Duke University

Why mercury is more dangerous in oceans

Even though freshwater concentrations of mercury are far greater than those found in seawater, it's the saltwater fish like tuna, mackerel and shark that end up posing a more serious health threat to humans ...

Jun 27, 2010 5 / 5 (8) 0 | with audio podcast

Retooling the ocean conveyor belt

For decades, oceanographers have embraced the idea that Earth's ocean currents operate like a giant conveyor belt, overturning to continuously transport deep, cold polar waters toward the equator and warm equatorial surface ...

Jun 18, 2010 4.7 / 5 (6) 4 | with audio podcast

Reinventing the wheel -- naturally

Humans did not invent the wheel. Nature did. While the evolution from the Neolithic solid stone wheel with a single hole for an axle to the sleek wheels of today's racing bikes can be seen as the result of ...

Jun 14, 2010 3.6 / 5 (8) 2 | with audio podcast