AS THE nights get longer in the northern hemisphere, scientists are heading to Antarctica in their thousands. Their quarry includes meteorites, penguins and revealing ice cores. Only about 1000 people overwinter in Antarctica, and the population is听set to quintuple for the next six听months as scientists make the most of the continent鈥檚 summer research season, which runs from November until April.
Constant daylight, sub-zero temperatures and brutal winds await. But that isn鈥檛 enough to put the travellers off. 鈥淲e are well kitted out, and we stay in pyramid tents, which are surprisingly cosy,鈥� says Katherine Joy from the听University of Manchester, UK,听who听is heading south with colleague Geoffrey Evatt in search of buried meteorites.
Antarctica is a particularly good place to collect these rocks 鈥� not only are they easy to spot there, but the ice acts as a conveyor belt that deposits them in hotspots. Meteorites from the frozen continent make up about two-thirds of the 35,000 space rocks collected so far, giving valuable information about the solar system.
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But very few iron-based meteorites have been found in this Antarctic bounty. These are made from the cores of destroyed small planets, so hold vital clues about how planets formed in the early solar system.
Evatt and Joy think these meteorites are missing because they get . In January, Evatt will be heading to the British Antarctic Survey field station, Sky-Blu, at the southern end of the Antarctic Peninsula, to test equipment 鈥� in essence, a metal detector and a chainsaw 鈥� for finding and extracting buried meteorites.
鈥淚t鈥檚 utterly exciting to be听at听the heart of this. We听may find meteorites from Mars or the moon鈥�
Joy is aiming to reach a rarely visited region south of the Shackleton mountain range, to scope out promising places to use this equipment the following season. 鈥淲e鈥檒l be out on skidoos for most of the day, exploring the ice fields. Hopefully the weather will be kind, because you need good visibility to spot small meteorites on the ice,鈥� she says.
If their buried meteorite hypothesis is correct, it might allow them to uncover a new trove听of space rocks. 鈥淚t鈥檚 utterly exciting to be at the heart of this. We may find a new Martian or lunar sample,鈥� says Joy.
On the other side of the continent, at France鈥檚 Dumont d鈥橴rville Station, work has already begun to survey the breeding success of a nearby colony of emperor penguins. There are only 54 breeding colonies of this iconic Antarctic resident, many of which are under threat from climate change. But the colony of some 4000 breeding pairs near Dumont d鈥橴rville seems to be doing well for now. Their chicks hatched in July. In some years, few听survive. But this year has been听a very successful one, says Christophe Barbraud of the French National Centre for Scientific Research (CNRS).
But one thriving colony doesn鈥檛 mean all is well for emperors elsewhere. 鈥淵ou can have very different breeding success at different colonies due to different ice conditions,鈥� says Barbraud.
To see how penguins are faring in less-accessible places, researchers use satellite imagery and aerial photography, including photos of five colonies taken on helicopter flyovers by a team at the US鈥檚 McMurdo Station.
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Meanwhile, 1200 kilometres inland, a European team is preparing to drill back in time.
Analysing the air bubbles trapped in ice cores extracted from the thick ice sheet that covers Antarctica has enabled us to study the climate of Earth going back hundreds of thousands of听years. These measurements have been invaluable for understanding how听our planet鈥檚 climate can change, but so far we have only looked back 800,000 years.
This summer, the 鈥淏eyond EPICA鈥� team is making preparations to drill a core that stretches back at least 1.2听million years. The group has identified a听place high on the Antarctic plateau called Little Dome C, where it thinks this ancient ice might lie.
If it works, an ice core from this听spot will enable us to study the period about 1听million years ago when Earth started having ice听ages every 40,000 years, instead of every 100,000 years. Understanding what drove this shift, and whether increasing carbon dioxide levels played a part, will help us to predict future climate responses to higher levels of greenhouse gases.
The team doesn鈥檛 yet know if it will be given European research funds to drill this core 鈥� a huge undertaking that will probably take place in two Antarctic summers鈥� time.
While waiting to hear, the team is drilling at Little Dome C to obtain ice chips, and measure isotopes within the ice to determine how old it is. 鈥淭his will听give us information about samples at depth, without waiting for the real core,鈥� says glaciologist Olaf Eisen of the Alfred Wegener Institute in Germany, who is coordinating the project.
The team can expect harsh conditions, he says. 鈥淚t鈥檚 -30掳C on a听warm day,鈥� says Eisen.
Picked up by a penguin
It is tempting to think of Antarctica as pristine and protected from human influence, but that isn鈥檛 the case.
The Antarctic summer sees many scientists arriving on the continent, some of whom go there to study how climate change is affecting penguin species (see main story).
But when we travel, we take our bacteria with us. Vanessa Marcelino at the University of Sydney, Australia, and her colleagues have compared the diversity of gut microbes carrying antibiotic-resistance genes in gentoo penguins living near two Chilean Antarctic bases.
Swabbing the throats and cloacas of 20 penguins, they found that both populations had resistance genes in their microbiomes, and that those living near O鈥橦iggins Base carried a greater number of resistance genes than those near the smaller, less-populated Gonz谩lez Videla Base (bioRxiv, ).
The study 鈥渄emonstrates really nicely the interlinkage between humans and the environment, which is very often overlooked鈥�, says Josef J盲rhult at Uppsala University in Sweden.
However, it is hard to know for sure that it is people鈥檚 presence in Antarctica that is causing these bacterial genes to spread to penguin populations. Antibiotic resistance can occur naturally, and microbes with resistance genes have been found in ancient Antarctic soils before.
Francois Balloux at University College London says more evidence is needed to tie the presence of this genetic material to human activity in the areas sampled. 鈥淭here鈥檚 no pristine place on Earth as far as antimicrobial resistance is concerned,鈥� he says.
Chris Baraniuk
This article appeared in print under the headline 鈥溈烀ǘ淌悠祍 migrate to Antarctica鈥�
