|Российская наука и мир|
(по материалам зарубежной электронной прессы)
Le Figaro / Le 05/01/17
En Sibérie, les immeubles risquent de s'effondrer avec le réchauffement
Таяние вечной мерзлоты угрожает не только северной флоре и фауне, но и строениям. Как показало совместное российско-американское исследование, к 2050 году способность грунта выдерживать вес конструкций может снизиться на 75-95%. Такие города, как Салехард и Анадырь, почувствуют изменения уже в 2025 году.
Le réchauffement climatique menace les sols gelés de Sibérie et fragilise les principales villes du grand Nord. Le phénomène sera massif dans 35 ans mais menacera certains lieux dès 2025.
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Les études se suivent et se ressemblent concernant les dangers de la fonte du pergélisol (ou permafrost en anglais), ce sol gelé en permanence que l'on trouve notamment au Groenland, en Alaska ou dans le grand nord russe ou canadien. Le réchauffement climatique menace la faune, la flore mais aussi les bâtiments selon une récente étude relayée par le Siberian Times.
À en croire une analyse russo-américaine, dans le pire des cas, on pourrait assister à une réduction de 75% à 95% de la portance des sols, c'est-à-dire de leur capacité à supporter le poids de constructions, à l'horizon 2050. Forcément, l'étude en conclut que «le dégel du pergélisol peut potentiellement mener à la déformation et à l'effondrement des structures». Même si ces zones ne sont pas densément peuplées, elles couvrent 63% du territoire russe.
Changer les techniques de construction
Un risque qui pèse aussi bien sur les immeubles d'habitation que sur les constructions industrielles et les infrastructures. Et le temps presse déjà car si les villes de Iakoutsk et Norilsk ne devraient être touchées que vers les années 2040, d'autres comme Salekhard et Anadyr devraient subir de rapides changements dès 2025, toujours selon cette étude financée par la Fondation russe pour les sciences et la US National Science Foundation.
Tout en se montrant prudente étant donné l'incertitude concernant les projections climatiques, l'étude précise que les techniques de construction devraient prendre en compte le changement de nature des sols dans ces régions. Plusieurs études ont démontré que la zone arctique russe se réchauffait de quasiment 0,12°C par an, un chiffre significativement plus élevé que la moyenne pour les auteurs de l'étude. Dans les scénarios les plus optimistes, la portance des sols sibériens ne reculerait que de 25% «ce qui n'affecterait pas les structures bien conçues» suggère l'étude. Ce qui ne laisse pas à l'abri les constructions moins élaborées. D'ailleurs la région observe déjà régulièrement des fissures voire des effondrements de bâtiments fragilisés par des mouvements de sol.
Eurasia Review / January 11, 2017
Airborne Thermometer To Measure Arctic Temperatures
Российским ученым из МИСиС, МФТИ и Института общей физики имени А.М.Прохорова удалось повысить точность дистанционного измерения температуры воды. Метод основан на комбинационном рассеянии света - при прохождении через среду свет (в данном случае - излучение импульсного лазера) меняет длину волны, а значит, и цвет. Оказалось, что зависимость длины волны света от температуры воды очень точная и позволяет определить температуру с точностью до 0,15 градусов.
Russian scientists from the National University of Science and Technology MISiS, MIPT, and Prokhorov General Physics Institute (GPI) of the Russian Academy of Sciences have compared the effectiveness of several techniques of remote water temperature detection based on laser spectroscopy and evaluated various approaches to spectral profile interpretation. The paper detailing the study was published in Optics Letters.
The researchers examined four data processing techniques drawing on the relevant analyses in prior publications. The technique which the authors themselves previously proposed, developed and obtained a patent for proved to be precise up to 0.15 degrees Celsius. The research findings will support further development of sea surface temperature remote sensing solutions, enabling scientists to keep track of thermal energy flows in hard-to-reach areas such as the Arctic region, where average temperatures are rising approximately twice as fast as they are elsewhere on the planet.
In their study, the scientists focused on Raman spectroscopy, which is based on the phenomenon of Raman scattering discovered in the 1920s. It involves the interaction of a medium with a light wave: The scattered light is modulated by the molecular vibrations of the medium, resulting in the wavelengths of some of the photons being shifted; in other words, some of the scattered light changes its color. Raman scattering and, by extension, the field of Raman spectroscopy were named after Sir C. V. Raman, an Indian physicist who was awarded a Nobel Prize for the discovery of this effect. Interestingly, Russian scientific literature tends to refer to the same phenomenon as "combination scattering," a term coined to emphasize its independent discovery by Soviet researchers.
"With the climate changing so rapidly, remote sensing of water temperature is a priority, but the radiometry techniques currently in use are only precise up to about a half degree. Raman spectroscopy enables measurements with a much greater precision," claims Mikhail Grishin, one of the authors of the study, a Ph.D. student at MIPT, and a researcher at the Laser Spectroscopy Laboratory of the Wave Research Center at GPI.
The experiment carried out by the scientists involved probing water with a pulsed laser and using a spectrometer to analyze the light that was scattered back. Depending on the temperature of the water, its characteristic OH stretching vibrations spectral band was variably transformed. The scientists needed to find out whether it is possible to establish a clear relationship between water temperature and one of the spectral band parameters.
The scientists examined the temperature dependence of several spectral band parameters (aka metrics), viz., certain parts of the area below the graph, differential spectra (the result of subtraction of two spectra), and the location of the peak of the curve fitting the band spectrum. Although it proved possible to establish a relationship between water temperature and each of the abovementioned metrics, the estimated temperature measurement accuracy of the respective techniques varied. Statistical analysis of experimental data showed that temperature dependence was most pronounced when the wavelength that corresponds to the peak of the curve fitting the band spectrum was used as a metric. The scientists were granted a patent for the corresponding approach to spectral profile interpretation by the Russian patent office.
Seawater temperatures in the Arctic are currently monitored using a range of techniques including direct measurements made by weather buoys and merchant or research vessels. However, to track the temperature dynamics of sea surface water in real time and over vast areas, it is necessary to make aerial observations using sensing equipment installed on aircraft or satellites, which irradiates the water with a laser and collects the scattered light. A spatial resolution of less than one kilometer enables researchers to create very detailed temperature maps which can be used to monitor the transfer of heat by ocean currents, predict how fast Arctic ice is going to melt, and make a global climate change forecast. As unmanned aerial vehicles (UAVs) become better, remote sensing equipment should also be improved to be more precise, lightweight, compact, and energy-efficient. The scientists are developing both the software and the laser-detector system.
Vasily Lednev, one of the authors of the study, a leading expert at the Department of Certification and Analytical Control of NUST MISiS, told us how he sees the future of this research:
"One of the main hurdles faced in remote sensing of the sea surface is the necessity to calibrate equipment and verify satellite measurement results against contact measurements of seawater parameters (temperature, chlorophyll concentration, etc.). The development and design of compact autonomous lidar (laser radar) systems which can be mounted on UAVs will enable us to obtain detailed sea charts featuring a range of water parameters. These lidar systems are also of immediate interest to the study of hard-to-reach and dangerous objects like icebergs or ice shelves."
The average annual changes in the temperature of the world's oceans tend to be very small. It is currently heating up by a mere tenth of a degree every ten years, whereas seasonal temperature variations can amount to several degrees. This means that an error of just half of a degree will cause a significant drop in precision of the overall picture of temperature dynamics that we get. In the case of seasonal measurements, the uncertainty can reach 20 percent or more, while long-term climate trends may remain unidentified due to the measurement error.
The remote-sensing thermometers currently in use operate in the microwave spectral range. Raman scattering spectrometry has a significant advantage over microwave radiometry in that the probing laser radiation falls into the visible (blue-green) part of the spectrum. Unlike microwave radiation, to which water is almost completely opaque, visible light can penetrate a layer of water that is 1-10 meters thick. With microwave sensing, the data is only available for the 30-micron-thick surface layer whose temperature is significantly affected by the cold Arctic winds. This gives rise to an error, which is almost entirely avoided in measurements based on Raman scattering. To correct errors of this kind, satellite-based microwave radiometers need to be calibrated against ground-based measurements. By contrast, Raman spectrometry does not face this obstacle and can produce useful data independently from contact observations.
Copyright 2017 | By Eurasia Review.
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AFP / 11 Jan 2017
Father of Russian environmental movement Yablokov dies
Скончался известный российский эколог и зоолог, основатель российского отделения Greenpeace, общественный и политический деятель, член-корреспондент РАН Алексей Владимирович Яблоков (3 октября 1933 - 10 января 2017).
Leading Russian ecological campaigner Alexei Yablokov, the founder of Greenpeace Russia and one of the pioneers of the post-Soviet environmental movement, has died at 83, the Russian Academy of Sciences said Wednesday.
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Yablokov, who studied marine zoology in the Soviet era, spearheaded major campaigns in the perestroika era that formed a new generation of activists and acted as advisor both to the government and various NGOs.
A respected scientist, Yablokov wrote seminal books, including scholarly titles and children's literature, and launched the country's first green party.
Despite old age and declining health, he continued to support environmental campaigns even as activism in Russia became increasingly politically risky and new legislation crippled many NGOs during Vladimir Putin's latest term as president.
He died on Tuesday in Moscow after a long illness.
Born in Moscow, Yablokov studied whales and dolphins before branching out into environmental policy, but "always remained true to science," Russian Academy of Sciences said in a statement.
He became a lawmaker in the Soviet Union's first popularly elected parliament and chaired its environment committee in 1989-91 before serving as president Boris Yeltsin's environment advisor. In 1989, he founded the Soviet Union branch of Greenpeace, which three years later became Greenpeace Russia. In 2005 he launched a short-lived green party called Union of Russian Greens, which later merged with the opposition Yabloko party, of which he became one of the leaders.
Yablokov "left a deep impression in all the fields he worked in: marine biology, nature protection and politics," said Maria Vorontsova, the head of the Russian branch of the International Fund for Animal Welfare.
For Russia's environmentalists, Yablokov was like "a true saint," said Dmitry Lisitsyn, an activist on the Far Eastern island of Sakhalin. "He was a truly extraordinary person" who served as an example, he said.
"He was one of the founders and the inspiration for Russia's modern environmentalist movement."
The Science Explorer / January 11, 2017
Lamprey Gene Helps Scientists Discover How the Human Brain Appeared
Сотрудники Института биоорганической химии имени М.М.Шемякина и Ю.А.Овчинникова РАН совместно с коллегами из Института проблем экологии и эволюции имени А.Н.Северцова подтвердили свою гипотезу о том, что конечный мозг (передний отдел головного мозга, из которого развиваются большие полушария) возник у позвоночных - в том числе и у человека - благодаря появлению гена Anf/Hesx1. Данный ген удалось обнаружить у миноги - самого древнего из ныне живущих позвоночных, а также доказать, что в ее случае ген выполняет ту же самую функцию, что и у других позвоночных.
Researchers at the M.M. Shemyakin and Yu.A. Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences have collaborated with their colleagues from the A.N. Severtsova Institute of Ecology and Evolution in groundbreaking research work in which they discovered the homeobox gene Anf / Hesx1 in lampreys. It is the most ancient gene in modern vertebrates.
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The research findings that they published in Scientific Reports support the hypothesis that the appearance of this gene in vertebrates created the conditions necessary for the emergence of the telencephalon.
The telencephalon (known as the "end of the brain") is the anterior part of the brain that is characteristic only of vertebrates, including humans. It is from this section that such important structures as the larger cerebral hemisphere develop.
"All other types of multicellular animals do not possess pronounced anatomical structures that are similar to the vertebrate telencephalon," explained Professor Andrey Zaraiskii of the Russian Academy of Sciences. "This means that during evolution, the telencephalon developed only in the ancestors of modern vertebrates."
Aromorphosis is the term that scientists use to describe the emergence of the telencephalon during the evolution of the vertebrate. The term describes a major evolutionary change leading to an overall increase in the level of organization of the body. In this regard, the question of the genetic mechanisms underlying this process becomes very important. Andrey Zaraiskii and his colleagues discovered a previously unknown homeobox (involved in the regulation of development) gene Anf / Hesx1 that is responsible for the inclusion of the telencephalon development process in representatives of several classes of vertebrates. Scientists have suggested that the formation of the vertebrate telencephalon may be associated with the appearance of the Anf / Hesx1 homeobox gene in their ancestors.
To confirm this hypothesis, the scientists had to demonstrate that the Anf / Hesx1 gene is present in all classes of vertebrates. However, until now, this gene could not be detected in jawless vertebrates (lampreys and hagfish), the representatives of the most ancient of living classes in existence. Other researchers recently conducted a genome sequencing (determination of the nucleotide sequence, DNA and RNA "building blocks") of lamprey that also showed no presence of the Anf / Hesx1 gene in these vertebrates. In order to identify it, Professor Zarayskiy's team used special approaches based on high-precision isolation of RNA from the cells of the telencephalon rudiment of embryonic lamprey. Consequently, they were able to clone the Anf / Hesx1 in three species of these animals. Simultaneously, by means of special experiments, the researchers demonstrated that in lamprey, this gene regulates the early development of the telencephalon, i.e. it performs the same function as in other vertebrates.
"We discovered in lampreys, the most ancient living vertebrates, the homeobox gene Anf / Hesx1," said Andrey. "This discovery is very important for confirming the hypothesis that we had previously put forward. We believe that the key event in the creation of the conditions necessary for the emergence in vertebrates, including ourselves, of telencephalon, was the development of the Anf / Hesx1 gene in their ancestors."
The confirmation that the gene carries out the same function in lampreys as that in other vertebrates suggests the universality of the early telencephalon development mechanism.
Flightglobal / 18 January, 2017
Russian institute studies "ekranoplan" freighter
В Центральном аэрогидродинамическом институте имени Н.Е.Жуковского провели испытания модели грузового экранолета. В отличие от экраноплана, он способен летать на больших высотах, при этом расход топлива меньше, чем у самолета, а грузоподъемность больше - до 500 тонн.
Russian researchers are analysing the potential of a heavy freighter design which would rely on ground-effect lift.
The aircraft would feature a cargo compartment which would act as a wing, with a capacity for 500t of freight in standardised containers. This arrangement would ensure "optimal use" of the internal volume, says the Moscow-based Central Aerohydrodynamic Institute, and increase the efficiency.
The institute has conducted subsonic windtunnel testing of the four-engined design, which includes a twin vertical stabiliser and a liquefied natural gas fuel tank in the central fuselage.
While the aircraft would use conventional runways, most of its flight would take place just 3-12m (10-40ft) above terrain, water or ice by taking advantage of ground-effect forces. These forces include a combined reduction of drag and increased lift resulting from a wing's creating a cushion of air, and disrupting vortices, when close to the ground.
Freight would be loaded through the front of the wing, says the institute, which has assessed cruising and landing configurations of the design. It says that the modelling indicates the aircraft could conduct "sustained and controlled" flight, with the ground effect helping to reduce fuel consumption and increase range.
Analysis of the aircraft design echoes previous Soviet-era experimentation with a variety of ground-effect "ekranoplan" vehicles including the huge craft - the Alexeyev KM - tested on the Caspian Sea in the 1960s.
Flightglobal © Copyright 2017.
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Christian Science Monitor / January 23, 2017
How a few millimeters of Russian rock helped unwind a meteorite mystery
Meteorites that struck Earth more than 466 million years ago were very different than those we see today, according to new research published in Nature Astronomy.
Геологи из США, Швеции и России выяснили, что за последние 500 млн лет падающие на Землю метеориты заметно изменились по составу, что, соответственно, говорит об изменении в результате какого-то события химического состава небесных тел в Солнечной системе.
Are the meteorites of today just like the ones that used to strike our planet hundreds of millions of years ago?
The answer to that question is of interest not just for its own sake, but for the insights it can provide into the evolution of our solar system's asteroid belt, as well as the interaction of other celestial bodies in general.
And, according to some fresh research published in the journal Nature Astronomy, the answer is a resounding "no."
"We found that the meteorite flux, the variety of meteorites falling to Earth, was very, very different from what we see today," lead author Philipp Heck, an associate curator at The Field Museum in Chicago, said in a press release.
The key to understanding how that change came to pass lies in a cataclysmic collision that took place 466 million years ago, when something struck an asteroid, tore it apart, and sent chunks of rock hurtling through space. Ever since, the majority of meteorites - flying bits of debris ripped off asteroids, comets, moons, or planets when they collide - peppering Earth's surface have originated from that one event.
In seeking to study meteorites originating even earlier, Dr. Heck's colleagues traveled to a Russian river valley, where an ancient seafloor lies exposed. There, they were able to source micrometeorites, hunks of space rock measuring no more than 2 millimeters in diameter, from the time in question.
Extracting the samples and dissolving them in acid left one thing: microscopic chromite crystals.
"Chrome-spinels, crystals that contain the mineral chromite, remain unchanged even after hundreds of millions of years," Heck explained. "Since they were unaltered by time, we could use these spinels to see what the original parent body that produced the micrometeorites was made of."
Examining those spinels, scientists discovered the striking differences between the meteorites of today and those of times gone by. They found that prior to the big collision, 34 percent of meteorites were of a kind called primitive achondrites; today, that figure stands at 0.45 percent.
Heck says that studying the meteorite record just from the past few hundred million years since that one explosive collision is like looking outside during a snowstorm and concluding that the weather on Earth is always snowy: The debris from that one event is likely to have masked the bigger picture.
"Ultimately, we want to study more windows in time," said Heck, "not just the area before and after this collision during the Ordovician period, to deepen our knowledge of how different bodies in [the] solar system formed and interact with each other."
© The Christian Science Monitor. All Rights Reserved.
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Le Courrier de Russie / Le lundi 23 janvier 2017
Changement climatique : les Russes, les Français et les sols sibériens
Si les sols gelés de Sibérie occidentale et centrale sont relativement bien connus de la communauté scientifique, d'immenses zones de la région n'ont encore jamais été étudiées.
С 2007 г. сотрудники Центра исследований биоты, климата и ландшафтов «БиоКлимЛанд» Томского государственного университета совместно с французскими коллегами (лаборатория Миди-Пиренеи, Университет Тулузы) занимаются изучением арктических и субарктических районов Сибири в контексте климатических изменений.
Longtemps ignorés par la communauté scientifique internationale, les sols de Sibérie sont pourtant le théâtre de phénomènes uniques, précieux pour comprendre l'évolution du climat à l'échelle mondiale. Les premiers scientifiques étrangers à s'y être intéressés sont les Français, qui, depuis dix ans, étudient avec les Russes la fonte du pergélisol, les gaz qui s'en dégagent et leurs effets sur l'environnement. Le Courrier de Russie s'est penché sur cette collaboration fructueuse, à laquelle les deux côtés partenaires souhaitent aujourd'hui donner une nouvelle impulsion.
Une région hostile mais cruciale
Avec sa superficie de 13 millions de km2 et ses températures pouvant chuter jusqu'à -77,8°C, la Sibérie est une région qui effraie autant qu'elle fascine. Le territoire, immense, est difficile à couvrir, et les scientifiques sont peu nombreux à se lancer dans une étude approfondie des sols.
« La région mérite pourtant que l'on s'y attarde », assure Sergueï Kirpotine - directeur du centre russe de recherche sur le changement climatique Bio-clim-land et vice-directeur des relations internationales de l'université d'État de Tomsk, qui étudie la Sibérie depuis plus de vingt ans.
Pour le scientifique, la Sibérie a une influence déterminante sur le climat de la planète. « Les phénomènes qui s'y produisent ont un impact significatif sur l'environnement », insiste-t-il. Ainsi, poursuit le chercheur, la question de savoir si, par exemple, le Bangladesh sera un jour totalement inondé dépend largement de ce qui se passe en Sibérie.
Un défi de taille
C'est en 2007 que des chercheurs français ont rejoint leurs collègues russes dans l'étude des sols et du climat sibériens, l'Observatoire Midi-Pyrénées de Toulouse et l'université d'État de Tomsk ayant alors créé alors un réseau de laboratoires à cette fin.
« De nombreuses études biochimiques ont été réalisées dans des régions aux conditions similaires, tels l'Alaska ou le Canada, mais la Sibérie restait méconnue - c'est ce qui nous a attirés », a indiqué au Courrier de Russie Stéphane Audry, chercheur à l'Observatoire Midi-Pyrénées, qui collabore avec la Russie depuis six ans.
Face à l'ampleur de la tâche, les scientifiques russes et français ont procédé méthodiquement - en commençant par s'attaquer aux sols de la Sibérie occidentale. « Il s'agit d'une superficie de 2,7 millions de km2, qui s'étend de l'extrémité sud de Tomsk aux alentours des rivières Nadym et Pour », précise le chercheur français.
Au programme de leurs recherches, plus particulièrement, l'étude des lacs thermokarstiques, ces étendues d'eau qui se forment à la fonte du pergélisol. « La Sibérie est constituée d'énormes surfaces plus ou moins gelées, et l'on sait encore mal, si celles-ci commencent à fondre, comment le phénomène contribuera au changement climatique », souligne Stéphane Audry.
Depuis dix ans, les chercheurs français se rendent donc sur le terrain pour recueillir des échantillons d'eau. Au cours de ces missions, qui durent de dix jours à trois semaines, ils sont totalement pris en charge par les Russes. « Une aide indispensable, car échantillonner dans ces régions est très difficile du fait des conditions climatiques, surtout en hiver, poursuit Stéphane Audry. Sans eux, nous ne pourrions même pas nous rendre sur place. »
Les scientifiques étudient ensuite ensemble, dans leurs laboratoires communs de Tomsk ou de Toulouse, la composition de ces masses d'eau riches en carbone qui, avec la fonte des glaces, rejettent des gaz à effet de serre dans l'atmosphère. « C'est dans l'eau que le carbone organique des sols se transforme le plus rapidement en dioxyde de carbone », précise le chercheur français.
Forte concentration de gaz à effet de serre
S'ils ne disposent pas encore de suffisamment de données pour pouvoir tirer des conclusions générales, les membres de l'équipe de recherche franco-russe sont du moins les premiers à avoir prouvé que les petits lacs - d'une surface inférieure à 300 m2, indétectables par satellite et ne figurant sur aucune carte - émettent beaucoup plus de gaz à effet de serre que ceux plus étendus.
« La toundra sibérienne compte des millions de ces lacs qui, du fait de leur taille négligeable, n'étaient pas comptabilisés jusque récemment », indique Sergueï Kirpotine.
La fonte croissante du pergélisol en Sibérie occidentale fait craindre aux scientifiques que les grands lacs thermokarstiques ne se décomposent en une multitude de petits lacs. « Un phénomène qui pourrait provoquer une augmentation importante des émissions de gaz à effet de serre et une dissolution des émissions organiques de carbone dans les rivières et l'océan Arctique », alerte le directeur du centre Bio-clim-land.
Parmi les gaz émis par les lacs, c'est le méthane qui inquiète tout particulièrement les spécialistes. « Nous le savons aujourd'hui : il n'existe aucun autre endroit sur terre où les émissions de méthane sont si importantes », souligne Sergueï Kirpotine. Présent en quantité moindre dans l'atmosphère que le dioxyde de carbone, le méthane possède un pouvoir réchauffant de plus de 25 fois supérieur à celui du CO2.
À en croire les chercheurs, si le pergélisol dégèle à grande échelle, l'amplification des flux de CO2 et de méthane dans l'atmosphère entraînera un accroissement significatif de l'effet de serre.
Une première prometteuse
Des observations qui ont fait l'objet de plusieurs articles, largement diffusés au sein de la communauté scientifique internationale. « Personne n'avait encore collecté des informations aussi précises sur un territoire aussi vaste », insiste Sergueï Kirpotine.
Jusqu'à présent, l'équipe a pu compter sur une bourse de l'État russe, d'un montant de 30 millions de roubles par an, obtenue en 2014 pour une durée de trois ans. « Les comptes-rendus de nos premières études ont suscité un tel intérêt que le gouvernement a décidé de prolonger l'octroi de cette aide pour deux années supplémentaires, explique le directeur de Bio-clim-land. Et le montant a été maintenu ! »
Côté français, l'intérêt est tout aussi vif pour ces découvertes conjointes en Sibérie. Sergueï Kirpotine s'est ainsi vu remettre, en 2015, l'insigne de chevalier de l'Ordre des palmes académiques, récompense française la plus prestigieuse dans le domaine de l'éducation et de la recherche, avec, à la clé, une bourse répartie sur plusieurs projets.
Des ambitions à la hauteur de l'enjeu
Toutefois, les financements demeurent insuffisants face à l'ampleur de la tâche : « Nous n'avons étudié pour l'heure qu'une poignée de lacs, et la Sibérie en compte des centaines ! », indique le chercheur russe.
« C'est une région immense - il est tout simplement impossible, pour les quelques chercheurs que nous sommes, de la couvrir entièrement et en profondeur, poursuit Sergueï Kirpotine. Ajoutant : Il est temps de passer à la vitesse supérieure en créant un véritable réseau de stations scientifiques à travers toute la Sibérie ».
Mais un projet de cette dimension exige des infrastructures si importantes, complexes et coûteuses qu'aucun pays ne pourrait se permettre d'en assumer seul la mise en place. Les scientifiques russes et français recherchent donc aujourd'hui d'autres partenaires. « Plusieurs pays, dont la Chine, ont déjà exprimé leur intérêt », se réjouit le directeur du centre Bio-clim-land.
L'objectif, à terme, est d'impliquer le plus d'acteurs possible pour récolter des échantillons toute l'année - même l'hiver et lors de la fonte, quand les conditions sont les plus difficiles - en établissant des standards communs pour toute la Sibérie.
L'Université de Tomsk pourrait se charger de la coordination des recherches et chapeauter des équipes russes et étrangères réparties entre la Yakoutie et Krasnoïarsk - que séparent tout de même 5000 km.
« Un projet qui n'est pas si ambitieux, vu la hauteur de l'enjeu », estime Sergueï Kirpotine. En effet, à l'en croire, leurs recherches sur les émissions des gaz à effet de serre risquent de contraindre la communauté mondiale des chercheurs à revoir à la hausse leur objectif maximal de 2° de réchauffement climatique d'ici 2100. L'équipe franco-russe affirme ainsi que la quantité de gaz à effet de serre émis en Sibérie pourrait réchauffer l'ensemble de planète plus vite que prévu.
© Le Courrier de Russie 2017.
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EurekAlert / 23-Jan-2017
One of the world largest digital herbaria launched
Lomonosov Moscow State University launched one of the world largest digital herbaria.
В МГУ имени М.В.Ломоносова создали цифровой гербарий - коллекцию отсканированных изображений гербарных образцов из фондов биологического факультета. Гербарий МГУ содержит более миллиона образцов, из них отсканировано почти 800 тыс., 500 тыс. изображений уже доступны на сайте проекта.
Within the framework of the "Noah's ark" project, scientists from the Lomonosov Moscow State University have developed the largest digital herbarium in Russia - a collection of scanned images of herbarium samples from the Faculty of Biology funds.
Piotr Kamenski, the project scientific coordinator, a Senior Scientist at the Lomonosov Moscow State University shares: "The "Noah's ark" project is absolutely unique for Russia and even worldwide. Its main goal is saving, studying and beneficial using of the biological diversity of our planet. Undoubtedly, many other projects also have served and are serving this goal. However, within the framework of the "Noah's ark" project we work with all possible types of biological samples - from dried insects to human biomaterial. The creation of the common biological collection information space is an important part of the project. In other words, we are working out a digital resource, which will join maximum possible amount of information about biological collections. Meantime we work within the Lomonosov Moscow State University, but in the future we are going to extend, including the whole of Russia. The digital herbarium of the Lomonosov Moscow State University turns out to be a first shot of our information system, clearly demonstrating all profits, provided by the global approach to analysis of biological diversity".
At the moment the digital herbarium of the Lomonosov Moscow State University numbers 786 thousands of samples. Images are freely available at the web portal of the National bank-depository of the living systems, existing at the Lomonosov Moscow State University.
Alexey Seregin, one of the digital herbarium developers, Doctor of Biological Sciences, Senior Scientist at the Lomonosov Moscow State University Herbarium, and Plants Division Manager within the "Noah's ark" project, says: "We have begun to digitize the University Herbarium in spring 2015 and till now have scanned all numerous floral forms of Eastern Europe, Siberia and the Far East, Crimea, Caucuses, Mongolia, African and South Asian countries. The database created is the largest storage of information about plants diversity and propagation in Russia. It could be used not only by specialists, but also by non-biology people who are interested in flora. In order to take advantage of the digital herbarium, it's enough to enter the scientific name of a plant or use a function of advanced search. All images are of high resolution, so one could study the given pieces of the sample without digitizing every detail separately. The scientific stuff of the Lomonosov Moscow State University has digitized samples by its own forces. Only six members of the Lomonosov Moscow State University Herbarium have taken part in this process, however, many volunteers from the students of our University also have helped a lot".
Judging from the quantity of the scanned samples, the digital herbarium of the Lomonosov Moscow State University is at the moment number one in the world among university collections and in the sixth place "in the overall standing", being behind only the collections from the largest scientific centers of the world, namely Paris, Leiden, Beijing, New-York and Washington.
The Lomonosov Moscow State University Herbarium (MW) is a collection of universal importance, mentioned for the first time in 1780. Moreover, it's one of the leading centers of studying and registration of plant diversity. The funds size is above 1 011 000 samples. One could find here the most valuable historical antiquities, connected with names like Carl Linnaeus and James Cook, as well as comprehensive materials left by subsequent flora investigators.
The herbarium is constantly added by new digitized samples. Members of the Lomonosov Moscow State University have discovered 60 species of flowering plants for the past five years, and only eight of them have been found in Russia. 16 new plant species were found only in 2016. The sample of each plant is herbarized and added into the collection of that institution, with which the scientist cooperates. After that the images of every discovered plant is also put into the digital herbarium. It's also possible to get study materials from foreign herbaria - scientific organization get learnt which plants or geographical regions are interesting for each side and afterwards a bunch of samples is exchanged on the principle of "one sample to another one".
Copyright © 2017 by the American Association for the Advancement of Science (AAAS).
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International Business Times UK / January 25, 2017
Russian scientists attempt to solve mystery surrounding Lake Cheko in Siberia
Years of controversy surround Lake Cheko and arguments it was formed by 1908 Tunguska event.
Исследователи из Института геологии и минералогии имени В.С.Соболева СО РАН и Института биофизики СО РАН опровергли версию итальянских геологов о том, что озеро Чеко в Красноярском крае является кратером Тунгусского метеорита. Изучение отложений из самого глубокого места озера показало, что водоему не менее 270 лет.
Lake Cheko is a small lake, about 350 metres across and 700 metres long. It is a fairly ordinary looking lake but is has been at the subject of controversy for many years, with its location putting it at the centre of a scientific puzzle.
The lake lies about 8 kilometres away from the suspected epicentre of the Tunguska event on 30 June 1908 in Siberia. The event was enormous explosion that could be seen across the skies from Europe to Central Asia. The energy released in the explosion is estimated to have been equivalent to around 30 megatonnes of TNT detonating.
The incident is thought to have been a large meteorite exploding in Earth's atmosphere. Scientists have speculated whether shards of the meteorite may have made it to the surface and left impact craters.
Lake Cheko was identified as one candidate for an impact crater 10 years ago. In 2007, a team of scientists from the University of Bologna, Italy, first proposed in the journal Terra Nova that Lake Cheko had been formed from a meteorite fragment.
This finding had already been briefly considered and dismissed by a Russian expedition about 50 years earlier. But study author Luca Gasperini and his colleagues argued that the lake's funnel-like shape and the structure of its sedimentary deposits suggested it had all the hallmarks of an impact crater. The lake was formed when water filled the crater made by a 10m fragment that survived the journey through the atmosphere, they argued.
This was in turn disputed in a 2008 comment article in the same journal by another group of scientists led by Gareth Collins at Imperial College London in the UK. They argued the shape of the lake's basin did not resemble other impact craters on Earth of a similar size. There was also another clue from the trees surrounding the lake, they said.
A total area of about 2,000 square kilometres of the Siberian forest had been devastated by the 1908 blast. The trees in the area had been flattened, and even today are still at an angle pointing away from the epicentre of the Tunguska event.
But next to Lake Cheko there were mature trees growing straight. This made it very unlikely that there had been a secondary blast in the area to form the lake, Collins argued.
Russian scientists have now completed an expedition to take further sediment samples from the lake to determine its age. The Russian Geographical Society said in an announcement that a team based in Siberia had found evidence that the lake was at least 270-years-old, although the results have not been peer-reviewed or published yet.
The team, led by Denis Rogozin, senior researcher at the Krasnoyarsk Scientific Center of the Russian Academy of Sciences, is currently preparing its findings for review. If the results are found to be valid, they would add another layer to the evidence suggesting Lake Cheko had nothing to do with the blast.
"The Tunguska event was in 1908, therefore if the lake were a meteorite impact it would have an age of 2016 minus 1908, which is 108 years," Rogozin told IBTimes UK.
Rogozin and his team claim to have found that the lake is much older than the event, by analysing sediment cores taken from the deepest part of the lake, close to its centre. He said the team used 137-caesium and 210-lead isotope dating combined with visual analysis of sediment layers, or varves.
"We have not determined the total age of Lake Cheko, we have determined the age of deepest part of 120 cm-long sediment core," Rogozin stated. "Because three independent methods give the same estimate we are sure that the age of the core is about 270 years. Thus, the lake is surely older than 270 years."
However, Gasperini and his colleagues also used 137-caesium and 210-lead dating to try to date the sediments but found no conclusive results as to the age of the lake, but said that the sediments supported their hypothesis that the lake is an impact crater from the 1908 event.
"The problem is that only using the isotopes - we carried out measures on several cores - interpolating linearly towards the past, no one could really understand what the lake sediments tell us about their age and the lake's origin," Gasperini said. "The problem is more complex. We tried to explain our point in several papers - some of them with question mark in their titles - and we are happy that someone is trying to test what we have found."
Gasperini said that he was curious to see the Russian team's results when they are eventually published. "We were always open to discussion," he said.
Even if the Russian team's results are found to be valid after they have been scrutinised, they are only attempting to find out the age of one part of the lake. The origin of Lake Cheko and its absolute age will remain yet another mystery to be solved.
© Copyright 2017 IBTimes Co., Ltd. All Rights Reserved.
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Scientific Computing / Wed, 01/25/2017
The Speed Limit for Intra-Chip Communications in Microprocessors of the Future
Физики из МФТИ разработали теорию, позволяющую точно предсказать уровень шума, возникающего при усилении фотонных и плазмонных сигналов в наноразмерных оптоэлектронных схемах. Зная мощность шума, можно высчитать максимально возможную скорость передачи информации по такому каналу.
Researchers at the Moscow Institute of Physics and Technology have developed a theory that gives the possibility to precisely predict the level of noise caused by the amplification of photonic and plasmonic signals in nanoscale optoelectronic circuits. In their research published in Physical Review Applied, the scientists propose an approach that can be used to evaluate the ultimate data transfer rates in the emerging optoelectronic microprocessors and discover fundamental limitations on the bandwidth of nanophotonic interfaces.
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Surface plasmon polaritons are collective electron oscillations on a metal surface coupled to an electromagnetic field. A surface plasmon could be viewed as a compressed quantum of light, and that explains why plasmonic devices are very promising for many applications: They are almost as compact as nanoelectronic components, but at the same time, they enable up to four orders of magnitude higher data transfer rates than electrical wires. Replacing even some of the electrical interconnects on a chip with plasmonic (nanophotonic) components would give a much-needed boost to microprocessor performance.
The main obstacle currently faced by plasmonics is signal attenuation. Due to high losses, surface plasmons can propagate over long distances only in so-called active plasmonic waveguides. Such waveguides not only guide the plasmonic signal from the transmitter to the receiver but also amplify it using the energy of the electric current flowing through the device. This added energy compensates for signal losses and allows surface plasmons to propagate freely along the waveguide, just like the energy supplied by a battery keeps a quartz clock ticking.
However, there is a fundamental problem associated with signal amplification and loss compensation. Every amplifier does not just increase the amplitude of the input but also adds some unwanted random signals. Physicists refer to these signals as noise. According to the laws of thermodynamics, it is impossible to remove all noise from a system. The distortion of the original signal is largely determined by noise, which fundamentally limits data transfer rates and causes errors in the received bits if information is transferred at higher rates. To increase the data transfer rate, the signal-to-noise ratio needs to be improved. The importance of this ratio is obvious to anyone who has had the experience of talking to someone on a busy street or tuning in on a radio station.
"Noise plays a key role in nearly half of all the devices in our homes: from cell phones and television sets to the fiber-optic channels that are the backbone of the high-speed internet. Signal amplification inevitably decreases the signal-to-noise ratio. In fact, the more gain an amplifier provides, or, in our case, the greater the signal loss it needs to compensate, the higher the level of noise it produces. This problem is especially pronounced in plasmonic waveguides with gain," explains Dmitry Fedyanin.
A recent study by Dmitry Fedyanin and Andrey Vyshnevyy published in Physical Review Applied deals with a particular kind of noise, namely the photonic noise produced when plasmonic signals are amplified in semiconductor devices. Its main cause is the so-called spontaneous emission. When a photonic signal is amplified, the power of the optical wave increases due to transitions of electrons from higher to lower energy states, namely the difference in energy between the two energy states is released as quanta of light. This emission can be both stimulated and spontaneous.
While the stimulated emission amplifies the signal, the spontaneous emission produces random quanta of various energies, i.e., noise with a broad spectrum. Noise can be observed as random fluctuations in signal power, resulting from the interference of frequency components of the signal and of the spontaneous emission (this phenomenon is known as beat). Any increase in the gain provided by an amplifier increases the noise level and broadens the spectra of emission, both stimulated and spontaneous. The applicability of the well-established approaches of quantum optics, which are meant to describe the interaction of light with individual atoms, decreases as the spectra in the studied system become broader. To tackle the case of high-gain amplification at the nanoscale, the researchers basically had to start the work from scratch.
"We had to bridge the gap between three different areas in physics that rarely intersect with one another: quantum optics, semiconductor physics, and optoelectronics. We have developed a theoretical framework that can be used to describe photonic noise in structures incorporating active media with a broad gain spectrum. Although this approach was initially conceived for plasmonic waveguides with gain, it can be applied with no change to all optical amplifiers and similar systems," Dmitry Fedyanin points out.
Noise causes errors during transmission, which reduces the effective data transfer rate considerably due to the need to implement error correction algorithms. As far as hardware is concerned, error control also requires additional on-chip components that realize correction, making new devices more difficult to design and manufacture.
"If we know the noise power in a nanophotonic communication channel, as well as its spectral characteristics, it is possible to evaluate the maximum rate of data transfer along that channel. Furthermore, we can identify ways to reduce the amount of noise by choosing certain regimes of device operation and using optical and electrical filtering techniques," adds Andrey Vyshnevyy.
The proposed theory sheds light on the prospects of a new class of devices which combine the advantages of electronics and photonics on the same chip. In a chip of that kind, plasmonic components would be used for ultrafast communication between processor cores and registers. Although signal attenuation was previously regarded as the proposed chip's main drawback, the recent study by Russian researchers shows that as soon as the loss of signal has been compensated, a way must be found to deal with the issue of noise. Otherwise, the signal might simply get drowned out by spontaneous emission noise, making the chip virtually useless.
The calculations performed by the researchers demonstrate that an active plasmonic waveguide with a cross section of just 200×200 nanometers could be used to transmit signals over a distance of 5 millimeters. This may not seem like much in terms of the distances we deal with in everyday life, but this number is actually rather typical for modern-day microprocessors. As for the data transfer rates, they would exceed 10 Gbit/s per spectral channel, i.e., a data communication channel, which uses a specific wavelength of light. Not to mention that a single nanoscale waveguide can be simultaneously used by several dozen of these spectral channels if the wavelength-division multiplexing (WDM) technology is used, which is a standard in all optical communication lines including broadband internet. To put that in perspective, the maximum rate of data transfer through an electrical interconnect (a copper conductor) of similar dimensions is only 20 Mbit/s, which is at least 500 times slower!
The scientists found how the noise power and noise characteristics depend on the parameters of plasmonic waveguides with gain and showed how the level of noise can be reduced to ensure the maximum bandwidth of the nanophotonic interface. They proved that it is possible to combine a miniature size and a low error count with a high data transfer rate and a relatively high energy efficiency in a single device, heralding a "plasmonic breakthrough" in microelectronics that could come in the next ten years.
News-Medical.net / January 26, 2017
TSU scientists developing new method to treat autism and cognitive disorders
Во время физической нагрузки в мышцах вырабатываются белки миокины, способные усиливать когнитивные функции человека. Специалисты Томского государственного университета планируют использовать это свойство для коррекции таких состояний как последствия инсульта, аутизм, гиперактивность, нарушения памяти и внимания.
Scientists at the Tomsk State University (TSU, Russia) are exploring myokines, proteins that are produced in the muscles during physical activities. It is found that these active agents enhance human cognitive function. Scientists plan to use this feature to correct conditions such as autism, hyperactivity, and memory disorders.
"The fact that physical activity helps to maintain good memory and mental longevity has been known for a long time", says Anastasia Kabachkova, an employee of the TSU. "We are interested in the mechanism, in other words, what kind of myokines are produced as a result of certain exercises. Knowing how this happens, we will be able to choose a set of exercises that will replace medication and treat cognitive disorders without pills."
In order to determine the conditions of the production of myokines in the body, scientists at the Faculty of Physical Education conducted comprehensive studies involving volunteers. Volunteers were divided into three groups, which were characterized by different movement modes - sedentary lifestyle, normal, and excessive physical activity (athletes).
During the tests they carried out complexes of exercise, and in some cases, combined physical and mental exercises. For example, they held down a barbell while looking at the monitor and producing mathematical calculations in their mind. Scientists evaluated a number of parameters, including the indicators of brain activity and blood flow in the brain.
In addition to people, animals also were involved in the experiments. Laboratory mice were also doing exercise: running and swimming, and weight training. After that, scientists sampled their biological material and examined the content of myokines in the animals' skeletal muscles.
"The next step will be experimenting with cell cultures", says Anastasia Kabachkova. "We will grow muscle cells of rats and humans in the laboratory. Then, using an electric current, we will simulate the contractions that occur in the muscles during exercise and investigate the myokines that are formed."
At the end of the experiments, the researchers will summarize the data and develop a complex of exercises that allow obtaining the necessary myokines that make the brain work. These complexes will be offered to kids with autism and hyperactivity, those who had a stroke, and patients with impaired memory and attention disorder.
TSU scientists have been studying myokines for several years. In the course of joint research conducted with colleagues from the University of Montreal, they found that proteins affect the fat tissue and brain circulation, that is, the muscles in the body operate not only in motor function but also as an endocrine organ. The scientists want to use this property for the treatment of diseases associated with metabolic disorders: diabetes, obesity, and other ailments. This project is supported by a grant from Russian Science Foundation.
AZoM.com Limited Copyright 2000-2017.
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Space Daily / Jan 27, 2017
Russian-Japanese research helps understand the effects of microgravity on bone tissue
Одна из самых серьезных проблем космонавтов после длительного пребывания на орбите - потеря костной ткани. Российско-японская группа ученых изучила японских пресноводных рыбок Oryzias latipes, побывавших на МКС, и обнаружила, что микрогравитация меняет работу генов, которые отвечают за развитие клеток костной ткани.
The co-authors from the Russian side are Oleg Gusev (Extreme Biology Lab, Kazan Federal University) and Vladimir Sychyov (Institute of Medical and Biological Problems of RAS).
As is well-known, space flights bring with them a unique set of health hazards. That includes bone and muscle deterioration. Loss of bone density is currently one of the most serious problems for astronauts. It is similar in nature to osteoporosis, an ailment common for senior people. Understanding microgravity and its effects on living organisms can help find new clinical methods of coping with this issue.
Oleg Gusev explains, "Fishes are one of the test organisms that give an opportunity to outline space flight effects on one's health. Water stabilizes overloads and compensates microgravity. What we see in this research are the results of other factors, possibly space radiation or other sensitivities to gravity. Medaka fish also grows fast, so that's another benefit for the testing process. Their genome has been deciphered".
Soyuz TMA-06M delivered several medakas to the International Space Station. Its other name - rice fish - indicates its special affinity for rice paddies. Medakas first visited space in 1994 on Columbia - they successfully spawned during that flight. This time they will stay in ISS for several years.
As it turned out, medakas start losing bone density much faster than humans - almost immediately after arriving. The paper aims to explain what events and genes influence the progress of osteoporosis in medakas.
These particular fishes have been genetically modified - they have fluorescent proteins in them (in red and green light). These different proteins are formed in osteoclasts (bone cells that eliminate the old bone tissue) and osteoblasts (the ones that create new bone tissue).
Both types of cells started appearing more quickly on the orbit than on the Earth. Microgravity leads to different changes in the body, such as redistribution of liquids, hypertension, and vertigo. Mineralization of bones decreases, but little is understood about how osteoclasts and osteoblasts react to these conditions.
The researchers hypothesize about up-regulation of genes osterix, osteocalcin, TRAP, and MMP9 in microgravity. Specific genes osterix and osteocalcin can react to gravity shifts because their activity rose simultaneously during the experiment.
Transcriptomic analysis of fishes' throat bones showed a significant increase in regulation of 2 genes of osteoblasts and 3 genes of osteoclasts. More detailed analysis in space showed increases in activities of the genes c-fos, jun-B-like, pai-1, ddit4, and tsc22d3.
Earlier other researchers have shown that glucocorticoid hormones increase the activity of transcription factor AP-1 that regulates gene expression in response to a variety of stimuli, including cytokines, growth factors, stress, and bacterial and viral infections.
Glucocorticoid receptors may be involved in osteoclast activity fluctuations. Also, stress is known to elevate blood pressure, which leads to nitrous oxide production and in turn - to blood pressure decrease. Glucocorticoid receptors and nitrous oxide, as some recent observations have proved, act in unison through the changes in activities of such genes as tsc22d3 and ddit4 which react to microgravity.
Thus, the paper suggests the participation of NO - GCR signal pathway in microgravity stress.
Copyright 1995-2017 - Space Media Network.
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EurekAlert / 30-Jan-2017
Where the cladocerans came from
Biologists have deduced the "hyperborean" lineage of cladocerans.
По последовательностям нуклеотидов в ДНК российские биологи проследили за путями расселения по Евразии микроскопических рачков кладоцер (входят в состав планктона). Выяснилось, что несколько групп распространялось с крайних северных точек, пережив там, к тому же, плейстоценовое оледенение.
A group of scientists, including the researchers from the White Sea Biological Station, Lomonosov Moscow State University has studied dispersal routes of cladocerans through Northern Eurasia, which are a food for many fish species. The scientists have shown that at least several cladoceran taxa began collonization of the whole Palearctic right from its north, and a part of them - from the Beringian region. Keeping in mind that the Bering Strait closed numerous times in the past, current Kamchatka, Chukotka, Alaska and a part of Aleutian Islands were a part of so called Beringia - a large part of land with much larger area than nowadays. The results of this study are published in PLOS ONE journal.
The technical part of the project - namely determination of the nucleotide sequence in some genes of the cladocerans - was fulfilled at the White Sea Biological Station, Lomonosov Moscow State University. Tatyana Neretina, Ph.D., a researcher of the Biological station and research co-author notes: "It could seem ridiculous to bring samples to the White Sea, to Polar Circle, but our laboratory is equipped so well and it's so convenient to work there that colleagues come to us and work with our collections, as well as with samples from all over the world, including that ones, gathered in Antarctica by the "Polarstern" research icebreaker. In most cases we study samples in order to understand, what species inhabit these high latitudes. However, in this particular case we've studied biogeography."
Freshwater invertebrates, and among them small crustaceans, turn out to be a cornerstone of many ecosystems, and evolution of their lines is closely intertwined with fates of many other species. All these have created the basis of biodiversity development in the Northern Hemisphere. Cladocerans' eggs could travel from one water body to another whitin special containers left after molting, which are called ephippia, and disperse to new inhabiting areas (for instance, on feathers of some water birds).
The Russian team of hydrobiologists from Nikolai Smirnov's scientific school (who is one of the greatest specialists in carcinology in the XXth century) has devoted its research to this group of organisms. The published paper is dedicated to 89th anniversary of him.
Biogeography deals with investigations of dispersal routes of living organisms. According to the opinion of this paper authors, biogeography of freshwater animals is much less developed, but and dispersion patterns in freshwater animals strongly differ from those of terrestrial inhabitants. It happens due to differences in the biology and geological age of freshwater and terrestrial animals.
Where have "horned" small crustaceans come from?
It's impossible to study all groups of organisms in one research, that's why scientists usually choose particularly specific groups as their models. Phylogeography - a science studying a distribution of genetic lines and dealing with the analysis of the dispersion peculiarities of such groups.
Previous researchers studied almost only cladocerans belonging to the genus Daphnia. According to these data, Japan was the center of dispersion of several groups of species across Eastern Eurasia. In order to check such conclusions on other groups of the cladocerans, hydrobiologists are conducting now their genetic analysis. A strong progress in this direction has been achieved by Russian scientists by means of a study of the cladocerans from the Chydorus sphaericus group, which are common and most typical inhabitants of the northern regions. To achieve this aim, scientists have investigated the samples of cladocerans from different regions of Russia, including Kronotsky and Komandorsky Nature Reserves, as well as samples from Norway and South Korea.
In order to reveal the centers of dispersion, scientists compare features of descendants and ancestors of a group. Afterwards, they look for taxa, which have more ancestral features as these taxa are regarded as nearest to an initial group. Such comparisons have been made previously based exclusively on morphological features, however, modern scientists understand that it's not enough for adequate conclusions. Tatyana Neretina explains: "Studying only morphological features could say a little about how they evolve and disperse. That's why nowadays every zoologist and botanist needs to know molecular genetic methods."
Routes of cladocerans and zoologists
The molecular genetic laboratory was established in 2006 at the White Sea Biological Station due to the activity of Tatyana Neretina and Nikolai Mugue, Ph.Ds, and the first international workshop on molecular methods in zoology was also conducted there in 2009. Eugenia Bekker, who was at that time a Ph.D. student under the supervision of Alexey Kotov, a project co-author from A.N. Severtsov Institute of Ecology and Evolution, was among the participants of this workshop.
Comparison of the gene sequences allows to understand, how old is the division of different lines and groups of living organisms. The speed of mutation accumulation varies among different genes. Most important genes are less variable, and vice versa. As a result, scientists apply "molecular clocks" for determining of congeniality and age of divergence of various groups of living organisms.
Tatyana Neretina continues: "You collect material from different places, preserve it in alcohol, extract DNA and after that with the help of polymerase chain reaction (PCR) determine the order of nucleotides in the genome fragment, you need, in different samples and look at the similarity between different specimens. This allows to form phylogenetic trees, which help to understand the relationships between organisms."
In case of the Chydorus sphaericus group we've studied two genes: 1) a portion of mitochondrial gene (containing in a mitochondria - power producers in each cell) encoding an important enzyme - cytochrome c; 2) a portion of the nuclear DNA, where two parts of ribosomal RNA (necessary for protein synthesis in a cell) are coded and the indel between them.
Small crustaceans have survived glaciation in the north.
Comparison of gene sequences have helped hydrobiologists to determine relationships between groups and trace pattern of their dispersion across Northern Eurasia. For this purpose scientist have built median-joining haplotype networks (a haplotype is a group of organisms, which all have exactly the same gene sequence) in order to determine regions, where ancestral groups of
Chydorus sphaericus inhabit, and understand, from which region they colonized other territories and where their initial center of dispersion is located. It was found that centers of dispersion of two groups were located in the European part of the continent, when of two others - in the Asian one. One clade survived during harsh environment of the Pleistocene glaciation in a northern refugium - at the territory of current Arkhangelsk Oblast and the Komi Autonomous Republic, while another clade did it in the south (what was already shown numerous times for other species of animals in the previous studies).
Tatyana Neretina comments: "The concept of a refugium implies the absence of ice there, and it's not so important whether it was southern or northern. No special adaptations are needed in order to survive glaciation inside a refugium. In contrast, our study shows that in refugia the animals already had all necessary adaptations to be widely dispersed".
Another group of Chydorus sphaericus colonized Bering Island from the continental Beringian region (the former was not connected with the latter in the past) but three times independently, not simultaneously. Another result of this project lies in a preliminary detection of the area of secondary contact between the Beringian and European Siberian super-complexes in the Yenisey River basin. Moreover, similar conclusion has been made by the same research group for the other cladoceran genus - Moina. Finally, Eastern Siberia and Northern Atlantic (Greenland and Iceland) region contain some relict endemic clades.
In the future this scientific team, which also includes researchers from the Severtsov Institute of Ecology and Evolution of Russian Academy of Sciences, Institute for Inland Water Biology of Russian Academy of Sciences and the Faculty of Biology of the State University of New York, is going to test applicability of revealed scheme flexibility to other cladoceran genera.
Copyright © 2017 by the American Association for the Advancement of Science (AAAS).
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