The discharge of ballast water collected from one region into the ecosystem of another has long been recognized as a major environmental problem. In January Biological Conservation, Mario Tamburri and colleagues at the Monterey Bay Aquarium Research Institute show that deoxygenating ballast water can prevent the introduction of exotic invasive species and also reduce ship corrosion (Biological Conservation 2002, 103:331-341).

Investigations by Sumitomo Heavy Industries Ltd., showed that ballast water deoxygenated by having nitrogen bubbled through it was much less corrosive to steel ballast tanks, resulting in significant reductions in the amount of anti-corrosion paint applied to an individual ship.

Tamburri et al. decided to adapt this technique to the oxygen sensitive larvae of three invasive species found commonly in US coastal waters; an Australian tubeworm (Ficopomatus enigmaticus), the European green crab and the European zebra mussel. Larvae incubated in vitro in the...