Forest ecosystems may produce large volumes of nitrous oxide (N2O), an important greenhouse gas, which affects the atmosphere's chemical and radiative properties. Yet, our understanding of controls on forest N2O emissions is insufficient. This study investigates the quantitative and qualitative relationships between nitrogen-cycling and N2O production in European forests.
The authors conclude that changes in forest composition in response to land use activities and global change may have serious implications for regional budgets of greenhouse gases. It also became clear that accelerated nitrogen inputs predicted for forest ecosystems in Europe may lead to increased greenhouse gas emissions from forest ecosystems.
Read article: http://www.biogeosciences.net/3/135/2006/bg-3-135-2006.html
Bacterial carbon sources in coastal sediments: a cross-system analysis based on stable isotope data of biomarkers.
Coastal ecosystems are among the most productive regions in the world ocean. Because of the ample nutrient supplies, the coastal zone accounts for about 20% of oceanic primary production — despite its small geographic extent. Local organic producers span from phytoplankton to bottom-dwelling algae to seagrasses and mangroves. Because of the high rates of sediment accumulation, among other factors, a comparatively large percentage of this new organic matter survives early decay and is buried into the geologic record. Coastal regions also receive large inputs of organic material reworked and transported from surrounding regions by strong currents, including contributions from rivers that drain adjacent land areas. Through the combined effects of high production, large inputs of reworked material, and efficient sequestration, a vast majority of the world’s organic carbon burial occurs in these marginal marine settings.
As the dominant site of oceanic organic carbon burial, the coastal zone factors prominently in most models for short- and long-term carbon cycling and, correspondingly, in scientists’ estimates for CO2 variation in the atmosphere on a variety of time scales. In this paper, Bouillon and Boschker explore this complex organic reservoir through carbon isotope analysis of the many constituents, including large plant fragments and lipid biomarkers that are chemically extracted from the sediments and fingerprint bacterial sources.
Using this approach the authors explored which of the organic components bacteria most easily degrade and thus which have the potential for burial and removal from at least the short-term carbon cycle. Importantly, the authors compared the carbon isotope properties of bacterial biomarkers from a wide range of coastal settings and concluded that the microbes are feeding on a diverse assortment of organic constituents. In fact, at most sites where organic matter is readily available, bacteria show little selectivity in the compounds they decompose.
In light of the previous consensus that such materials should show widely varying biodegradability, this result will certainly raise questions, fuel future work, and ultimately refine our understanding of how carbon flows through its global biogeochemical cycle and impacts the composition of the atmosphere.
Read article: http://www.biogeosciences.net/3/175/2006/bg-3-175-2006.html
Upcycling of PET Bottles: New Ideas for Resource Cycles in Germany
25.06.2018 | Fraunhofer-Institut für Betriebsfestigkeit und Systemzuverlässigkeit LBF
Dry landscapes can increase disease transmission
20.06.2018 | Forschungsverbund Berlin e.V.
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
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