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Scientists and tourists bring thousands of alien seeds into Antarctica

Aliens are invading Antarctica. Thanks largely to scientists, they have already established a foothold on the frozen continent, and their numbers are set to increase. This might sound like the plot of John Carpenter’s classic film The Thing, but it is very real.

The aliens in question are not body-snatching monsters, but plants from other parts of the world. Steven Chown from Stellenbosch University found that in just one summer, visitors unwittingly imported around 70,000 seeds to Antarctica. And even though the continent has a reputation for being harsh and desolate, many of these immigrants have already founded populations in their new homes.

This is a new chapter in an old story. Wherever humans go, seeds hitch a lift on our clothes and belongings. If these foreigners germinate where they don’t belong, they can often out-compete native plants and uproot local ecosystems. From Japanese knotweed to kudzu vines, these invasive species cause problems throughout the world. Inhospitable though Antarctica is, it’s not immune to such invasions. It does, however, present a valuable opportunity to study them. Read more

Blood Falls – bacteria thrive for millions of years beneath a rusty Antarctic glacier

Antarctica normally conjures images of white and blue, but the frozen continent can sometimes bear more unexpected colours. Take the Taylor Glacier – when geologist Griffith Taylor first explored it a century ago, he found a bizarre reddish stain that seemed to spill waterfall-like from the glacier’s snout. The area became evocatively known as Blood Falls. 

The source of the blood-red colour is an underground saltwater lake that was trapped by the encroaching glacier at least 1.5 million years ago. The temperature of the water is -5 Celsius, but it’s so salty that it doesn’t freeze. It’s also rich in iron salts, which are slowly leaching the ice – these are the source of the distinctive red hue. Blood Falls is a rust glacier.

But it also houses another secret, which scientists from Harvard University have started to uncover – it’s home to an entire ecosystem of bacteria, trapped for millennia in conditions that could hardly be more inhospitable to life. Read more

Sins of the Aral Sea

“This is what the end of the world looks like,” says Yusup Kamalov, sweeping his hand toward the scrub-covered desert stretching before us. “If we ever have Armageddon, the people of Karakalpakstan are the only ones who will survive, because we are already living it.”

For millennia the Aral Sea reigned as one of the planet’s largest inland bodies of water, straddling what is now Kazakhstan and Uzbekistan. Today its decline serves as a cautionary tale.

From our perch atop this sandy bluff in northern Uzbekistan, the view could be of just about any desert—that is, if it weren’t for the mounds of seashells and the half dozen marooned fishing boats rusting into the sand. This spot was once the tip of a peninsula jutting into the Aral Sea, which up until the 1960s was the world’s fourth largest inland body of water, covering some 26,000 square miles—an area larger than the state of West Virginia. Behind us lies the town of Muynoq, formerly a thriving fishing village with a sprawling cannery that even as recently as the 1980s processed thousands of tons of fish annually. Fifty years ago the southern shore of the Aral was right where we stand; now it lies 55 miles away to the northwest. Read more

Fountains of Enceladus

Recent Cassini images of Enceladus at high phase show the fountain-like sources of the fine spray of material that towers above the moon’s south polar region. This image was taken looking more or less broadside at the “tiger stripe” fractures observed in earlier Enceladus images and shows discrete and small-scale plumes above the limb of the moon.

The color-coded image at right was processed to enhance faint signals, making contours in the plume of material even more apparent. The greatly enhanced and colorized image shows the enormous extent of the fainter, larger-scale component of the plume. Read more

The Colorado River Runs Dry

Dams, irrigation and now climate change have drastically reduced the once-mighty river. Is it a sign of things to come?

Reservoirs along the river may never rise to previous levels. Utah’s Lake Powell has a “bathtub ring” that rises at least 70 feet above the water.

From its source high in the Rocky Mountains, the Colorado River channels water south nearly 1,500 miles, over falls, through deserts and canyons, to the lush wetlands of a vast delta in Mexico and into the Gulf of California.

Then, beginning in the 1920s, Western states began divvying up the Colorado’s water, building dams and diverting the flow hundreds of miles, to Los Angeles, San Diego, Phoenix and other fast-growing cities. The river now serves 30 million people in seven U.S. states and Mexico, with 70 percent or more of its water siphoned off to irrigate 3.5 million acres of cropland. Read more