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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Tiny Grazers Play Key Role in Marine Ecosystem Health

LAFAYETTE – Tiny sea creatures no bigger than a thumbtack are being credited for playing a key role in helping provide healthy habitats for many kinds of seafood, according to a new study by the Virginia Institute of Marine Science and U.S. Geological Survey.

The little crustacean “grazers,” some resembling tiny shrimp, are critical in protecting seagrasses from overgrowth by algae, helping keep these aquatic havens healthy for native and economically important species.  Crustaceans are tiny to very large shelled animals that include crab, shrimp, and lobster.   (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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Human Impact Felt on Black Sea Long Before Industrial Era

When WHOI geologist Liviu Giosan first reconstructed the history of how the Danube River built its delta, he was presented with a puzzle.

In the delta’s early stages of development, the river deposited its sediment within a protected bay. As the delta expanded onto the Black Sea shelf in the late Holocene and was exposed to greater waves and currents, rather than seeing the decline in sediment storage that he expected, Giosan found the opposite. The delta continued to grow. In fact, it has tripled its storage rate.

If an increase in river runoff was responsible for the unusual rapid build up of sediment in the delta, says Giosan, the question is, “Was this extraordinary event in the Danube delta felt in the entire Black Sea basin? And if so, what caused it?” (more…)

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