Quite obviously, billions and billions of bacteria and viruses are moved in every ship’s ballast every day, but the real issue is whether that matters. Since bacteria and viruses are common throughout the planet, does it make a difference in which body of water they live? Scientists are increasingly suspecting the answer is yes, that these microorganisms have a natural home, known as a biogeography, and that they could very well one day prove to be just as invasive a species as a mussel. The only difference being we could end up as the infected. There are proposals floating about to address the issue in ships with decontamination systems, and a handful are currently monitoring their efficacy. But because there have been no known outbreaks associated with ballast water, very little water testing is ever done. Via PhysOrg
