Spreading Aliens, Arctic Experience, and Antarctica *suitable for home teaching*

This podcast from the Planet Earth Online collection and the Natural Environment Research Council (NERC) looks at how hikers and walkers could be unwittingly changing the landscape by spreading alien species; what it's like to work as a marine biologist in the Arctic in temperatures of minus 40°C; and exactly how stable is the West Antarctic Ice Sheet? Alien, or invasive, species are plants and animals that spread so much they cause problems for local biodiversity. Japanese knotweed, the grey squirrel and the harlequin ladybird are all examples of species that have been brought into the UK. But invasive species are not just a UK problem; they are now recognised as a major threat to biodiversity around the world. In a recent study, scientists calculated that hikers in one Australian national park could be spreading as many as two million invasive plant seeds on their socks alone in just one season. Sue Nelson goes to the River Thames in Oxfordshire to find out a bit more about why this study has its roots in the Dorset coastline. In an audio diary entry, Ceri Lewis from the University of Exeter reports from the Catlin Arctic Survey, where she found out how tiny marine creatures called copepods are adapting to climate change. She describes the challenges of doing science at minus 40°C. Finally, Richard Hollingham goes to Exeter to find out how cosmic rays can help geologists figure out how stable the West Antarctic Ice Sheet is. A transcript of the recording is provided to assist those who find text-based content more accessible than audio. This podcast is dated 27 September 2011. NERC is one of the research councils in the Research Councils UK (RCUK) partnership.