Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New Nature study illuminates 55 million years of the carbon cycle and climate history

30.08.2012
A study in the August 30 issue of Nature provides, in unprecedented detail, the history of a crucial indicator of the relationship between the carbon cycle and climate processes over the past 55 million years.

Over this time period, when the Earth is known to have transitioned from "hothouse" to "icehouse" conditions, the oceans also experienced a dramatic shift in the carbonate compensation depth, or CCD. Defined as the depth below which carbonate minerals (such as calcite) dissolve completely, the CCD is known to fluctuate over time – it shallows during warm periods, and deepens when ice age conditions prevail. Now, however, scientists have a detailed and quantifiable record of just how much the CCD has shifted during recent geological history.

The study, which relies on seafloor sediment cores collected during a pair of 2009 expeditions on board the JOIDES Resolution, demonstrates that 55 million years ago, the CCD of the Pacific Ocean sat at an average of about two miles (3.3-3.6 km) below the sea surface. As the Earth cooled, however, the CCD sank – reaching its deepest point of almost three miles (4.8 km) between 13 and 11 million years ago. Today, the Pacific's CCD sits just less than three miles (4.5 km) deep, and is thought to be on the rise as a result of modern, human-induced climate change.

"Long-term change in CCD and changes in Earth's atmospheric carbon dioxide concentration both result from shifts in how carbon is cycled by earth processes," says study co-author Mitchell Lyle, a geoscientist at Texas A&M University who co-led the second of the two expeditions. "Adding geologic reserves of carbon into the oceans and atmosphere – by burning coal or petroleum, for example – causes oceans to become more acidic and causes the atmosphere and oceans to warm. This new CCD record is an important step toward understanding how the carbon system balances out over long time frames."

The Pacific Ocean has remained the largest ocean on Earth for millions of years. Today, it covers one third of the planet's surface, and its biologically productive equatorial region plays a very important role in the global carbon cycle and long-term climate patterns. Over four months, the drilling vessel JOIDES Resolution – operated by the U.S. Implementing Organization on behalf of the National Science Foundation (NSF) and the Integrated Ocean Drilling Program (IODP) – drilled nearly four miles of core samples at eight different locations across the center of the Pacific basin.

"We often discuss global warming induced by man-made carbon dioxide. However, on geological timescales of millions of years, other processes determine the carbon cycle," says lead author Heiko Pälike, a geoscientist at the University of Bremen who co-led the first expedition. Volcanoes are a major natural source of atmospheric carbon dioxide, while the weathering of carbonate rocks can remove the gas from the atmosphere. "The overall balance of these processes is reflected in the CCD," explains Pälike.

In the Nature study, Pälike, Lyle and their co-authors demonstrate that, in the equatorial Pacific, the CCD did not follow a one-way path to the depths as the planet cooled down. Rather, the data reveals five intervals in the "greenhouse" world (prior to 33 million years ago) during which the CCD fluctuated upwards and downwards in a range between 650 and 3,000 feet (200-900 meters), and at least four more major excursions in the last 20 million years. "These events, which often mirror warming and cooling phases, persisted between 250,000 and one million years," Pälike explains. They resulted from minor differences between how much calcium was added to the oceans by weathering versus how much carbon dioxide was added to the ocean-atmosphere system by volcanic eruptions. The cycling of carbon between the sea surface and deep ocean further complicated the situation.

"Understanding the processes that caused these CCD excursions will provide important new insights about how the carbon cycle and climate are linked," Lyle says. "And, they will help us better understand how and when the current spike in atmospheric carbon dioxide will eventually level out."

To access more data and information from the Pacific Equatorial Age Transect (PEAT) expeditions, please see: http://publications.iodp.org/proceedings/320_321/32021toc.htm

The paper, titled "A Cenozoic record of the equatorial Pacific carbonate compensation depth," appears in the August 30, 2012 issue of the journal Nature. (doi:10.1038/nature11360)

About IODP

The Integrated Ocean Drilling Program (IODP) is an international research program dedicated to advancing scientific understanding of the Earth through drilling, coring and monitoring the subseafloor. The JOIDES Resolution is a scientific research vessel managed by the U.S. Implementing Organization of IODP (USIO). Together, Texas A&M University, Lamont-Doherty Earth Observatory of Columbia University, and the Consortium for Ocean Leadership comprise the USIO. IODP is supported by two lead agencies: the U.S. National Science Foundation (NSF) and Japan's Ministry of Education, Culture, Sports, Science, and Technology. Additional program support comes from the European Consortium for Ocean Research Drilling (ECORD), the Australia-New Zealand IODP Consortium (ANZIC), India's Ministry of Earth Sciences, the People's Republic of China (Ministry of Science and Technology), and the Korea Institute of Geoscience and Mineral Resources. For more information, visit www.iodp.org.

Connect with us online!

Web: www.joidesresolution.org

Facebook: http://www.facebook.com/theJR

Twitter: @theJR and @SeafloorSci

Media Contacts:

Mitchell Lyle
Texas A&M University
College Station, Texas, USA
mlyle@ocean.tamu.edu
+1-979-845-3380
Matthew Wright Consortium for Ocean Leadership
Washington, D.C. USA
mwright@oceanleadership.org
+1-202-448-1254
Heiko Pälike
MARUM, University of Bremen
Bremen, Germany
hpaelike@marum.de
+49-421-218-65980
Albert Gerdes
MARUM, University of Bremen
Bremen, Germany
agerdes@marum.de
+49-421-218-65540
More news about Texas A&M University, go to http://tamutimes.tamu.edu/
Follow us on Twitter at http://twitter.com/tamu/

Keith Randall | EurekAlert!
Further information:
http://www.tamu.edu

More articles from Studies and Analyses:

nachricht Reusable carbon nanotubes could be the water filter of the future, says RIT study
30.03.2017 | Rochester Institute of Technology

nachricht Pan-European study on “Smart Engineering”
30.03.2017 | IPH - Institut für Integrierte Produktion Hannover gGmbH

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

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

Im Focus: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

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...

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

'On-off switch' brings researchers a step closer to potential HIV vaccine

30.03.2017 | Health and Medicine

Penn studies find promise for innovations in liquid biopsies

30.03.2017 | Health and Medicine

An LED-based device for imaging radiation induced skin damage

30.03.2017 | Medical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>