This is the finding of scientists from the University of Southampton's School of Ocean and Earth Science at the National Oceanography Centre, Southampton (NOCS), reported in Nature.
The Eocene epoch (55 to 34 million years ago) was the last interval of sustained global warmth in Earth's history, a likely consequence of atmospheric carbon dioxide levels much higher than today. It has been known for some time that, at the end of the Eocene, ice sheets on Antarctica first expanded to close their modern size. However, in a recent controversial move, it was proposed that, despite the high global temperatures of the time, very large ice sheets existed 8 million years earlier, not just on Antarctica but also in the Northern Hemisphere.
New findings from NOCS researchers show that, if ice sheets did exist during the controversial interval they must have been small and would have been easily accommodated on Antarctica with no need to invoke Northern Hemisphere glaciation. This result is more in keeping with other geological records and climate model results suggesting that the threshold for ice sheet inception would have been crossed earlier in the Southern Hemisphere than in the Northern Hemisphere because the South Pole has a continent sitting over it (Antarctica) while the North Pole has an ocean (the Arctic).
The NOCS group also identifies a short-lived event immediately preceding the controversial interval during which ocean temperatures briefly increased, the deep ocean became more acidic and the carbon cycle was perturbed by the contribution of isotopically light carbon to the ocean/atmosphere system. This finding hints at the operation of carbon cycle processes common to those thought responsible for the famous transient extreme warming events that occurred between 50 and 55 million years ago, providing a focus for future work aimed at better understanding climate-carbon cycle feedbacks.
Kirsty Edgar, Dr Paul Wilson and Philip Sexton of the University of Southampton's School of Ocean and Earth Science, based at NOCS, used stable isotope analysis of fossil shells of foraminifera (microscopic marine organisms) and bulk sediment from deep-sea sediments to generate a record of climate change and estimate potential global ice volumes in the Eocene. Sediment cores were taken in the tropical Atlantic Ocean by the Ocean Drilling Program (ODP).
The Natural Environment Research Council funded this research via a UK ODP grant. Collaborator Yusuke Suganuma is based at the University of Tokyo, Japan.
Sarah Watts | alfa
New insights into the ancestors of all complex life
29.05.2017 | University of Bristol
A 3-D look at the 2015 El Niño
29.05.2017 | NASA/Goddard Space Flight Center
The world's highest gain high power laser amplifier - by many orders of magnitude - has been developed in research led at the University of Strathclyde.
The researchers demonstrated the feasibility of using plasma to amplify short laser pulses of picojoule-level energy up to 100 millijoules, which is a 'gain'...
Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.
Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....
Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.
The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
24.05.2017 | Event News
23.05.2017 | Event News
22.05.2017 | Event News
30.05.2017 | Life Sciences
30.05.2017 | Power and Electrical Engineering
29.05.2017 | Earth Sciences