Removing oxygen from the water used as ballast in ocean going vessels could help stem the spread ofinvasive species, while also protecting the ships from corrosion, a new study suggests. A novel method for combating ship ballast tank corrosion - using nitrogen gas to remove oxygen from the ballast water - presents a rare win-win solution for the shipping industry and environmentalists, says marine ecologist Mario Tamburri of the Monterey Bay Aquarium Research Institute (MBARI), who led the study reported in the January issue of the journal "Biological Conservation."
Current solutions to sterilizing ballast water, such as filtration, heat treatments and poisons, are expensive, can be dangerous to ship crews, and can harm the surrounding environment where the treated waters are discharged. Deoxygenation presents the first solution that removes the majority of organisms found in ballast water while also providing an economic benefit for ship owners. "Deoxygenation was seen as too expensive for controlling invasive species in ballast water but our study shows that the anticorrosion benefit of this technique is a strong economic incentive for the shipping industry," said Tamburri. "It's a win-win treatment for solving an environmental problem and reducing ship maintenance costs."
Deoxygenating ballast water can prevent invasions of non-native species like Australian tubeworms, shown here taking over regions of Elkhorn Slough, California. Photo © 2001 Wasson