Российская наука и мир (дайджест)

За свою историю Земля пережила пять волн массового вымирания биологических видов в результате природных катаклизмов. Последний раз подобное случилось 65 млн. лет назад, когда погибло 88 процентов видов, в том числе динозавры. Сейчас ученые-биологи все чаще говорят о шестой волне, причем вызванной во многом действиями человека.

History of life on the Earth witnessed five mass extinctions of species as a result of natural calamities. Currently, biologists are talking more and more often about the sixth wave of extinction provoked in many respects by human beings. This opinion is shared by a Russian sea fauna diversity specialist A.V.Adrianov (Institute of Maritime Biology, Far-East Branch, Russian Academy of Sciences). Research in this area has been supported by the Far-East Branch of the Russian Academy of Sciences, CRDF, Ministry of Education and Science of the Russian Federation, and the Foundation for Promotion of Russian Science and the Russian Foundation for Basic Research.
As of today, taxonomists have already described nearly 2 million species, although in fact their number varies, according to various estimates, from 5 to 100 million. But 90 to 99 percent of species ever existing on the planet have already become extinct. The overwhelming majority vanished as a result of the so-called normal or background extinction due to the limited period of biological species existence, which fluctuates from 1 million years with mammals through 11 million years with some marine invertebrates. Besides the background extinction, the fauna experienced five mass extinctions, as a result of which 50 to 95 percent of then existing species disappeared within a limited historical period. The first mass extinction occurred 440 million years ago, at the end of Ordovic, as a result of temperature fall and the ocean level lowering. The second wave took place during the late Devonian, again due to temperature fall and sea reliction. During the third wave of extinction, at the end of Permian, approximately 250 million years ago, 95 percent of marine species and nearly 70 percent of terrestrial ones disappeared. The catastrophe was probably caused by active reconstruction of the earth's crust and change of climate during formation of the supercontinent Pangaea. The forth extinction happened in the late Trias, and the fifth one – the most renowned extiction – hit 65 million years ago. Researchers are inclined to believe that the Earth came into collision with a large bolide at that time. As a result, sea shoals suffered from tsunami and acid rains, the seabed was covered by enormous amount of organic matter, and only 12 percent of the then existing species survived on land.
At present, according to numerous specialists' opinion, the sixth - pleistocene - wave of extinction is coming, which has been in many respects provoked by men. Given the current average extinction rate of 40 species a day, it would take only 16 thousand years for the extinction of 96 percent of the contemporary biota – exactly as much as died out during the period of disastrous Permian extinction. The major reason for the oncoming calamity is destruction of plants' and animal's ecotope. Scientists have estimated that the species life span for contemporary mammals and birds has decreased up to 10 thousand years, i.e. it became 100 to 1000 times shorter than that of fossil forms. If the habitat continues to be destroyed at the same pace, the life span of these species will soon make only 200-400 years. There are no such estimates for the invertebrates, but they are undoubtedly affected both by the global environment and climate change, and by disappearance of local biotopes.
Death reigns on land and at sea. Thus, about 1 percent of tropical rainforests disappears annually. Up to 70 plant and animal species become extinct every day, which makes about 3 species per hour. At present, one tenth of coral reefs – zones of the highest biological diversity at shallow water – perishes; about 30 more percent will be ruined in the next decades. Corals die out mainly due to global environment and climate change, reef fish catching, water contamination and warming, hurricanes, destruction of symbiotic organisms. Any events taking place in shallow water also affects sea depths. Perhaps only "autonomous" superorganisms of deep-water gas-hydrotherm have not been touched upon by anthropogenic impact and they will evidently be able to escape consequences of the planet's global environment and climate changes even in case of nuclear holocaust.
Nevertheless, the sixth mass extinction is oncoming. That will be the first extinction which did not happed due to natural reasons but as a result of activity of one biological species, whose quantity increases annually by 100 million individuals.

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PhysOrg.com / July 19, 2004

Major science prize for Russian physicist's Universe in a Helium Droplet

Российский физик Григорий Воловик получил одну из самых престижных наград в области физики - Мемориальную премию Саймона - за исследование эффектов симметрии в сверхтекучих жидкостях и сверхпроводниках, а также за применение разработанных концепций в квантовой теории поля, космологии, квантовой гравитации и физике частиц.

Today the Low Temperature Group of the Institute of Physics announced the winner of one of the world's most coveted prizes for physics, the Simon Memorial Prize, to Professor Grigory Volovik from the Low Temperature Laboratory, Helsinki University of Technology, and the Landau Institute for Theoretical Physics in Moscow. The Simon Memorial Prize is one the world's top academic prizes and often an indicator of future Nobel glory. In the past thirty years, five Simon Prize winners have gone on to win Nobel Prizes, including last year's British winner Professor Sir Anthony Leggett.
The international Simon Memorial Prize commemorates the outstanding contribution to science of Sir Francis Simon, noted for his research in low temperatures at the University of Oxford, and who was also the science correspondent of the Daily Telegraph. It is awarded for distinguished work in experimental or theoretical low temperature physics. Professor Volovik has been chosen for his pioneering research on the effects of symmetry in superfluids and superconductors and the extension of these ideas to quantum field theory, cosmology, quantum gravity and particle physics.
Professor Mike Lea, Chair, Simon Memorial Selection Panel said: "Professor Grigory Volovik is an outstanding theorist who has shown how novel ideas and experiments from low temperature physics might lead to a new understanding about the early Universe and particle physics, in a unique synthesis. This is described in his forthcoming book The Universe in a Helium Droplet."
The Prize will be awarded at a Simon Memorial Prize Conference in London on 22 September 2004 where Professor Volovik will present a lecture, Emergent physics: a condensed matter primer.

© PhysOrg.com 2003-2004

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