After Hurricane Katrina devastated New Orleans, the United States Army Corps of Engineers got to work on a massive network of levees and flood walls to protect against future catastrophes. Finally completed in 2012, the project ended up costing $14.5 billion —and that figure didn’t include the upkeep these defenses will require in years to come, not to mention the cost of someday replacing them altogether.

But levees aren’t the only things that protect coasts from storm damage. Nature offers protection, too. Coastal marshes absorb the wind energy and waves of storms, weakening their impact farther inland. And while it’s expensive to maintain man-made defenses, wetlands rebuild themselves.

Continue reading “Putting a Price Tag on Nature’s Defenses” →

Joshua Osborn, 14, lay in a coma at American Family Children’s Hospital in Madison, Wis. For weeks his brain had been swelling with fluid, and a battery of tests had failed to reveal the cause.

The doctors told his parents, Clark and Julie, that they wanted to run one more test with an experimental new technology. Scientists would search Joshua’s cerebrospinal fluid for pieces of DNA. Some of them might belong to the pathogen causing his encephalitis.

The Osborns agreed, although they were skeptical that the test would succeed where so many others had failed.

Continue reading “In a First, Test of DNA Finds Root of Illness” →

All animals do the same thing to the food they eat — they break it down to extract fuel and building blocks for growing new tissue. But the metabolism of one species may be profoundly different from another’s. A sloth will generate just enough energy to hang from a tree, for example, while some birds can convert their food into a flight from Alaska to New Zealand.

For decades, scientists have wondered how our metabolism compares to that of other species. It’s been a hard question to tackle, because metabolism is complicated — something that anyone who’s stared at a textbook diagram knows all too well. As we break down our food, we produce thousands of small molecules, some of which we flush out of our bodies and some of which we depend on for our survival.

Continue reading “Stronger Brains, Weaker Bodies” →

Just a few centuries ago, Madagascar was home to a monstrous creature called the elephant bird. It towered as high as nine feet. Weighing as much as 600 pounds, it was the heaviest bird known to science. You’d need 160 chicken eggs to equal the volume of a single elephant bird egg.

The only feature of the elephant bird that wasn’t gigantic was its wings, which were useless, shriveled arms. Instead of flying, the elephant bird kept its head down much of the time, grazing on plants.

Scientists aren’t precisely sure when this strange creature became extinct, but it probably endured well into our human-dominated age.

Continue reading “A Theory on How Flightless Birds Spread Across the World: They Flew There” →