인천항과 울산항으로의 생물종 침입에 영향을 미치는 환경요인

Abstract

Possible introduction of foreign species through ship ballast water was tested by incubation experiment to regulate the ship ballast water discharge in the receiving water. Phytoplankton was sampled by vertical hauls with the standard type net (20 and 10 µm mesh) through manhole type ballast tanks of commercial ships in Incheon and Ulsan port in 2005 and 2006. Recovery experiments were conducted by inoculation of phytoplankton transported through ballast water into two types of media such as filtered port sea water (0.2 µm membrane filter paper) and F/2 media in Incheon port. Following time series incubation, it was evident that some species like Skeletonema costatum and Leptocylindrus danicus can grow fast in the natural seawater after being discharged rather than in F/2 media. In the incubation experiment of Ulsan port, incubating conditions consisted of filtered port seawater, ballast water and F/2 media at two conditions of temperature during January to March. In the optimal condition (20℃), fluorescence of phytoplankton rapidly reached maximum values compared to the ambient condition (14℃). And fluorescence of phytoplankton in the F/2 media was higher than that in the port and ballast water in the ambient and optimal condition of temperature. These results indicated that alive non-indigeneous species will be successfully established, providing that nutrient concentration and temperature of receiving water are optimal to introduced species.