Survival potential of autotrophic phytoplankton species collected from ballast water in international commercial ships

To understand the impact of environmental factors on the survival success of introduced species by ship ballast water, we investigated the survival potential of autotrophic phytoplankton from international commercial ships. Ballast water was collected from chemical tankers that originated in three different bioregions. A laboratory experiment was designed to simulate the resource-limited waters of the ballast tank as well as the eutrophic water of port and coastal waters in which nutrients are plentiful. Phytoplankton survival and population growth were significantly higher in nutrient-enriched water than in water from the shipside or ballast water. In particular, the centric diatom Thalassiosira pseudonana was able to tolerate a wide range of salinities (0-30 PSU) and its high survival potential indicated that it could colonise novel ecosystems successfully.