Environmental Science & Technology
( First paragraph) A complex assemblage of microorganisms exists in nearly every aquatic system on earth. In lakes and oceans, every milliliter of water contains about 102 protists (single-celled eukaryotes), 106 bacteria, and 107–109 viruses. Therefore, billions of microorganisms inevitably enter ships’ ballast tanks during normal operations. It has been argued that microorganisms must certainly be frequent invaders of coastal ecosystems, given the high densities of bacteria and viruses in ballast water—108 and 109 organisms per liter, respectively (1)—their potentially high reproductive rates, broad tolerances to physical conditions, and ability to form resting stages (2). The “propagule pressure” of microorganisms contrasts sharply with the mere tens of thousands of mesozooplankton that might be released during ballast discharge (3). The phylogenetic diversity of microbes in ballast water is reportedly composed of large, easily recognized forms, such as dinoflagellates, diatoms, ciliates, and foraminifera (1, 4). However, the bacterial and viral diversity in ballast water is absolutely unknown. Our understanding of the microbial diversity found in ballast tanks depends on new, sophisticated molecular biological techniques and certainly will increase with more advanced studies (5, 6).
Original Publication Citation
Dobbs, F. C., & Rogerson, A. (2005). Ridding ships' ballast water of microorganisms. Environmental Science & Technology, 39(12), 259A-264A. doi:10.1021/es053300v
Dobbs, Fred C. and Rogerson, Andrew, "Ridding Ships' Ballast Water of Microorganisms" (2005). OEAS Faculty Publications. 302.