* Jurassic Super Fleas * Dark Matter Bulges * A Skilled Saw-fish * Frost Flowers Pump Pollution * Early Worm Gets the Bird * Two Birds, One Stone *


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Jurassic Super Fleas
jurassic_flea.jpg D. Huang et al, Nature

Everything in the Jurassic was large.  It was, after all, the time of the great Dinosaurs.  So it shouldn't be surprising that even the parasites that infested the animals of the Jurassic were big as well.  Dr. Michael Engel, professor of Ecology and Evolutionary Biology and Senior Curator of Entomology at the University of Kansas, and his colleagues have found fossil fleas that are 20mm long - more than twice as long as the largest modern flea.  These fleas had vicious sawlike mouthparts, suitable for cutting through tough skin, but lacked the powerful jumping legs of modern fleas.  Most interesting are their hooked feet, which suggest they might have been adapted to holding on to the feathered dinosaurs of the time.
          
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Dark Matter Bulges Where it Shouldn't

abell520.jpgComposite image of Abell 520. The blue-green area pinpoints the location of the dark matter clump. Credit: NASA, ESA, CFHT, CXO, M. J. Jee (University of California, Davis), and A. Mahdavi (San Francisco State University, California).
Dr. Arif Babul, astrophysicist and University of Victoria Distinguished Professor, and his colleagues have found debris from a huge cosmic collision that really shouldn't be there.  They have been studying Abell 520, a distant place where several clusters of galaxies, representing thousands of billions of stars, have come together at high speeds.  Much of the debris has scattered after the collision, but Dr. Babul has identified a clump of dark matter that has somehow stuck together in the aftermath of the event.  Since most theories of dark matter suggest that it shouldn't interact or stick to itself, this could be an important piece of information about the real nature of the mysterious "missing mass" of the universe.                

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A Skilled Saw-fish


Sawfish are part of the ray family and live in tropical and subtropical areas of the Atlantic and Pacific.  They prefer shallow bays and inlets and can even venture inland into fresh water, where they are equally comfortable.  One species can grow to about 7 metres in length, about 20 percent of which is its most noteable feature: a long, flat snout that looks like a saw.  Little was known about how the saw actually functioned until a new study by Dr. Barbara Wueringer, a Research Associate in the School of Animal Biology at the University of Western Australia in Perth.  The sides of the saw have tooth-like structures, called denticles, used in the hunting of prey fish.  But the saw itself is also covered with motion and electro-sensitive pores called electro-receptors.  This allows the sawfish to detect the electric fields of its prey.  When the prey is detected, the sawfish can swipe its saw from side to side as fast as five times per second, in some cases cutting a fish in half.  Information from this new study may help better understand how to protect this endangered species.  

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Frost Flowers Pump Pollution

frost-flowers.jpgFrost Flowers, courtesy University of Manitoba
Changes in Arctic sea ice are having a cascade of effects in the North.  One surprising one is the way the chemistry of ocean, ice and atmosphere are interacting.  Dr. David Barber, Canada Research Chair in Arctic Systems Science at the University of Manitoba, and his colleagues have been studying the much larger amount of thin, fresh ice that is forming annually, because multi-year sea ice has declined so much.  This thin ice forms structures on its surface called "frost flowers," which channel briny water from the ocean to the surface of the ice.  Chemicals in the brine, including bromine, then evaporate into the air.  Bromine then reacts with the mercury in the atmosphere, which comes from industrial pollution in the South.  The mercury then falls out of the atmosphere, and is entering the northern food chain.  

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Early Worm Gets the Bird

wormy_forest.jpgA northern Midwest forest in the U.S. experiencing heavy earthworm invasion (Photo Credit: Photo by Scott Loss)
The ice that covered much of North America, ten thousand years ago, may have wiped out all the earthworms, if they were here at all - because there is no fossil evidence to suggest otherwise.  But when European settlers first arrived, they brought earthworms with them; either inadvertently in the ballast of their ships, or perhaps intentionally for agricultural purposes.  These are the earthworms we see today in our gardens and on sidewalks after it rains.  But they are creating a problem, particularly in the forests of the northern and northeastern U.S. and parts of Canada.  A new study by Dr. Scott Loss from the Smithsonian Migratory Bird Centre in Washington, has found that as the earthworms rapidly deplete the layer of leaf-litter on the forest floor, one species of songbird is in decline.  The forest floor no longer supports the plant life essential for the ground-nesting ovenbird to hide its eggs from predators.  It is estimated that 80 percent of these forests have been invaded by the invasive earthworm, resulting in a 25 percent decline in ovenbirds.

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Two Birds, One Stone

willow_ptarmigan.jpgA Willow ptarmigan male in Spring plumage - Dave Mossop
The Willow Ptarmigan is common throughout Yukon and other parts of Canada's North.  These bantam-sized grouse are considered a keystone species because of their role in the Arctic ecosystem.  They are an important food source for many other species, including Arctic foxes, owls and other raptors.  One species - the gryfalcon - depends on the abundance of willow ptarmigan more than any other.  But at a time when the willow ptarmigan population should have increased, according to a natural ten-year cycle, it decreased.  Dave Mossop, a Biology Instructor and Professor Emeritus with the Yukon Research Centre at Yukon College in Whitehorse, has recently studied a consequence of that population decline.  The number of gyrfalcon have also decreased because it breeds according to the abundance of its food supply.  It is hoped that the willow ptarmigan population will rebound by the end of the next ten-year cycle in 2020, and that the gyrfalcon will follow suit.

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Theme music bed copyright Raphaël Gluckstein, Creative Commons License by-nc-nd-2.0