How can organisms survive long journeys inside the bowels of a ship?
A. A modern cargo ship can carry up to 10 million gallons of ballast water. Given that most ships dump their ballast water every two or three weeks, this much water gives traveling organisms an ample amount of oxygen and other nutrients to survive. In addition, when faced with unfavorable conditions, some microorganisms and plankton species will form spores or other tough outer coverings for protection. As a spore, an organism may survive for a long time without food or in a different salinity or temperature than its natural environment. Once the environment becomes favorable again, such as when they are discharged into a port, the organism may change back to its active form.
