Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Oceans’ acidity influences early carbon dioxide and temperature link estimates

17.03.2004


An international team of geoscientists believes that carbon dioxide, and not changes in cosmic ray intensity, was the factor controlling ancient global temperatures. The new findings resulted from the researchers inclusion of the ocean’s changing acidity in their calculations.



"Reviewing the geologic records of carbon dioxide and glaciations, we found that carbon dioxide was low during periods of long-lived and widespread continental glaciations and high during other, warmer periods," says Dr. Dana L. Royer, research associate in geosciences at Penn State. "Previous suggestions that cosmic ray flux correlated better with ancient temperatures than carbon dioxides do not appear true. While cosmic ray flux may be of some climatic significance, it is likely of second-order importance on a multimillion year timescale."

The researchers looked at climate changes that occurred over the past 570 million years. A direct record of global temperature and carbon dioxide exists for the past 100 years and ice cores provide carbon dioxide information for the past 400,000 years. However, for the remainder of the years, there are no direct measurements.


"A close correspondence between carbon dioxide and temperature has generally been found for the past 570 million years," says Royer. Scientists typically use proxies to determine carbon dioxide and temperatures in the distant past. Oxygen isotope ratios in shallow marine carbonate fossils were used by some researchers to determine surface water temperatures, and this indicated that carbon dioxide and temperature were not correlated, but that cosmic ray fluxes were correlated to temperature. Other proxies can determine carbon dioxide concentrations in both the atmosphere and the oceans.

Royer, working with Robert A. Berner, The Alan M. Bateman professor of geology and geophysics, Yale University; Isabel P. Montanez, professor of geology, University of California Davis; Neil J. Tabor, research associate, Southern Methodist University; and David J. Beerling, professor of animal and plant sciences, University of Sheffield, U.K., compared the results of a variety of carbon dioxide proxies to a model, GEOCARB III, that predicts carbon dioxide over time by tracking carbon entering and leaving the atmosphere. "Proxy estimates of paleo carbon dioxide agree, within modeling errors with GEOCARB model results," the researchers reported in the March issue of GSA Today.

The researchers also found good correlation between low levels of carbon dioxide in the atmosphere and the presence of extensive continental glaciations.

However, the proxy for temperature obtained from shallow oceanic carbonate deposits did not correlate well with the other temperature proxies or the carbon dioxide estimates.

"The acidity of the oceans changes depending on the amount of carbon dioxide in the atmosphere and the amounts of calcium and calcium carbonate in the water," says Royer. "When corrected for acidity, the temperature curve matches the glacial record much better."

The researchers applied correction factors for changes in acidity due to changes in carbon dioxide alone, changes in calcium ions in the water and carbon dioxide in the atmosphere and also for changes in calcium ions, carbon dioxide and calcium carbonate saturation of the water. The corrected temperature curves correctly predicted two major glaciations, one around 300 million years ago and one 30 million years ago. The cosmic ray flux does predict these glaciations, but also predicts cold temperatures when there is no evidence for ice.

"The global temperatures inferred from the cosmic ray flux model do not correlate with the temperature record determined from oxygen isotopes in shallow marine carbonate fossils, when these estimates were corrected for past changes in oceanic acidity," says the Penn State researcher.


The U.S. Department of Energy and the National Science Foundation supported this research.

A’ndrea Elyse Messer | EurekAlert!
Further information:
http://www.psu.edu/

More articles from Earth Sciences:

nachricht Sea ice extent sinks to record lows at both poles
23.03.2017 | NASA/Goddard Space Flight Center

nachricht Less radiation in inner Van Allen belt than previously believed
21.03.2017 | DOE/Los Alamos National Laboratory

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

When Air is in Short Supply - Shedding light on plant stress reactions when oxygen runs short

23.03.2017 | Life Sciences

Researchers use light to remotely control curvature of plastics

23.03.2017 | Power and Electrical Engineering

Sea ice extent sinks to record lows at both poles

23.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>