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Antarctica's Adolescence
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By Brooks Hanson. Antarctica, particularly East Antarctica, harbours much of the world's ice. Thus, accurate knowledge of its sensitivity to melting from global warming is critical for assessing likely sea-level rise in the years ahead. To this end, two recent studies examine the region's dynamics during past glacial cycles and the period when it first grew. Lilly et al. use cosmogenic isotopes, which accumulate in exposed bedrock, to show that the height of the East Antarctic ice sheet fluctuated by only about 100 m through at least the last glacial cycle; the best model fit to the data includes a slow decline in height over longer times. Thus, the East Antarctic ice sheet has had a stable height during past glaciations. In exploring its stability during warmer times, Peters et al. show that an incised coastal valley in Egypt records a sudden and rapid change (within 2 million years) in sea level of about 40 m, at the time when global records imply that major ice sheets first grew in Antarctica, about 35 million years ago. Several smaller fluctuations in sea level (of about 10 m) are also recorded. The rapid changes correlate with estimated fluctuations in atmospheric CO2 levels and occurred when levels dropped below about 750 ppm. |
| To read the abstracts or full texts of the articles, see the August 2010 issue (v. 38, no. 8) of Geology Lilly et al., p. 703; Peters et al., p. 723. |
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IceCube Neutrino Observatory Picks Up Cosmic Rays
Next year, scientists will cut the ribbon on IceCube, a neutrino observatory consisting of strings of detectors buried deep in Antarctic ice. But eager researchers have already used the unfinished detector to search for a different type of particle from space, called cosmic rays—mostly energetic protons and helium nuclei of cosmic origin. Both cosmic rays and neutrinos create the same particles—muons—when they collide with matter, and muons are what the observatory is designed to detect. Only neutrinos, however, can travel through Earth. So muons that come from below are from neutrino collisions inside the ice, whereas the vast majority of muons that come from above are created by cosmic ray collisions in Earth's atmosphere. Next month in The Astrophysical Journal Letters, researchers report that they used IceCube to study a longstanding puzzle: whether the distribution of cosmic ray arrivals is uneven across the southern sky, as scientists have previously observed in the northern hemisphere. Indeed, the team found, IceCube detected a disproportionate number of cosmic rays arriving from some parts of the sky. But the reason for this uneven distribution remains unclear.
For a photograph of the observatory, see the original Science article.
Untangling the Threads
During the last deglaciation, between approximately 18,000 and 10,000 years ago, the atmospheric concentration of CO2 rose from around 180 to more than 260 parts per million. Although several plausible explanations for this increase have been proposed, it has not yet been possible to assign one over the others definitively. Lourantou et al. provide an additional constraint for the competingscenarios: a record of the isotopic composition of the carbon in atmospheric CO2 over the time interval in question. Because different sources of atmospheric CO2 have distinct carbon isotopiccompositions, the authors could determine where in the carbon system the CO2 was coming from by comparing their data with proxy records related to carbon cycle processes, and also by conducting simulations using carbon cycle box models. They conclude that most of the increase in atmospheric CO2 was caused by Southern Ocean ventilation and upwelling, with additional contributions at various times from a decline in marine productivity and a buildup of terrestrial carbon. More sophisticated Earth system models that incorporate carbon cycle–climate feedbacks could help to disentangle the contributions of the processes involved in the rise.
By H. Jesse Smith in Global Biogeochem. Cycles 24, GB2015 (2010).
Warming the Deep
The coldest ocean waters are located at the bottoms of the major ocean basins, and, because it takes a long time for water to sink from the surface to these regions, they are relatively isolated from the warming trends that are now occurring at shallower depths. However, warming in these deep waters has recently been observed, sooner than anticipated. Masuda et al. in Science performed computer simulations of ocean circulation and found that internal waves are able to transport heat rapidly from the surface waters around Antarctica to the bottom of the North Pacific, which can occur within four decades, rather than the centuries that conventional mechanisms have suggested.
Read the full Science article.
The History of the Antarctic - available to download
Melvyn Bragg discusses the geological and political history of the Antarctic (BBC Radio 4, 'In Our Time'), with Jane Francis, David Walton and Julian Dowdeswell.
Listen to the programme (BBC iPlayer)
Download the programme (Podcast)
Could East Antarctica Be Headed for Big Melt?
New research highlighted in Science (Science 25 June 2010: Vol. 328. no. 5986, pp. 1630) suggests that the world's largest ice sheet may be more vulnerable than once thought to rising CO2 levels and temperatures.
The Orangeburg Scarp, a band of hard, crusty sediment teeming with tiny plankton fossils that runs from Florida to Virginia, marks an ancient shoreline where waves eroded bedrock 3 million years ago. That period, the middle Pliocene, saw carbon dioxide levels and temperatures that many scientists say could recur by 2100. The question is: Could those conditions also result in Pliocene-epoch sea levels within the next 10 to 20 centuries, sea levels that may have been as much as 35 meters higher than they are today? The answer, say climate scientists, may lie 17,000 kilometers away in East Antarctica. The East Antarctic Ice Sheet is the world's largest, a formation up to 4 km thick and 11 million km2 in area that covers three-quarters of the southernmost continent. Its glaciers were thought to sit mostly above sea level, protecting them from the type of ocean-induced losses that are affecting the West Antarctic Ice Sheet. But studies of ancient sea levels that focus on the Orangeburg Scarp and other sites challenge that long-held assumption.
Not everybody believes the records from Orangeburg. But combined with several other new lines of evidence, they support the idea that parts of East Antarctica could indeed be more prone to melting than expected.
For further details, see the full Science article.
Underwater Ridge clue to Antarctic ice loss
The discovery of an underwater ridge in West Antarctica could help explain why there has been an acceleration in the ice flowing from a glacier in the area. Researchers suggest that the base of Pine Island Glacier once sat on the ridge, but recently became detached from the feature. The team made the discovery during surveys that used an unmanned submarine to examine waters under the glacier. The findings have been published in the journal Nature Geoscience and highlighted by the BBC. "We found something very unexpected," said co-author Pierre Dutrieux, from the British Antarctic Survey (BAS), referring to the 400m-high ridge. "Acoustic instruments on the submarine told us that there was a ridge at the bottom of the ocean, sitting transverse to the flow of ice." Dr Dutrieux said that there was also evidence that the base of the glacier was once attached to the ridge. "Some decades ago, the glacier was sitting on this ridge and the friction of the ridge was restraining the flow of the glacier," he explained. "When the glacier became detached from the ridge, the ice flow was able to accelerate significantly." Dr Dutrieux said that the glacier was located in an area where there was intense melting of land ice, which was flowing into the ocean and contributing to sea level rise. Researchers estimate that the accelerating flow of glaciers in West Antarctica is contributing about 10% of the observed rise in the mean global sea level.
For further details, see the full BBC News article.
How Do Polar Marine Ecosystems Respond to Rapid Climate Change?
In a recent article in Science, Oscar Schofield and co-authors discuss how Southern Ocean observations are required in order to study the future of polar ecosystems as climate change progresses. Climate change will alter marine ecosystems; however, the complexity of the food webs, combined with chronic undersampling, constrains efforts to predict their future and to optimally manage and protect marine resources. Sustained observations at the West Antarctic Peninsula show that in this region, rapid environmental change has coincided with shifts in the food web, from its base up to apex predators. New strategies will be required to gain further insight into how the marine climate system has influenced such changes and how it will do so in the future. Robotic networks, satellites, ships, and instruments mounted on animals and ice will collect data needed to improve numerical models that can then be used to make predictions of how the ecosystem will change. The SCAR/SCOR Oceanography Expert Group, co-chaired by one of the co-authors of the article, Mike Meredith, is producing a plan for a Southern Ocean Observing System (SOOS) in consultation and partnership with the science, logistics and other communities.
Read the full Science article.
Southern Ocean store of CO2
Past glacial-interglacial increases in the concentration of atmospheric carbon dioxide (CO2) are thought to arise from the rapid release of CO2 sequestered in the deep sea, primarily via the Southern Ocean. Two recent articles in Science (28 May 2010:Vol. 328. no. 5982) discuss this in terms of radiocarbon evidence from the Atlantic sector of the Southern Ocean that strongly supports this hypothesis (Ventilation of the Deep Southern Ocean and Deglacial CO2 Rise, Skinner et al.). Anderson and Carr (Uncorking the Southern Ocean's Vintage CO2) discuss the scenarios involved. In particular, how CO2 records from ice cores and 14C records from marine archives reveal that the 14C content of atmospheric CO2 declined as CO2 rose during the last deglaciation. This relationship supports hypotheses that attribute the rise in CO2 to the release of 14C-depleted CO2 from a reservoir long isolated from the atmosphere. The deep ocean (below 2000 m) is thought to provide such a reservoir.
Discovery of the Ozone hole: 25th Anniversary
The discovery of the Antarctic ozone hole, as reported in Nature 25 years ago, was one of the most dramatic scientific findings of modern times. To mark the anniversary, Nature presents the original research paper reporting the considerable decline in springtime atmospheric ozone concentration over Antarctica, along with a new Opinion piece from one of the paper's authors, plus a collection of related articles that have advanced our understanding of the stratosphere and the ozone layer, or told the story of the discovery.
Access selected contents here.
An oceanic 'fast-lane' for climate change
Work in Japan and Australia has revealed that a deep-ocean current is carrying frigid water rapidly northward from Antarctica along the edge of the Kerguelen Plateau, a more than 2,200-kilometre-long rise some 3,000 kilometres south-west of Australia.
Yasushi Fukamachi, an ocean scientist at Hokkaido University in Sapporo, Japan, led a team effort to determine the exact nature of the current. The researchers moored over 30 current and temperature recorders across its probable path and left these in place for two years. When they retrieved their instruments, the scientists discovered that the current, which flows at depths well below 3,000 metres, sometimes hit speeds greater than 700 metres per hour, carrying volumes as high as 30 million cubic metres per second. No other deep current in the Southern Hemisphere is known to move that quickly.
The current is formed by cold water sinking in the Ross Sea and off the coast of Adelie Land, on the Australian-facing side of Antarctica. Once in the abyss, the water flows eastward along the coast of Antarctica before hitting the Kerguelen Plateau. Then, just as the Gulf Stream hugs the eastern edge of North America, Coriolis force from Earth's rotation causes the Antarctic water to embrace the plateau's eastern flank. The result is a narrow, and so fast-moving, stream, about 50 kilometres wide.
This is significant because it represents a "fast lane" by which climatic and environmental changes affecting the Southern Ocean can propagate northward, says Alejandro Orsi, a physical oceanographer at Texas A & M University in College Station, who was not involved in the study. Proof that this is already occurring, he adds, can be seen from the fact that the deep waters near the Kerguelen Plateau already show "clear signs" of reduced salinity relating to changes in the rate of melting of Antarctic ice sheets.
Read the full Nature article.
Announcement of POGO Opportunities in Capacity Building
The Partnership for Observation of the Global Oceans (POGO) announces three capacity building programmes. In collaboration with the Scientific Committee on Oceanic Research (SCOR), it announces the POGO-SCOR Visiting Fellowship Programme for 2010, which offers successful candidates the opportunity to visit other oceanographic centres for a period of between 1 and 3 months. POGO also announces a special AMT Visiting Fellowship for on-board training on an Atlantic Meridional Transect (AMT) Cruise, offering the successful candidate the opportunity to participate in the preparation of the cruise at Plymouth Marine Laboratory or at the National Oceanography Centre in Southampton for up to a month prior to the cruise, participation in the cruise itself (12 October-25 November) and up to two months in the same institute after the cruise to participate in the data analysis and processing on completion of the cruise. Priority for both fellowships will be given to applicants in the early stages of career development.
POGO also announces the POGO Visiting Professorship for 2010, which allows for a visit by a distinguished scientist from an advanced oceanographic institute to an institute in a developing country or country with economy in transition, to provide training and mentoring, to develop collaborations and to enhance networking. The duration of visits may range from 2 weeks to 3 months.
Full information for all three schemes, including applications forms and deadlines, can be found on the POGO website.
Rocks available for study from Pensacola Mountains, Antarctica
The US Polar Rock Repository has added many samples over the past year, particularly from the Pensacola Mountains region. We currently have over 18,000 samples at the USPRR available for research (including using destructive techniques), teaching or museum use. Requests are welcome from both the US and international community. In some cases, we have accompanying petrographic thin sections and analytical metadata associated with the samples. The easiest way to search our collection is through the highlighted 'Detailed Search' choice listed on the Polar Rock Repository home page.
Loan requests can be made through the website 'sample bag' feature. If you have a particular area of interest and do not see the samples you need, please contact us (curator@bprc.ohio-state.edu) because we have collections that are not yet cataloged. We also measure magnetic susceptibility on all samples larger than 6cm x 6cm and can provide this data in an Excel file.
Antarctic Science Career Development Bursaries
The Antarctic Science Career Development Bursaries are awards of up to £5000, made annually to support the development of the careers of promising young scientists, working in any field of Antarctic science. The purpose of the award is to broaden the scope of an existing research project, especially for postdoctoral studies, through:
- funding extra field or laboratory work,
- purchasing/contributing towards the cost of a key piece of equipment, or
- funding international collaboration
Applications must be submitted to arrive at the Antarctic Science Office, no later than 2400 GMT on March 31st of each year. Allowance will not be made for late submission from other time zones. Applicants should be at least post-graduate or, preferably, post-doctoral and, if the latter, should be not more than 10 years from the start of their PhD. A condition of acceptance of the Antarctic Science Career Development Bursary is that the recipient must undertake to offer to Antarctic Science a first- or lead-author paper following on from the outcomes of the science activity for which the Bursary was awarded, or from science activity associated with it. Subject to satisfactory review by the usual processes, the paper will be published in Antarctic Science and the author identified as the winner of an Antarctic Science Bursary. In addition the recipient must acknowledge the award in presentations and publications.
For application forms and detailed requirements, please visit the Antarctic Science website.
Australia and Antarctica Linked by Climate
A recent study by Tas Van Ommen and Vin Morgan (Nature Geiscience, DOI: 10.1038/ngeo761) suggests that the 40-year drought that has blighted Australia may be linked to heavy snowfall over Antarctica. The researchers noticed the link after nearly 30 years of studying Antarctic ice cores extracted from Law Dome, an ice field near Cape Poinsett, which lies almost exactly south of the southwestern tip of Australia. There they found evidence that the area had been experiencing abnormally large amounts of snowfall for several decades. They also knew that southwestern Australia had been suffering from severe droughts for approximately the same time.
They compared the 750 year long ice-core records with meteorological records to gauge precipitation patterns in southwestern Australia, as well as atmospheric circulation patterns in the Southern Hemisphere for the past four decades. About 40% of the rainfall variations in southwestern Australia were mirrored by snowfall variations at Law Dome. More intriguing, the Law Dome snowfall patterns seem to have intensified over the past several decades. Indeed, climate models predict such an anomaly when anthropogenic carbon dioxide (CO2) emissions over the last century are factored in. According to the models, higher levels of CO2, coupled with reductions in atmospheric ozone, create an atmospheric circulation pattern in the Southern Ocean that brings drier air to the farming regions of southwestern Australia and heavier snows to Law Dome. But as the models show, by boosting CO2 and cutting ozone, the normal cycles can be disrupted, and that is what seems to be happening now.
Antarctic Glacier Off Its Leash
An unmanned autonomous submarine has discovered a sea-floor ridge that may have been the last hope for stopping the now-accelerating retreat of the Pine Island Glacier, a crumbling keystone of the West Antarctic Ice Sheet, researchers announced at the fall meeting of the American Geophysical Union.
The Pine Island and adjacent Thwaites glaciers are key to the fate of West Antarctic ice, says glaciologist Richard Alley of Pennsylvania State University, University Park, in an e-mail. And West Antarctica is key to how fast and far sea level will rise in a warming world. "To a policymaker, I suspect that the continuing list of [such] ice-sheet surprises is not reassuring," he writes.
Read the full Science article.
The Southern Ocean and uptake of anthropogenic CO2
The Southern Ocean accounts for only about 6% of the world's ocean area, although it is estimated that it absorbs as much as 40% of the CO2 taken in by the seas. However, the Southern Ocean retains only about 9% of the CO2 it absorbs. What happens to the rest of it? Ito et al. were able to pinpoint the wind patterns and currents that distribute ocean CO2 (primarily related to the so called Ekman transport). As the team report, instead of sinking in place, almost all of the CO2 is carried away from the Antarctic and toward the subtropics - hence the missing CO2 in the Southern Ocean.
Takamitsu Ito said that "the atmosphere overlying the Southern Ocean is undergoing significant climate change". It's possible, he says, that "changing the atmospheric wind pattern in the region could alter the rate at which the Southern Ocean absorbs CO2," possibly reducing the ocean's ability to consume the gas and leading to further global warming.
For further details, see the full article in Nature.
2009
50th Anniversary of the Antarctic Treaty
December 1st was the 50th anniversary of the signing of the 1959 Antarctic Treaty. To identify lessons learned about international cooperation from the Antarctic Treaty during its first fifty years - "with the interests of science and the progress of all mankind" (as noted in the Preamble of the Antarctic Treaty) - the Antarctic Treaty Summit: Science-Policy Interactions in International Governance was convened at the Smithsonian Institution from 30 November through 3 December 2009.
A Congressional Resolution (Recognizing the 50th Anniversary of the Signing of the Antarctic Treaty) that related directly to the Antarctic Treaty Summit was adopted with unanimous consent by the United States House of Representatives (H. Con Res. 51) on 30 September 2009 and by the United States Senate (S. Res. 365) on 1 December 2009. Also on 1 December 2009, His Excellency Ban Ki-moon (Secretary-General of the United Nations) delivered a video message to the Antarctic Treaty Summit. In addition, on the 50th anniversary of the Antarctic Treaty, HSH Prince Albert II of Monaco, along with collaborators in the Antarctic Treaty Summit, signed the "Forever Declaration" on behalf of global civil society to promote peace, security, environmental protection and international co-operation for the lasting benefit of all humanity.
Before communicating it to the General Assembly of the United Nations, Secretary-General of the United Nations and governments of all states parties to the Antarctic Treaty - the "Forever Declaration" is now open for digital signature by anyone anywhere in the world (visit the Antarctic Treaty Summit website to read and sign the "Forever Declaration").
Operation Ice Bridge: Mission Antarctica begins
NASA's Operation Ice Bridge got underway in the Southern Hemisphere on Friday October 16, with a DC-8 plane flying the first of a series of missions to measure Antarctic ice. Although ice can and is measured from satellites, there will be a gap in NASA's measurements after ICESat-I comes to the end of its life this year and before the start of ICESat-II in 2014. To plug this gap, the space agency is stepping up with a six-year programme of ice-measuring plane flights. "The DC-8 flew two parallel tracks along the coast, one just offshore over the floating ice shelf, and one just inland. By measuring on either side of the 'grounding line' between the floating ice and the ice on land, scientists can determine the rate at which this near-shore part of the ice shelf is melting," said NASA. The plane is too large for Antarctic runways so it launched from Chile at 9:11 local time and flew south to the Getz Ice Shelf.
Although Friday's flight is being reported as the start of Operation Ice Bridge, the very first OIB flights were actually made in April in the Northern Hemisphere.
Article taken from the Nature blog.
Antarctic and Greenland Ice Sheets may be shrinking faster than thought
As reported in Science (9 October 2009,Vol. 326. no. 5950, p. 217) losses from the great ice sheets of Antarctica and Greenland appear to have accelerated during the past 7 years. The results, in press at Geophysical Research Letters, are based on measurements by the Gravity Recovery and Climate Experiment (GRACE) satellite mission.
The mass changes of Greenland and Antarctica during the past seven years have all been negative, geophysicist Isabella Velicogna of NASA's Jet Propulsion Laboratory in Pasadena, California, concludes in the study. On Greenland, she calculates, the rate of ice mass loss doubled over the seven-year period, producing an acceleration of –30 cubic kilometers of water lost per year. On Antarctica, the loss rate more than doubled to produce a similar acceleration. Together, that would make for a 5% acceleration each year in the rise of sea level. Compounded year after year, "that is a big thing," says Velicogna. "We should be more concerned." For further details, please read the full Science article.
Daily Antarctic MODIS Mosaics
Daily MODIS mosaics of Antarctica are now available from the NASA Rapid Response website in near-realtime. A complete mosaic of previous day(s) can be viewed by clicking on the 'Prev' button on the top of the Antarctic Mosaic page.
Each day a set of true colour images are generated from data from the Terra and Aqua satellites at 4km, 2km, 1km and 250m resolutions along with a 367 false-colour image generated from Terra. By clicking on each individual tile within the mosaic, a page featuring that tile will come up, and the 250m image for that tile can be downloaded.
The images are mapped using the Polar Stereographic projection with origin at 0 longitude and -90 latitude with a -71 standard parallel (also known as EPSG code 3031). Each one of the files can be downloaded with the metadata file and directly used in GIS and remote sensing software for integration into other products and services.
Information on using the mosaic image in GIS and image processing software packages is available on the NASA FAQ page.
This project was funded through the Earth Sciences Division, NASA Goddard Space Flight Center.
US Antarctic Program support for this product will be provided though the Antarctic Geospatial Information Center, funded through the National Science Foundation Office Office of Polar Programs.
USGS Antarctic Air Photography now digital and online
The USGS Antarctic Resource Center has completed the medium resolution scans of their entire air photography collection from 1947 to the present of 330,000 photos. All photos have been placed online with known digitised flightlines and calibration information by the Antarctic Geospatial Information Center and can be downloaded from USGS Air Photography website. If requested, all of the images can be written to a 2 tb hard disk and shipped to researchers and other programmes. Contact Michelle LaRue at larue010@umn.edu for more information.
Climate Change Colloquium
From 27 to 31 October, Punta Arenas in Chile will host an international Colloquium on Climate Change. The Colloquium, sponsored by the Regional Fund for Innovation and Competitiveness (FIC-R) and the National Commission for Science and Technology (CONICYT), will host a meeting of outstanding international and Chilean scientists, with local authorities, students and other members of the civil society, to examine Climate Change from different perspectives. They will share the results of relevant research activities and their impact on biophysical systems of the planet, particularly in the Magellanic and Antarctic Region. For more information, please visit the Colloquium website.
Ice Bridge Supporting Wilkins Ice Shelf Collapses
(From NSIDC News) An ice bridge connecting the Wilkins Ice Shelf on the Antarctic Peninsula to Charcot Island disintegrated in early April. The event continues a series of breakups that began in March 2008 on the ice shelf, and highlights the effect that a changing climate is having on the region. Images from the NASA Moderate Resolution Imaging Spectroradiometer (MODIS) sensors on the Terra and Aqua satellites showed the shattering of the ice bridge between 31 March 2009 and 6 April 2009. The loss of the ice bridge, which was bracing the remaining portions of the Wilkins Ice Shelf, will allow a mass of broken ice and icebergs to drift into the Southern Ocean. Scientists at NSIDC and around the world have been watching the ice bridge since March 2008, anticipating its collapse. Now that it has broken up, researchers are closely monitoring the remaining portion of the Wilkins Ice Shelf to see if the loss of the ice bridge allows the ice shelf to collapse further. For updates and links to other news on the Wilkins Ice Shelf, see the Wilkins Ice Shelf News Web page.
Advanced Biology Training Course in Antarctica, January 2010
A National Science Foundation sponsored course, entitled "Integrative Biology and Adaptation of Antarctic Marine Organisms", will be held in Antarctica at the United States' McMurdo Station for one month, starting January 2010. This is an international course, open to all nationalities. Applications are invited from graduate students currently enrolled in a Ph.D. program, postdoctoral fellows, and early-career faculty who are interested in the study of extreme environments and the biology of Antarctic organisms. Full scholarships are available for each participant accepted into the course to cover the cost of travel from home institution to Antarctica, and room and board while in Antarctica. The emphasis of the Antarctic Biology Course is on integrative biology, with laboratory- and field-based projects focused on biological adaptations in an extreme environment, with an emphasis on rapid climate change in polar regions. A diverse teaching faculty will offer students the opportunity to study a wide range of Antarctic organisms (bacteria/archaea, algae, invertebrates, and fish), as well as studying several different levels of biological analysis (molecular biology, biomechanics, physiological ecology, species diversity, and evolution). The deadline for receipt of completed applications is August 1, 2009. For more information and on-line applications, please visit the course website.
Penguins Scooped by Their Own Poop
Scientists have discovered 10 emperor penguin colonies along the Antarctic coast by scanning satellite photos (from the Landsat Image Mosaic of Antarctica) for the reddish-brown stains of their guano. The approach - apparently the first time anyone has used satellite images to locate the breeding populations of an animal - could prove to be a valuable new way to monitor how penguins are responding to climate change.
Of the 34 previously known colonies, six had disappeared; the ice in those places was squeaky clean. The researchers also found 10 unknown colonies, represented by washes of guano, they report online this week in Global Ecology and Biogeography. "The big question is, why are some of the colonies missing?" says penguin biologist Phil Trathan of the British Antarctic Survey, who carried out the research with cartographer Peter Fretwell. Trathan suspects climate change; the lost colonies were generally farther north, in areas with warmer temperatures.
Read the full ScienceNOW article.
Scientists rethink sea level rise from a melted west Antarctic
The potential contribution to sea level rise from a collapse of the west Antarctic ice sheet has been overestimated by around a half, according to a study published by Bamber et al. in Science.
The new research suggests if the ice sheet collapsed sea level would rise by an average of 3.3 metres rather five or six, as previously thought. The largest increases would be around the Atlantic and Pacific seaboards of North America, with sea levels high enough to pose a serious threat to New York, Washington DC and San Francisco. Sea levels would rise to around 3.5 metres around Britain.
For further details, read the full Science article, or listen to the Podcast.
Ancient Ecosystem Discovered Beneath Antarctic Glacier
Scientists have found life in an ecosystem trapped underneath a glacier in Antarctica for nearly 2 million years. The microbes, they suggest, are surviving the dark, oxygen-free waters by drawing energy from sulphur and iron. The findings provide insight into how life may have survived "Snowball Earth" - periods when some scientists speculate that the planet was entombed in ice - and hint at the possibility of life in other inhospitable environments, such as Mars and Jupiter's icy moon Europa.
Read the full ScienceNOW article.
Ice bridge ruptures in Antarctic
The ice bridge that has linked the Wilkins Ice shelf to Charcot and Latady islands has broken. The collapse could mean the Wilkins Ice Shelf is on the brink of breaking away, and provides further evidence of rapid change in the region. While the break-up will have no direct impact on sea level because the ice is floating, it heightens concerns over the impact of climate change on this part of Antarctica.
Over the past 50 years, the peninsula has been one of the fastest warming places on the planet. Many of its ice shelves have retreated in that time and six of them have collapsed completely (Prince Gustav Channel, Larsen Inlet, Larsen A, Larsen B, Wordie, Muller and the Jones Ice Shelf). Separate research shows that when ice shelves are removed, the glaciers and landed ice behind them start to move towards the ocean more rapidly. It is this ice which can raise sea levels, but by how much is a matter of ongoing scientific debate. Such acceleration effects were not included by the UN's Intergovernmental Panel on Climate Change (IPCC) when it made its latest projections on likely future sea level rise. Its 2007 assessment said ice dynamics were poorly understood.
For further details, see the BBC News website.
Giant Ice Sheet Is Safe ... for Now
Science (18 March 2009) reports on how one of the world's biggest ice masses, the West Antarctic Ice Sheet, could melt over the next few thousand years and raise sea level by as much as 5 metres, if nearby ocean temperatures rise by several degrees Celsius. Although such a dramatic rise in temperature may seem unlikely in the near term, such conditions are possible based on paleoclimate data and a new computer model, which show that the ice sheet has collapsed multiple times in the past.
Researchers are investigating what warmer temperatures might do to the world's largest ice masses, including the 2-kilometre-thick ice mass that constitutes the West Antarctic Ice Sheet, lying to the southwest of the southern tip of South America. If the ice sheet melts, many of the world's coastal areas, including Bangladesh, southern Florida, and southern Louisiana, could be under water.
Forecasting the ice sheet's behaviour has been difficult, however, because over the past million years, global temperatures have been too cool to provide much insight about what might happen in a balmier climate. So, two teams of researchers tried a new approach. One group examined a pristine drill core from sediment below the sea bottom near the ice. In the part of the core that dates back from about 5 million to 3 million years ago, when temperatures and greenhouse gas levels were somewhat higher than they are today, the group found evidence of multiple, 40,000-year cycles of melting and refreezing.
Then the second group compared that data with a new, three-dimensional computer model that simulated the ice sheet's behaviour over the past 5 million years. The teams report in two papers tomorrow in Nature that the West Antarctic Ice Sheet could indeed begin to collapse sometime in the next century or so if nearby ocean temperatures increase roughly 5°C - a possibility if current warming trends continue. If that warming occurs, the sheet could totally collapse in a few thousand years but contribute to sea-level rise much sooner.
Read the full ScienceNOW article
Trapped under ice
When the Autosub 3 robot submarine began its pioneering 110-kilometre round trip under the Antarctic ice, there was no guarantee that it would ever come back. Its sister craft, Autosub 2, had been lost on a similar mission in 2005. Autosub 3 was being sent on a much more ambitious mapping expedition, in an environment in which escaping to the surface is not an option. But it was also packing the latest technology. The 7 metre-long, 3.5 tonne autonomous robot can dive to 1,600 metres under the surface of the ocean and travel 400 kilometres, powered only by 5,000 standard D-cell batteries. Nature (20th March 2009) interviews the team behind the risky submarine mission to map the underside of an Antarctic glacier.
Read the full Nature News article
Antarctic Worms Make Antifreeze
Researchers from Brigham Young University are reporting a hardy Antarctic worm that withstands its cold climate by cranking out antifreeze. Not only that but, when its notoriously dry home runs out of water, it just dries itself out and goes into suspended animation until liquid water brings it back to life. The research trip by Byron Adams, associate professor of molecular biology, and his Ph.D. student Bishwo Adhikari, in December 2008 was intended to help determine how the fate of a half-millimeter worm can actually impact an entire ecosystem, and how that information can serve as an important baseline for understanding climate change's impact on more complex systems, such as a farmer's field in the United States. Discovering the anti-freeze gene in this nematode was something of a surprise. This particular species' unique genetic response to its environment means it is likely to flourish as Antarctica gets wetter, Adams says, while other nematode species diminish. That's how this molecular-level research ties back into predicting how the composition and distribution of soil species will change in response to climate change.
Read the full news story (courtesy of the Ukrainian Scientific Club)
The lost world beneath the Antarctic ice
British scientists have been given the go-ahead to search for life forms hidden for more than 400,000 years beneath Antarctic ice. A team of scientists will drill through a two-mile-thick sheet of ice that has sealed sub-glacial Lake Ellsworth in West Antarctica from the rest of the biosphere for at least as long as Homo sapiens has walked the Earth. They are hoping to find species that have survived beneath the ice sheet since it formed between 400,000 and two million years ago. Finding life in such an extreme environment would be one of the most important discoveries of the century.
Read the full article from The Independent
Gamburtsev Mountains revealed
Results from a recent expedition to the Gamburtsev Mountains hidden beneath the Antarctic ice sheet have now been revealed. The findings may cause geologists to rethink their ideas about the continent's history. For details, see the full Nature News article.
New German Antarctic station opens
A new German base, Neumayer III, built on a stilt-carried platform above the Ekstrom Icefield in northwestern Antarctica, and connected to a garage under the snow, has just been inaugurated by German science minister, Annette Schavan. Nine over-wintering staff will run the station during the dark Antarctic winter. In summer, it will host up to 50 scientists and technicians, allowing for continuous field work and measurements in meteorology, geophysics and atmospheric chemistry.
Germany's old Neumayer Station, just a few kilometres from the new base,has sunk twelve meters deep into the ice since it was built in 1992 and will have to be abandoned soon. However, the new station's retractable stilts should keep it 'dancing' on the shifting ice beneath. For further details see the Neumayer Station page on the AWI website.
New Antarctic research station is carbon-free
The world's first zero-emission polar research station has opened in Antarctica and was welcomed by scientists as proof that alternative energy is viable even in the coldest regions. Pioneers of Belgium's Princess Elisabeth station in East Antarctica said if a station could rely on wind and solar power in Antarctica — mostly a vast, icy emptiness — it would undercut arguments by sceptics that green power is not reliable. Constructed over two years, the steel-encased station uses micro-organisms and decomposition to enable scientists to re-use shower and toilet water up to five times before discarding it down a crevasse. Wind turbines on the Utsteinen mountain ridge and solar panels on the bug-like, three-story building ensure the base has power and hot water. Even the geometry of windows helps conserve energy.
"If we can build such a station in Antarctica we can do that elsewhere in our society. We have the capacity, the technology, the knowledge to change our world," Alain Hubert, the station's project director, told Reuters at the inauguration ceremony.
Scientists monitoring global warming predict higher temperatures could hasten melting at Antarctica, the world's largest repository of fresh water, raising sea levels and altering shorelines. If Antarctica ever melted, world sea levels would rise by about 180 feet. That would impact some 146 million people living in low-lying coastal regions less than three feet above current sea levels, researchers said.
Read the full article.
Russian researchers suspend drilling to subglacial Lake Vostok until December 2009
Researchers drilling a well to reach subglacial Lake Vostok in Antarctica have used special liquid to plug the hole till the end of the year. "Winter is coming in the Southern Hemisphere, and all seasonal research and on-site experiments that are usually carried out at the station inside the continent during summer have been suspended till the next field season," deputy head of the Russian Antarctic Expedition Vyacheslav Martyanov said on Saturday. "Eleven polar researchers are staying at the Vostok station but the next flight bringing a new group of researchers and specialists, equipment and food from the coastal Progress station is scheduled for December 2009. There are slightly more than 70 metres left to the surface of the lake. We will try to reach it the next season in 2009-2010."
The head of the previous expedition's winter team, Viktor Venderovich, said lake located beneath four kilometres of ice "stands out in terms of huge size among more than 145 subglacial bodies of water discovered by way of radar probing in Antarctica". Venderovich believes that the project will help answer a key question about the existence of life in the lake, which has had no contact with the atmosphere for millions of years.
Read the full TASS article.
The Sea-Level Fingerprint of West Antarctic Collapse
In the journal Science (6 February 2009) Mitrovica and co-authors discuss how recent projections of sea-level rise after a future collapse of the West Antarctic Ice Sheet assume that meltwater will spread uniformly (that is, eustatically) across the oceans once marine-based sectors of the West Antarctic are filled. A largely neglected 1977 study predicted that peak values would be 20% higher than the eustatic in the North Pacific and 5 to 10% higher along the US coastline. Mitrovica et al. show, with use of a state-of-the-art theory, that the sea-level rise in excess of the eustatic value will be two to three times higher than previously predicted for US coastal sites.
Read the full Science article
Decline in penguin populations due to a predicted decrease in sea ice
Emperor penguins are completely dependent on sea ice. They breed on it, and they eat fish that ultimately rely on the plankton that grows under it. Many models, however, predict a decline in Antarctic sea ice over the next century.
To gauge the impact on emperor penguins, ecologist Stéphanie Jenouvrier of the Woods Hole Oceanographic Institution in Massachusetts focused on a population in Pointe Géologie, Antarctica. The penguins there spend the winter on ice close to Dumont d'Urville, the main French base in Antarctica, and records on them stretch back to the 1960s. Jenouvrier and her colleagues used the long-term data set to create a model describing the birds' life histories. They plugged in figures such as the age of the penguins when they start breeding and how likely the chicks are to survive. These details can reveal a more accurate picture of how a population will respond to a change in the environment. The team then linked this model to another set of models predicting how often the penguins will experience a major drop in sea ice as the climate changes between now and 2100.
Given the increasing frequency of 10% to 15% dips in sea ice forecast over the next century by the climate models the team used, Jenouvrier and colleagues predict that the number of Pointe Géologie penguins will plummet from 3000 to 400 breeding pairs. Finding a new home isn't an option, says Jenouvrier, because the penguins have to stick to the coast - and in that part of the continent, it's solid land to the south.
Read the full Science article.
Iron Fertilization Experiment Goes Ahead
Following some controversy about the objectives of the joint German-Indian LOHAFEX expedition on the Polarstern, during which the cruise plans were temporarily halted, it has been agreed that the cruise may continue. The following press release from the Alfred Wegener Institute carries the details:
'Independent scientific and legal reviews sought by the Federal Ministry of Education and Research and the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety concluded that the iron fertilisation experiment LOHAFEX is neither against environmental standards nor the international law in force. There are thus no ecological and legal reasons to further suspend the iron fertilisation experiment LOHAFEX.
Reacting to the positive news from the Federal Ministry of Research, Dr. Karin Lochte, Director of the Alfred Wegener Institute, said: "We are glad that the experts have fully confirmed our own ecological risk assessment. Now an independent party has also made it clear that the environmental impacts in the study area will be negligibly small." LOHAFEX will provide valuable data for climate and earth system research if the experiment is conducted as planned.
Lochte further stated: "The controversy on LOHAFEX has been basically reduced to a political conflict that we as a research institute cannot solve. This situation is unusual for the Alfred Wegener Institute. Nevertheless, I am absolutely convinced myself that only independent scientific studies like LOHAFEX will help in arriving at a substantiated and fact-based political decision on whether or not iron fertilisation in the ocean is a useful technique that could contribute to climate protection."
"We are relieved, of course, by the decision of the Federal Ministry of Research to proceed with the experiment," Lochte commented. This decision will send out an important signal to the international scientific community that Germany remains a reliable partner even in difficult political situations. The decision is also of great importance for our Indian partner, the National Institute of Oceanography, which is bearing half the personnel and financial costs of this experiment and for whom this is the main contribution to the Indo-German cooperation.
"I wish to strongly emphasise that our experiment was developed on the basis of purely scientific issues in order to better understand the role of iron in the global climate system. A large number of reports are circulating on the Internet and in the international press claiming that the Alfred Wegener Institute is conducting the experiment to test the geo-engineering option of ocean fertilisation as a means to sequester large quantities of carbon oxide from the atmosphere. This is definitely not the case," Lochte defends herself against these insinuations. "We are upset that such a controversial discussion was ignited on the basis of wrong, internationally propagated information. We hope that through this experiment we will be able to contribute to a better understanding of ocean biogeochemistry and pelagic ecosystem functioning."
After several days of pre-examinations, the team of scientists on board Polarstern has in the meantime found a closed eddy that is suitable for the experiment. It is located at Lat. 48°S and Long. 15° 302W. First, a drift buoy with a position tracking device will be deployed near the centre of this eddy. From this point, Polarstern will then spread dissolved ferrous sulfate along a spiral trajectory in the upper 15 metres of the water layer. The fertilisation will take approximately 30 hours. Immediately after the termination of the iron input, numerous biological, chemical and physical parameters will be continuously measured inside and outside the fertilised area, and ecological changes in all layers of the water column - from the surface to the seafloor in 3,800 metres depth - will be monitored for 40 days. The plankton community biomass is expected to increase substantially about two weeks following fertilisation, and the fate of the organic matter produced will be investigated in detail.
As usual, the Alfred Wegener Institute will make the data and research results concerning LOHAFEX known, not only to the scientific community but also to authorities and environmental organisations. Further information can be found on the website of the Alfred Wegener Institute.'
Unexpected Warming across Antarctica
In a breakthrough article in Nature this week, Eric Steig and colleagues show that overall the Antarctic continent has warmed over the past 50 years. Until now, incomplete records led researchers to believe that the continent's entire interior may be cooling whilst the peninsula region warms. The authors use existing weather station records combined with recent satellite measurements and statistical models to provide a fuller picture of the continent's temperature from 1957 to 2006. They conclude that the eastern region of the continent, which is larger and colder than the western portion, is warming at 0.1C per decade, and the west at 0.17C per decade - faster than the global average.
Read the full article.
Updated Antarctic Chronology Published
Many Antarctic researchers have found useful, as a source of information on the chronology of Antarctic events, the comprehensive compendium published by Bob Headland in 1989. Bob has now published the revised version, with the title A Chronology of Antarctic Exploration: A Synopsis of Events and Activities from the Earliest Times until the International Polar Years 2007-09. It is a hardbound volume of 722 pages (including 40 plates, 27 maps, and 21 histograms) available at a price of £110 (plus local, sea, or air postage), from Bernard Quaritch Ltd, Lower John Street, Golden Square, London, W1F 9AU, UK; e-mail contact: <C.Scheybeler@quaritch.com>. The ISBN is 978-0-9550852-8-4. For more information, download the detailed book description.
The response of the Antarctic Circumpolar Current to recent climate change
Observations show a significant intensification of the Southern Hemisphere westerlies, the prevailing winds between the latitudes of 30° and 60° S, over the past decades. A continuation of this intensification trend is projected by climate scenarios for the twenty-first century. The response of the Antarctic Circumpolar Current and the carbon sink in the Southern Ocean to changes in wind stress and surface buoyancy fluxes is currently under debate.
In a relatively recent paper published in Nature (23 November 2008), Böning and co-authors analyse the Argo network of profiling floats and historical oceanographic data. They detect coherent hemispheric-scale warming and freshening trends that extend to depths of more than 1,000 m. The warming and freshening is partly related to changes in the properties of the water masses that make up the Antarctic Circumpolar Current, which are consistent with the anthropogenic changes in heat and freshwater fluxes suggested by climate models. However, their study detects no increase in the tilt of the surfaces of equal density across the Antarctic Circumpolar Current, in contrast to coarse-resolution model studies. Their results imply that the transport in the Antarctic Circumpolar Current and meridional overturning in the Southern Ocean are insensitive to decadal changes in wind stress.
Read the full article.
2nd International Forum on the Sub-Antarctic Announced
Antarctic Tasmania takes pleasure in inviting you to the 2nd International Forum on the Sub-Antarctic, to be held 26 - 27 April 2009 in Hobart, Tasmania, Australia.
Entitled "Environmental Change in the Sub-Antarctic", the 2009 Forum follows on from the very successful 2006 Forum, which was believed to have been the first forum to comprehensively develop the perception that the Sub-Antarctic islands and surrounding seas should be viewed not as a sub-division of Antarctica but as a distinct circumpolar domain. Further information is available on the Forum website, including a one page flyer, Forum registration form, draft program and accommodation details, including a map to the conference.
Given the ACE CRC climate change forum will also be held in Hobart the week before, we expect a lot of interest in the Sub-Antarctic Forum and strongly recommend attendees submit their registration forms as early as possible.
China Building Base at Dome A
A Chinese expedition has begun building the Kunlun research base at 'Dome A', 4093 metres above sea level; it is scheduled to open on 28 January. It will be a major legacy of the International Polar Year and will propel China to the heart of the Antarctic map. The other Chinese stations are Great Wall station, in the South Shetland Islands, and Zhongshan station in East Antarctica. Kunlun will have a main building of 230 square metres, with 11 units for sleeping, eating and working. It will have space for up to 25 people. Six more units will be added next year, for a total area of 327 square metres.
Having a base at Dome A offers the prospect of finding older ice than that drilled at Dome C, where past climate has been reconstructed back to 800,000 years from an ice core. The ice underneath Dome A is over 3,000 metres thick, which could push the climate record back to 1.5 million years.
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