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
Conservationists are sounding the alarm: parrots much more threatened than assumed
15.09.2017 | Justus-Liebig-Universität Gießen
A new indicator for marine ecosystem changes: the diatom/dinoflagellate index
21.08.2017 | Leibniz-Institut für Ostseeforschung Warnemünde
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.
MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...
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21.09.2017 | Health and Medicine