Using tiny bone fragments from fossilized fish, scientists have traced the roots of the climate phenomenon known as El Niño, the intermittent warming of ocean waters off the coast of Peru that can affect weather worldwide. According to a report published in the current issue of the journal Science, modern El Niño conditions arose around 5,000 years ago.
Image: Courtesy of C. Fred T. Andrus
Previous research based on fossilized mollusk remains had suggested that El Niño conditions did not exist thousands of years ago, but those findings were preliminary. In the current study, C. Fred T. Andrus of the University of Georgia and colleagues analyzed isotopes of oxygen present in the ear stones, or otoliths (see micrograph at right), of a species of catfish that lives off the coast of Peru and does not migrate. Like tree rings, otoliths grow concentrically and incorporate elements indicative of the environment in which they formed. "By looking at the entire otolith," co-author Douglas E. Crowe of the University of Georgia explains, "we can reconstruct the water temperature history throughout the life of the fish, from season to season and year to year."
In this case, the researchers focused on the amount of oxygen isotope 18 in the otoliths--an indicator of the water temperature in which the fish lived. The team examined fossils recovered from two Peruvian archaeological sites approximately 6,000 years old and found that ocean temperatures then were on average three to four degrees Celsius warmer and less variable than current sea temperatures are.
Sarah Graham | Scientific American
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Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
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Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
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An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
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A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
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