Typical sand crab
Courtesy Wikimedia CommonsDid you know it takes two-and-a-half times more energy for us humans to walk on sand than on a hard surface? We can reduce that expenditure (to one-and-a-half times the effort) by running but the fact remains getting across sand is not easy for us. It's a different story for some of our animal friends. Some creatures, such as the ghost crab (Ocypode cordimana), can move effortlessly across a heap of sand like they're skating on ice. Others, such as the sand skink (Neoseps reynoldsi), can swim through sand like they're swimming through water. Read here about how scientists at Georgia Institute of Technology in Atlanta (along with colleagues at the University of Pennsylvania and Northwestern) have been studying such creatures to help design robots that will be able to move effortlessly through sand and other complex terrains.
Tags : I read this really cool piece in yesterday's Star Tribune editorial page about scientific topics that crop up in the current hot movie, Spider-Man 3. I'm not a huge Spider-Man fan and haven't seen the movie, but I'll have to check it out now.
In the aftermath of Hurricane Wilma in 2005, Cancun has had a hard time keeping sand on its beaches in its resort areas. Rebuilding efforts from the hurricane are quickly eroding away again, with up to 30 percent losses.
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What a beach: In the aftermath of Hurricane Wilma in 2005, Cancun has had a hard time keeping sand on its beaches in its resort areas. Rebuilding efforts from the hurricane are quickly eroding away again, with up to 30 percent losses.After a devastating hit by Hurricane Wilma in 2005, Mexico spent $19 million to rebuild beaches in the popular tourist destination of Cancun. Now, those efforts appear to be quickly eroding away.
Following the devastating impacts of the hurricane, ocean depths were dredged and eight miles of popular beach front were rebuilt, and actually expanded, to try to prevent the huge loss of beach to happen again.
But less than two years later, up to 30 percent of that sand is now missing. On some portions of the beach, swimmers and tanners have to jump down a three-foot drop in the beach to get to the current sand level.
What’s going on?
Environmentalists in the area insist any efforts will be wasted efforts unless more vegetation is worked into the areas between hotels and beaches. The roots of those plants and trees would help stabilize the impacts of erosion along the coast, they contend.
But the people in the tourist industry feel that building an artificial reef along the beach would help to lessen the impacts of waves and tides on the beaches. They’re drawing up plans to create a public/private partnership to develop and maintain such a reef.
The tourist industry concerns also say that there is a cyclical action to the growth and decrease of Cancun’s beaches. It contends that erosion happens in the winter months when coastal winds and currents are stronger. Then the sands return to the beach in calmer months.
But the environmentalists contend that situation has been getting progressively worse since the 1970s when large hotels began being developed along the beaches and native vegetation was pulled out.
What do you think? Share your thoughts here with other Science Buzz readers.
Sand comes in many colors, thanks to various minerals mixed in among the grains. The black sand here contains magnetite, a form of iron.
Photo courtesy of Kate Hintz, SMM
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