Sediments that lie hundreds of meters below the ocean floor contain living bacteria, an analysis has shown. And according to the study these microbes could produce significant amounts of methane, a gas implicated in global warming, nature.com said.
Marine sediments cover about 70% of the Earth and harbor more than half of the microorganisms on the planet. Unable to discriminate between living and dead cells in the deep ocean floor, scientists have long debated how much of its biological content is active.
To solve this riddle, a team of researchers set out in 2001 to take samples from below the Pacific Ocean with the support of the Integrated Ocean Drilling Program. They collected sediments that were up to 16 million years old from 400 meters under the floor.
The group then ran tests on the samples to detect the presence of ribosomal RNA from bacteria. As a genetic molecule that breaks down quickly after being produced, this RNA is a sign of living cells, and the tests found substantial quantities of it.
“We didn’t have clear evidence that bacteria there were alive until now,“ says ecologist Lev Neretin of the Max Planck Institute for Marine Microbiology in Bremen, Germany, who was a member of the team. He and his fellow researchers estimate that, overall, about 10-30% of the cells in ocean sediment are alive.
According to their calculations, populations of bacteria living beneath the ocean floor multiply at a rate similar to those in surface environments.

NGC 7479 is the type of galaxy astronomers would have expected to see based on the measurements taken.

Researchers have discovered an invisible galaxy that could be the first of many that will help unravel one of the universe’s greatest mysteries, SPACE.com said.
The object appears to be made mostly of “dark matter,“ material of an unknown nature that can’t be seen.
Theorists have long said most of the universe is made of dark matter. Its presence is required to explain the extra gravitational force that is observed to hold regular galaxies together and that also binds large clusters of galaxies.
Theorists also believe knots of dark matter were integral to the formation of the first stars and galaxies. In the early universe, dark matter condensed like water droplets on a spider web, the thinking goes. Regular matter--mostly hydrogen gas--was gravitationally attracted to a dark matter knot, and when the density became great enough, a star would form, marking the birth of a galaxy.
The theory suggests that pockets of pure dark matter ought to remain sprinkled across the cosmos. In 2001, a team led by Neil Trentham of the University of Cambridge predicted the presence of entire dark galaxies.
The newfound dark galaxy was detected with radio telescopes. Similar objects could be very common or very rare, said Robert Minchin of Cardiff University in the UK.

The fossil record shows that bigger brains are not always smarter brains, a neurobiologist reported.
According to psychport.com, the human brain evolved to roughly its current size several hundred thousand years ago. It was only recently, however, in fossil records some 75,000 years old, that archeologists begin to find indications of an increase in cleverness as evidenced by improved tool making.
“Thanks to the archaeologists, we know that our ancestors went through two periods, each lasting more than a million years, when tool-making techniques didn’t gradually improve, despite a lot of gradual brain-size increase,“ said Calvin, a neurobiologist at the University of Washington in Seattle.
This calls into question the idea that bigger brains are always linked to greater intelligence, he said.
“So bigger is better may be true for something, say the big payoffs associated with protolanguage or sharing or accurate throwing,“ he said. “But for long periods in human evolution, general intelligence may not have improved very much.“

A new toothpaste could end the need for small fillings and prevent new holes appearing, ananova.com said.
In tests the paste, made from synthetic enamel, was able to repair small holes that were beginning to form.
Normally cavities are treated by drilling out the affected region and then filling reports the Mirror.
As well as repairing small cavities it also helps prevent more damage by strengthening the tooth.
Japanese researchers in Tokyo tested the past on an early site of tooth decay and an electron microscope showed that the natural and artificial enamel had become bonded as if they were one substance.
The researchers wrote in the journal Nature: “We have shown that our synthetic material can reconstruct enamel without prior excavation, in a process that not only repairs early caries lesions but can also help to prevent their re-occurrence by strengthening the natural enamel.“
The researchers added it was important that the paste did not come in contact with the gum as it could cause inflammation.

Quantum chemists have discovered a new type of chemical bond in molecules that contain two uranium atoms. A total of ten electrons--the equivalent of five covalent bonds--are involved in the bonds. Previously the record for the largest number of covalent bonds in a molecule was four, PhysicsWeb.org said.
A covalent bond usually consists of a pair of electrons shared between two atoms. Single, double and triple covalent bonds are well known for many elements, and more complex bonds can form when large numbers of atomic orbitals are free to participate in bond formation. For instance, chemists discovered quadruple bonds between transition-metal atoms in the 1960s.
Now, using quantum chemistry computer simulations, Laura Gagliardi of the University of Palermo and Bj?rn Roos at the Chemical Center in Lund have found that uranium, a member of the actinide group of elements, can form molecules with five covalent bonds.
Each uranium atom has a total of 16 atomic orbitals that are available for bond formation. Gagliardi and Roos used an approach called CASSCF/CASPT2 to model how all the valence orbitals in one atom merge with those in the other atom to form the most stable chemical bond -- that is, the one with minimum energy.
Gagliardi and Roos found that the uranium-uranium bond is more complex than any other known diatomic bond: it contains three normal electron-pair bonds and four weaker one-electron bonds.