By examining 800,000-year-old polar ice, scientists increasingly are learning how the climate has changed since the last ice melt and that carbon dioxide has become more abundant in the Earth's atmosphere.
For two decades, French scientist Jérôme Chappellaz has been examining ice cores collected from deep inside the polar ice caps of Greenland and Antarctica. His studies on the interconnecting air spaces of old snow -- or firn air -- in the ice cores show that the roughly 40 percent increase of carbon dioxide in the atmosphere since the Earth's last deglaciation can be attributed in large part to changes in the circulation and biological activity of the oceanic waters surrounding Antarctica.
Chappellaz presented his findings today in Knoxville, Tenn. during the Goldschmidt Conference, an international gathering of several thousand geochemists who converge annually to share their research on Earth, energy and the environment. The event, hosted by the University of Tennessee, Knoxville, and Oak Ridge National Laboratory, is taking place June 13-18.
By measuring the carbon isotopes in the firn air, scientists can pinpoint the source of atmospheric carbon during the millennia. Because living organisms at the surface of the oceans tend to take up the lighter of the carbon isotopes, 13C, and this isotope is then released when the organisms decay, scientists know the higher concentration of 13C is originating from the oceans.
Normally, the organisms die, sink to the ocean depths, and decompose, releasing carbon that remains stored in the cold, deep waters for centuries. But a growing concentration of the isotope 13C in the air during the last deglaciation indicates that this "old" carbon from decomposition was released from the southern polar waters, where the Antarctic Circumpolar Current transports more water than any other current in the world. Here, oceanic circulation is increasing in intensity and the deep water is releasing carbon dioxide at the surface.
For two decades, Chappellaz has examined polar ice cores to decipher how the primary greenhouse gases -- carbon dioxide, methane and nitrous oxide -- have changed in concentrations and ratios since ancient times and what has caused those changes. He notably showed for the first time the tight link existing between atmospheric methane and global climate at glacial-interglacial time scales. Chappellaz is research director at the Laboratoire de Glaciologie et Geophysique de Environnement in Grenoble, France.
The Goldschmidt Conference is named for Victor Goldschmidt (1888-1947), the Swiss-Norwegian scientist who is considered the father of geochemistry. This year's conference is sponsored by a number of international geochemical societies.
Whitney Holmes | EurekAlert!
Diving robots find Antarctic seas exhale surprising amounts of carbon dioxide in winter
16.08.2018 | National Science Foundation
Diving robots find Antarctic winter seas exhale surprising amounts of carbon dioxide
15.08.2018 | University of Washington
New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference
Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...
Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...
Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.
When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...
Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.
Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....
Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.
Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...
17.08.2018 | Event News
08.08.2018 | Event News
27.07.2018 | Event News
17.08.2018 | Physics and Astronomy
17.08.2018 | Information Technology
17.08.2018 | Life Sciences