Ballast water, water used by ships for stabilization, is a known vector for the transport of foreign species from port to port. It is estimated that as many as 10,000 different species are transported daily, including invaders that could and have caused millions of dollars of economic damage and untold environmental impacts on the ecosystems to which they have been introduced. Many methods have been suggested and used for the control of ballast water, both mechanical and chemical. These include ballast water exchange, where water from the harbor is let out in exchange for water from the open ocean, and various methods that can be used on board the ships, including biocides, filtration, and thermal and chemical treatments. However, each of these approaches has different strengths and weaknesses.
Tara Porter of Duke University has suggested a way to identify ballast water organisms on board moving ships. To do this, she suggests testing first the ability of DNA microarray systems to identify different organisms in lab by setting up tanks with similar environments to those found in the ballast areas of ships. Porter’s study will then introduce different known invasive species to the tank, which will next be tested using DNA microarrays. The results from this analysis will then be compared to the species actually introduced to the tanks to see which species the technique was able to detect. To test this method on board, Porter then plans to partner with a shipping company to use the technique aboard their ships.
Porter hopes to find a way to determine the types of invasive species on board without having to send samples off ship for testing. This is at present not possible, and will prove a major enhancement in monitoring invasive species and preventing their spread through shipping. Furthermore, the results of the study could be used to analyze the efficacy of current treatments, and help find the most effective technique for the on board treatment of ballast water and the prevention of the spread of invasive species.