Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists study ocean to understand global cooling

07.01.2005


The depth in the ocean where calcium carbonate dissolves at a faster rate than it is deposited is called the calcite compensation depth (CCD). At present this depth is approximately 4,500 meters (14,700 feet) with some variation between and within ocean basins. Because the CCD is linked to ocean acidity, which is, in turn, linked to atmospheric carbon dioxide concentrations and, hence, to global climate, it is important for scientists to understand the impact of possible changes in its depth.

In the current issue of Nature, URI Graduate School of Oceanography (GSO) visiting scientist Helen Coxall describes how the deepening of the CCD in the Pacific Ocean correlated to global cooling approximately 34 million years ago, when the first significant permanent ice sheets appeared on Antarctica. Other members of the scientific team include Paul Wilson, Southampton Oceanography Center, UK, Heiko Pälike and Jan Backman, University of Stockholm, Sweden, and Caroline H. Lear, Rutgers University, New Jersey.

"This event 34 million years ago marks the transition from a warm ’greenhouse’ climate state, when atmospheric carbon dioxide levels were naturally high and there was no or very little ice at the poles, to the cold glaciated climate state of the modern world that was characterized by lower carbon dioxide," said Coxall. "It is therefore equivalent to global warming in reverse. The results of our study are crucial to the understanding of how climate change works, especially how rapidly major changes in ice-sheet growth and sea level rise and fall occur under altered conditions of atmospheric carbon dioxide."



Coxall and her colleagues analyzed sediment records and found that the deepening of the CCD was more rapid than previously documented and occurred in two jumps of about 40,000 years each, in step with the onset of Antarctic ice-sheet growth. The 40,000-year interval was separated by a plateau of 200,000 years.

The glaciation began after the Earth entered a cooler phase during an interval when the Earth’s orbit of the Sun favored cool summers. The researchers’ observations suggest that it was the prolonged absence of warm summers, inhibiting summer snow melt, not the occurrence of cool winters favoring accumulation, that was important for establishing the first major ice sheets on Antarctica. Although the pattern of Earth’s orbital configuration was the ultimate trigger for creating conditions that led to ice-sheet growth, a natural long-term decrease in atmospheric carbon dioxide levels, which promoted global cooling, was responsible for increasing Earth’s sensitivity to this factor.

In addition, analysis of the data indicates that along with the growth of the Antarctic ice sheet, glaciation in the Northern Hemisphere must also have been taking place.

Lisa Cugini | EurekAlert!
Further information:
http://www.gso.uri.edu

More articles from Ecology, The Environment and Conservation:

nachricht How does the loss of species alter ecosystems?
18.05.2017 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig

nachricht Excess diesel emissions bring global health & environmental impacts
16.05.2017 | International Institute for Applied Systems Analysis (IIASA)

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A quantum walk of photons

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....

Im Focus: Turmoil in sluggish electrons’ existence

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...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

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...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

Physicists discover mechanism behind granular capillary effect

24.05.2017 | Physics and Astronomy

Measured for the first time: Direction of light waves changed by quantum effect

24.05.2017 | Physics and Astronomy

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>