Tag Archives: sediment

‘Tiger stripes’ underneath Antarctic glaciers slow the flow

Narrow stripes of dirt and rock beneath massive Antarctic glaciers create friction zones that slow the flow of ice toward the sea, researchers at Princeton University and the British Antarctic Survey have found. Understanding how these high-friction regions form and subside could help researchers understand how the flow of these glaciers responds to a warming climate.

Just as no-slip strips on flooring prevent people from slipping on a wet floor, these ribs or “tiger stripes” — named in reference to Princeton’s tiger mascot — provide friction that hinders the glaciers from slipping along the underlying bed of rock and sediment, the researchers report online in the journal Science. (more…)

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Japan braucht Hilfe

NABU fordert internationalen Rettungsplan für Fukushima

Anlässlich der heute abgeschlossenen Untersuchungen durch die internationale Atomenergiebehörde (IAEO) fordert der NABU einen internationalen Rettungsplan für den Katastrophen-Reaktor. „Schlimm genug, dass die japanische Regierung mehr als zwei Jahre brauchte, um die internationale Gemeinschaft um Hilfe zu bitten. Bis heute ist Japan nicht in der Lage, Schritt für Schritt die Schäden rund um die havarierte Atomanlage in Fukushima einzudämmen. Es sind viele Firmen vor Ort, aber es gibt keinen Masterplan“, kritisierte Bundesgeschäftsführer Leif Miller. (more…)

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Scientists Find Possible Solution to an Ancient Enigma

The widespread disappearance of stromatolites, the earliest visible manifestation of life on Earth, may have been driven by single-celled organisms called foraminifera.

The findings, by scientists at Woods Hole Oceanographic Institution (WHOI); Massachusetts Institute of Technology; the University of Connecticut; Harvard Medical School; and Beth Israel Deaconess Medical Center, Boston, were published online the week of May 27 in the Proceedings of the National Academy of Sciences. (more…)

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Life underground

Active microbes discovered far beneath seafloor in ancient ocean sediment

Microbes are living more than 500 feet beneath the seafloor in 5 million-year-old sediment, according to new findings by researchers at the University of Delaware and Woods Hole Oceanographic Institution (WHOI).

Genetic material in mud from the bottom of the ocean — called the deep biosphere —revealed an ecosystem of active bacteria, fungi and other microscopic organisms at depths deeper than a skyscraper is high. The findings were published in Nature on June 12. (more…)

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New analysis suggests wind, not water, formed mound on Mars

A roughly 3.5-mile high Martian mound that scientists suspect preserves evidence of a massive lake might actually have formed as a result of the Red Planet’s famously dusty atmosphere, an analysis of the mound’s features suggests. If correct, the research could dilute expectations that the mound holds evidence of a large body of water, which would have important implications for understanding Mars’ past habitability.

Researchers based at Princeton University and the California Institute of Technology suggest that the mound, known as Mount Sharp, most likely emerged as strong winds carried dust and sand into the 96-mile-wide crater in which the mound sits. They report in the journal Geology that air likely rises out of the massive Gale Crater when the Martian surface warms during the day, then sweeps back down its steep walls at night. Though strong along the Gale Crater walls, these “slope winds” would have died down at the crater’s center where the fine dust in the air settled and accumulated to eventually form Mount Sharp, which is close in size to Alaska’s Mt. McKinley. (more…)

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Sandy’s Underwater Sandscapes

UD researchers studying ‘fingerprint’ left on seafloor by Hurricane Sandy

Beneath the 20-foot waves that crested off Delaware’s coast during Hurricane Sandy, thrashing waters reshaped the floor of the ocean, churning up fine sand and digging deep ripples into the seabed. Fish, crustaceans and other marine life were blasted with sand as the storm sculpted new surfaces underwater.

UD scientists cued up their instruments to document the offshore conditions before, during and after Sandy’s arrival to scrutinize the differences and better predict the environmental impact of future storms. (more…)

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Sediment Chemicals in Coastal Rivers Overall Lower in U.S. than Worldwide Averages

Almost all the sediment-associated chemical concentrations found in 131 of the nation’s rivers that drain to the Atlantic, Pacific and Gulf Coasts are lower than worldwide averages, according to a new study by the USGS. These coastal rivers are a significant pathway for the delivery of sediment-associated chemicals to the world’s coastal zones and oceans.

“I hope that the results of this new study will remind everyone that it is not only river water that can transport chemicals and pollutants, but also the associated sediment load,” said USGS Director Marcia McNutt. “Our citizens expect high environmental quality as compared with worldwide averages, but clean water alone will not suffice if river sediments are host to toxic heavy metals and concentrated organics that can produce dead zones.” (more…)

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Sediment Sleuthing

Radioactive medicine being tracked through rivers

A University of Delaware oceanographer has stumbled upon an unusual aid for studying local waterways: radioactive iodine. Trace amounts of the contaminant, which is used in medical treatments, are entering waterways via wastewater treatment systems and providing a new way to track where and how substances travel through rivers to the ocean.

“This is a really interesting convergence of medicine, public health and environmental science,” said Christopher Sommerfield, associate professor of oceanography in UD’s College of Earth, Ocean, and Environment. (more…)

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