Magnetic storm acceleration of radiation belt electrons observed by the Scintillating Fibre Detector (SFD) onboard EQUATOR-S

On the basis of the currents induced by electron fluxes in the Scintillating Fibre Detector (SFD) onboard the EQUATOR-S satellite launched on 2 December 1997, an in-situ acceleration of radiation belt electrons is found to possibly contribute to the increase of the flux of electrons with energies greater than 400 keV. The data acquired between 16 December 1997 and 30 April 1998 on the 500–67300 km, 4° inclination EQUATOR-S orbit show that the increase of the energetic electron flux corresponds to the enhanced geomagnetic activity measured through the Dst index.     

A Global Inventory of Burned Areas at 1 Km Resolution for the Year 2000 Derived from Spot Vegetation Data

Biomass burning constitutes a major contribution to global emissions of carbon dioxide, carbon monoxide, methane, greenhouse gases and aerosols. Furthermore, biomass burning has an impact on health, transport, the environment and land use. Vegetation fires are certainly not recent phenomena and the impacts are not always negative. However, evidence suggests that fires are becoming more frequent and there is a large increase in the number of fires being set by humans for a variety of reasons. Knowledge of the interactions and feedbacks between biomass burning, climate and carbon cycling is needed to help the prediction of climate change scenarios. To obtain this knowledge, the scientific community requires, in the first instance, information on the spatial and temporal distribution of biomass burning at the global scale. This paper presents an inventory of burned areas at monthly time periods for the year 2000 at a resolution of 1 kilometer (km) and is available to the scientific community at no cost. The burned area products have been derived from a single source of satellite-derived images, the SPOT VEGETATION S1 1 km product, using algorithms developed and calibrated at regional scales by a network of partners. In this paper, estimates of burned area, number of burn scars and average size of the burn scar are described for each month of the year 2000. The information is reported at the country level. This paper makes a significant contribution to understanding the effect of biomass burning on atmospheric chemistry and the storage and cycling of carbon by constraining one of the main parameters used in the calculation of gas emissions.     

Making seed systems more resilient to stress

While seed security is key to food security, concrete means for building resilient seed systems remain unexplored in research and practice. A new toolkit, the Seed System Security Assessment (SSSA), examines what actually happens to seed systems during crises and highlights specific features that foster or undermine resilience. Drawing evidence from SSSAs in contexts of political and civil conflict (Zimbabwe and South Sudan), earthquake (Haiti) and drought (Kenya), the article shows that seed systems prove to be relatively resilient, at least in terms of meeting farmers’ planting needs for the upcoming season. Altering crop profiles, making use of multiple delivery channels, and innovating (for example, with new barter mechanisms) all become key, as does mobilizing cross-scale seed supply linkages. However, despite short-term survival, in the medium term, both formal and informal seed systems will have to be transformed to address agro-ecological and farming system challenges, partially shaped by global environmental changes. Key is that formal seed systems will play a catalytic but supporting role, with the onus on resilience response lying within informal systems, and especially with local markets and their traders. Also key is that achieving seed security in fluctuating environments will hinge on developing resilience-linked information systems which put as much weight on helping farmers strategize as on delivering the planting material itself. The article defines seed system resilience, identifies eight principles linked to processes that build such resilience, and makes 15 practical recommendations for enhancing seed system resilience in the short and medium term. Finally, drawing insights from seed systems, processes central for building resilience in other development sectors are highlighted.     

Comparing CO2 Storage and Advection Conditions at Night at Different Carboeuroflux Sites

Anemometer and CO₂ concentration data from temporary campaigns performed at six CARBOEUROFLUX forest sites were used to estimate the importance of non-turbulent fluxes in nighttime conditions. While storage was observed to be significant only during periods of both low turbulence and low advection, the advective fluxes strongly influence the nocturnal CO₂ balance, with the exception of almost flat and highly homogeneous sites. On the basis of the main factors determining the onset of advective fluxes, the ‘advection velocity’, which takes net radiation and local topography into account, was introduced as a criterion to characterise the conditions of storage enrichment/depletion. Comparative analyses of the six sites showed several common features of the advective fluxes but also some substantial differences. In particular, all sites where advection occurs show the onset of a boundary layer characterised by a downslope flow, negative vertical velocities and negative vertical CO₂ concentration gradients during nighttime. As a consequence, vertical advection was observed to be positive at all sites, which corresponds to a removal of CO₂ from the ecosystem. The main differences between sites are the distance from the ridge, which influences the boundary-layer depth, and the sign of the mean horizontal CO₂ concentration gradients, which is probably determined by the source/sink distribution. As a consequence, both positive and negative horizontal advective fluxes (corresponding respectively to CO₂ removal from the ecosystem and to CO₂ supply to the ecosystem) were observed. Conclusive results on the importance of non-turbulent components in the mass balance require, however, further experimental investigations at sites with different topographies, slopes, different land covers, which would allow a more comprehensive analysis of the processes underlying the occurrence of advective fluxes. The quantification of these processes would help to better quantify nocturnal CO₂ exchange rates.     

Consequences of a simulated rapid ocean acidification event for benthic ecosystem processes and functions

Whilst the biological consequences of long-term, gradual changes in acidity associated with the oceanic uptake of atmospheric carbon dioxide (CO₂) are increasingly studied, the potential effects of rapid acidification associated with a failure of sub-seabed carbon storage infrastructure have received less attention. This study investigates the effects of severe short-term (8 days) exposure to acidified seawater on infaunal mediation of ecosystem processes (bioirrigation and sediment particle redistribution) and functioning (nutrient concentrations). Following acidification, individuals of Amphiura filiformis exhibited emergent behaviour typical of a stress response, which resulted in altered bioturbation, but limited changes in nutrient cycling. Under acidified conditions, A. filiformis moved to shallower depths within the sediment and the variability in occupancy depth reduced considerably. This study indicated that rapid acidification events may not be lethal to benthic invertebrates, but may result in behavioural changes that could have longer-term implications for species survival, ecosystem structure and functioning.     

Rhönit aus einem Melaphonolith vom Puy de Saint-Sandoux (Auvergne)

Zusammenfassung Mineralbestand, Chemismus und Erstarrungsbedingungen eines rhönitreichen melaphonolithischen Differentiates der Olivinnephelinitplatte des Puy de Saint-Sandoux (Auvergne) werden beschrieben. Von dem Rhönit aus dem Melaphonolith und einem weiteren aus dem Nephelindolerit vom Löbauer Berg (Sachsen) werden die Ergebnisse der chemischen Analysen sowie die optischen Konstanten mitgeteilt. Es wird versucht, im Verein mit in der Literatur enthaltenen Beobachtungen und experimentellen Untersuchungen, die Bildungsbedingungen des Rhönits abzuleiten.

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Rhoenite from a metaphonolite of Puy de Saint-Sandoux (Auvergne)

Summary Modal and chemical composition of a melaphonolithic differentiate in an olivine-nephelinite layer of the Puy de Saint-Sandoux (Auvergne) are given together with a discussion of the conditions of crystallization. The chemical composition and the optical data of the rhoenite in this rock and of another rhoenite from Löbauer Berg (Saxony) are presented. The conditions of rhoenite-formation are discussed on the basis of observations made in this and previous studies, as well as on experimental data.

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Mit 2 Abbildungen     

Groundwater flow model of the Pipiripau watershed, Federal District of Brazil

In order to understand the groundwater dynamics and to improve the management of water resources in the Federal District of Brazil, this research proposes a 3D groundwater flow model to represent the groundwater level and flow system. The selected test site was the Pipiripau catchment. The development of the model was based on available geological, hydrogeological, geomorphological, climatological and pedological data. Geological and hydrogeological data were used to generate the 3D groundwater flow model. The 3D mesh elements of the domain were generated through the Groundwater Modeling System software, based on the logs of the well materials. The numerical simulation of the finite element method was implemented in the framework of the scientific software OpenGeoSys. With the 3D mesh-appropriated boundary conditions, annual average infiltration data and hydrogeological parameters were incorporated. Afterwards, the steady-state model was calibrated by the PEST software using available data of the water level from wells. The results showed the distribution of the steady-state hydraulic heads in the model domain, where the highest values occurred in the east and west recharge areas and the lowest values were found in the southwest of the basin. The results of this study can be a used as initial condition for the transient groundwater flow simulation and to provide a scientific basis for water resource management.     

Identification and characterization of secondary minerals formed in tungsten mine tailings using transmission electron microscopy

Secondary minerals formed in tailings derived from a W-rich deposit were investigated in detail using transmission electron microscopy (TEM). The study focused on secondary minerals that formed in the vicinity of oxidized sphalerite [ZnS] and tennantite [Cu₁₀(Fe,Zn)₂As₄S₁₃] grains. Samples for TEM analysis were prepared directly from petrographic thin sections using a focused ion beam instrument. This method insured that spatial relationships among primary grains, secondary minerals and the pore spaces were maintained. The results from this study indicate that the secondary coatings associated with sphalerite and tennantite are composed of several discrete phases. The phases identified in this study include an Fe–Zn–As–O phase, secondary sulfides, native Cu, an Fe–Si–O phase, an In–O phase, and wulfenite [PbMoO₄]. The Fe–Zn–As–O phase precipitates directly from the pore water and the nearby primary mineral grains act as a source for some of the elements (e.g., Zn from sphalerite, As from tennantite). Secondary Cu sulfides were found at the outer margins of sphalerite and roquesite [CuInS₂] grains. It is likely that these Cu sulfides form as a result of interactions between the primary grain and aqueous Cu(II) present in the pore water, similar to what occurs in supergene environments. A secondary sulfide that was composed of variable amounts of Cu, Zn, As, Fe and S was also identified along the outer margins of tennantite. Native Cu was found in association with chalcopyrite [CuFeS₂] inclusions that were present in one of the sphalerite grains and probably represents a low-temperature secondary phase. The oxidation of chalcopyrite in the presence of aqueous Si leads to the formation of a nanocrystalline or amorphous Fe–Si–O phase. Roquesite oxidation leads to the formation of a crystalline In–O phase, which is likely dzhalindite [In(OH)₃]. Wulfenite was found in the interstitial voids present in the Fe–Zn–As–O phase suggesting that it forms by direct precipitation from the local pore water. The results from this study indicate that secondary coatings consist of complex secondary phases that may only be distinguished at the nanoscale. The TEM investigations reveal details regarding mineralogical sinks and sources for aqueous components that may otherwise be overlooked.     

Conditioning Facies Simulations with Connectivity Data

When characterizing and simulating underground reservoirs for flow simulations, one of the key characteristics that needs to be reproduced accurately is its connectivity. More precisely, field observations frequently allow the identification of specific points in space that are connected. For example, in hydrogeology, tracer tests are frequently conducted that show which springs are connected to which sink-hole. Similarly well tests often allow connectivity information in a petroleum reservoir to be provided.