Ballast Water - A Pathway for Aquatic Invasive Species
More than 21 billion gallons of ballast water are discharged into U.S. waters from international ports every year. An estimated 10,000 marine species are transported around the world in ballast water every day (Source: NOAA CSC, 2007).
In order to remain stable when loading and unloading cargo, filling up or burning fuel, and when traveling under a bridge, ships may take on and release ballast water. Once ballast water is taken on board, it may be released half-way around the world. Ballast water usually contains a variety of biological organisms including animals, plants and pathogens. The result is the introduction of these species into a new environment. If the organisms survive, they can cause major ecological and economic damage to the ecosystem. George Smith, a marine biologist with the Smithsonian Environmental Research Center, discusses methods to test and treat ballast water.
Transcript (pdf). Source: Smithsonian Environmental Research Center
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Cross section of ships showing ballast tanks and the ballast water cycle.
Source: International Maritime Organization. http://globallast.imo.org
A ship releasing ballast water.
Credit: Smithsonian Environmental Research Center Marine Invasive Laboratory
Closer Look
Relevant Links
U.S. Geological Survey Nonindigenous Aquatic Species
http://nas.er.usgs.gov/
Aquatic Nuisance Species Task Force
http://anstaskforce.gov/default.php
Smithsonian Environmental Research Center - Marine Invasions Research Laboratory
http://serc.si.edu/labs/marine_invasions/
