Organisms Found in Ballast Water
Organisms Present in Ballast Water
Ballast water is one of the major vectors for aquatic species invasions. On any given day, it is estimated that more than 5,000 species of freshwater, brackish and marine organisms may be transported in the ballast water of ocean-going vessels around the world.
Many studies have documented the great diversity of organisms present in ballast water. In one study, scientists sampled 159 vessels in
A separate study sampled vessels traveling from
The organisms found in ballast water are not only plants and animals, but researchers have found species of dinoflagellates (phytoplankton) responsible for creating red tide (also known as harmful algal blooms). Scientists also commonly find many species of bacteria and even the virus known to cause Cholera.
Specific Examples of Species Invasions Attributed to Ballast Water Release
The zebra mussel Dreissena polymorpha was first found in the
Typical densities of the clam in the northern Bay exceed 2,000 clams per square meter. Corbula amurensis is capable of filtering the entire water column in shallow water almost 13 times per day. At this rate of filtration, there are very few planktonic organisms left in the water column for larger animals to feed upon. This clam also accumulates selenium at roughly three times higher concentrations than the clams that had lived in the northern part of the bay before. The birds and fish that commonly feed on Corbula amurensis are thus ingesting selenium at levels that may lead to reproductive damage, including birth defects, impaired hatching, and reduced growth of young life stages. More information on Corbula amurensis.The overbight clam Corbula amurensis was first found in the San Francisco Bay/Delta region in 1986.
Carlton, J.T. and J.B. Geller. 1993. Ecological roulette: the global transport of nonindigenous marine organisms. Science, 261: 78-82.
Chu, K.H., Tam, P.F., Fung, C.H. and Q.C. Chen. 1997. A biological survey of ballast water in container ships entering Hong Kong. Hydrobiologica, 352: 201-206.
Gollasch, S., Lenz, J., Dammer, M. and H-G Andres. 2000. Survival of tropical ballast water organisms during a cruise from the INdian Ocean to the North Sea. Journal of Plankton Research, 22(5): 923-937.
Ruiz, G.M., Carlton, J.T., Grosholz, E.D. and A.H. Hines. 1997. Global invasions of marine and estuarine habitats by non-indigenous species: mechansism, exten, and consequences. American Zoologist, 37: 621-632.