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Polar Bears and Tires | Earth Wise

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There is lots of interest in traction.  People want to find better ways to move across wet and frozen surfaces safely.   This applies to both the shoes on our feet and the tires on our cars. 

Researchers at the University of Akron along with colleagues at Syracuse University and at Bridgestone, the tire company, have been studying how many arctic animals can walk and run across the ice without slipping and falling.  Their research focused on the paws of polar bears.

Previous studies discovered that polar bears have papillae – little bumps on the pads of their feet – that provide improved traction on snow.  The new research also looked at the paws of other species of bear – brown bears and black bears – and found that these others also have papillae on their paw pads, but that those of polar bears are as much as 50% taller.  These taller bumps give the pads a 30-50% increase in frictional shear stress.

The research may lead to various applications. For example, snow tires typically have deeper treads, but the polar bear study may lead to some new designs that would improve traction.  People who do high-altitude climbing are interested in the research as are companies that deliver goods in bad weather.  Anyone who has to be out and about in bad weather would like to get a better grip.

There are various other animals with traction-improving adaptations that are probably worth studying.  These include dogs, wolves, foxes, and mountain goats.  The same researchers at Akron have also studied other animals with unique abilities to deal with challenging surfaces including geckos, spiders, and mussels.  The natural world is filled with examples of creatures who can easily function in environments that we humans find very challenging.

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UA researchers’ focus on tire traction leads to investigation of polar bear paws

Photo, posted March 2, 2008, courtesy of Sam Weng via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Atmospheric Plastic Polluting The Ocean | Earth Wise

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According to estimates, by 2040 there will likely be nearly 90 million tons of plastic pollution entering the environment each year.  Particles of plastic have been found in virtually all parts of our planet including the land, the water, and even the air.  Tiny plastic particles have been found in the Arctic, the Antarctic, and at the tops of the highest mountains.

A new study has shown that winds can carry plastic particles over great distances and in fact can bring them from their point of origin to the most remote places in a matter of days.   As a result, micro- and nanoplastics can penetrate the most remote and otherwise largely untouched regions of the planet

How does plastic get into the atmosphere?  Particles produced by tires and brakes in road traffic or ones in the exhaust gases from industrial processes rise into the atmosphere, where they are transported by winds.  There is also evidence that a substantial number of these particles are transported by the marine environment.  Microplastic from the coastal zone finds its way into the ocean through beach sand.  A combination of sea spray, wind, and waves forms air bubbles in the water containing microplastic.  When the bubbles burst, the particles find their way into the atmosphere.

Understanding the interactions between the atmosphere and ocean is important because the atmosphere turns out to be a major mechanism in depositing substantial amounts of plastic into a broad range of ecosystems.

The impact of plastic particles on ecosystems is not well understood.  Neither is the effect of plastic particles in the air upon human health.  In a recent British study, microplastic was detected in the lungs of 11 out of 13 living human beings.

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Micro- and nanoplastic from the atmosphere is polluting the ocean

Photo, posted April 25, 2016, courtesy of Bo Eide via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Octopuses And Litter | Earth Wise

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Octopuses are remarkably intelligent animals.  They have a larger brain for their body size than all other animals apart from birds and mammals.  They exhibit high-order cognitive behaviors including tool use and problem solving.  Some captive octopuses learned to shoot jets of water at aquarium light switches to turn them off.  Others have learned to unscrew jar lids to get at food.

A recent analysis of underwater imaging has shown that octopuses are increasingly using discarded bottles, cans, and other human-generated litter as shelter or as a place to lay eggs.

The research documented 24 species of octopus sheltering inside glass bottles, cans, and even an old battery.  Some buried themselves under a mixture of bottle caps and seashells.  Others even carried plastic items around while walking on just two tentacles to disguise themselves from predators.

The octopuses showed a preference for unbroken items and for darker or opaque containers.  Normally, octopuses make use of natural shelters such as seashells.  Whether they are making use of litter simply because there is so much of it around or because there is an increasing lack of natural items is not clear.

As with all other aspects of the growing problem of litter in the oceans, this new trend is not a good one.  Sheltering or laying eggs inside discarded tires, batteries, or plastic items has the potential to expose octopuses to heavy metals and other harmful chemicals.

Octopuses are intelligent and resourceful animals, and they will use whatever they have at their disposal to continue sheltering or moving around with protection from potential predators.

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Octopuses Have Learned to Make Use of Ocean Litter, Study Finds

Photo, posted May 13, 2014, courtesy of Elias Levy via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

What’s Been Killing Salmon? | Earth Wise

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For decades, there have been mysterious deaths of Coho salmon.  The salmon return from the Pacific Ocean each year to spawn along the West Coast.   They can be found from Alaska all the way down into California.  After heavy rain events each fall, fish have been turning up dead in huge numbers before they spawn.  Normally, less than 1% of adult Coho die before spawning. In these mass death events, anywhere from 40% to 90% of fish can perish in affected streams.  The mysterious phenomenon has been the subject of intense research for years.

Recently, scientists announced that they may have solved the mystery.  There is a chemical antioxidant known as 6PPD that is used in the manufacture of tires around the world to make them last longer.  As tire treads break down over time, they leave behind bits of microplastics on roads.  The 6PPD in the plastic bits reacts with ozone to become another chemical:  a previously unreported substance called 6PPD-quinone.

That chemical turns out to be toxic to Coho salmon.  Researchers have found the presence of 6PPD-quinone in roadway water runoff samples taken from across the West Coast.  Based on these observations, they believe it is likely that exposure to this chemical is the main cause of the Coho salmon population decline.

Coho salmon are a favorite of sport fishermen and have great cultural significance to many Native American tribes on the West Coast.  The central California Coho population is classified as endangered and three other Coho populations are listed as threatened.

Tire industry representatives call the study results “preliminary” but say the industry is deeply committed to protecting the environment.  A safe chemical substitute for 6PPD is clearly needed.

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Salmon have been dying mysteriously on the West Coast for years. Scientists think a chemical in tires may be responsible

Photo, posted November 17, 2011, courtesy of Lynn Ketchum/Oregon State University via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Tires From Trees

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Car tires are generally considered environmentally unfriendly because they are predominantly made from fossil fuels.  Natural rubber is generally not used anymore; most tires are made from isoprene, which is chemically very like rubber but is produced by thermally breaking apart molecules in petroleum in a process called cracking.  The isoprene is separated out and purified and then reacted to form the artificial rubber that is the major component in car tires.  The tires eventually end up discarded in giant piles that represent one of our biggest waste disposal problems.

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