Taxonomy term

september 2014

Benchmarks: October 10, 1913: Atlantic and Pacific waters meet in the Panama Canal

On Oct. 10, 1913, U.S. President Woodrow Wilson pressed a button in his Washington, D.C., office. At that moment, more than 6,400 kilometers away, about seven metric tons of dynamite exploded, clearing the final obstruction in the Panama Canal. Deep within the Culebra Cut, waters from the Atlantic Ocean finally met waters from the Pacific Ocean, marking the end of major construction on the 77-kilometer-long canal.

09 Oct 2014

How the Spanish invasion altered the Peruvian coast

When Francisco Pizarro landed in Peru in 1532, his band of Spanish conquistadors set off a chain of far-reaching consequences for the people and economics of western South America. A new study has found that the Spanish invasion also changed the shoreline of northern Peru, by actually ending a several-thousand-year cycle of anthropogenic alteration.
 

05 Oct 2014

Santiaguito Volcano's clockwork behavior provides an exceptional laboratory

If Earth breathes, Santiaguito Volcano in the Western Highlands of Guatemala could be its mouth. Roughly every half hour, like volcanic clockwork, Santiaguito’s active Caliente lava dome expands, filling with gas from depressurizing magma below. Then it exhales, often explosively, and deflates. Over the course of a day, you could almost keep time by it.

28 Sep 2014

Out of Africa, time and again

There is widespread agreement among scientists based on fossil and geochemical evidence that modern humans evolved in Africa between 200,000 and 100,000 years ago before spreading around the world. But the timing and route of this dispersal, and whether it occurred as a single exodus or in multiple pulses, remain contested. Now, a new study throws its weight behind a multiple-dispersal hypothesis, suggesting a first group of modern humans left Africa as early as 130,000 years ago, followed by a second about 80,000 years later.

27 Sep 2014

High-powered simulation tracks evolution of universe in detail

The universe burst into existence 14.6 billion years ago, and has been expanding ever since. Of course, humans have only been around to glimpse the most recent fraction of stellar history. Now, a new high-powered computer simulation called Illustris, which traces more than 13 billion years of cosmological evolution, is giving scientists and the public alike an armchair view of how things came to look the way they do.

26 Sep 2014

Boron proxies detail past ocean acidification

Pockmarked plankton shells and dead coral are becoming the hallmark images of ocean acidification. But this isn’t the first time seawater has dropped on the pH scale. Based on models of seawater chemistry, the ocean acidity during the Paleocene-Eocene Thermal Maximum (PETM), beginning about 56 million years ago, is the closest-known analog to today. Now, researchers using boron proxies preserved in microfossils to reconstruct surface-ocean chemistry suggest that acidification was more extensive and lasted longer than previously thought, although the PETM conditions still don’t outpace the current rate of ocean acidification.

25 Sep 2014

Climate impacting a few of our favorite foodstuffs

Researchers have found that the number of foggy winter days in California’s agriculture-heavy Central Valley has dropped 46 percent on average over the past three decades. Fog shields the valley from sunlight and contributes to the amount of “winter chill” — the amount of time spent between zero and 7 degrees Celsius during winter dormancy — that fruit and nut trees there experience. Sufficient winter chill is necessary for buds, flowers and fruit to develop properly, and although winter chill has previously been observed to have decreased since the 1950s, no one had conducted a long-term analysis of fog occurrence trends in the area, according to Dennis Baldocchi and Eric Waller of the University of California at Berkeley.

24 Sep 2014

Bare Earth Elements: Search the seafloor firsthand (and live!)

If you’ve ever wanted to take a dive into the ocean depths and explore the seafloor below the waves, but just haven’t had the time (or financing) to build your own deep-sea submersible, here’s another solution. NOAA’s 68-meter Okeanos Explorer — the only federally funded ship dedicated to “solely to exploration” — is currently trolling the Atlantic Ocean on the three-week third leg of a mission dubbed “Our Deepwater Backyard: Exploring Atlantic Canyons and Seamounts 2014,” and it’s offering to take guests along for part of the ride.

24 Sep 2014

Colorado River Basin sees severe groundwater depletion

Over the past 14 years, the Colorado River Basin has experienced its worst drought since precipitation records have been kept, starting in the 1960s. The basin supplies water used for agriculture and in households in seven states, affecting more than 40 million people. In a study recently published in Geophysical Research Letters, researchers have found that the reservoirs that store water in the basin are at record low levels. What’s more, the research shows that in addition to shrinking reservoirs, groundwater is being depleted much faster than previously thought, which could have major implications for the region’s future water security.

24 Sep 2014

Seeing beneath Greenland's ice

Save the handful of Vikings who settled an ice-free stretch of Greenland’s southwest coast during the Medieval Warm Period a millennia ago, few humans have ever laid eyes on even a fraction of the land that lies below Greenland’s 1.7-million-square-kilometer ice sheet. Now, courtesy of a new model, scientists are seeing a detailed view of the topography underlying the ice sheet, which is an important control on the flow and discharge of ice into the ocean.

23 Sep 2014

Pages