Geochemistry of salt marsh sediments deposited during simulated sea-level rise and consequences for recent and Holocene coastal development of NW Germany

De-embankment in the salt marshes of the island of Langeoog was carried out in 2004, thereby inducing an artificial transgression within an area of 2.2 km². Material from three suspended matter traps (SMTs) located along a N–S transect was collected monthly between January 2006 and February 2007. Besides geochemical (major and trace elements) and grain-size analyses, the duration and height of water cover were continuously measured by pressure gauges during the sampling period at two sites, thus revealing inundation frequency (max. 280 year⁻¹) and level (max. 2.4 m). Generally, the silt-dominated SMT material exhibits a geochemical composition similar to that of suspended particulate matter from the adjacent Wadden Sea. However, distinctly increasing enrichments of TOC, P, Mn and Mo from the shoreline towards the higher salt marsh clearly indicate fractionation processes during material transport. Geochemical comparison with older Holocene coastal deposits reveals a mixture of brackish and tidal flat sediments, thus reflecting an early stage of sea-level rise and the development from a terrestrial towards a marine-dominated system. Sedimentation rates are higher than the local sea-level rise, as revealed by vertical salt marsh growth. Storm surges deliver the highest amounts of sediment and play an important role in salt marsh accumulation within the study area. Average accumulation rates of TOC (780 t year⁻¹), P (54 t year⁻¹) and Mn (5.2 t year⁻¹) in the de-embanked area suggest that the former sand-dominated sediments currently receive significant amounts of reactive organic-rich material, thus fostering biogeochemical cycling.     

The influence of gas expulsion and initial mass segregation on the stellar mass function of globular star clusters

Recently, De Marchi, Paresce & Pulone studied a sample of 20 globular clusters and found that all clusters with high concentrations have steep stellar mass functions while clusters with low concentration have comparatively shallow mass functions. No globular clusters were found with a flat mass function and high concentration. This seems curious since more concentrated star clusters are believed to be dynamically more evolved and should have lost more low-mass stars via evaporation, which would result in a shallower mass function in the low-mass part.
We show that this effect can be explained by residual-gas expulsion from initially mass segregated star clusters, and is enhanced further through unresolved binaries. If gas expulsion is the correct mechanism to produce the observed trend in the   c –α  -plane, then observation of these parameters would allow to constrain cluster starting conditions such as star formation efficiency and the time-scale of gas expulsion.     

Thallium Distribution in Sediments from the Pearl River Basin,China

Thallium (Tl) is a rare element of high toxicity. Sediments sampled in three representative locations near industries utilizing Tl‐containing raw materials from the Pearl River Basin, China were analyzed for their total Tl contents and the Tl contents in four sequentially extracted fractions (i.e., weak acid exchangeable, reducible, oxidizable, and residual fraction). The results reveal that the total Tl contents (1.25–19.1 µg/g) in the studied sediments were slightly high to quite high compared with those in the Chinese background sediments. This indicates the apparent Tl contamination of the investigated sediments. However, with respect to the chemical fractions, Tl is mainly associated with the residual fraction (>60%) of the sediments, especially of those from the mining area of Tl‐bearing pyrite minerals, indicating the relatively low mobility, and low bioavailability of Tl in these sediments. This obviously contrasts with the previous findings that Tl is mainly entrapped in the first three labile fractions of the contaminated samples. Possible reasons were given for the dominating association of Tl with the residual fraction (>95%) of the mining area sediments. The significant role of certain K‐containing silicates or minerals of these sediments on retaining Tl in the residual fraction, discovered by this study, provides a special field of research opportunity for the Tl‐containing wastewater treatment.     

Vaca Muerta mesosiderite strewnfield

Abstract A field investigation is presented of the strewnfield of the mesosiderite Vaca Muerta, originally found in 1861. The area, 11.5 km long, 2.1 km wide, is located about 60 km southeast of Taltal, Chile, in the Atacama Desert. It has yielded 80 meteorites with a total mass exceeding 3782 kg. Most fragments were found in an undisturbed state, but some had been broken by prospectors. The present studies, in connection with historical records, indicate that the original mass of Vaca Muerta exceeded 6 metric tons. One impact feature, somewhat modified by man, consists of a 10.5-m diameter, 1.7-m deep hole, without an uplifted rim. Small masses were scattered up to 85 m from the hole.     

The Late Paleozoic felsic lava-dominated large igneous province in northeast Germany: volcanic facies analysis based on drill cores

In the deep subsurface of the northeast German basin products of extensive volcanism are present that formed during the waning phase of the Variscan orogeny (Permian–Carboniferous boundary). Large volumes (≥48,000 km³) of dominantly felsic magma were emplaced in the northern foreland of the Variscan mountains in a terrestrial semi-arid environment. Most of these units were inferred by previous authors to represent the products of explosive volcanic eruptions such as ignimbrites. However, a detailed analysis of the volcanic texture and lithofacies association shows that most units are best interpreted as coherent lavas emplaced either as extrusive units or as shallow intrusions, with important implications for the reconstruction of the paleo-environment. This study shows that detailed textural examination of drill cores provide important observations, which can be applied as criteria for the interpretation of the mode of volcanic eruptions. Furthermore, phenocryst logging and geochemical fingerprinting based on immobile element ratios can be employed for the classification and discrimination of individual emplacement units.     

Seasonal and Inter-Annual Climate Forecasting: The New Tool for Increasing Preparedness to Climate Variability and Change In Agricultural Planning And Operations

Climate variability and change affects individuals and societies. Within agricultural systems, seasonal climate forecasting can increase preparedness and lead to better social, economic and environmental outcomes. However, climate forecasting is not the panacea to all our problems in agriculture. Instead, it is one of many risk management tools that sometimes play an important role in decision-making. Understanding when, where and how to use this tool is a complex and multi-dimensional problem. To do this effectively, we suggest a participatory, cross-disciplinary research approach that brings together institutions (partnerships), disciplines (e.g., climate science, agricultural systems science, rural sociology and many other disciplines) and people (scientist, policy makers and direct beneficiaries) as equal partners to reap the benefits from climate knowledge. Climate science can provide insights into climatic processes, agricultural systems science can translate these insights into management options and rural sociology can help determine the options that are most feasible or desirable from a socio-economic perspective. Any scientific breakthroughs in climate forecasting capabilities are much more likely to have an immediate and positive impact if they are conducted and delivered within such a framework. While knowledge and understanding of the socio-economic circumstances is important and must be taken into account, the general approach of integrated systems science is generic and applicable in developed as well as in developing countries. Examples of decisions aided by simulation output ranges from tactical crop management options, commodity marketing to policy decisions about future land use. We also highlight the need to better understand temporal- and spatial-scale variability and argue that only a probabilistic approach to outcome dissemination should be considered. We demonstrated how knowledge of climatic variability (CV), can lead to better decisions in agriculture, regardless of geographical location and socio-economic conditions.     

Holocene relative sea-level change, isostatic subsidence and the radial viscosity structure of the mantle of northwest Europe (Belgium, the Netherlands, Germany, southern North Sea)

A comprehensive observational database of Holocene relative sea-level (RSL) index points from northwest Europe (Belgium, the Netherlands, northwest Germany, southern North Sea) has been compiled in order to compare and reassess the data collected from the different countries/regions and by different workers on a common time–depth scale. RSL rise varies in magnitude and form between these regions, revealing a complex pattern of differential crustal movement which cannot be solely attributed to tectonic activity. It clearly contains a non-linear, glacio- and/or hydro-isostatic subsidence component, which is only small on the Belgian coastal plain but increases significantly to a value of ca 7.5 m relative to Belgium since 8 cal. ka BP along the northwest German coast. The subsidence is at least in part related to the Post-Glacial collapse of the so-called peripheral forebulge which developed around the Fennoscandian centre of ice loading during the Last Glacial Maximum. The RSL data have been compared to geodynamic Earth models in order to infer the radial viscosity structure of the Earth's mantle underneath NW Europe (lithosphere thickness, upper- and lower-mantle viscosity), and conversely to predict RSL in regions where we have only few observational data (e.g. in the southern North Sea). A very broad range of Earth parameters fit the Belgian RSL data, suggesting that glacial isostatic adjustment (GIA) only had a minor effect on Belgian crustal dynamics during and after the Last Ice Age. In contrast, a narrow range of Earth parameters define the southern North Sea region, reflecting the greater influence of GIA on these deeper/older samples. Modelled RSL data suggest that the zone of maximum forebulge subsidence runs in a relatively narrow, WNW–ESE trending band connecting the German federal state of Lower Saxony with the Dogger Bank area in the southern North Sea. Identification of the effects of local-scale factors such as past changes in tidal range or tectonic activity on the spatial and temporal variations of sea-level index points based on model-data comparisons is possible but is still complicated by the relatively large range of Earth model parameters fitting each RSL curve, emphasising the need for more high-quality observational data.     

Improved regional scale processes reflected in projected hydrological changes over large European catchments

For the fourth assessment report of the Intergovernmental Panel on Climate Change (IPCC), the recent version of the coupled atmosphere/ocean general circulation model (GCM) of the Max Planck Institute for Meteorology has been used to conduct an ensemble of transient climate simulations These simulations comprise three control simulations for the past century covering the period 1860–2000, and nine simulations for the future climate (2001–2100) using greenhouse gas (GHG) and aerosol concentrations according to the three IPCC scenarios B1, A1B and A2. For each scenario three simulations were performed. The global simulations were dynamically downscaled over Europe using the regional climate model (RCM) REMO at 0.44° horizontal resolution (about 50 km), whereas the physics packages of the GCM and RCM largely agree. The regional simulations comprise the three control simulations (1950–2000), the three A1B simulations and one simulation for B1 as well as for A2 (2001–2100). In our study we concentrate on the climate change signals in the hydrological cycle and the 2 m temperature by comparing the mean projected climate at the end of the twenty-first century (2071–2100) to a control period representing current climate (1961–1990). The robustness of the climate change signal projected by the GCM and RCM is analysed focussing on the large European catchments of Baltic Sea (land only), Danube and Rhine. In this respect, a robust climate change signal designates a projected change that sticks out of the noise of natural climate variability. Catchments and seasons are identified where the climate change signal in the components of the hydrological cycle is robust, and where this signal has a larger uncertainty. Notable differences in the robustness of the climate change signals between the GCM and RCM simulations are related to a stronger warming projected by the GCM in the winter over the Baltic Sea catchment and in the summer over the Danube and Rhine catchments. Our results indicate that the main explanation for these differences is that the finer resolution of the RCM leads to a better representation of local scale processes at the surface that feed back to the atmosphere, i.e. an improved representation of the land sea contrast and related moisture transport processes over the Baltic Sea catchment, and an improved representation of soil moisture feedbacks to the atmosphere over the Danube and Rhine catchments.     

High-resolution aquifer analog of fluvial–aeolian sediments of the Guarani aquifer system

The Guarani aquifer system (GAS) represents one of the biggest aquifers in the world and is the most relevant groundwater resource in South America. For the first time, by combining field and laboratory measurements, a high-resolution aquifer analog model of fluvial–aeolian sediments of the GAS in São Paulo State (Brazil) is constructed. Three parallel sections of frontal outcrops, 28 m × 5.8 m, and two parallel sections of lateral outcrops, 7 m × 5.8 m, are recorded during open-pit mining of sandy sediments and describe in detail the three-dimensional distribution of the local lithofacies and hydrofacies. Variations of hydraulic conductivity, K, and porosity, n, are resolved on the centimeter scale, and the most permeable units of the fluvial–aeolian facies association are identified. The constructed aquifer analog model shows moderate hydraulic heterogeneity and a mean K value of 1.36 × 10^?4 m/s, which is greater than the reported range of K values for the entire GAS in São Paulo State. The results suggest that the examined sedimentary unit constitutes a relevant portion of the GAS in São Paulo State in the context of groundwater extraction and pollution. Moreover, the constructed aquifer analog is considered an ideal basis for future numerical model experiments, aiming at in-depth understanding of the groundwater flow and contaminant transport patterns at this GAS portion or at comparable fluvial–aeolian facies associations.     

Glacial isostatic adjustment in Fennoscandia from GRACE data and comparison with geodynamical models

The Earth’s gravity field observed by the Gravity Recovery and Climate Experiment (GRACE) satellite mission shows variations due to the integral effect of mass variations in the atmosphere, hydrosphere and geosphere. Several institutions, such as the GeoForschungsZentrum (GFZ) Potsdam, the University of Texas at Austin, Center for Space Research (CSR) and the Jet Propulsion Laboratory (JPL), Pasadena, provide GRACE monthly solutions, which differ slightly due to the application of different reduction models and centre-specific processing schemes. The GRACE data are used to investigate the mass variations in Fennoscandia, an area which is strongly influenced by glacial isostatic adjustment (GIA). Hence the focus is set on the computation of secular trends. Different filters (e.g. isotropic and non-isotropic filters) are discussed for the removal of high frequency noise to permit the extraction of the GIA signal. The resulting GRACE based mass variations are compared to global hydrology models (WGHM, LaDWorld) in order to (a) separate possible hydrological signals and (b) validate the hydrology models with regard to long period and secular components. In addition, a pattern matching algorithm is applied to localise the uplift centre, and finally the GRACE signal is compared with the results from a geodynamical modelling. The GRACE data clearly show temporal gravity variations in Fennoscandia. The secular variations are in good agreement with former studies and other independent data. The uplift centre is located over the Bothnian Bay, and the whole uplift area comprises the Scandinavian Peninsula and Finland. The secular variations derived from the GFZ, CSR and JPL monthly solutions differ up to 20%, which is not statistically significant, and the largest signal of about 1.2 Gal/year is obtained from the GFZ solution. Besides the GIA signal, two peaks with positive trend values of about 0.8 Gal/year exist in central eastern Europe, which are not GIA-induced, and also not explainable by the hydrology models. This may indicate that the recent global hydrology models have to be revised with respect to long period and secular components. Finally, the GRACE uplift signal is also in quite good agreement with the results from a simple geodynamical modelling.