NATURE|Vol 446|8 March 2007 POLAR RESEARCH NEWS FEATURE POLAR YEAR PROJECTS
The fourth International Polar Year (IPY) But there are complications. The Antarctic deeper 4,700 metres of ice, but covers a small is a bit of a misnomer — it’s actually two ice cap acts as an insulator, lying like a blanket area in which the surrounding rock may have years long. From March 2007 to March across the continent and trapping geothermal distorted the ice at the bottom. Farther afield, 2009, a host of scientists will head out heat below it. The thicker the ice, the greater there are other areas in Antarctica likely to hold to both the Arctic and Antarctic for the insulation, and so when the ice gets really very old ice (see map), but they are trapped in targeted research, from marine biology thick its base will frequently become warm mountain ranges where the ice record is much to anthropology. Here’s a look at some of enough to melt, shortening the record. thinner and more squashed. the projects being planned — although Also, the topography of the rock beneath funding for some is still pending. the ice is complex, to say the least. A mountain Disturbing the peace range lies down there (see ‘The hidden moun- Dome A thus remains the prime candidate for Whale movement tains’, overleaf). If the ice at the bottom of the drilling. But too little is known for research- Several hundred beluga whales ice sheet has been forced to move up and over ers to draw an X in the snow and plant their (Delphinapterus leucas) in the Arctic will rocky ridges, it will be folded, muddled and drill. So starting next year, if funding comes be tagged with satellite transmitters and, mixed, making it impossible to date it or to through, the sky over Dome A will be filled in some cases, oceanographic data extract clean information from it. The bottom with the rare noise of low-flying planes, bur- collectors. Understanding the 70 metres of the Dome C core were like this, dened with radar and equipment to measure timing and pattern of beluga making its oldest ice unusable. gravity and magnetic fields. movements in relation to ice Models suggest that the flow of ice away Particularly helpful will be the radar sur- and ocean conditions may from the base of Dome A is small, so older veys, which can pick up changes in density, help efforts to protect the ice should still be preserved at the bottom. crystal structure or dust content in the ice. By whales in the face of climate change. A map of ice ages by modeller Philippe Huy- flying from Dome C to Dome A, the IPICS brechts of the Dutch-speaking Free Univer- team hopes to be able to track ancient layers Ocean microbes sity Brussels in Belgium (see map), confirms along the 1,000-kilometre flight path, thus A Norwegian-led effort to document the that an area near the peak of Dome A — a vast revealing the depth of correlated layers in the biodiversity of microorganisms in the polar swath about the size of Britain — is suitable for ice at Dome A. seas could provide a basis for understanding
an old-ice hunt. Given the remoteness of Dome A, the how these creatures help to regulate the K. SCHAFER/CORBIS Apart from Dome A, other candidate planes will need local bases from which to ecosphere. sites for the oldest ice do exist. The Aurora refuel. Ideally, these will be placed around the basin, near Dome C but closer to the coast, dome at slightly lower altitudes, as the height Polar astronomy for example, is about 4,500 metres deep and of the dome makes the air so thin that propel- Because of their extremely cold, dry, stable could potentially hold very old ice. Australia ler planes have trouble taking off and pilots’ air, the polar plateaus provide the best plans to drill a 400-metre test core there in the functioning can be impaired. “Technically, sites on Earth for a range of astronomical 2008–09 season, says Vin Morgan of the Aus- the pilots should be using supplementary oxy- observations. An Australian-led team will tralian Government Antarctic Division near gen,” says Wolff. And in similar circumstances, assess just how good the conditions are for Hobart, Tasmania. But this area is lower and loaded Twin Otter planes have had to use jets astronomy at sites including Dome A on the warmer than Dome A, increasing the chances strapped to their wings to gain enough lift. Antarctic plateau. that its bottom ice has melted substantially. That same season, the Chinese research- The nearby Astrolabe basin has an even ers plan to return, this time carrying French Spider survey German researchers hope to lead a survey of ANTARCTICA’S OLDEST ICE spider biodiversity across the Arctic. Because Height: 4.1 km 0 Anticipated depth of ice core: 3+ km spiders adjust their lifecycles to microclimatic Age back in time: 1 million years+? 20 conditions, studying them can help scientists Height: 3.8 km track the effects of rising temperatures on Depth of ice core: 3 km 100 Age back in time: 720,000 years terrestrial habitats. 300 3 500
P. HUYBRECHTS, VRIJE UNIV. BRUSSEL VRIJE UNIV. HUYBRECHTS, P. 700 2 900
1,200 present* before of years Thousands *modelled at 98.5% depth J. HAMMEL/STUTTGART UNIV. HAMMEL/STUTTGART J.
RESEARCH STATIONS Height: 3.5 km (mentioned in text) Carbon pools Ross Ice Depth of ice core: 3.6 km McMurdo (US); An international effort, led by Sweden, plans Shelf 1 Age back in time: 420,000 years 1 Scott (New Zealand) to assess the quantity and quality of organic 2 Zhongshan (China) matter in high-latitude soils. The work may Height: 3.3 km prove crucial to predicting what could happen Depth of ice core: 3.2 km 3 Halley (UK) to the enormous stock of carbon trapped Age back in time: 800,000 years there if the soils thaw.
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Martian mimics CORBY WEST/JPL CORBY
The Phoenix spacecraft will land on Mars during the IPY. Scientists hope to compare data from the planet‘s northern polar region with soil measurements from an analogous ‘extreme environment’: the Antarctic Dry Valleys.
Antarctic aliens More than 40,000 people visit the Antarctic each year — and they probably bring with them the seeds and spores of non-native species. The IPY will see the first full assessment of the environmental impact of these visitors.
Past warming One way to predict what might happen in a warmer climate is to look back in time. The WARMPAST project will use Arctic sediment cores to reconstruct ocean temperatures for the past tens of thousands of years.
Icy lakes Scientists from Canada
P. WEST/NSF P. School of rock and Russia will pore over LANDSAT The rocks of Antarctica are obscured literally, and sometimes historical data to see how the timing of ice freezing scientifically, by its ice. But drilling efforts are now showing what and breaking up on Arctic we can learn from the hard stuff. Alexandra Witze reports. lakes has changed over the past 50 years.
Changes in sea level hen it comes to Antarctica’s his- a new Antarctic record for drilling depth. tory, ice cores get all the glory. The period covered by the core — from UK and other researchers plan to add gauges Large-scale ice-drilling efforts, the present to more than 5 million years ago to monitor the sea level and tides in the Wsuch as Europe’s EPICA and — seems to be quite active. Preliminary analy- waters around Antarctica. Russia’s Vostok cores, capture headlines and sis has revealed thick layers of a greenish rock the lion’s share of people and funding. After interspersed throughout the core. This is an Arctic greening all, these cores contain air bubbles that are hun- indication of open-water conditions, sug- Climate change is likely to alter the dreds of thousands of years old, a frozen time gesting that the Ross shelf retreated and then distribution and type of plants at high capsule from Earth’s icy past. advanced at least 50 times within the past 5 mil- latitudes. Assessing satellite data, and doing But buried beneath the thick layers of ice, the lion years. With this nearly unbroken record, field studies to produce new vegetation maps rocks of Antarctica have far older stories to tell. scientists can explore the history of the shelf in for Russia, Alaska and Canada, will help Trapped within layers of mud and sand are geo- unprecedented detail. scientists predict such changes. logical records stretching back millions of years. “It’s going to be a benchmark that we hope we As Antarctica’s ice teams continue to hunt for the can refer to for years to come,” says Ross Pow- Reindeer herders oldest ice their drills will reach (see page 126), a ell, a geologist at Northern Illinois University in The knowledge and experience of nomadic smaller band of rockhounds is on a similar quest DeKalb. “It may be the geological equivalent of reindeer herders, accumulated over to plug the gaps in the geological record. the Vostok ice-core record.” As project co-leader, generations, will be documented to establish The team now has a core that promises Powell is understandably enthusiastic about how herders living across Norway, Russia and fresh insight into how Antarctica’s ice waxed the core, but then so are other geologists.
Alaska can sustain their way of life. EIRA/EALÁT INGER MARIE GAUP and waned over the past few million years. On The Ross ice shelf, the largest in the world, is 26 December, a US$30-million international a floating extension of the even more massive project called ANDRILL pulled up the final West Antarctic Ice Sheet. That part of Antarc- piece of a core from beneath the Ross ice shelf tica is regarded as the most unstable and poten- (see map, page 127). Previous coring efforts tially prone to collapse in a globally warmed have offered peeks into Antarctica’s deep his- world. If the west Antarctic ice sheet melted tory — back as far as 34 million years when the entirely, it would raise the global sea level by continent was first covered in ice. But the new about 5 metres. The Ross shelf is a tiny but core fills a gap in the ice shelf’s history, and sets important fraction of that. Its behaviour over
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Warm vents Studying hydrothermal vents on the Arctic mid-ocean ridge is a challenge as major portions of the ridge lie more than 4,000 metres under pack ice. In July and August, robotic vehicles will dive to the Gakkel Ridge — and therefore the ice — back to search for vents. to its source. They might turn
P. WEST/NSF P. out to have come from some- where else in west Antarctica, Satellite shots says Powell, or perhaps even as The photographic power of Earth-observing far as east Antarctica. Know- satellites is being pooled to yield a wide range ing the path the ice took could of snapshots of the world’s polar regions in help researchers better under- the highest resolution possible. stand how ice flows across the continent, thus aiding future models of ice flow as Antarc- tica warms. Other insights could come from comparing the ANDRILL core with ice cores such as EPICA. There isn’t much over- lap; only the upper 80 metres or so of the ANDRILL rock repre- sent the past 1 million years, Chilled out: the ANDRILL rig on the Ross ice shelf in Antarctica. and the whole of EPICA cov- AGENCY SPACE POLAR RES. CENTER/CAN. BYRD ers only the past 800,000 years. Solar activity day. And stronger-than-expected ocean currents But comparing rock and ice records could help Scientists will take measurements from the bent the pipe surrounding the drill as it stretched palaeoclimatologists correlate increases and polar regions to assess whether variation more than 900 metres through the ice shelf and decreases in carbon dioxide levels with what the in the Sun’s activity affects Earth’s weather the water below, before finally entering the sea ocean and the Ross shelf were doing at the time. and climate by influencing a global electrical floor. But after two months of non-stop drilling, “It will be very exciting to see how the records circuit in the atmosphere. the team recovered 1,285 metres of rock. of ice-sheet changes they have are related to the The core, now stored in the freezers of the changes in Antarctic temperature we have,” says Particle physics Antarctic geologic repository at Florida State Eric Wolff, an ice-core specialist with the Brit- Physicists will use the IceCube observatory University in Tallahassee, has yet to reveal all ish Antarctic Survey in Cambridge, UK, and a being built at the South Pole to search for its secrets. The first challenge, says Powell, is member of the EPICA team. subatomic particles called neutrinos. During pinning down its age. The top half of the core The next chapter in the story will start in the IPY, glaciologists are being invited to use seems to cover the past 5 million October, when the second leg the detectors to study ice flow. years, and that’s what contains “It’s spectacular. of ANDRILL gets under way. the 50-plus cycles of ice-shelf I was surprised For that, the researchers will collapse. The sediments show drill through the 7-metre-thick Polar bears repeated layers of ground-up at the striking sea ice in the southern part of A Danish-led team will examine rock debris scraped off the con- differences that the McMurdo Sound, through the contaminants in the muscles and bones of tinent by glaciers, interspersed core brought out.” ocean and again into the sea polar bears killed by with the open-water greenish floor. There, they are expected Inuit hunters. Chemical ooze rich in the marine organ- — Peter Barrett to pick up where the current analyses of the bears’ isms known as diatoms. The core left off — probably around body tissues could transitions between the glacial sediments and 7 million years ago — and extend the record to also shed light on how the open-water ooze seem to be quite sharp, around 17 million years ago. With that, geolo- much climate change is says Powell — suggesting that they took place gists hope, they will finally have a complete stressing the animals. relatively quickly. history of the Ross shelf. This is key because it seems likely that Ant- Debris and ooze arctica will undergo some serious changes in the Peter Barrett, a geologist at the Victoria Uni- future. Both atmospheric carbon dioxide lev- versity of Wellington in New Zealand, who was els and temperatures are projected to increase chief scientist for the Cape Roberts Project, says beyond historical highs over the next several he was struck by the number of transitions over centuries. “Just how long will it be before the such a short period. “I think it’s spectacular,” he temperature increase catches up and we watch Open leads says of the core. “We’d talked about what they the Ross ice shelf go away?” asks Barrett. With Some 200 researchers from 15 countries will might find beforehand of course. But I was sur- the Ross gone, the scenario goes, melting on the study the circumpolar flaw lead — an area of prised at the striking differences that the core main part of the west ice sheet could accelerate. open water that forms each autumn when the brought out.” That’s something neither the ice experts nor the main Arctic pack ice pulls away from coast. B & C ALEXANDER/NHPA Another major question is where the rockhounds want to contemplate. ■ With thin ice becoming more common in the ground-up glacial deposits in the ANDRILL Alexandra Witze, Nature’s chief of Arctic seas, this region offers a glimpse of core came from. Studying the sediments in correspondents for America, has been to the how changes to the ice affect ocean life. the core could help the team trace the material North Pole but not Antarctica — yet. Lucy Odling-Smee
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