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New source found for cold, deep Antarctic currents

Seal
© Iain Field, Graduate School of the Environment, Macquarie University, AustraliaSeals helped scientists track cold, deep currents in Antarctica.
With help from seals, scientists have discovered a new source for the coldest, deepest water in the ocean.

Instruments glued to seals' heads tracked Antarctic Bottom Water flowing down deep canyons off Cape Darnley in East Antarctica. The spot was an unexpected font of the bottom water - cold, dense, salty water - because it lacks the broad underwater shelf of the unique current's three known sources. These shallow shelves stick out from the continent's edge. Cold water flows over the edge to the abyssal depths like a frigid underwater waterfall.

Finding the Cape Darnley bottom water, which accounts for about 10 percent of the world's Antarctic Bottom Water, solves a long-standing problem. The amount of cold water coming from Antarctica exceeded that from the three other sites.

"At least one more source was inferred to exist, but had stubbornly eluded detection," Michael Meredith, an oceanographer with the British Antarctic Survey, wrote in an article accompanying the study in the journal Nature Geoscience. Meredith was not involved in the research.

"Our discovery is the missing piece of a 30-year-old puzzle regarding the circumpolar distribution of global Antarctic Bottom Water supply," said Kay Ohshima, an oceanographer at Hokkaido University in Japan and lead author of the study.

The discovery will also affect climate change models, in which bottom water circulation plays an important role. The deep bottom current drives large-scale ocean circulation, helping regulate Earth's climate, Ohshima said.

"It is vital that this newly found Cape Darnley Bottom Water be incorporated into the global assessment of the meridian ocean circulation, a key element of the climate system. This will improve numerical simulations predicting its response to long-term climate change," Ohshima told OurAmazingPlanet.

The findings are detailed in the Feb. 24 issue of the journal Nature Geoscience.

Question

Lost land beneath the waves?

Buried Continent
© Ebbe Hartz Ancient cargo. By analyzing the composition of sand from the island of Mauritius (shown here), researchers learned that a microcontinent may lie under the ocean.
Geological detectives are piecing together an intriguing seafloor puzzle. The Indian Ocean and some of its islands, scientists say, may lie on top of the remains of an ancient continent pulled apart by plate tectonics between 50 million and 100 million years ago. Painstaking detective work involving gravity mapping, rock analysis, and plate movement reconstruction has led researchers to conclude that several places in the Indian Ocean, now far apart, conceal the remnants of a prehistoric land mass they have named Mauritia. In fact, they say, the Indian Ocean could be "littered" with such continental fragments, now obscured by lava erupted by underwater volcanoes.

The Seychelles, an archipelago of 115 islands about 1500 kilometers east of Africa, are something of a geological curiosity. Although a few of Earth's largest islands, such as Greenland, are composed of the same continental crust as the mainland, most islands are made of a denser, chemically distinct oceanic crust, created midocean by magma welling up beneath separating tectonic plates. Geologists think they separated from the Indian subcontinent 80 million to 90 million years ago.

But those islands might not be so unique. Researchers from Norway, Germany, and Britain, writing in Nature Geoscience, now suggest that the Indian Ocean is harboring other fragments of ancient continental crust. Those fragments, the researchers say, lie buried beneath more recent oceanic crust erupted by underwater volcanoes.

Radar

The sound heard around the world: Russian meteor explosion produced largest infrasonic soundwaves ever recorded

Infrasound, or extremely low frequency sound waves, from the meteor that broke up over Russia's Ural mountains were some of the largest ever recorded by the CTBTO's network of infrasound stations.


Credit: CTBTO

Brick Wall

Peer review, a flawed process at the heart of science and journal publications

Image
Peer review is at the heart of the processes of not just medical journals but of all of science. It is the method by which grants are allocated, papers published, academics promoted, and Nobel prizes won. It has allowed government agencies to approve untold numbers of drugs and vaccines, or rubber stamp thousands of chemicals as safe. It has until recently been unstudied. And its defects are easier to identify than its attributes. Yet it shows no sign of going away.

When something is peer reviewed it is in some sense blessed. Even journalists recognize this. When the BMJ published a highly controversial paper that argued that a new 'disease', female sexual dysfunction, was in some ways being created by pharmaceutical companies, a friend who is a journalist was very excited - not least because reporting it gave him a chance to get sex onto the front page of a highly respectable but somewhat priggish newspaper (the Financial Times). 'But,' the news editor wanted to know, 'was this paper peer reviewed?'. The implication was that if it had been it was good enough for the front page and if it had not been it was not.

Comet 2

New Comet: C/2013 C2 (Tenagra)

Discovery Date: February 14, 2013

Magnitude
: 19.0 mag

Discoverer
: P. R. Holvorcem, M. Schwartz (Tenagra Observatory)

C/2013 C2 (Tenagra)
© Aerith Net
The orbital elements are published on M.P.E.C. 2013-D22.

Comet

New Comet: P/2013 CE31 (MOSS)

Discovery Date: February 5, 2013

Magnitude: 20.3 mag

Discoverer: Claudine Rinner (Morocco Oukaimeden Sky Survey)

P/2013 CE31
© Aerith Net

Comet 2

New Comet: C/2013 D1 (Holvorcem)

Discovery Date: February 16, 2013

Magnitude: 19.2 mag

Discoverer:
Paulo Holvorcem (Tenagra III astrograph)

C/2013 D1
© Aerith NetMagnitude graph.
The orbital elements are published on M.P.E.C. 2013-D41.

Info

Chinese population study reveals schizophrenia gene mutations

Chinese People
© Medical Daily
A team of Chinese researchers has identified a group of genes that may hold the key to the genetic basis of schizophrenia.

Schizophrenia is a psychiatric condition that affects up to 1% of the world's population, with many heritable factors that are passed down through generations.

Symptoms typically appear late in life, with patients experiencing disordered thought and disturbances in cognition and emotion like hallucinations, psychosis, delusions, and apathy. If not treated effectively, it can be debilitating.

The discovery of a genetic screen for schizophrenia could allow people at risk to take precautions against developing it, or learn to cope with symptoms before they get out of hand.

Recently, scientists have been using genome-wide association studies (GWAS) to analyze genetic variations across entire populations. The technology used in GWAS allows the identification of specific genetic markers for many complex human diseases.

Solar Flares

NASA sees monster sunspot growing fast, solar storms possible

sun black spots
© SPACE.com/NASA/SDO/AIA/HMI/Goddard Space Flight CenterThe bottom two black spots on the sun, known as sunspots, appeared quickly over the course of Feb. 19-20, 2013. These two sunspots are part of the same system and are over six Earths across.
A colossal sunspot on the surface of the sun is large enough to swallow six Earths whole, and could trigger solar flares this week, NASA scientists say.

The giant sunspot was captured on camera by NASA's Solar Dynamics Observatory as it swelled to enormous proportions over the 48 hours spanning Tuesday and Wednesday (Feb. 19 and 20). SDO is one of several spacecraft that constantly monitor the sun's space weather environment.

"It has grown to over six Earth diameters across, but its full extent is hard to judge since the spot lies on a sphere, not a flat disk," wrote NASA spokeswoman Karen Fox, of the agency's Goddard Space Flight Center in Greenbelt, Md., in an image description.

The sunspot region is actually a collection of dark blemishes on the surface of the sun that evolved rapidly over the last two days. Sunspots form from shifting magnetic fields at the sun's surface, and are actually cooler than their surrounding solar material.

Saturn

Saturn's shockwaves reach supernova force

saturn
© NASA/JPL
During a chance encounter with what appears to be an unusually strong blast of solar wind at Saturn, NASA's Cassini spacecraft detected particles being accelerated to ultra-high energies. This is similar to the acceleration that takes place around distant supernovas. "Cassini has essentially given us the capability of studying the nature of a supernova shock in situ in our own solar system, bridging the gap to distant high-energy astrophysical phenomena that are usually only studied remotely," said Adam Masters of the Institute of Space and Astronautical Science, Sagamihara, Japan.

Scientists are particularly interested in "quasi-parallel" shocks, where the magnetic field and the "forward"-facing direction of the shock are almost aligned, as may be found in supernova remnants. The new study, led by Masters describes the first detection of significant acceleration of electrons in a quasi-parallel shock at Saturn, coinciding with what may be the strongest shock ever encountered at the ringed planet.