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
Impacts of mass coral die-off on Indian Ocean reefs revealed
21.02.2017 | University of Exeter
How much biomass grows in the savannah?
16.02.2017 | Friedrich-Schiller-Universität Jena
In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport
Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...
The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.
The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...
Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...
Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".
Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...
13.02.2017 | Event News
10.02.2017 | Event News
09.02.2017 | Event News
21.02.2017 | Earth Sciences
21.02.2017 | Medical Engineering
21.02.2017 | Trade Fair News