Our Changing World for Thursday 16 June 2011
Life in Antarctic Sea Ice
Andrew Martin and Ken Ryan drilling an ice core (Scott's Terra Nova hut in the background), and Ken Ryan showing algae growing on the bottom of an ice core (Mount Erebus in the backgroun). Images: A. Ballance
Each winter the sea around Antarctica freezes (click here to see the extent of Antarctic sea ice over the preceding 30 days).. By mid June the sea ice already wraps Antarctica in a giant frozen blanket, and it reaches its maximum extent of about 18 million square kilometres in late September. While it looks desolate and inhospitable, the sea ice is actually home to a great diversity of algae and microbes that live within or on the underside of the ice.
While Alison Ballance was at Scott Base last summer she visited a research project called Life in the Ice, in their field camp at Cape Evans. Ken Ryan and Meghana Rajanahally from Victoria University, Julie Deslippe from the University of British Columbia, and Andrew Martin from the University of Tasmania explained their work and demonstrated some of their techniques. Ken began the tour by explaining why the sea ice is the Antarctic equivalent of a sheep farm, with the algae on the underside of the sea ice being the grass, and tiny krill being the sheep.
You can listen to stories on the physics of sea ice which played earlier this year here: Tim Haskell and Pat Langhorne.
Ken Ryan sawing up an ice core, and Andrew Martin about to deploy a CTD into a large dive hole drilled in the sea ice (Images: A. Ballance)
Limits to Freshwater
Last week, scientists gathered to discuss Earth’s biophysical limits and whether continued economic growth is possible within finite resources. This interview focuses on freshwater, a renewable but increasingly limited resource. Only 3% of the planet’s water is fresh, but most of it (about two thirds) is not available as it is frozen in glaciers and polar ice caps. Most countries already face shortages of freshwater.
New Zealand is one of few countries in the world with an abundance of freshwater, but some rivers and aquifers are at risk of depletion. As a new policy on freshwater is coming into effect on July 1, Clive Howard-Williams, an aquatic ecologist at the National Institute of Water and Atmosphere, discusses limits on freshwater quality and quantity and how water management could be improved.
Oxygen and Free Radicals
University of Otago, Christchurch’s Christine Winterbourn (above) and Amelia Albrett are studying oxygen and free radicals. In particular, they’re looking at the process whereby our white blood cells generate superoxide to kill bacteria, a process which involves the generation of chlorine bleach by an enzyme, myeloperoxidase. Ruth Beran visits them in their temporary laboratory in Christchurch, to find out why her work could have implications for people with cystic fibrosis.
Christine Winterbourn will be giving a seminar entitled Living with Oxygen on 28 June at 7.30pm at the Speirs Centre, Palmerston North Boy’s High School, Featherston Street, Palmerston North as part of the Marie Curie Lecture Series - a year-long national tour of talks by female New Zealand chemists in honour of Curie’s Nobel Prize in Chemistry.