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IPY Oslo Science Conference: June 2010 Archives

Oslo: Seals unlock Wilkins Ice Shelf mystery

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It's clear that Antarctica's Wilkins Ice Shelf has suffered considerable disintegration, breaking up in 1998, 2008 and 2009. What's been less clear is exactly where all of the heat to cause the collapses came from. Now elephant seals carrying sensors on their heads have helped solve the mystery.

The sensors revealed the seals were diving to greater depths than current bathymetry records acknowledged existed, Daniel Costa of the University of California explained at the International Polar Year Oslo Science Conference. This indicated the presence of troughs in the continental shelf underneath the ice; it seems these troughs enabled warm circumpolar deep water to travel onto the continental shelf and help weaken the ice above. A paper on these results is currently under review at GRL.

Not only have the seals helped oceanographers and glaciologists but the data they have collected could help predict their own future as climate changes in the Antarctic Peninsula. Information gathered during an IPY project shows that elephant seals tend to forage in circumpolar deep water. Crabeater seals, on the other hand, feed in both circumpolar deep water and Antarctic surface water, and stray much less far from the ice shelf around the peninsula.

If winds speed up in the future as climate change predicts they will, this is likely to cause more circumpolar deep water to intrude onto the continental shelf, bringing additional heat to the region. While probably a bonus for the elephant seals that forage for fish and squid in such water, it's likely to reduce the amount of sea ice off the Antarctic Peninsula. That could be bad news for crabeater seals as they feed on krill, which like to live under pack ice. Crabeater seals also rely on sea ice to breed, unlike land-breeding elephant seals. So it looks like elephant seals could become more abundant in the Antarctic Peninsula and crabeater seals less so.

That said, the past has also seen changes in the distribution of wildlife in the Antarctic region, Costa explained. Analysis of seal fur from old haul-out sites in the Ross Sea region has shown that elephant seals used to visit the region but they no longer do.

Oslo: frost flowers create a mercury bouquet

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Frost flowers, the delicate structures that form on the surface of fresh sea ice, have been implicated in mercury depletion events – the drop in atmospheric mercury levels at the poles in springtime. Now researchers have come up with a potential mechanism for how the flowers take up mercury.

Speaking at the IPY Oslo Science Conference, Jody Deming of the University of Washington, US, explained how she and her colleagues discovered microbes living in the frost flowers, the first indication that the structures can support organisms. It's protective exopolymers secreted by these bacteria that absorb the mercury.

Deming doesn't think that anyone had looked for microbiology inside frost flowers before because of their extreme conditions – low temperatures (frost flowers form at temperatures of less than –8 °C), high salinity due to the expulsion of brine as the sea ice freezes below, high ultraviolet levels, and a brief lifetime before being dispersed by wind or squashed beneath snow.

As part of Canada's Circumpolar Flaw Lead project, the team found lots of frost flowers, with dendrites 3–5 cm long, on thin ice in December 2007 and January 2008. Epifluorescence spectroscopy revealed the presence of microbes. What's more, when the team grew frost flowers in the laboratory it found that the saltier the frost flower, the more bacteria it contained. It seems that bacteria are forced out of sea ice as it freezes, alongside salt. "Bacteria are impurities just like brine is," said Deming.

Exopolymer concentrations in the frost flowers were 26 times higher than in sea ice. These gelatinous substances are secreted by microbes to help protect them from dessication, freezing and heavy metals. The polymer binds to the metal; it's this action that the researchers believe is causing frost flowers to adsorb mercury during depletion events.

A paper on the work is in press at Geophysical Research Letters.

Castration might sound like a controversial solution to the human population growth that is boosting carbon emissions, but the operation in question is for reindeer, not people. Rising winter temperatures can cause freeze-thaw cycles that create thick ice layers on top of snow; this makes it harder for reindeer to reach the lichen that they feed on beneath.

So how can castration help? Unlike normal males, castrated males retain their antlers during the winter, enabling them to dig grazing holes through snow and ice, explained Eli Risten Nergård of Sami University College and the Norwegian School of Veterinary Science at the IPY Oslo Science Conference. Although females also retain their antlers they may not be strong enough to dig effectively; both females and young reindeer can exploit the holes made by castrated males.

But animals castrated using the modern tong method have weaker antlers and less muscle bulk than those treated with the traditional biting technique used by the Sami people of Northern Scandinavia. Nergård has found that the tong technique cuts the reindeers' testosterone levels to zero whereas the traditional technique, which is no longer permitted under Norwegian animal welfare legislation, leaves the animals with a reduced level of testosterone. So reindeer castrated in the traditional "gaskin" way are likely to be better able to clear ice and snow with their antlers over the winter than other castrated males. Castrated males also have an increased chance of survival over entire males because they don't lose weight and body condition during the rutting season.

Nergård, who has been working as part of the EALAT study, says preliminary results indicate that it may also be possible to castrate the reindeer using a vaccine.

Oslo: Polar vision meets Eurovision

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International Polar Year science conference kicks off in Oslo

It seems that the organizers of the International Polar Year Oslo Science Conference were inspired by the city's hosting of the Eurovision Song Contest just a couple of weeks ago. Delegates at the opening ceremony this morning were greeted by Norwegian teens dressed in snowsuits singing, playing the drums and issuing apparent cries for help through a frozen trumpet as the first number ended with the sound of melting water and cracking ice. Interspersed between the musical entertainment, which included Norwegian Eurovision host Haddy N'jie and culminated with a rendition of Michael Jackson's Heal The World, were more serious messages about International Polar Year. This vast international collaboration brought more than 50,000 scientists from 60 countries together to work on 160 projects over the course of 30 months; more than 2000 researchers are now in Oslo to share their findings in the largest-ever gathering of the polar-science community.

Russian scientist Artur Chilingarov, who planted a Russian flag beneath the North Pole in 2007, announced at the ceremony that he is lobbying for an International Polar Decade to start in 2011. David Carlson, director of the International Polar Year International Programme Office, told environmentalresearchweb that he believes this move is a compliment to International Polar Year and indicates that scientists think it's worked well. He is less keen on the concept of a decade, however, as it is both too long and too short a time period. International Polar Year was sold to funding bodies as an intense 30-month research push, so in this sense 10 years is overly long but polar research will be vital over more than the next decade. Indeed, there is still much analysis to carry out from the data collected during International Polar Year.

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