Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

One type of carbon so resilient it skews carbon cycle calculations

23.01.2004


Scientists interested in the Earth’s carbon cycle – something that must be understood to assess the ongoing effects of carbon dioxide created by human actions, such as driving cars – have a new problem. They need to adjust various calculations because one component, graphitic black carbon, similar to the material found in pencil lead, turns out to be so tough.



In a letter in today’s issue of Nature, researchers say that graphitic black carbon is created as sedimentary rocks undergo metamorphism – unlike forms of combustion-derived black carbon such as soot, charcoal and other debris that’s left when biomass such as forests or fossil fuels don’t burn completely. Eroding from rocks on land, graphitic black carbon appears to be one of the only kinds of carbon that resists conversion to other forms of carbon, such as combining with oxygen to form carbon dioxide, as it cycles between land, atmosphere and oceans.

"Carbon is generally considered to pass fairly freely between reservoirs, or ’boxes,’ of the carbon cycle," says lead author Angela Dickens, a doctoral student in chemistry and oceanography at the University of Washington. "The carbon stays in one box for a variable amount of time – for hundreds of years in trees, a few days in a bug, thousands of years as organic carbon dissolved in the world’s oceans and such, but not generally staying more than a few thousand years in any one form before being converted into a different form.


"Of course carbon in rocks cycles on a much longer time scale – millions of years – but it has been assumed that once that carbon weathers out of rocks it will enter a different box, perhaps becoming atmospheric carbon dioxide or part of the biomass. This isn’t the case for graphitic black carbon," Dickens says. "It’s tough stuff."

This gives it a chance to become so old its exact age can’t even be determined using radiocarbon dating methods, meaning it’s at least 50,000 years old and, Dickens suspects, much, much older.

This really old graphitic black carbon, referred to as fossil graphitic black carbon, was inseparable from combustion-derived black carbon in marine sediments until co-author Yves Gélinas of Concordia University in Montreal developed a new technique in recent years. One implication of this latest work is that where fossil graphitic black carbon is present with combustion-derived black carbon or other organic carbon, it skews the radiocarbon data scientists have been using to understand the carbon cycle.

Although fossil graphitic black carbon makes up only roughly 0.5 percent of the total organic carbon and perhaps 10 percent of the total black carbon buried in most marine sediments, the "widespread presence of fossil graphitic black carbon in sediments has therefore probably led to significant overestimates of burial of combustion-derived black carbon in marine sediments," the scientists write in the letter to Nature.

For example, in the equatorial Pacific Ocean the scientists estimate that, of published results, somewhere between 20 percent and 60 percent of the open-ocean black carbon fluxes might actually consist of fossil graphitic black carbon.

The authors also say their results imply that a significant fraction of sedimentary organic carbon in marine sediments is fossil graphitic black carbon. That changes, for example, the age of organic carbon from Washington coastal sediments by 75 to 530 years and makes scientists believe organic carbon stays longer than it actually does in intermediate reservoirs, such as soil.

"These interpretations are important for understanding the time scales of carbon cycling in the environment. For example, for understanding whether carbon in a watershed is very rapidly eroded, carried to the oceans and buried – implying that this system is a carbon sink – or if it sits around in soils for a very long time so that presumably most of it is oxidized back to carbon dioxide before what little remains erodes away," Dickens says.


The work was supported by Lawrence Livermore National Laboratory, where the radiocarbon analyses were done; the National Science Foundation; the Natural Sciences and Engineering Research Council of Canada; and Quebec’s Fonds Quebecois de la Recherche sur la Nature et les Technologies. Other co-authors are Caroline Masiello of the University of California, Santa Barbara, and California Institute of Technology in Pasadena, Stuart Wakeham of the Skidaway Institute of Oceanography in Savannah, Ga., and the late John Hedges of the University of Washington.

For more information: Dickens, dickensa@u.washington.edu, 206-221-6747
Gélinas, ygelinas@alcor.concordia.ca, 514-848-2424 x3337
Masiello, masiello@gps.caltech.edu, 626-395-6496

Sandra Hines | EurekAlert!
Further information:
http://www.washington.edu/

More articles from Interdisciplinary Research:

nachricht New approach: Researchers succeed in directly labelling and detecting an important RNA modification
30.04.2018 | Westfälische Wilhelms-Universität Münster

nachricht Start of work for the world's largest electric truck
20.04.2018 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt

All articles from Interdisciplinary Research >>>

The most recent press releases about innovation >>>

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

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

Im Focus: Computer-Designed Customized Regenerative Heart Valves

Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.

Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...

Im Focus: Light-induced superconductivity under high pressure

A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.

Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Supersonic waves may help electronics beat the heat

18.05.2018 | Power and Electrical Engineering

Keeping a Close Eye on Ice Loss

18.05.2018 | Information Technology

CrowdWater: An App for Flood Research

18.05.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>