Environmental conditions of a salt-marsh biodiversity experiment on the island of Spiekeroog (Germany)

Field experiments investigating biodiversity and ecosystem functioning require the observation of abiotic parameters, especially when carried out in the intertidal zone. An experiment for biodiversity–ecosystem functioning was set up in the intertidal zone of the back-barrier salt marsh of Spiekeroog Island in the German Bight. Here, we report the accompanying instrumentation, maintenance, data acquisition, data handling and data quality control as well as monitoring results observed over a continuous period from September 2014 to April 2017. Time series of abiotic conditions were measured at several sites in the vicinity of newly built experimental salt-marsh islands on the tidal flat. Meteorological measurements were conducted from a weather station (WS, https://doi.org/10.1594/PANGAEA.870988), oceanographic conditions were sampled through a bottom-mounted recording current meter (RCM, https://doi.org/10.1594/PANGAEA.877265) and a bottom-mounted tide and wave recorder (TWR, https://doi.org/10.1594/PANGAEA.877258). Tide data are essential in calculating flooding duration and flooding frequency with respect to different salt-marsh elevation zones. Data loggers (DL) for measuring the water level (DL-W, https://doi.org/10.1594/PANGAEA.877267), temperature (DL-T, https://doi.org/10.1594/PANGAEA.877257), light intensity (DL-L, https://doi.org/10.1594/PANGAEA.877256) and conductivity (DL-C, https://doi.org/10.1594/PANGAEA.877266) were deployed at different elevational zones on the experimental islands and the investigated salt-marsh plots. A data availability of 80% for 17 out of 23 sensors was achieved. Results showed the influence of seasonal and tidal dynamics on the experimental islands. Nearby salt-marsh plots exhibited some differences, e.g., in temperature dynamics. Thus, a consistent, multi-parameter, long-term dataset is available as a basis for further biodiversity and ecosystem functioning studies

Aquaculture induced erosion of tropical coastlines throws coastal communities back into poverty

Shallow tropical coastlines harbour unique mangrove ecosystems, which support livelihoods and provide a natural barrier against coastal flooding. Non-sustainable land-use practices, such as large-scale clear cutting of mangroves for aquaculture, ground water withdrawal and alteration of river flows, result in rapid subsidence. The collapse of aquaculture production, due to pollution and disease, is followed by coastal erosion, damage to infrastructure, intrusion of salt water and coastal flooding. Standard engineered interventions for protection often fail or are extremely expensive in these soft muddy environments. Subsidence and erosion render re-planting of mangroves in front of retreating coastlines impossible. Short-term solutions should focus on restoration of abiotic conditions, such as hydrology and sediment fluxes, to facilitate rapid establishment of protective mangrove belts. However, to ensure long-term sustainability, improved governance frameworks are required that put in place criteria for sustainable aquaculture, guide coastal infrastructure designs and limit ground water extraction

Personalised information spaces for chemical digital libraries

[No abstract available

Cross-shore gradients of physical disturbance in mangroves: Implications for seedling establishment

10.5194/bg-10-5411-2013Biogeosciences1085411-541

Anomalous transport properties of the halfmetallic ferromagnets Co2TiSi, Co2TiGe, and Co2TiSn

In this work the theoretical and experimental investigations of Co2TiZ (Z = Si, Ge, or Sn) compounds are reported. Half-metallic ferromagnetism is predicted for all three compounds with only two bands crossing the Fermi energy in the majority channel. The magnetic moments fulfill the Slater-Pauling rule and the Curie temperatures are well above room temperature. All compounds show a metallic like resistivity for low temperatures up to their Curie temperature, above the resistivity changes to semiconducting like behavior. A large negative magnetoresistance of 55% is observed for Co2TiSn at room temperature in an applied magnetic field of 4T which is comparable to the large negative magnetoresistances of the manganites. The Seebeck coefficients are negative for all three compounds and reach their maximum values at their respective Curie temperatures and stay almost constant up to 950 K. The highest value achieved is -52muV/K m for Co2TiSn which is large for a metal. The combination of half-metallicity and the constant large Seebeck coefficient over a wide temperature range makes these compounds interesting materials for thermoelectric applications and further spincaloric investigations.Comment: 4 pages 4 figure

4D X-Ray CT Reconstruction using Multi-Slice Fusion

There is an increasing need to reconstruct objects in four or more dimensions corresponding to space, time and other independent parameters. The best 4D reconstruction algorithms use regularized iterative reconstruction approaches such as model based iterative reconstruction (MBIR), which depends critically on the quality of the prior modeling. Recently, Plug-and-Play methods have been shown to be an effective way to incorporate advanced prior models using state-of-the-art denoising algorithms designed to remove additive white Gaussian noise (AWGN). However, state-of-the-art denoising algorithms such as BM4D and deep convolutional neural networks (CNNs) are primarily available for 2D and sometimes 3D images. In particular, CNNs are difficult and computationally expensive to implement in four or more dimensions, and training may be impossible if there is no associated high-dimensional training data. In this paper, we present Multi-Slice Fusion, a novel algorithm for 4D and higher-dimensional reconstruction, based on the fusion of multiple low-dimensional denoisers. Our approach uses multi-agent consensus equilibrium (MACE), an extension of Plug-and-Play, as a framework for integrating the multiple lower-dimensional prior models. We apply our method to the problem of 4D cone-beam X-ray CT reconstruction for Non Destructive Evaluation (NDE) of moving parts. This is done by solving the MACE equations using lower-dimensional CNN denoisers implemented in parallel on a heterogeneous cluster. Results on experimental CT data demonstrate that Multi-Slice Fusion can substantially improve the quality of reconstructions relative to traditional 4D priors, while also being practical to implement and train.Comment: 8 pages, 8 figures, IEEE International Conference on Computational Photography 2019, Toky