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 Geophysicists and atmospheric scientists partner to track typhoons' seismic footprints
16.02.2018 | Princeton University

nachricht NASA finds strongest storms in weakening Tropical Cyclone Sanba
15.02.2018 | NASA/Goddard Space Flight Center

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

Im Focus: Interference as a new method for cooling quantum devices

Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters

Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

New tech for commercial Lithium-ion batteries finds they can be charged 5 times fast

20.02.2018 | Power and Electrical Engineering

Hidden talents: Converting heat into electricity with pencil and paper

20.02.2018 | Materials Sciences

Rare find from the deep sea

20.02.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>