And you're listening to Living On Earth.