The rising of the sun and the running of the deer

This post contributed by Liza Lester, ESA communications officer In November, Norwegians Arnoldus Schytte Blix, Lars Walløe and Lars Folkow brought us the news that running reindeer cool themselves through open-mouthed panting, as Sara Reardon explains at ScienceNOW. Their heavy winter coats are so effective at insulating the animals from arctic temperatures that they have trouble dumping excess heat through their skin. Deep cooling breaths through their noses aren’t enough when reindeer are working hard. At speed on Blix et al’s treadmill, reindeer tongues loll from open mouths to cool their blood through evaporation, just like hard racing reindeer neck-and-neck in a skijor competition in northern Finland, documented in exciting, goofy, copyrighted detail by photographer Henri Bonell. Do Reindeer bite their giant tongues? “Fortunately they only have bottom incisors, although their molars are sharp so I imagine they avoid closing their mouths until their tongues are safely inside,” said veterinarian Christina Ramirez. Deer have a bony plate in place of top teeth in the very front of their mouths. A big gap separates the few pointy teeth at the front of the bottom jaw from molars in the back. As Permafrost Thaws, Scientists Study the Risks In reindeer (known as caribou in the New World) territory, climactic change is palpably present. Melting permafrost is a vivid symptom. Tilting buildings and falling trees, undermined by the thaw, are big reminders of the invisible frozen soil that underlies much of the arctic and molds geology, ecology and human construction. In a long article in the New York Times, Justin Gillis describes an invisible consequence of melting permafrost: methane, a potent greenhouse gas, emanating from rotting plants released from frozen ground. Microorganisms are busy decomposing leaves and branches that have been on ice for thirty thousand years, producing methane as a byproduct of their gluttony. The US Department of Energy is investing $100 million dollars in an attempt to estimate the amount of carbon frozen in the soil and predict the future of the arctic. A slideshow of working scientists, and beautiful images of methane bubbling up from new Alaskan lake beds and collecting under surface ice, accompanies the article. NOAA’s year of extreme weather: 12 disasters. The National Oceanic and Atmospheric Association says it’s been a record year for disastrous weather in the US, with a succession of tornados, hurricanes, blizzards, wildfires, heatwaves and flooding hitting the country. Re-experience it on their website. 12 Days of Christmas-y Citizen Science Projects The folks at Talking Science, a non-profit partner of NPR’s Science Friday, list twelve ways to participate in research, from sifting data from the Milky Way to counting your (prairie) chickens....

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Climate change, heat stress, and animal evolution

Climate change has the potential to not only increase average temperatures around the world, but also to increase the likelihood and severity of now-rare temperature events, like heat waves.  The fate of many animal populations, therefore, can hinge on their ability to tolerate (relative) extreme heat. In the April issue of Functional Ecology, scientists explore the possible responses of animal populations to a changing climate. Mike Angilletta of Indiana State contributes an editorial that poses two very relevant questions: Will physiological and evolutionary responses (i.e. acclimation and adaptation) allow animal populations to persist in the face of thermal stress?  And if so, will their compositions change radically? The answers – of course – are not yet clear. Simon Bahrndorff of the University of Arhus in Denmark and his colleagues studied heat shock proteins, whose function is to keep other proteins from denaturing or folding improperly when temperatures get too hot or too cold. They found that in the wake of exposure to extreme heat, these proteins conferred greater thermotolerance on springtails, an insect-like arthropod. However, even though heat shock proteins were produced quickly, the springtails didn’t reach peak thermal tolerance for almost a day, suggesting that the response might not be quick enough to save the animals from a more extreme heat event. Animals that don’t produce enough of these het-shock proteins are likely to be weeded out of populations; another paper by Jesper Sørensen, also of Aarhus, shows that fruit flies that can’t produce heat shock proteins could not find a food station on a hot day, whereas their normal conspecifics could. What consequences will increased temperatures have for the overall demographics of animal populations? Lloyd Peck of the Natural Environment Research Council in the U.K. and his colleagues found that larger and more sedentary species are more susceptible to the negative consequences if increased temperatures, suggesting that natural selection might favor smaller, more active individuals under climate change scenarios. A final paper headed by Anthony Dixon of the Institute of Systems Biology & Ecology in the Czech Republic suggests that in developing insects, tolerance to heat usually means lessened tolerance to cold. In these cases, the benefits of being a generalist with a large thermal tolerance must be weighed against the costs of achieving it. Extreme heat events, the papers conclude, are just one more way that the climate change can shape the evolution of animal populations, and ecologists should keep a watchful eye on its progression. Angilletta Jr., M. (2009). Looking for answers to questions about heat stress: researchers are getting warmer Functional Ecology, 23 (2), 231-232 DOI: 10.1111/j.1365-2435.2009.01548.x Bahrndorff, S., Mariën, J., Loeschcke, V., &...

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