Quarrying of Stonehenge ‘bluestones’ dated to 3000 BC
Excavations at two quarries in Wales, known to be the source of the Stonehenge ‘bluestones’, provide new evidence of megalith quarrying 5,000 years ago, according to a new UCL-led study. (more…)
Tag Archives: source
New Technology Helps Pinpoint Sources of Water Contamination
Berkeley Lab develops better method of environmental monitoring using the PhyloChip, finds surprising results in Russian River watershed
When the local water management agency closes your favorite beach due to unhealthy water quality, how reliable are the tests they base their decisions on? As it turns out, those tests, as well as the standards behind them, have not been updated in decades. Now scientists from Lawrence Berkeley National Laboratory (Berkeley Lab) have developed a highly accurate, DNA-based method to detect and distinguish sources of microbial contamination in water. (more…)
The source of the sky’s X-ray glow
ANN ARBOR — In findings that help astrophysicists understand our corner of the galaxy, an international research team has shown that the soft X-ray glow blanketing the sky comes from both inside and outside the solar system.
The source of this “diffuse X-ray background” has been debated for the past 50 years. Does it originate from the solar wind colliding with interplanetary gases within our solar system? Or is it born further away, in the “local hot bubble” of gas that a supernova is believed to have left in our galactic neighborhood about 10 million years ago? (more…)
Coastal sea change
UD oceanographer reports on human-caused changes to carbon cycling
Carbon dioxide pumped into the air since the Industrial Revolution appears to have changed the way the coastal ocean functions, according to a new analysis published this week in Nature.
A comprehensive review of research on carbon cycling in rivers, estuaries and continental shelves suggests that collectively this coastal zone now takes in more carbon dioxide than it releases. The shift could impact global models of carbon’s flow through the environment and future predictions related to climate change. (more…)
Mercury levels in Pacific fish likely to rise in coming decades
ANN ARBOR — University of Michigan researchers and their University of Hawaii colleagues say they’ve solved the longstanding mystery of how mercury gets into open-ocean fish, and their findings suggest that levels of the toxin in Pacific Ocean fish will likely rise in coming decades.
Using isotopic measurement techniques developed at U-M, the researchers determined that up to 80 percent of the toxic form of mercury, called methylmercury, found in the tissues of deep-feeding North Pacific Ocean fish is produced deep in the ocean, most likely by bacteria clinging to sinking bits of organic matter. (more…)
Study Identifies Deepwater Horizon Debris as Likely Source of Gulf of Mexico Oil Sheens
A chemical analysis of oil sheens found floating recently at the ocean’s surface near the site of the Deepwater Horizon disaster indicates that the source is pockets of oil trapped within the wreckage of the sunken rig. Both the Macondo well and natural oil seeps common to the Gulf of Mexico were confidently ruled out.
Researchers from Woods Hole Oceanographic Institution (WHOI) and the University of California, Santa Barbara (UCSB) used a recently-patented method to fingerprint the chemical makeup of the sheens and to estimate the location of the source based on the extent to which gasoline-like compounds evaporated from the oil sheens. The study was published online in Environmental Science & Technology. (more…)
Black Hole Naps amidst Stellar Chaos
Nearly a decade ago, NASA’s Chandra X-ray Observatory caught signs of what appeared to be a black hole snacking on gas at the middle of the nearby Sculptor galaxy. Now, NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR), which sees higher-energy X-ray light, has taken a peek and found the black hole asleep.
“Our results imply that the black hole went dormant in the past 10 years,” said Bret Lehmer of the Johns Hopkins University, Baltimore, and NASA’s Goddard Space Flight Center, Greenbelt, Md. “Periodic observations with both Chandra and NuSTAR should tell us unambiguously if the black hole wakes up again. If this happens in the next few years, we hope to be watching.” Lehmer is lead author of a new study detailing the findings in the Astrophysical Journal. (more…)
Glaciers Contribute Significant Iron to North Atlantic Ocean
All living organisms rely on iron as an essential nutrient. In the ocean, iron’s abundance or scarcity means all the difference as it fuels the growth of plankton, the base of the ocean’s food web.
A new study by biogeochemists and glaciologists at Woods Hole Oceanographic Institution (WHOI) identifies a unexpectedly large source of iron to the North Atlantic – meltwater from glaciers and ice sheets, which may stimulate plankton growth during spring and summer. This source is likely to increase as melting of the Greenland ice sheet escalates under a warming climate. (more…)
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