Tag Archives: atmospheric carbon dioxide

Newly discovered ocean plume could be major source of iron

Study reveals micronutrient riches rising from the Southern Mid-Atlantic Ridge

Scientists have discovered a vast plume of iron and other micronutrients more than 1,000 km long billowing from hydrothermal vents in the South Atlantic Ocean. The finding, soon to be published in the journal Nature Geoscience, calls past estimates of iron abundances into question, and may challenge researchers’ assumptions about iron sources in the world’s seas.

“This study and other studies like it are going to force the scientific community to reevaluate how much iron is really being contributed by hydrothermal vents and to increase those estimates, and that has implications for not only iron geochemistry but a number of other disciplines as well,” says Mak Saito, a WHOI associate scientist and lead author of the study. (more…)

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Testing Artificial Photosynthesis

Berkeley Lab Researchers Develop Fully Integrated Microfluidic Test-bed for Solar-driven Electrochemical Energy Conversion Systems

With the daily mean concentrations of atmospheric carbon dioxide having reached 400 parts-per-million for the first time in human history, the need for carbon-neutral alternatives to fossil fuel energy has never been more compelling. With enough energy in one hour’s worth of global sunlight to meet all human needs for a year, solar technologies are an ideal solution. However, a major challenge is to develop efficient ways to convert solar energy into electrochemical energy on a massive-scale. A key to meeting this challenge may lie in the ability to test such energy conversion schemes on the micro-scale.

Berkeley Lab researchers, working at the Joint Center for Artificial Photosynthesis (JCAP), have developed the first fully integrated microfluidic test-bed for evaluating and optimizing solar-driven electrochemical energy conversion systems. This test-bed system has already been used to study schemes for photovoltaic electrolysis of water, and can be readily adapted to study proposed artificial photosynthesis and fuel cell technologies. (more…)

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Artificial Forest for Solar Water-Splitting

Berkeley Lab Researchers Report First Fully Integrated Artificial Photosynthesis Nanosystem

In the wake of the sobering news that atmospheric carbon dioxide is now at its highest level in at least three million years, an important advance in the race to develop carbon-neutral renewable energy sources has been achieved. Scientists with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) have reported the first fully integrated nanosystem for artificial photosynthesis. While “artificial leaf” is the popular term for such a system, the key to this success was an “artificial forest.”

“Similar to the chloroplasts in green plants that carry out photosynthesis, our artificial photosynthetic system is composed of two semiconductor light absorbers, an interfacial layer for charge transport, and spatially separated co-catalysts,” says Peidong Yang, a chemist with Berkeley Lab’s Materials Sciences Division, who led this research. “To facilitate solar water- splitting in our system, we synthesized tree-like nanowire  heterostructures, consisting of silicon trunks and titanium oxide branches. Visually, arrays of these nanostructures very much resemble an artificial forest.” (more…)

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Global Warming: New Research Emphasizes The Role of Global Economic Growth

ANN ARBOR, Mich.—It’s a message no one wants to hear: To slow down global warming, we’ll either have to put the brakes on economic growth or transform the way the world’s economies work.

That’s the implication of an innovative University of Michigan study examining the evolution of atmospheric CO₂, the most likely cause of global warming.

The study, conducted by José Tapia Granados and Edward Ionides of U-M and Óscar Carpintero of the University of Valladolid in Spain, was published online in the peer-reviewed journal Environmental Science and Policy. It is the first analysis to use measurable levels of atmospheric carbon dioxide to assess fluctuations in the gas, rather than estimates of CO₂ emissions, which are less accurate. (more…)

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Bacterial Communication Could Affect Earth’s Climate

Woods Hole Oceanographic Institution (WHOI) scientists have discovered that bacterial communication could have a significant impact on the planet’s climate.

In the ocean, bacteria coalesce on tiny particles of carbon-rich detritus sinking through the depths. WHOI marine biogeochemists Laura Hmelo, Benjamin Van Mooy, and Tracy Mincer found that these bacteria send out chemical signals to discern if other bacteria are in the neighborhood.  If enough of their cohorts are nearby, then bacteria en masse commence secreting enzymes that break up the carbon-containing molecules within the particles into more digestible bits. It has been suggested that coordinated expression of enzymes is very advantageous for bacteria on sinking particles, and Hmelo and her colleagues have uncovered the first proof of this in the ocean. (more…)

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UF Study Shows Tundra Fires Could Accelerate Climate Warming

GAINESVILLE, Fla. — After a 10,000-year absence, wildfires have returned to the Arctic tundra, and a University of Florida study shows that their impact could extend far beyond the areas blackened by flames.

In a study published in the July 28 issue of the journal Nature, UF ecologist Michelle Mack and a team of scientists including fellow UF ecologist Ted Schuur quantified the amount of soil-bound carbon released into the atmosphere in the 2007 Anaktuvuk River fire, which covered more than 400 square miles on the North Slope of Alaska’s Brooks Range. The 2.1 million metric tons of carbon released in the fire — roughly twice the amount of greenhouse gases put out by the city of Miami in a year — is significant enough to suggest that Arctic fires could impact the global climate, said Mack, an associate professor of ecosystem ecology in UF’s department of biology. (more…)

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Main Culprit of Deadly Russian Heat Wave? Natural Variability

WASHINGTON — The deadly Russian heat wave of 2010 was due to a natural atmospheric phenomenon often associated with weather extremes, according to a new study. And while the scientists could not attribute the intensity of this particular heat wave to climate change, they found that extreme heat waves are likely to become increasingly frequent in the region in coming decades.

The research team drew from scientific observations and computer climate models to evaluate the possible roles of natural and human-caused climate influences on the severity of the heat wave. The study has been accepted for publication in Geophysical Research Letters, a journal of the American Geophysical Union. (more…)

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