Исследователи подсчитали общий баланс воды в озере Восток, находящегося глубоко подо льдом Антарктики

Study is a 'critical step' in possible exploration of lake

LAKE VOSTOK, which lies buried under thousands of meters of ice high on the Antarctic Plateau, is thought to be home to unique habitats and microorganisms. Confirming the existence of life forms and unique biological niches without contaminating the pristine lake waters, however, is a difficult scientific and technical challenge with international ramifications.
According to a paper to be published in the March 21 issue of Nature, the hydrodynamics of the lake may make it possible to search for evidence of life in the layers of ice that accumulate on the lake’s eastern shore. Scientists say such a possibility would provide another avenue for exploring the lake’s potential as a harbor of microscopic life, in addition to actually exploring the waters of the lake itself. The paper is authored by Robin E. Bell of Columbia University’s Lamont-Doherty Earth Observatory and her colleagues. Their research, who were supported by the National Science Foundation (NSF), reveals that although the lake is perhaps millions of years old, its waters are relatively young. Bell's paper demonstrates that over a period of 13,300 years, all of the water was removed by the overlying ice sheet and replaced from other sources. The lake water captured by the moving ice sheet was carried as layers of ice over Lake Vostok’s eastern shoreline, and then eastward away from the lake. Exploring those ice layers, they argue, is equivalent to exploring the lake itself. "Our study is a critical step in the exploration of Lake Vostok", Bell said.
"These frozen lake water samples will record the passage of the ice sheet and the processes across the lake. The data show that the location of the current research station on the lake may not be optimal for biological studies."
Bell added that that "Lake Vostok is absolutely devoid of interference. The youngest water in it is 400,000 years old. It doesn’t know anything of human beings, fossil fuels, or plastics. It is a window into life forms and climates of primordial eras." Radar maps of the Antarctic interior made in 1996 revealed that a lake lay under the ice sheet. Lake Vostok is thought to be one of the world’s largest, 48 kilometers (30 miles) wide by 225 kilometers (140 miles) long and 914 meters (3,000 feet) deep. Its waters have been sealed from air and light for perhaps as long as 35 million years under the tremendous pressure of the continental ice sheet.
An ice core - one of the world’s longest - was drilled by a joint U.S., Russian, and French team at Russia’s Vostok Station on the lake’s western shore. But coring was stopped roughly 100 meters (328 feet) above what is thought to be the surface of the water to prevent contamination of the lake. The ice layers reveal a 400,000-year environmental record with microorganisms present throughout most of the core. During the 2000-2001 Antarctic research season, NSF supported a detailed aerial mapping of the lake by specially equipped Twin Otter aircraft flown by the Support of Office for Aerogeophysical Research at the University of Texas at Austin. The radar sounding, laser altimetry, magnetics, and gravity surveys were a first, non-invasive step to explore Lake Vostok.
Bell and her team analyzed the radar data and determined that the ice formation in the southern half of Lake Vostok holds buckling patterns frozen into the ice sheet as it flows over the lake.
Following the trends of the buckled ice patterns, scientists were able to construct movement trajectories across the lake. They then calculated the time it took ice to move from the west side of the lake to the east-20,000 years over a distance of about 56 kilometers (35 miles). By examining the ice flux out of the lake, the team determined that every 13,300 years the ice sheet removes the equivalent of the entire volume of Lake Vostok.
As the ice sheet removes lake water like a continuous conveyor belt, lake waters must be replenished, either by melting of the ice sheet or by subglacial meltwater. The source of this water remains a mystery.

Около 425-430 миллионов лет назад территория в юго-восточном штате Аляска, известная под названием Архипелаг Александра, соединялась морем с Сибирью и Уральскими горами

Geologists generally accept that some of Alaska's landscape originated as part of the North American continent, but the origins of the Alexander terrane in southeastern Alaska have been much more vague. New research studies reveal that the southeast part of Alaska known as the Alexander terrane once shared a seaway with Siberia and the Ural Mountains about 425-430 million years ago.
For the past decade, Constance Soja from Colgate University has been working with U.S. and Russian colleagues and her students compiling fossil and other geological evidence to understand the origins of the Alexander terrane.
"Until recently, the unclear affinities of many of the Alaskan fossils provided inconclusive information about which islands or continental margins were the source of some of the species that eventually colonized the Alexander terrane", Soja explained. "But the strong similarities in Silurian marine fossils in southeast Alaska, the Urals, and Siberia indicate that all these areas in the Silurian must have shared a contiguous seaway in the Northern Hemisphere that allowed organisms, generation upon generation, to transmigrate, intermingle, and undergo genetic exchange."
The distinctive sponge-microbial fossils the team found in limestone bedrock in Alaska and the Ural Mountains formed barrier reefs in the Uralian Seaway. This confutes a competing hypothesis that the Alexander terrane had been located in the Southern Hemisphere during the Silurian.
"All of the data agree that the location of the Alexander terrane can be circumscribed to the Uralian Seaway for a particular interval of time", Soja said. "Thus by placing the origin and distribution of Alaskan fossils in an evolutionary and tectonic context, our research has contributed new insights into the geologic history of the Alexander terrane, the Northern Urals, and, to some extent, other areas."
Soja will co-present the team's findings with her student, Alicia Newton, at the Geological Society of America's Northeastern Section Meeting on March 27 in Springfield, Massachusetts. Newton has been working on sponge-microbial fossils found in the western slope of the Ural Mountains to refine the team's understanding of the similarities and differences between the Alaskan and Russian fossils.
Distinctive microorganisms that formed the reefs include Ludlovia, Sphaerina, and Hecetaphyton, which are preserved with aphrosalpingid (sphinctozoan) sponges-the very same sponges that are characteristic of the Alexander terrane in southeast Alaska and, to some extent, the Farewell terrane in southwestern Alaska.

К концу этого столетия средняя температура на земле может увеличивать от 1.5 до 4.5 градусов Цельсия, сказал на пресс-конференции директор российского Гидрометеорологического центра, ссылаясь на ученых

MOSCOW, Mar 20, 2002 (Itar-Tass via COMTEX) -- The average temperature on the earth may increase by 1.5 to 4.5 degrees Centigrade by the end of this century, Russian Hydro Meteorological Centre head Alexander Bedritsky told a press conference on Wednesday, referring to scientists.
Over the past 100 years, the average temperature increased by 0.6 degrees, but the warming spreads over countries unevenly. For example, Russia has warmer winters than before - the temperature is 1-3 degrees higher.
Many scholars believe the warming process is linked with the natural climate changing, since the earth at present has a warming cycle that recurs once in 150,000 years.
However, it is quite clear that concentration of hothouse gases in the atmosphere has an effect on a climate, Bedritsky said.
The decreasing ice areas are also a serious indicator that the temperature becomes higher. Over the past 20 years, the total ice area on the globe decreased by 10 percent.

На создание компьютерных классов в школах планируется затратить свыше 2-х миллионов рублей

MOSCOW, Mar 19, 2002 (Itar-Tass via COMTEX) -- A total of 2.5 billion roubles are planned to be allocated this year for the creation of computer classes at city and village schools of Russia, Russian Minister of Education Vladimir Filippov said on Tuesday, addressing the all-Russia conference, whose subject is "The main results of the social development of the Russian federation in 2001 and tasks for 2002."
Filippov explained that modern computers together with software would be given to every city and village school within the framework of the programme. Aside from it, the computer training of teachers will be organized.
Speaking about other aspects of the reforming of the Russian public education system, he pointed out that all the educational establishments of the country would be given the status of legal entities this year.
Much attention will be devoted to the development of physical fitness and gymnastics training at schools, he continued. At present teachers from most of the Russian schools are of the opinion that schoolchildren should have one hour of physical fitness training every day. A special programme will be drawn up for providing school gyms with sports equipment and for using them additionally for non-class physical fitness training.

Ongoing excavations in Russia indicate anatomically modern humans were developing new technologies for survival in the cold, harsh region some 30,000 to 40,000 years ago, according to a University of Colorado at Boulder researcher.
John Hoffecker of CU-Boulder’s Institute of Arctic and Alpine Research said that excavations at Kostenki - a series of more than 20 sites about 250 miles south of present-day Moscow - have yielded bone and ivory needles with eyelets that are 30,000 years old.
In addition, the research team uncovered nearly articulated bones of both arctic foxes and hares at the site, which is along the Don River. These discoveries strongly hint that ancient residents of Kostenki had developed trapping techniques to obtain furs that would help keep them warmer in the winters.
The many discoveries at Kostenki since the 1940s imply that anatomically modern humans who had migrated out of Africa 40,000 to 50,000 years ago were adapting to the frigid temperatures of the central east European Plain, he said.
"The use of furs is particularly important, given these were a slender people with long limbs recently arrived from southern latitudes, making the cold even more of a challenge to survive in", Hoffecker said.
The Kostenki sites, which date beyond 40,000 years ago, may have hosted Neanderthals as well as modern humans, he said. "It looks like there were two separate industries at work here. One culture was advanced in terms of bone and ivory tool-making and decorative figurine art, while the other produced little more than crude stone tools."
Although modern human remains have been found at Kostenki associated with the advanced culture, no human skeletal materials have been found with the cruder tools, and their makers are unknown, said Hoffecker.
Hoffecker gave a talk on the latest research at Kostenki at the annual Society for American Archaeology meeting held in Denver March 18 and March 19.
Other participants in the study include Michael Anikovich and Andre Sinitsyn of the Russian Academy of Sciences, Vance Holiday of the University of Wisconsin and Steve Forman, a former CU-Boulder researcher now at the University of Illinois at Chicago.
Hoffecker also will give a talk on Kostenki research at the larger annual meeting of the 2002 Society for American Archaeology, which meets March 20 to March 22 at the Adam’s Mark Hotel on Denver’s 16th Street Mall.
"It was critical for these people to adapt to cold climates in order to survive," said Hoffecker, an INSTAAR Fellow whose research has been funded by the Leakey Foundation, the National Science Foundation and the National Geographic Society.
The modern humans at Kostenki also were creating symbols, art and language, as evidenced by decorated and engraved figurines, as well as some supporting anatomical evidence, he said.
"There may have been a relationship between their ability to formulate and communicate concepts through language and their ability to manipulate their environment through complex technology", he said.
"The exciting aspect is that we continue to find evidence of these people in deeper layers of sediment", he said. The evidence for modern humans at Kostenki is buried under 3 meters to 5 meters of silt.
Dating the early human sites beyond 40,000 years is a challenge because it is roughly the limit of radiocarbon dating, he said. The researchers turned to luminescence dating, which involves heating rock crystals from the sites and counting photons emitted from the crystals - which have been trapped under sediments for millennia - in order to determine accurate dates for specific sites.
Animal remains found at modern human sites at Kostenki included horses, mammoth, bison, moose and reindeer, said Hoffecker. In addition, other researchers recently found evidence for high consumption of fish based on analyses of bone chemistry from 30,000-year-old human remains, another indication that anatomically modern humans were advancing human technology.
"The fishing activity shows these people were probably manipulating the environment with fish weirs or traps", said Hoffecker. "They appear to have been using their sophisticated technology to expand the range of their diet, in comparison to Neanderthals."
In addition to trapping fur-bearing mammals, there also is evidence at Kostenki that modern humans were killing other small mammals and possibly birds using darts. "There is no evidence that Neanderthals were using this technique", he said.
###
Hoffecker recently authored a book titled "Desolate Landscape: Ice Age Settlement in Eastern Europe", which was published by Rutgers University Press.

Российский Верховный суд отклонил предложение закончить дело российского ученого Игоря Сутягина, который обвиняется в измене государству и шпионаже

MOSCOW, Russia, Mar 20, 2002 (RosBusinessConsulting via COMTEX) -- The Russian Supreme Court has declined to terminate criminal proceedings against Russian scientist Igor Sutyagin, who is charged with treason against the state and espionage. The Supreme Court has disallowed the private claim of his attorneys to remand the case.
The attorneys of the accused asked the court to reconsider its previous order, terminate the case, dismiss the charges and release the defendant from custody. One of the scientist's attorneys said after the court session that the defense was planning to apply to the Deputy Chairman of the Russian Supreme Court with a request to pay attention to the protest of the defense. In the event of refusal, the attorneys will immediately apply to the European Court for Human Rights in Strasbourg. Sutyagin was not present at today's court session, since he is currently detained on remand in Kaluga. According to the defendant's lawyer Kuznetsov, the Kaluga court's ruling to remand the case that was made on December 27, 2001, says that during the investigation there were cases of the violation of the Russian criminal legislation. Additionally, the investigators did not check out the defendant's explanations that the data he had transferred to foreign citizens were previously published by the mass media.

С помощью ракетоносителя "Рокот", созданного в Государственном научно-производственном центре им. Хруничева, на орбиту запущены американский и немецкий спутники, которые составят, как надеются ученые, самую точную карту гравитационного поля Земли

MOSCOW, (AP) -- Russia's premier aerospace company has developed a range of new booster rockets for foreign satellites in a bid to hold onto its share of the market for commercial launches, its director said Tuesday.
A Rokot booster developed by the Khrunichev State Research and Production Center put twin U.S.- German satellites into orbit on Sunday. The rocket was converted from a Soviet-designed SS-19 ballistic missile.
The unmanned German spacecraft, nicknamed Tom and Jerry, will fly in tandem to create what scientists hope will be the most accurate map ever of the Earth's gravitational field.
Khrunichev's director, Alexander Medvedev, said his company earned about $10 million for the launch, which was barely above production cost.
"We have to charge bottom price" to remain competitive, he said at a news conference.
Medvedev said that the launch price could be increased later as Rokot wins a market niche. He said another three Rokot launches are set for this year.
Thanks to its heavy-lift Proton, Khrunichev has become the top cash cow for the beleaguered Russian space industry, putting commercial satellites - mostly foreign - into high, geostationary orbits throughout the 1990s.
Russia receives tens of millions of dollars for each launch, a coveted revenue source for an industry struggling to survive on a fraction of generous Soviet-era state funding.
Medvedev blamed a sluggish global market for commercial space launches for last year's drop in the number of Proton launches. Khrunichev launched only two Western satellites into orbit atop Protons last year. Another two commercial launches set for 2001 were postponed until this year because of problems with satellites, Medvedev said.
He said his company had invested part of the earnings from commercial launches into research and development works for Rokot, Proton-M and the next-generation Angara rocket.
Khrunichev has also paid for upgrading the crumbling Soviet-era infrastructure of the Baikonur cosmodrome, which Russia leases from the former Soviet republic of Kazakhstan, and Russia's own Plesetsk cosmodrome used for Sunday's launch.
Medvedev said Khrunichev paid for a backup power system at the Baikonur after the Kazakh authorities once cut power to the launch pad minutes before a scheduled commercial liftoff.
"Such incidents can land you in the madhouse", he said.

С космодрома в Плисецке запущены два космических корабля, которые будут измерять гравитационное поле Земли

MOSCOW, (AP) -- Two spacecraft that will measure the Earth's gravitational field as part of a joint U.S.-German mission were launched at Russia's Plesetsk Cosmodrome on Sunday.
The twin spacecraft of the Gravity Recovery And Climate Experiment, or Grace, blasted off atop a Russian-made Rokot booster at 12:21 p.m., Russian space forces spokesman Sergei Derevyashkin said. It was the first launch of a NASA spacecraft from a foreign site.
The unmanned spacecraft, nicknamed Tom and Jerry, will fly in tandem to create what scientists expect will be the most accurate map ever of the Earth's gravitational field.
The $127 million mission is a collaboration between NASA and Germany's German Center for Air and Space Travel. It is being managed by NASA's Jet Propulsion Laboratory in Pasadena, Calif.
The two satellites, each weighing 1,100 pounds, will map the Earth's gravitational field, which is lumpy because of the variations in the density and types of materials that make up the Earth. Grace should reveal just how uneven it is, providing a view 100 times more accurate than that contained in current maps.
During their five-year mission, the spacecraft will also chart large-scale movements of water around the Earth. Those shifts in mass result in measurable differences in the planet's gravitational field.
Scientists expect Grace to track the depletion of large aquifers, the melting of glaciers and flow of currents within the oceans.
The two spacecraft will circle the planet 16 times a day. A precise microwave ranging system will constantly measure the distance between the two satellites. That, coupled with satellite navigation technology, will permit scientists on the ground to monitor changes in the speed and distance between the German-built spacecraft.
Those changes indicate differences in the mass of the Earth's surface below and any corresponding variations in its gravitational pull.
Plesetsk, the site of the launch about 400 miles northeast of St. Petersburg, is a former Soviet intercontinental ballistic missile site.

Начало дайджеста за МАРТ 2002 года (часть 1)

предыдущий месяц

1998-2002

следующий месяц