How many seeds do you think the average visitor to Antarctica might inadvertently take with them? One or two, right? How about an average of nine per visitor — or 2,700 over only a few months. That's a serious alien invasion. Wired reports on the issue, which relates to both the influx of people to Antarctica and the change in climate that makes it possible for cold weather plants to thrive in Antarctica's frosty environment.
A group headed up by Steven Chown, an environmental scientist at Stellenbosch University in South Africa used vacuums to inspect the travel equipment of more than 850 scientists, tourists and support personnel in late 2007 and 2008, and harvested nearly 2,700 seeds. To make matters more alarming, that's only around two per cent of the visitors during that period. Roughly half of the seeds that travelled in on clothing and equipment were cold weather climate seeds that could spread and drastically change the Antarctic environment.
I know this is a potentially serious problem, but (my own fan biases being what they are), I can't help but think of Doctor Who at a time like this — if not only because the scriptwriters used this as the basis of not one, but two stories; firstly in "The Seeds Of Death" in 1969, and then in "The Seeds Of Doom" in 1976.