149 research outputs found
Auswirkungen der Torfmooskultivierung auf die Treibhausgasbilanz von Spender-, Vermehrungs- und kommerziellen Anbauflächen sowie Bewässerungspoldern
Die Entwässerung der Moore für Landwirtschaft, Forstwirtschaft und Torfabbau hat diese Ökosysteme in Hotspots der Treibhausgasemission verwandelt. Klassische Wiedervernässungsprojekte können die natürliche Funktion der Moore als Senken des atmosphärischen Kohlenstoffs wiederherstellen, schließen jedoch eine Nutzung aus. Eine Möglichkeit, ökologische und ökonomische Ziele zu vereinen, ist die Kultivierung von Torfmoosen als qualitativ hochwertiges Substrat für den professionellen Gartenbau. Das hier vorgestellte Projekt begleitet den Versuch einer kommerziellen Torfmooskultivierung auf abgetorften Schwarztorfflächen in Niedersachsen.
Dabei wird der Austausch von Kohlendioxid (CO2), Methan (CH4) und Lachgas (N2O) der gesamten moorbasierten Produktionskette von einer naturnahen Spenderfläche über die Vermehrungsfläche (einschließlich eines Bewässerungspolders) bis hin zur Kultivierungsfläche über zwei Jahre in einer hohen zeitlichen Auflösung mit der manuellen Haubenmethode gemessen. Die gewonnenen Daten werden Rückschlüsse über die Klimabilanz der Torfmooskultivierung im Vergleich zu einer naturnahen Referenzfläche und über das Potenzial der Torfmooskultivierung, degradierte Moorstandorte wieder zu Kohlenstoff- bzw. Treibhausgassenken umzuwandeln, erlauben. Im Rahmen dieses Projekts untersuchen wir den Einfluss verschiedener biotischer und abiotischer Einflussfaktoren: Zum einen werden auf der Vermehrungsfläche unterschiedliche Torfmoosarten (Sphagnum palustre L., Sphagnum papillosum Lindb. sowie eine Artenmischung) untersucht, und zum anderen wird der Effekt von Wassermanagement und (potenzieller) Erwärmung evaluiert. Dazu kommen auf den Kultivierungsflächen unterschiedliche Bewässerungstechniken zum Einsatz, während in ausgewählten Varianten zusätzlich „Open Top Chambers“ installiert wurden, um den Treibhausgasaustausch unter möglichen zukünftigen Klimawandelbedingungen abschätzen zu können. Bei der Tagung werden erste Messergebnisse präsentiert
High soil solution carbon and nitrogen concentrations in a drained Atlantic bog are reduced to natural levels by 10 years of rewetting
Anthropogenic drainage of peatlands releases additional greenhouse gases to the
atmosphere, and dissolved carbon (C) and nutrients to downstream ecosystems.
Rewetting drained peatlands offers a possibility to reduce nitrogen (N) and
C losses. In this study, we investigate the impact of drainage and rewetting
on the cycling of dissolved C and N as well as on dissolved gases, over a
period of 1 year and a period of 4 months. We chose four sites within one
Atlantic bog complex: a near-natural site, two drained grasslands with
different mean groundwater levels and a former peat cutting area rewetted
10 years ago.
Our results clearly indicate that long-term drainage has increased the
concentrations of dissolved organic carbon (DOC), ammonium, nitrate and
dissolved organic nitrogen (DON) compared to the near-natural site. DON and
ammonium contributed the most to the total dissolved nitrogen. Nitrate
concentrations below the mean groundwater table were negligible. The
concentrations of DOC and N species increased with drainage depth. In the
deeply-drained grassland, with a mean annual water table of 45 cm below
surface, DOC concentrations were twice as high as in the partially rewetted
grassland with a mean annual water table of 28 cm below surface. The deeply
drained grassland had some of the highest-ever observed DOC concentrations of
195.8 ± 77.3 mg L−1 with maximum values of
>400 mg L−1. In general, dissolved organic matter (DOM) at the
drained sites was enriched in aromatic moieties and showed a higher
degradation status (lower DOC to DON ratio) compared to the near-natural
site. At the drained sites, the C to N ratios of the uppermost peat layer
were the same as of DOM in the peat profile. This suggests that the uppermost
degraded peat layer is the main source of DOM. Nearly constant DOM quality
through the profile furthermore indicated that DOM moving downwards through
the drained sites remained largely biogeochemically unchanged. Unlike DOM
concentration, DOM quality and dissolved N species distribution were similar
in the two grasslands and thus unaffected by the drainage depth.
Methane production during the winter months at the drained sites was limited
to the subsoil, which was quasi-permanently water saturated. The recovery of
the water table in the winter months led to the production of nitrous oxide
around mean water table depth at the drained sites.
The rewetted and the near-natural site had comparable DOM quantity and
quality (DOC to DON ratio and aromaticity). 10 years after rewetting quasi-pristine biogeochemical conditions have been re-established under
continuously water logged conditions in the former peat cut area. Only the
elevated dissolved methane and ammonium concentrations reflected the former
disturbance by drainage and peat extraction. Rewetting via polder technique
seems to be an appropriate way to revitalize peatlands on longer timescales
and to improve the water quality of downstream water bodies
Analysis of Localization Phenomena in Weakly Interacting Disordered Lattice Gases
Disorder plays a crucial role in many systems particularly in solid state
physics. However, the disorder in a particular system can usually not be chosen
or controlled. We show that the unique control available for ultracold atomic
gases may be used for the production and observation of disordered quantum
degenerate gases. A detailed analysis of localization effects for two possible
realizations of a disordered potential is presented. In a theoretical analysis
clear localization effects are observed when a superlattice is used to provide
a quasiperiodic disorder. The effects of localization are analyzed by
investigating the superfluid fraction and the localization length within the
system. The theoretical analysis in this paper paves a clear path for the
future observation of Anderson-like localization in disordered quantum gases.Comment: 9 pages, 13 figure
Phosphatidic acid phospholipase A1 mediates ER-Golgi transit of a family of G protein-coupled receptors
The coat protein II (COPII)-coated vesicular system transports newly synthesized secretory and membrane proteins from the endoplasmic reticulum (ER) to the Golgi complex. Recruitment of cargo into COPII vesicles requires an interaction of COPII proteins either with the cargo molecules directly or with cargo receptors for anterograde trafficking. We show that cytosolic phosphatidic acid phospholipase A1 (PAPLA1) interacts with COPII protein family members and is required for the transport of Rh1 (rhodopsin 1), an N-glycosylated G protein-coupled receptor (GPCR), from the ER to the Golgi complex. In papla1 mutants, in the absence of transport to the Golgi, Rh1 is aberrantly glycosylated and is mislocalized. These defects lead to decreased levels of the protein and decreased sensitivity of the photoreceptors to light. Several GPCRs, including other rhodopsins and Bride of sevenless, are similarly affected. Our findings show that a cytosolic protein is necessary for transit of selective transmembrane receptor cargo by the COPII coat for anterograde trafficking
Pseuduscalar Heavy Quarkonium Decays With Both Relativistic and QCD Radiative Corrections
We estimate the decay rates of ,
, and ,
, by taking into account both relativistic and
QCD radiative corrections. The decay amplitudes are derived in the
Bethe-Salpeter formalism. The Bethe-Salpeter equation with a QCD-inspired
interquark potential are used to calculate the wave functions and decay widths
for these states. We find that the relativistic correction to the
ratio is negative and tends to compensate the positive contribution from
the QCD radiative correction. Our estimate gives and ,
which are smaller than their nonrelativistic values. The hadronic widths
and are then indicated accordingly to the first order
QCD radiative correction, if . The decay widths for
states are also estimated. We show that when making the assmption
that the quarks are on their mass shells our expressions for the decay widths
will become identical with that in the NRQCD theory to the next to leading
order of and .Comment: 14 pages LaTex (2 figures included
PEAT-CLSM : A Specific Treatment of Peatland Hydrology in the NASA Catchment Land Surface Model
Peatlands are poorly represented in global Earth system modeling frameworks. Here we add a peatland-specific land surface hydrology module (PEAT-CLSM) to the Catchment Land Surface Model (CLSM) of the NASA Goddard Earth Observing System (GEOS) framework. The amended TOPMODEL approach of the original CLSM that uses topography characteristics to model catchment processes is discarded, and a peatland-specific model concept is realized in its place. To facilitate its utilization in operational GEOS efforts, PEAT-CLSM uses the basic structure of CLSM and the same global input data. Parameters used in PEAT-CLSM are based on literature data. A suite of CLSM and PEAT-CLSM simulations for peatland areas between 40 degrees N and 75 degrees N is presented and evaluated against a newly compiled data set of groundwater table depth and eddy covariance observations of latent and sensible heat fluxes in natural and seminatural peatlands. CLSM's simulated groundwater tables are too deep and variable, whereas PEAT-CLSM simulates a mean groundwater table depth of -0.20 m (snow-free unfrozen period) with moderate temporal fluctuations (standard deviation of 0.10 m), in significantly better agreement with in situ observations. Relative to an operational CLSM version that simply includes peat as a soil class, the temporal correlation coefficient is increased on average by 0.16 and reaches 0.64 for bogs and 0.66 for fens when driven with global atmospheric forcing data. In PEAT-CLSM, runoff is increased on average by 38% and evapotranspiration is reduced by 19%. The evapotranspiration reduction constitutes a significant improvement relative to eddy covariance measurements.Peer reviewe
The minimum information required for a glycomics experiment (MIRAGE) project: improving the standards for reporting glycan microarray-based data
MIRAGE (Minimum Information Required for A Glycomics Experiment) is an initiative that was created by experts in the fields of glycobiology, glycoanalytics and glycoinformatics to produce guidelines for reporting results from the diverse types of experiments and analyses used in structural and functional studies of glycans in the scientific literature. As a sequel to the guidelines for sample preparation (Struwe et al. 2016, Glycobiology, 26:907–910) and mass spectrometry data (Kolarich et al. 2013, Mol. Cell Proteomics, 12:991–995), here we present the first version of guidelines intended to improve the standards for reporting data from glycan microarray analyses. For each of eight areas in the workflow of a glycan microarray experiment, we provide guidelines for the minimal information that should be provided in reporting results. We hope that the MIRAGE glycan microarray guidelines proposed here will gain broad acceptance by the community, and will facilitate interpretation and reproducibility of the glycan microarray results with implications in comparison of data from different laboratories and eventual deposition of glycan microarray data in international databases
The Minimum Information Required for a Glycomics Experiment (MIRAGE) project: improving the standards for reporting glycan microarray-based data
MIRAGE (Minimum Information Required for A Glycomics Experiment) is an initiative that was created by experts in the fields of glycobiology, glycoanalytics, and glycoinformatics to produce guidelines for reporting results from the diverse types of experiments and analyses used in structural and functional studies of glycans in the scientific literature. As a sequel to the guidelines for sample preparation (Struwe et al. 2016, Glycobiology, 26, 907-910) and mass spectrometry (MS) data (Kolarich et al. 2013, Mol. Cell Proteomics. 12, 991-995), here we present the first version of guidelines intended to improve the standards for reporting data from glycan microarray analyses. For each of eight areas in the workflow of a glycan microarray experiment, we provide guidelines for the minimal information that should be provided in reporting results. We hope that the MIRAGE glycan microarray guidelines proposed here will gain broad acceptance by the community, and will facilitate interpretation and reproducibility of the glycan microarray results with implications in comparison of data from different laboratories and eventual deposition of glycan microarray data in international databases
Land use change impacts on floods at the catchment scale: Challenges and opportunities for future research
Research gaps in understanding flood changes at the catchment scale caused by changes in forest management, agricultural practices, artificial drainage and terracing are identified. Potential strategies in addressing these gaps are proposed, such as complex systems approaches to link processes across time scales, long-term experiments on physical-chemical-biological process interactions, and a focus on connectivity and patterns across spatial scales. It is suggested that these strategies will stimulate new research that coherently addresses the issues across hydrology, soil and agricultural sciences, forest engineering, forest ecology and geomorphology
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