Ballast water is one of the most important vectors for marine species transfer throughout the world. Organisms transported through ballast water have resulted in the unintentional introduction of hundreds of freshwater and marine species to the U.S. and elsewhere (Carlton and Geller 1993, NRC 1995, Carlton and Cohen, 1998).
Ballast water is carried by ships to provide balance, stability, and trim during sailing and to keep them upright during loading and offloading operations. Ballast water is typically held in dedicated ballast tanks located around cargo holds and near the bow and stern of the ship. The cross-section on the container vessel below shows how ballast tanks surround the cargo hold to provide stability and support to the vessel. Ballast water is loaded from the surrounding port or coastal waters as cargo is offloaded. This port water contains a diverse assembly of marine life, that if released into a new port, can sometimes establish non-native populations, resulting in biological invasions. Some biological invasions have severe ecological or economic impacts.
|The cross-section of a container ship being dismantled in Busan Harbor, Korea. Notice the ballast tanks (dark grey) surrounding the cargo hold (light grey) to provide stability and support to the ship.|
We have developed a research program which investigates several different facets of ballast-mediated invasions including:
- The ecology of ballast water tanks and
- The effectiveness of management tools utilized to slow the rate of invasion due to ballast water discharge and exchange.
Although the effects of many introductions remains undetermined, it is clear that some invaders do have significant economic, ecological and human-health consequences. Ballast water introductions such as zebra mussels in the U.S Great Lakes and toxic dinoflagellates in Australia have had tremendous ecological and economic impacts.