What caused the end of a warm climate phase and an expansion of the Antarctic ice sheet 14 million years ago? This is the question addressed by Kiel and Bremen palaeoclimatologists in an article for the latest issue of Nature (24/11/05). Their research uncovered a temporal link between a reduction in carbon dioxide (CO²) levels on earth, ice sheet formation and global cooling. The "global cooling" that took place 14 million years ago is attributed by Dr. Ann Holbourn, Professor Wolfgang Kuhnt, Professor Michael Schulz and Dr. Helmut Erlenkeuser to changes in the marine carbon cycle, associated with variations in Earth’s orbit and tilt.
Kuhnt: "We know that the orbital situation, i.e. the path followed by the Earth around the Sun, changes regularly. One such change occurred during the global cooling period 14 million years ago, bringing with it a period of cool Antarctic summers. The Antarctic ice sheet was no longer melting down in summer and began to grow steadily. For the first time we can reconstruct in great detail the history of this glacial expansion, which took place in about 80,000 years, a short time in geological terms.”
Researchers at the Institute for Geosciences of the Christian-Albrechts-Universität in Kiel and their colleague from DFG Research Center Ocean Margins in Bremen studied marine sediments from two cores in the eastern and western subtropical Pacific. The analysis of oxygen and carbon isotopes in the calcite shells of tiny organisms (foraminifers) living at the sea floor allowed to track changes in ice volume and carbon dioxide levels. The team investigated an interval of about two million years with a sampling resolution of 4,000 years.
Susanne Schuck | alfa
In times of climate change: What a lake’s colour can tell about its condition
21.09.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)
Did marine sponges trigger the ‘Cambrian explosion’ through ‘ecosystem engineering’?
21.09.2017 | Helmholtz-Zentrum Potsdam - Deutsches GeoForschungsZentrum GFZ
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.
MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...
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21.09.2017 | Physics and Astronomy
21.09.2017 | Life Sciences
21.09.2017 | Health and Medicine