According to Bradley van Paridon, freelance writer, one of the largest geographic surveys of ballast and harbour water, conducted by Claudia Gunsch and William Gerhard, scientists at Duke University in North Carolina, showed that they can identify the source of ballast water based solely on the community of microbes in the tanks.
As the majority of global trade is occurring through vessels, the number of microbes, such as bacteria, viruses and fungi, are expected to increase.
As Mrs Claudia Gunsch commented
We’re just trying to understand what’s happening when this water is transferred transcontinentally, and now we actually have tools to be able to answer that question.
The development of technology means that it is easier today for scientists to sequence all of the bits of DNA in an environment by examining a small sample, such as of water or soil.
Yet, DNA scanning still needs improvement as it is not able to tell if the organisms found are alive or dead, or if the technology is only picking up the genetic residues of organisms that were once in the ballast tank but have since been dumped.
Also, the DNA analysis produces more information that needed, resulting to scientists being swamped.
However, scientists acknowledge that all the community members of an ecosystem are important.
In the case of ballast tanks, one plausible solution is to simply disinfect the tanks and kill unwanted microbes. Yet, as Olav Vadstein, a microbial ecologist at the Norwegian University of Science and Technology, explains, disinfection disrupts the balance of the ballast water ecosystem, and can actually encourage growth of opportunistic species.
This can potentially promote the growth of microbes that cause problems for wild and domestic aquatic life.
... Mr Vadstein noted.
For the research, the two scientists used these methods to take snapshots of the microbial residents in the ballast tanks from 41 ships, plus open ocean samples and water from four of the world’s busiest harbors.
They compared the living organisms with one another, and noted that they can identify the origin of them.
Unfortunately, they also found that the ballast water from five of the 41 ships tested did not comply with the International Maritime Organization standards for indicator organisms like E. coli and Enterococcus.