Using Microwaves To Cook Ballast Stowaways 186
Smivs writes "US researchers say they have developed an effective way to kill unwanted plants and animals that hitch a ride in the ballast waters of cargo vessels. Tests showed that a continuous microwave system was able to remove all marine life within the water tanks. The UN lists 'invasive species' dispersed by ballast water discharges as one of the four main threats to the world's marine ecosystems. For example European zebra mussels (Dreissena polymorpha) have infested more than 40% of the US's inland waterways. Between 1989 and 2000, up to $1B is estimated to have been spent on controlling the spread of the alien invader."
Too little too late (Score:5, Informative)
Re:Mussels?! (Score:5, Informative)
What can happen using low tech (Score:5, Informative)
http://www.wired.com/science/discoveries/magazine/16-03/ff_seacowboys?currentPage=all [wired.com]
*spoiler* essentially current cargo ships headed to the U.S. have to flush their ballast in international waters and refill with local seawater. The Cougar Ace somehow managed to screw up this step and went askew (see pic). There were many quite grave consequences.
Granted, it's not standard operating protocol to end up with losses like this just too keep out invasive species, but it does illustrate some of the challenges and extent of trouble people go to to comply with this kind of ecological directive. Plus it was a damn well-written story I enjoyed reading.
Re:Too little too late (Score:5, Informative)
Re:Too little too late (Score:5, Informative)
Re:Too little too late (Score:5, Informative)
The problem is that predators usually are not restricted to a single kind of prey, so they will not only control the organism you want to get rid of but prey on indigenous species that you don't want it to. A case in point is the rabbit problem in New Zealand, which has no indigenous mammals. Introducing predators such as foxes or coyotes is not an acceptable solution because they will also eat the various species of flightless birds. Even when there is a specialized predator, it is very difficult to be sure that it will stay specialized.
Re:Too little too late (Score:2, Informative)
Even if the predators are able to effectively kill off the invader (which they often aren't), and they don't just switch to some other native species, then the predators start dying too. Eventually, the predator goes extinct due to lack of food supply, but some small portion of the original invader remains to repopulate, and the problem remains unsolved.
Honestly, nobody has ever succeeded in controlling an invasive species once it becomes established, using any method. In that light, you may as well avoid control methods that are known to have massive collateral damage.
Re:Too little too late (Score:3, Informative)
It wasn't the best laid out plan.
If you do introduce a predator you have to ensure it is specialized for the target species and can not adapt to other creatures. The only sucessful release that I know of is the cactoblastis beetle which almost wiped out the pickly pear introduced into australia. Reminant populations still remain
Another way - Use nitrogen. (Score:5, Informative)
It purges the water of oxygen, killing any marine life. It also has the benefit of stopping corrosion.
It does have the downside of making the ships hull an instant death (asphyxiation) hazard.
swish and spit... (Score:3, Informative)
Starting this year cargo vessels are required to "swish and spit" - flush their ballast tanks 200 miles before entering the St. Lawrence seaway.
This probably doesn't do much good for saltwater invasive marine life but is a good solution for the freshwater nasties.
Re:Too little too late (Score:4, Informative)
Of course, if you are going to be introducing a non native species, you'd better be absolutely sure you know what you're doing. There are countless regulatory obstacles that typically need to be overcome, too, and it can take years before a species is approved to be released from quarantine into the field, if it ever is.
Typically, an introduced organism becomes a pest for one of two reasons: 1) it's a generalist that is a better competitor for resources than existing species (as is the case with the zebra mussel, which is unbelievably effective at filtering particulate organic matter from the water and subsequently undergoing rapid population growth) or 2) it becomes a pest or pathogen of a particular existing species. Many introduced plant pathogens fall into this second category- they have no natural predators in the new environment, as well as a food source that has not evolved any defense mechanisms against them. The balsam woolly adelgid or the chestnut blight fungus are two examples of the latter.
Although there are probably cases where introducing a new predator species can cause more problems than it solves (remember that Simpsons episode?), with careful planning and understanding of the ecology of the organism, such issues can hopefully be avoided. Usually, we err too far on the side of caution by choosing a species that is too much of a specialist, and we don't get the results we would hope for. Remember the Laricobius beetles I mentioned earlier? One problem with them is that they are so specialized, that when the hemlock woolly adelgid starts to become scarce the beetles have no other food source and begin to decline as well. They have no other food source, and thus have essentially no effect on existing native species.
Re:Life, lemons and unexpected outcomes (Score:3, Informative)
You're looking for the EPA study ...
http://www.epa.gov/glnpo/glwqa/usreport/part5.html [epa.gov]
In other words, some fish benefited, others didn't.
In other words, more zebra mussels == more fish. The lessened diversity could easily be explained by the fact that it takes time for these things to shake themselves out.
Maybe those nasty zebra mussels can be given some credit for making the water clean ... it's not like people were going to pay to set up a massive filtering system ...