Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Rising carbon dioxide levels at end of last ice age not tied to Pacific Ocean, as had been suspected

04.10.2011
After the last ice age peaked about 18,000 years ago, levels of atmospheric carbon dioxide rose about 30 percent. Scientists believe that the additional carbon dioxide—a heat-trapping greenhouse gas—played a key role in warming the planet and melting the continental ice sheets. They have long hypothesized that the source of the gas was the deep ocean.

But a new study by a University of Michigan paleoclimatologist and two colleagues suggests that the deep ocean was not an important source of carbon during glacial times. The finding will force researchers to reassess their ideas about the fundamental mechanisms that regulate atmospheric carbon dioxide over long time scales.

"We're going back to the drawing board. It's certainly fair to say that we need to have some other working hypotheses at this point," said U-M paleoclimatologist David Lund, lead author of a paper in this week's edition of the journal Nature Geoscience.

"If we can improve our understanding of the carbon cycle in the past, we will be better positioned moving forward as CO2 levels rise due to anthropogenic causes," said Lund, an assistant professor in the U-M Department of Earth and Environmental Sciences. Lund's co-authors are Alan Mix of Oregon State University and John Southon of the University of California, Irvine.

The study, which involved radiocarbon-dating of sediments from a core collected at a deep-ocean site (water depth 8,943 feet) off the coast of southwestern Oregon, was supported by the National Science Foundation and the University of Michigan.

The work involved radiocarbon dating dozens of sediment samples that contained microscopic shells created by plankton. The samples were collected from various locations in the core, spanning the period from 8,000 to 22,000 years ago. Over thousands of years, ocean water circulates from the surface to the bottom, then back to the surface. The radiocarbon results revealed the basin's circulation or "ventilation" rate, the amount of time that had passed since the various deep-water samples were last in contact with the atmosphere.

The scientists expected to find that the ventilation rate in the basin slowed during glacial times, allowing carbon dioxide to accumulate in the abyss and depleting atmospheric levels of the gas.

Surprisingly, they found that the ventilation rate during glacial times was roughly the same as it is today, suggesting that the Pacific was not an important reservoir of carbon during glacial times.

"Frankly, we're kind of baffled by the whole thing," said Oregon State University paleo-oceanographer Alan Mix, one of the co-authors. "The North Pacific was such an obvious source for the carbon, but it just doesn't match up."

"At least we've shown where the carbon wasn't," Mix said. "Now we just have to find where it was."

Jim Erickson | EurekAlert!
Further information:
http://www.umich.edu

More articles from Earth Sciences:

nachricht Supercomputing helps researchers understand Earth's interior
23.05.2017 | University of Illinois College of Liberal Arts & Sciences

nachricht How is climate change affecting fauna in the Arctic?
22.05.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

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...

Im Focus: Bacteria harness the lotus effect to protect themselves

Biofilms: Researchers find the causes of water-repelling properties

Dental plaque and the viscous brown slime in drainpipes are two familiar examples of bacterial biofilms. Removing such bacterial depositions from surfaces is...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

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

Innovation 4.0: Shaping a humane fourth industrial revolution

17.05.2017 | Event News

 
Latest News

Supercomputing helps researchers understand Earth's interior

23.05.2017 | Earth Sciences

Study identifies RNA molecule that shields breast cancer stem cells from immune system

23.05.2017 | Life Sciences

Turmoil in sluggish electrons’ existence

23.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>