Are ships spreading disease?
Ships are inadvertently carrying trillions of stowaways in the water held in their ballast tanks. When the water is pumped out, invasive species could be released into new environments. Disease-causing microbes could also be released, posing a risk to public health, according to an article in the May issue of Microbiology Today. “There is no romantic adventure or skullduggery at work here,” said Professor Fred Dobbs from Old Dominion University, Virginia, USA. Ships pump water in and out of ballast tanks to adjust the waterline and compensate for cargo loading, making the ship run as efficiently as possible. These tanks can hold thousands of tonnes of water. “Any organisms in the water are likely to be released when it is next pumped out.” Many non-native animals and plants have been taken to new environments and become invasive, threatening the survival of local species; some fundamentally alter the ecosystem. Zebra mussels were introduced in North America and the comb jelly in the Bl
