The effects of Freshwater Flushing on Marine Heterotrophic Protists- Implications for Ballast Water Management

摘要

Survivorship of ballast-entrained marine heterotrophic protists was examined following freshwater flushing. The recovered taxa, including Laypical marine rhizopods such as Platyamoeba murchelanoi, Labyrinthula spp, Pontifex Maximus, Thecamoeba orbis, and the ciliate Condylos- Toma arenarium, were reared in waters of various salini- Ties. After 2 months, the original salinity subsample Retained five protist taxa, the freshwater six, including the Amoeba Cochlipodium bilimbosum, the brackish water 22 taxta, and the seawater 19 taxa. Since protists form a major component of marine microbial food webs, their survival may be instrumental in supporting complex bal- last-entrained food webs. Our study raises questions as to the reliability of open-ocean exchange (OOE) or fresh- water flushing as effective control measures.