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News Article | May 3, 2017
Site: www.nature.com

Palaeobotanist Kseniia Ashastina took this picture of her supervisor, Frank Kienast, collecting samples of ancient plants from a permafrost exposure in northeast Siberia, in June 2014. Ashastina, who is a PhD student at the Senckenberg Research Station of Quaternary Palaeontology in Weimar, Germany, says it was a welcome 20 °C at the time; this region of the world endures temperatures below freezing for 7 months a year. Over hundreds of thousands of years, the water in the soil has frozen and thawed over and over, carving deep cuts into the ground and creating steep, icy formations like the one pictured. It's a remote area: Ashastina and Kienast were the only people there, and there was no phone signal. It doesn't look it, but it's noisy, says Ashastina. “There are tons of mosquitoes there trying to bite you. There is cracking ice and creaking trees. It's dangerous. You'd need to be crazy to enjoy it, but in a good way.” The permafrost under the exposed surface makes this area perfect for Ashastina's research, because it's too cold for her samples to be digested by bacteria. The same goes for the bones of the mammals that once roamed this area, around 20,000 years ago, when a green, energy-rich land bridge joined Asia and North America. Femurs, skulls, fibulas and tibias are churned up every summer as the ice melts along the formation, and the cut retreats further into the forest. Shortly after this photo was taken, as Ashastina and Kienast camped near the formation, two locals — drunk and carrying guns — emerged from the forest and demanded to know what the scientists were doing. Every summer, the pair had made money by pulling the tusks of long-dead woolly mammoths out of the mud and selling the ivory — and they were convinced that these newcomers wanted a piece of the action. But the locals were shocked sober, Ashastina says, when they looked inside her sample bags to find that the strangers before them were ignoring the ivory in favour of the mud. This kind of story is exactly what we hoped we'd find when we announced the Naturejobs Scientist at Work photo competition at the start of March. Scientists spend their time finding connections and building a research story. But they themselves often have fascinating, scary, guns-and-ivory tales to tell, and those stories are frequently best told with an image. When meteorologist Timo Palo, who also features in this article, started working in the Arctic in 2006, he realized that bringing his message back home could be achieved more easily with a camera. “It's often too hard for scientists to put their work into simple words,” he says. “Photography can help there.” Here we present five of the best images from the competition, which ran throughout March and attracted about 170 entries, from New Zealand to Norway, Canada to Qatar. Winners were chosen by a panel of Nature designers and journalists, who judged the images purely on their aesthetic impact. We did not ask for additional context, and we accepted only one image per person. Submissions could be made either through social media or by e-mail. “Science and art have quite a few things overlapping,” says Timo Kohler, whose picture also appears here. “Even as a non-expert, if you look at life under a microscope, for example, there's absolute beauty in it. You're looking at a completely different world that you've never seen before. There's art there.” In 2010, when Timo Palo's temporary home — the Chinese research and cargo vessel Xue Long (which translates as Snow Dragon) — gave up searching the Arctic Ocean for a stable berth and paused to allow scientists on to an ice floe instead, he climbed to the top deck to take this photograph using a fisheye lens. Palo, a meteorologist at the University of Tartu in Estonia, has watched this part of the world change dramatically. Temperatures in the Arctic are rising about twice as fast as the average temperature in the rest of the world, he says. “Sea ice is sinking. As a scientist, you can't have any conclusions before you analyse the data. But visually you can see it. And when you capture something that moves people, it can have a lot more impact than words can have.” Normally, Palo says, he uses a wide-angle lens to convey the scale of the Arctic. “There's this vast territory of snow and ice, and tiny human beings in the middle of it. You feel small there,” he wrote to me after our interview. But he realized that a fisheye lens would help him to impart a different message. “We know the Arctic Ocean is on the top of a globe. It's like a roof on our planet.” The distortion, he thinks, helps the viewer to visualize this roof — and the cracks that run across its surface. Volker Diekamp, a marine-geology technician at Marum — an ocean and sea-floor research institute at the University of Bremen in Germany — spends his working hours inspecting sediment from the bottom of the ocean. He's used to photographing scenes like this one, which was taken off the coast of the Canary Islands in winter 1997. It shows scientists and sailors struggling to pull ocean-analysis equipment aboard the German research vessel Meteor. He's travelled on board the same ship, as both technician and resident photographer, on trips to the oceans around South America, Africa and India (his first voyage was in 1991). When on land, he's equally busy taking pictures of academic colleagues. “Here at the university, scientists at work are my main topic,” he says. In July — “Summer, but it's still cold,” he says — he flies to Greenland to join the Merian, another German research vessel. In 1997, the water was mercifully warm. Just before this shot was taken, Diekamp says, he “felt the movement of the ship” and knew immediately that his colleagues were about to get very wet. What about him and his camera? “Almost not at all,” he says. “I was in a safe place. I could care about the picture, not the water. It's a once-in-a-lifetime shot.” When he took this photograph, biochemist Timo Kohler had just returned from a group skiing retreat organized by Florian Hollfelder, who runs a laboratory at the University of Cambridge, UK. Hollfelder likes to encourage his students to travel together, Kohler says. Since joining the lab, Kohler has been to Crete, India and Austria, and more trips are planned. “There's a lot of social bonding going on,” he says. “You make friends. The image shows one of Kohler's fellow PhD students inspecting a microfluidic chip. To take it, Kohler reversed the magnifying glass that's normally used to see the fine detail in these chips. “It's an artistic effect. In science, I'm not allowed to do it; in photography, I can point the light where I want,” he says. Mehmet Davrandi, a microbiologist at University College London, says the image above is the result of an error. He uses blood agar to grow and observe oral bacteria, so that he can better understand dental plaque. On this occasion, he spread the germs the wrong way. When he came to hold the plate up to the light, to check the bacterial colonies, he saw what looked like a tree. Davrandi is from Cyprus. “We have a lot of almond trees in the gardens,” he says. “So everyone from Cyprus loves almonds.” But he feels that the image has a deeper meaning: “It's surprising how rare things happen, and those rare events turn out to be very big things. It really represents how accidental life can be.” Davrandi wasn't worried that his experiment had gone wrong: he had more agar plates to work with. The next day, he brought in his camera and took the above picture. “Technically, we're not allowed to have that sort of thing in the lab, but I'm pretty sure nobody's going to complain.”

Menzel P.,University of Hamburg | Gaye B.,University of Hamburg | Wiesner M.G.,University of Hamburg | Prasad S.,German Research Center for Geosciences | And 5 more authors.
Limnology and Oceanography | Year: 2013

Lonar Lake is a eutrophic, saline soda lake with permanently anoxic deep water. The high pH and deoxygenation result in very elevated δ15N of suspended particulate matter (SPM) and sediments due to denitrification and pH-related loss of gaseous ammonium. SPM and sinking particles are predominantly aquatic in origin, whereas surface sediments are of mixed terrestrial plant and planktonic source. An indicator of degradation intensity was derived from a principal component analysis of the spectral distribution of amino acids and named Lonar degradation index (LI). A ratio of individual amino acids (Ox: Anox ratio) was additionally used to determine the relative degree of aerobic vs. anaerobic degradation. These two biogeochemical indicators can be used to detect changes in degradation intensity and redox conditions in the geological history, and thus the paleoclimatic interpretation of Lonar sediments. Surface sediments can be divided into three zones: (1) a nearshore, oxic zone of predominantly aquatic organic matter, in which oxidation leads to a strong diagenetic increase of δ15N; (2) an alluvial zone with a predominance of isotopically depleted land plant and soil organic matter degraded under oxic conditions; and (3) an anoxic, deep zone, which receives aquatic organic matter and land plant-derived material transported near the bottom and in which organic matter is well preserved due to anoxic diagenetic conditions. © 2013, by the Association for the Sciences of Limnology and Oceanography, Inc.

Menzel P.,University of Hamburg | Gaye B.,University of Hamburg | Mishra P.K.,Helmholtz Center Potsdam | Anoop A.,Helmholtz Center Potsdam | And 8 more authors.
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2014

We present the results of biogeochemical and mineralogical analyses on a sediment core that covers the Holocene sedimentation history of the climatically sensitive, closed, saline, and alkaline Lonar Lake in the core monsoon zone in central India. We compare our results of C/N ratios, stable carbon and nitrogen isotopes, grain-size, as well as amino acid derived degradation proxies with climatically sensitive proxies of other records from South Asia and the North Atlantic region. The comparison reveals some more or less contemporaneous climate shifts. At Lonar Lake, a general long term climate transition from wet conditions during the early Holocene to drier conditions during the late Holocene, delineating the insolation curve, can be reconstructed. In addition to the previously identified periods of prolonged drought during 4.6-3.9 and 2.0-0.6 cal ka that have been attributed to temperature changes in the Indo Pacific Warm Pool, several additional phases of shorter term climate alteration superimposed upon the general climate trend can be identified. These correlate with cold phases in the North Atlantic region. The most pronounced climate deteriorations indicated by our data occurred during 6.2-5.2, 4.6-3.9, and 2.0-0.6 cal ka BP. The strong dry phase between 4.6 and 3.9. cal. ka BP at Lonar Lake corroborates the hypothesis that severe climate deterioration contributed to the decline of the Indus Civilisation about 3.9 ka BP. © 2014 Elsevier B.V.

Prieto J.,Ludwig Maximilians University of Munich | Angelone C.,Autonomous University of Barcelona | Casanovas-Vilar I.,Autonomous University of Barcelona | Gross M.,Universalmuseum Joanneum | And 4 more authors.
Palaeobiodiversity and Palaeoenvironments | Year: 2014

The rich and diverse fossil mammalian assemblage from Gratkorn (Middle Miocene, Austria) is of primary importance for the understanding of the faunal evolution in Central Europe. Besides large mammals, the fauna comprises: Schizogalerix voesendorfensis, Galericinae gen. et sp. indet., Desmanodon fluegeli, Dinosorex sp., cf. Myotis sp., "Cricetodon" fandli, Megacricetodon minutus, Eumyarion sp., Spermophilinus bredai, Blackia sp., Forsythia gaudryi, Albanensia albanensis, Muscardinus aff. Sansaniensis, Miodyromys sp., Keramidomys sp., Euroxenomys minutus minutus, Prolagus oeningensis, cf. Eurolagus fontannesi and Ochotonidae indet. Based on the degree of corrosion on the dental elements and the presence of pellets, most, but not all, of the material is tentatively interpreted as a result of accumulation by nocturnal raptors. In addition to the information provided by the lower vertebrates and the molluscs, which occur in abundance in the same thin fossil-enriched layer, the mammal fauna gives a mixed picture of the environment (basically forested vs. open landscape). This could indicate the presence of different microhabitats around the excavation place, but may also be a taphonomical artefact based on various different agents of accumulation contributing to the thanatocoenosis. Nevertheless, the extreme quick accumulation of the fossils provides an exceptional windows in the late Sarmatian s. Str. ecosystems. © 2014 Senckenberg Gesellschaft für Naturforschung and Springer-Verlag Berlin Heidelberg.

Maul L.C.,Senckenberg Research Station of Quaternary Palaeontology | Masini F.,University of Palermo | Parfitt S.A.,University College London | Parfitt S.A.,Natural History Museum in London | And 2 more authors.
Quaternary Science Reviews | Year: 2014

The study of evolutionary rates dates back to the work of Simpson and Haldane in the 1940s. Small mammals, especially Plio-Pleistocene arvicolids (voles and lemmings), are particularly suited for such studies because they have an unusually complete fossil record and exhibit significant evolutionary change through time. In recent decades, arvicolids have been the focus of intensive research devoted to the tempo and mode of evolutionary change and the identification of trends in dental evolution that can be used to correlate and date fossil sites. These studies have raised interesting questions about whether voles and lemmings had unique evolutionary trajectories, or show convergent evolutionary patterns with other hypsodont rodents. Here we review evolutionary patterns in selected arvicolid lineages and endemic Messinian murids (Mikrotia spp.) and discuss reasons for convergence in dental morphology in these two groups of hypsodont rodents. The results substantiate previously detected patterns, but the larger dataset shows that some trends are less regular than previous studies have suggested. With the exception of a pervasive and sustained trend towards increased hypsodonty, our results show that other features do not follow consistent patterns in all lineages, exhibiting a mosaic pattern comprising stasis, variable rate evolution and gradual unidirectional change through time. Evidence for higher evolutionary rates is found in lineages apparently undergoing adaptations to new ecological niches. In the case of Mikrotia, Microtus voles and the water vole (Mimomys-A. rvicola) lineage, a shift to a fossorial lifestyle appears to have been an important driving force in their evolution. For other characters, different causes can be invoked; for example a shift to a semi-aquatic lifestyle may be responsible for the trend towards increasing size in Arvicola. Biochronological application of the data should take into account the complexity and biases of the data. © 2013 Elsevier Ltd.

Maul L.C.,Senckenberg Research Station of Quaternary Palaeontology | Bruch A.A.,Senckenberg Institute | Smith K.T.,Senckenberg Research Station of Quaternary Palaeontology | Shenbrot G.,Ben - Gurion University of the Negev | And 2 more authors.
Quaternary International | Year: 2015

Microvertebrates are generally well suited for drawing inferences on past environmental conditions because they are closely bound to the areas in which they lived. In this paper, we discuss palaeoecological implications of two microvertebrate concentrations in the Middle Pleistocene site Qesem Cave in Israel. The ecological preferences of the nearest living relatives of the microvertebrate taxa recorded in Concentration 1 (squares L-N/13-15) and 2 (squares G-H/16-17) at Qesem Cave allow us to infer a mosaic of open palaeoenvironment with sparse vegetation, shrubland, Mediterranean Forest, rocky areas and riverbanks. Additionally, we infer palaeoclimate from the bioclimatic distribution of extant species using the Coexistence Approach. To our knowledge, this is the first time the approach has been applied to microfaunal assemblages. These data suggest cooler and slightly drier winters and somewhat lower seasonality than at present around Qesem Cave; the differences are more pronounced for the time covered by Concentration 2 than Concentration 1.Among microvertebrates, micromammals are most suitable for biostratigraphic purposes. With the exception of Rattus cf. haasi and the Myomimus judaicus/. setzeri group, the small mammal fauna of Qesem Cave comprises only taxa that live today in the Levant. R. haasi and M. judaicus have been found in Israel in the Early and Middle Pleistocene, and their latest known record was from the Acheulian site of Oumm Qatafa. Their presence in Qesem Cave extends the previously known stratigraphic range of these species. The absence of R. haasi in Mousterian sites is thus consistent with the pre-Mousterian age of Qesem Cave. Morphometric data on molars of Guenther's Vole show that the lineage segment preserved in Concentration 2 is more primitive than in Concentration 1, indicating that the former concentration is older. The evolutionary level of the sample from Qesem Concentration 1 is similar to Tabun D (boundary of Acheulo-Yabrudian Cultural Complex and Mousterian), and that from Qesem Concentration 2 similar to Tabun Eb (Acheulo-Yabrudian). © 2015 Elsevier Ltd and INQUA.

Smith K.T.,Senckenberg Institute | Maul L.C.,Senckenberg Research Station of Quaternary Palaeontology | Flemming F.,Senckenberg Institute | Barkai R.,Tel Aviv University | Gopher A.,Tel Aviv University
Quaternary International | Year: 2015

Middle Pleistocene Qesem Cave, Israel, contains one of the richest known deposits of microvertebrate remains in the Near East, nearly a quarter of a million specimens. The remains have been excavated from two main concentrations, and over 16,000 have been identified to genus level. The faunal content of the two concentrations is broadly similar, and only a few taxa are restricted to the one or the other; most notably, the Myomimus judaicus/. setzeri group and Rattus cf. haasi are only known from the chronologically older Concentration 2. The identification of Stellagama stellio is presented as an example of tree-thinking in the Quaternary; a phylogenetic tree is an epistemic structure that provides a non-arbitrary means to determine the minimum number and phylogenetic position of extant comparative specimens required to identify an extinct population. The new mammal data show that the total proportion of lower vertebrates in the microfauna is lower than previously thought, although Chamaeleo chamaeleon remains by far the second most-abundant prey species. The assemblages from the two concentrations are significantly different from each other in terms of relative abundances: lower vertebrates, shrews, and bats are less abundant in the Concentration 2, and several rodents, most notably Microtus guentheri, are more abundant there. However, rank-order abundance between the two assemblages is strongly correlated, suggesting that the surrounding community was largely stable. The taphonomic data obtained so far suggest a Barn Owl as the predominant accumulator in Concentration 1, although natural history observations on Barn Owls and chameleons are strongly at odds with this actualistic inference. We suggest that this represents an example of non-analog behavior in the extinct Barn Owl population. Barn Owls, in turn, are sensitive to disturbance and unlikely to have occupied the cave at precisely the same time as the hominins. These observations suggest new ways to study human occupation patterns and behavioral adaptation. © 2015 Elsevier Ltd and INQUA.

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