Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

U. of Colorado study shows massive CO2 burps from ocean to atmosphere at end of last ice age

14.05.2007
A University of Colorado at Boulder-led research team tracing the origin of a large carbon dioxide increase in Earth's atmosphere at the end of the last ice age has detected two ancient "burps" that originated from the deepest parts of the oceans.

The new study indicated carbon that had built up in the oceans over millennia was released in two big pulses, one about 18,000 years ago and one 13,000 years ago, said Thomas Marchitto and Scott Lehman of CU-Boulder's Institute of Arctic and Alpine Research, who jointly led the study. While scientists had long known as much as 600 billion metric tons of carbon were released into the atmosphere after the last ice age, the new study is the first to clearly track CO2 from the deep ocean to the upper ocean and atmosphere and should help scientists better understand natural CO2 cycles and possible impacts of human-caused climate change.

"This is some of the clearest evidence yet that the enormous carbon release into the atmosphere during the last deglaciation was triggered by abrupt changes in deep ocean circulation," said Marchitto. Marchitto and Lehman are both faculty members in the CU-Boulder geological sciences department.

While much of the CO2 released by the oceans after the end of the last ice age about 19,000 years ago was taken up by the re-growth of forests in areas previously covered by ice sheets, enough remained in the atmosphere to pump up CO2 concentrations significantly, the authors said. Today, CO2 levels are higher than at any time in at least the past 650,000 years because of increased fossil fuel burning.

"The timing of the major CO2 release after the last ice age corresponds closely with deep-sea circulation changes caused by ice melting in the North Atlantic at that time," said Lehman. "So our study really underscores ongoing concerns about the ocean's capacity to take up fossil fuel CO2 in the future, since continued warming will almost certainly impact the mode and speed of ocean circulation."

The team analyzed sediment cores hauled from the Pacific Ocean seafloor at a depth of about 2,300 feet off the coast of Baja California using an isotopic "tracer," known as carbon 14, to track the escape of carbon from the deep sea through the upper ocean and into the atmosphere during the last 40,000 years. Extracted from the shells of tiny marine organisms known as foraminifera -- which contain chemical signatures of seawater dating back tens of thousands of years -- carbon 14 is the isotope most commonly used to radiocarbon date organic material like wood, bone and shell.

They found the carbon 14 "age" of the upper ocean water was basically constant over the past 40,000 years, except during the interval following the most recent ice age, when atmospheric CO2 increased dramatically. The study shows the carbon added to the upper ocean and atmosphere at the end of the last ice age was "very old," suggesting it had been stored in the deep ocean and isolated from the atmosphere for thousands of years, said Marchitto.

"Because carbon 14 works both as a 'tracer' and a 'clock,' we were able to show that the uptake and release of CO2 by the ocean in the past was intimately linked to how and how fast the ocean circulated," said Marchitto.

Humans have pumped an estimated 300 billion tons of carbon into the atmosphere since the Industrial Revolution, and the oceans have taken up about half of it, said Lehman.

"If the oceans were not such a large storage 'sink' for carbon, atmospheric CO2 increases in recent decades would be considerably higher," he said. "Since the uptake of CO2 on Earth's land surface is being offset almost entirely by the cutting and burning of forests, any decrease in the uptake of fossil fuel CO2 by the world's oceans could pose some very serious problems," Lehman said.

"When the ocean circulation system changes, it alters how carbon-rich deep water rises to the surface to release its carbon to the atmosphere," said Interim Director of INSTAAR Jim White, a climate scientist who was not involved in the study. "This is important not only for understanding why glacial times came and went in the past, but it is crucial information we need to understand how the oceans will respond to future climate change."

Studies by CU-Boulder and other institutions in the past several years have shown sharp declines in Arctic sea ice in recent decades and a loss in ice mass from Greenland, which some believe could combine to alter North Atlantic circulation and disrupt ocean circulation patterns worldwide.

Thomas Marchitto | EurekAlert!
Further information:
http://www.colorado.edu

More articles from Earth Sciences:

nachricht A promising target in the quest for a 1-million-year-old Antarctic ice core
24.05.2018 | University of Washington

nachricht Tropical Peat Swamps: Restoration of Endangered Carbon Reservoirs
24.05.2018 | Leibniz-Zentrum für Marine Tropenforschung (ZMT)

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Powerful IT security for the car of the future – research alliance develops new approaches

The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.

Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

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...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

In focus: Climate adapted plants

25.05.2018 | 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

 
Latest News

In focus: Climate adapted plants

25.05.2018 | Event News

Flow probes from the 3D printer

25.05.2018 | Machine Engineering

Less is more? Gene switch for healthy aging found

25.05.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>