Late Variscan exhumation histories of the southern Rhenohercynian Zone and western Mid-German Crystalline Rise: results from thermal modeling

Thermal modeling techniques constrained by published petrological and thermo-chronometric data were applied to examine late orogenic burial and exhumation at a Variscan suture zone in Central Europe. The suture separates the southern Rhenohercynian zone from the Mid-German Crystalline Rise and traces the former site of a small oceanic basin. Closure of this basin during Variscan subduction and subsequent collision of continental units were responsible for different tectono-metamorphic evolutions in the suture's footwall and hanging wall. Relative convergence rates between the southern Rhenohercynian zone and western Mid-German Crystalline Rise can be inferred from the pressure-temperature-time evolution of the Northern Phyllite Zone. During Late Viséan-Early Namurian times, horizontal thrusting velocities were at least 20 mm/a. Thermal modeling suggests that exhumation of the Mid-German Crystalline Rise occurred temporarily at rates of more than 3 mm/a. Such rapid exhumation cannot be produced by erosion only, but requires a substantial contribution of extensional strain. Exhumation by upper crustal extension occurred contemporaneously with convergence and is explained by continuous underplating of crustal slices and thrusting along faults with ramp-flat geometry. Finally, implications for the tectono-metamorphic history of the study area and the thermal state of the crust during late Variscan exhumation are discussed.     

Bioaugmentation with a Bacillus sp. to reduce the phytoavailable Cd of an agricultural soil: comparison of free and immobilized microbial inocula

In order to reduce the cadmium potentially available for plants, soil bioaugmentation was performed by using a Bacillus sp. In a pot experimentation, sterilized and non-sterilized soils were inoculated using free or immobilized cells entrapped in alginate beads. This test was carried out with different inoculum sizes (2 x 10(10) and 2 x 10(11)CFU kg(-1) dw of soil) and alginate bead compositions (10 and 15 g of both alginate and CaCl(2) l(-1)). Then, the soil pots were incubated at 20 degrees C and the soil humidity was kept at a level of 20%. After 3 weeks of a batch incubation, the potentially phytoavailable Cd was reduced up to a factor of 14. The bioaugmentation resulted in the soil colonization by Bacillus sp. thanks to an increase of the cell concentration up to 1.8 log units. However, in comparison to the cells being inoculated in a free mode, the immobilization of the cells did not significantly improve the survival of the cells in the soil. Although the resulting effect not being highly pronounced, the potentially phytoavailable Cd correlated with the cell concentration in a surprisingly positive way. What is more, the Bacillus concentrations in the soil were positively correlated with the inoculum, too.     

Modelling the dynamics of coral reef macroalgae using a Bayesian belief network approach

Macroalgae are a major benthic component of coral reefs and their dynamics influence the resilience of coral reefs to disturbance. However, the relative importance of physical and ecological processes in driving macroalgal dynamics is poorly understood. Here we develop a Bayesian belief network (BBN) model to integrate many of these processes and predict the growth of coral reef macroalgae. Bayesian belief networks use probabilistic relationships rather than deterministic rules to quantify the cause and effect assumptions. The model was developed using both new empirical data and quantified relationships elicited from previous studies. We demonstrate the efficacy of the BBN to predict the dynamics of a common Caribbean macroalgal genus Dictyota. Predictions of the model have an average accuracy of 55% (implying that 55% of the predicted categories of Dictyota cover were assigned to the correct class). Sensitivity analysis suggested that macroalgal dynamics were primarily driven by top–down processes of grazing rather than bottom–up nutrification. BBNs provide a useful framework for modelling complex systems, identifying gaps in our scientific understanding and communicating the complexities of the associated uncertainties in an explicit manner to stakeholders. We anticipate that accuracies will improve as new data are added to the model.     

Risk analysis in research environment – Part II: Weighting Lab Criticity Index using the Analytic Hierarchy Process

A new methodology for risk analysis, namely Laboratory Assessment and Risk Analysis – LARA, is proposed in the companion paper to assess risks in research/academia environment. The core of this methodology relies on defining the adequate role player factors to assess risks in research environment and their mathematical combination to quantify and assess the risk. Quantitative outcome of the analysis results in a Lab Criticity Index – LCI, constructed as a rather comprehensive function of probability, severity, risk worsening factors, research specificities and Hazard Detectability. Even though the LCI model can be used at this stage, its “surjective” and “linear” properties were outlined; the non differentiation between LCI factors remains to be solved.The present article addresses this problematic, bringing a solution based on a Multicriteria Decision Making – MCDM modeling, namely Analytic Hierarchy Process – AHP. This leads to a refined criticity index being “bijective” and unique for every combination of factors.A preliminary risk assessment based on the LARA methodology is discussed for a research lab working with lasers.     

Evaluating threats to an endangered species by proxy: air pollution as threat to the blue swallow (<Emphasis Type="Italic">Hirundo atrocaerulea</Emphasis>) in South Africa

Background, aim, and scope  

The blue swallow (Hirundo atrocaerulea) is one of the most threatened bird species in southern Africa. Among terrestrial birds, its plumage is known to be the most water repellent, an adaptation to foraging on the wing in dense fog. Despite this unique adaptation, the nesting success of the blue swallow at the Blue Swallow Natural Heritage Site (BSNHS) is lower during years with high incidence of fog. As the phenomenon is not observed at other nesting sites, we hypothesized that this is due to changes in the air chemistry at the BSNHS. In the immediate proximity of the BSNHS, plantations of exotic trees (e.g., pines and eucalypts), rich in volatile organic compounds (VOCs), are dominant features. In addition, air pollution from the Johannesburg area is transported with the surface winds and mix with VOCs released from exotic trees. Together with the high humidity and high elevation, these conditions may result in the formation of sulphonates. Sulphonates are strong detergents, and the presence of these in the fog could lead to decreased water repellence of the plumage. This study was performed in order to determine the occurrence and distribution of sulphonates in the BSNHS and to compare these with sulphonates formed in other locations in South Africa. Because the blue swallow is endangered, pine needles were used as proxy to detect formation of sulphonates.     

Climate change adaptation,mitigation and livelihood benefits in coffee production: where are the synergies?

There are worldwide approximately 4.3 million coffee (Coffea arabica) producing smallholders generating a large share of tropical developing countries’ gross domestic product, notably in Central America. Their livelihoods and coffee production are facing major challenges due to projected climate change, requiring adaptation decisions that may range from changes in management practices to changes in crops or migration. Since management practices such as shade use and reforestation influence both climate vulnerability and carbon stocks in coffee, there may be synergies between climate change adaptation and mitigation that could make it advantageous to jointly pursue both objectives. In some cases, carbon accounting for mitigation actions might even be used to incentivize and subsidize adaptation actions. To assess potential synergies between climate change mitigation and adaptation in smallholder coffee production systems, we quantified (i) the potential of changes in coffee production and processing practices as well as other livelihood activities to reduce net greenhouse gas emissions, (ii) coffee farmers’ climate change vulnerability and need for adaptation, including the possibility of carbon markets subsidizing adaptation. We worked with smallholder organic coffee farmers in Northern Nicaragua, using workshops, interviews, farm visits and the Cool Farm Tool software to calculate greenhouse gas balances of coffee farms. From the 12 activities found to be relevant for adaptation, two showed strong and five showed modest synergies with mitigation. Afforestation of degraded areas with coffee agroforestry systems and boundary tree plantings resulted in the highest synergies between adaptation and mitigation. Financing possibilities for joint adaptation-mitigation activities could arise through carbon offsetting, carbon insetting, and carbon footprint reductions. Non-monetary benefits such as technical assistance and capacity building could be effective in promoting such synergies at low transaction costs.     

Prenatal molecular diagnosis in RASA1-related disease

RASA1-related disease is a rare autosomal dominant disease characterized by capillary malformations, arteriovenous malformations (AVMs), and/or arteriovenous fistulas (AFVs). Penetrance is nearly complete and vascular malformations may cause serious complications such as organ injury due to oxygenation disorder, brain abscess, hemorrhage, and stroke. Early diagnosis is useful in order to discuss optimal management, including AVMs/AVFs embolization or surgical procedures, and try to prevent some of the complications. In this context, molecular testing of RASA1 gene mutation in relatives may help to better manage the family. All arteriovenous malformations are however not accessible to such procedures. In addition, these therapeutic procedures may result in potential side effects and complications. A couple was referred to our genetics unit and asked us for prenatal genetic testing about a RASA1 mutation. Here, we discuss about arguments that led our team to accept prenatal testing. To the best of our knowledge, no molecular prenatal diagnosis was reported until now in RASA1-related diseases. This first report of prenatal diagnosis in RASA1-related diseases may also offer perspectives for a more general discussion in the field of inherited arteriovenous malformations.