Giant manta ray gets its food from the deep – and may be at risk as fisheries expand

The iconic sea creature feeds on plankton well beneath the surface, isotope analysis shows.

The giant manta ray prefers to eat plankton in the deeper ocean rather than food at the surface, research has found. These plankton-feeders – or planktivores – can measure 7 metres across (23 feet). Their habits have proven elusive to biologists. Most information on the giant manta ray’s diet has come from chance observations at the sea surface in daylight. Read more.

Parts of nuclear waste may be converted into diamond nuclear batteries that will last a lifetime

Researchers, physicists, and chemists at the University of Bristol, UK, have discovered a way to convert thousands of tons of seemingly worthless nuclear waste into man-made diamond batteries that can generate a small electric current for longer than a thousand years. This is a truly fantastic breakthrough, given the fact that the main problem in dealing with nuclear waste is to really separate what is just waste and what can still be used as a valuable resource. Read more.

Marine sediments record variations in the Earth’s magnetic field

Past variations in the strength of the Earth’s magnetic field are reflected by the production of isotopes in the atmosphere. Researchers from the CNRS, Aix Marseille Universite and the French Alternative Energies and Atomic Energy Commission CEA have used an isotope extracted from marine sediments to identify such geomagnetic excursions over a particularly long period.

Beryllium-10 provides a timeline stretching back over the past 850,000 years, during which its concentration fluctuated according to the strength of Earth’s magnetic field. The work, published in Journal of Geophysical Research: Solid Earth, provides a new tool to study past variations in the Earth’s magnetic field and its behavior in the future. Read more.

Earth’s carbon-climate feedbacks varied in past warming episodes

Records from drill holes in the eastern equatorial Pacific indicate that Earth’s orbital eccentricity played an important role in controlling climate as the planet warmed.

Embedded within the Earth’s long-term cooling trend over the past 65 million years are several climate spikes—swift transitions to “hothouse” conditions—that had profound consequences for life. These spikes could serve as analogues for the future of our warming planet.

The cause of these spikes may in part be due to changes in the atmospheric concentration of carbon dioxide, an important greenhouse gas. But the complex feedbacks between the Earth’s climate and the carbon cycle have been hotly debated, and there is little scientific consensus on this issue. Read more.