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Jelmert, A and A. Jelmert, 2001. Gas Supersaturation, a Novel and Environmentally Friendly Method for Eliminating Unwanted Organisms in Ballast Water and Other Water Bodies, Austevoll Aquaculture Research Station. Proceedings of the Second International Conference on Marine Bioinvasions, New Orleans, La., April 9-11, 2001, p. 77. Gas Supersaturation, a Novel and Environmentally Friendly Method for Eliminating Unwanted Organisms in Ballast Water and Other Water BodiesGas supersaturation is known to affect various aquatic biota. When aquatic multicellular organisms are exposed to gas supersaturated water, and especially when subsequently subjected to lowered hydrostatic pressures, they are suffering from embolism and hemorrhages. If the level of supersaturation is high enough, the condition may be lethal. Also sublethal exposures represent a considerable stress to the organisms. While lethal effects occationally have been observed in natural or seminatural conditions, we have suggested it can be optimized and used to prevent the transfer of unwanted organisms translocated via ballast water (Jelmert 1999). The susceptibility to gas supersaturation varies between the different systematic groups of organisms such as molluscs Mya arenaria at 114% (Bisker and Castagna 1985), and Argopecten irridans concentricus at 116% (Bisker and Castagna 1987), subadults of the saltwater tilapia Oreochromis spilurus, at 112% (Saeed and Al-Thobaiti 1997), larvae of the white sturgeon Acipenser transmontanus at 131% (Counihanet al. 1998) We would not expect gas supersaturation to affect the microbial community directly, but the breakdown of dead and moribund macrobiota may lead to shifts in the species composition in the microbial community. Results from tests on the effect of gas supersaturated (air and nitrogen + air) seawater on the brine shrimp Artemia sp. and juveniles of the common mollusc Mytilus edulis will be presented and discussed. The method offers two major advantages: no need for storing or handling harmful chemicals, and no harmful chemical substances released when treated water is discarded. General applications and limitations of the method will be outlined. Literature cited: Bisker R. and Castagna, M. 1987. The effects of air-supersaturated sea-water on Argopecten irridans Lamarck and Crassostera virginica Gmelin with reference to gas bubble trauma. J. of Shellfish Research 6(2):79-83. Counihan, T.D., A.I. Miller, M.G. Mesa, and M.J. Parsley. 1998. The Effects of Dissolved Gas Supersaturation on White Sturgeon Larvae. Trans. Am. Fish. Soc.127(2): 316Ð322. Jelmert, A. 1999. Process and apparatus for the treatment of water systems. Norwegian patent nr. 1999 5582. Saeed M.and Al-Thobaiti. 1997. Gas bubble diseas in farmed fish in Saudi Arabia, Veterinary Record 140(26): 682-684. Contact: Anders Jelmert, Institute of Marine Research, Austevoll
Aquaculture Research Station, N-5392 Storebø, NORWAY |
