Towards an Open Information Infrastructure for Disaster Research and Management: Data Management and Information Systems Inside DFNK

The development of new and better methods for preventing and managing natural disasters requires a variety of different data sets, covering the range from referenced data, e.g. topographic data and digital elevation models, to various kinds of thematic data, e.g. data about soil, vegetation and land usage as well as monitoring data like precipitation and water levels. So a well-organised data and information management and the implementation of a modern processing environment to acquire, store, analyse and visualise data were decisive for the success of the German Research Network Natural Disasters (DFNK). An information infrastructure was established to support data management and information flows inside the network. A web-based portal offers general information to the public and internal documents, data and software tools to the project community. A catalog service allows the overview of existing but distributed data scombined with flexible data retrieval. Based on internet technology and global standards these concepts contribute to a superior information infrastructure and finally substantiate to the development of Spatial Data Infrastructures (SDI). SDIs aim is to improve availability and usability of spatial data for the manifold application areas. Disaster management is one field depending on a very high level on high-quality data equipment, and on a working SDI.     

Deciphering the source and contamination history of peraluminous magmas using δ18O of accessory minerals: examples from garnet-bearing plutons of the Sierra Nevada batholith

Peraluminous granitoids provide critical insight as to the amount and kinds of supracrustal material recycled in the central Sierra Nevada batholith, California. Major element concentrations indicate Sierran peraluminous granitoids are high-SiO₂ (68.9–76.9) and slightly peraluminous (average molar Al₂O₃/(CaO + Na₂O + K₂O)=1.06). Both major and trace element trends mimic those of other high-silica Sierran plutons. Garnet (Grt) in the peraluminous plutons is almandine–spessartine-rich and of magmatic origin. Low grossular contents are consistent with shallow (<4 kbar) depths of garnet crystallization. Metasediments of the Kings Sequence commonly occur as wallrocks associated with the plutons, including biotite schists that are highly peraluminous (A/CNK=2.25) and have high whole rock (WR) δ¹⁸O values (9.6–21.8‰, average=14.5±2.9‰, n=26). Ultramafic wallrocks of the Kings–Kaweah ophiolite have lower average δ¹⁸O (7.1±1.3‰, n=9). The δ¹⁸O(WR) of the Kings Sequence is variable from west to east. Higher δ¹⁸O values occur in the west, where quartz in schists is derived from marine chert; values decrease eastward as the proportion of quartz from igneous and metamorphic sources increases. Peraluminous plutons have high δ¹⁸O(WR) values (9.5–13‰) consistent with supracrustal enrichment of their sources. However, relatively low initial ⁸⁷Sr/⁸⁶Sr values (0.705–0.708) indicate that the supracrustal component in the source of peraluminous magmas was dominantly altered ocean crust and/or greywacke. Also, plutons lack or have very low abundances (<1% of grains) of inherited zircon (Zrc) cores. Average δ¹⁸O(Zrc) is 7.9‰ in peraluminous plutons, a higher value than in coeval metaluminous plutons (6–7‰). Diorites associated with peraluminous plutons also have high δ¹⁸O(Zrc), 7.4–8.3‰, which is consistent with the diorites being derived from a similar source. Magmatic garnet has variable δ¹⁸O (6.6–10.5‰, avg.=7.9‰) due to complex contamination and crystallization histories, evidenced by multiple garnet populations in some rocks. Comparison of δ¹⁸O(Zrc) and δ¹⁸O(Grt) commonly reveals disequilibrium, which documents evolving magma composition. Minor (5–7%) contamination by high δ¹⁸O wallrocks occurred in the middle and upper crust in some cases, although low δ¹⁸O wallrock may have been a contaminant in one case. Overall, oxygen isotope analysis of minerals having slow oxygen diffusion and different times of crystallization (e.g., zircon and garnet), together with detailed textural analysis, can be used to monitor assimilation in peraluminous magmas. Moreover, oxygen isotope studies are a valuable way to identify magmatic versus xenocrystic minerals in igneous rocks. Electronic Supplementary Material Supplementary material is available for this article at     

Sub-surface precipitation of salts in supercritical seawater

Extremely low solubility of typical seawater salts within certain supercritical sections of their pressure–temperature composition space is a proven experimental fact. Its consequences are often referred to as either 'shock crystallization' or 'out-salting'. Our alternative model for the formation of salt deposits hypothesizes that high temperatures and pressures characteristic for the high heat-flow zones of tectonically active basins may bring submarine brines into the out-salting regions and result in the accumulation of geological-scale salt depositions.
To confirm the laboratory observations, molecular-scale simulations (molecular dynamics) have been employed to study structural changes in a model seawater system where temperature increased from ambient to near-critical and supercritical. Fluid properties and phase transition regions extracted from the simulations were then used as input parameters for a reservoir simulator program to model out-salting in a simple hydrothermal geological system. Both numerical simulations and laboratory experiments confirm that supercritical out-salting is a viable process of geological significance for the formation and accumulation of evaporites. We suggest two regions where hydrothermally associated salts may be depositing today: Atlantis II Deep, in the Red Sea, and Lake Asale, Ethiopia.     

Anthropogenic Climate Change: A Reason for Concern Since the 18th Century and Earlier

During the last 20 years the concept of anthropogenic climate change has left academic circles and become a major public concern. Some people consider ‘global warming’ as the major environmental threat to the planet. Even though mostly considered a novel threat, a look into history tells us that claims of humans deliberately or unintentionally changing climate is a frequent phenomenon in Western culture. Climate change, due to natural and anthropogenic causes, has often been discussed since classical times. Environmental change including climate change was seen by some as a biblical mandate, to ‘complete the Creation’. In line with this view, the prospect of climate change was considered as a promising challenge in more modern times. Only since the middle of the 20th century, has anthropogenic climate change become a menacing prospect. The concept of anthropogenic climate change seems to be deeply embedded in popular thinking, at least in Europe, which resurfaces every now and then after scientific discoveries. Also, extreme weather phenomena have in the past often been explained by adverse human interference. A list of claims of anthropogenic climate modifications is presented; the remarkable similarity of the anthropogenic climate change debate in the second half of the 19th century is compared to the present situation. Of course, the present threat seems much more real than any of the historical predecessors, which turned out to be overestimated.     

Analysis of Patterns in Diadromous Fish Distributions Using GIS

Understanding the factors limiting migratory behaviour is fundamental to conservation of diadromous fish. Applications of indices of habitat suitability are problematic for diadromous fish because fish presence and abundance in relation to habitat quality are confounded by barriers to fish migration. An alternative approach is to assess diadromous fish distributions in proportion to distance inland and altitude above mean sea level, and subsequently generate trajectories for the various species. This approach, however, may be problematic. We show that river distance inland and elevation are only weakly correlated in our study area. Thus, in areas where steep slopes are not encountered, fish migrations to significant elevations and inland distances can be expected. In other areas, coastal cliffs and geologic fault lines provide for steep stream gradients close to the sea, and fish do not migrate far inland. To solve this issue, we developed methods for improving species trajectory approaches to explain the distribution of diadromous fish using a GIS. We adjusted distance and altitude categories so that each stratum was represented by the same number of site records, with flexible intervals for each stratum. For species capable of forming land‐locked populations we manipulated input values for elevation and river distance inland to account for migrations from lakes, rather than sea. Additionally, a new GIS derived variable was introduced to better explain the distribution of diadromous fish; the maximum stream slope a fish would encounter during upstream migration. This new slope variable, independent of distance inland and elevation, is likely to be a better predictor of migratory fish occurrences than elevation above mean sea level, as the different species will have different slope‐thresholds that they can overcome.     

Seismic tomographic imaging of P- and S-waves velocity perturbations in the upper mantle beneath Iran

The inverse tomography method has been used to study the P - and S -waves velocity structure of the crust and upper mantle underneath Iran. The method, based on the principle of source–receiver reciprocity, allows for tomographic studies of regions with sparse distribution of seismic stations if the region has sufficient seismicity. The arrival times of body waves from earthquakes in the study area as reported in the ISC catalogue (1964–1996) at all available epicentral distances are used for calculation of residual arrival times. Prior to inversion we have relocated hypocentres based on a 1-D spherical earth's model taking into account variable crustal thickness and surface topography. During the inversion seismic sources are further relocated simultaneously with the calculation of velocity perturbations. With a series of synthetic tests we demonstrate the power of the algorithm and the data to reconstruct introduced anomalies using the ray paths of the real data set and taking into account the measurement errors and outliers. The velocity anomalies show that the crust and upper mantle beneath the Iranian Plateau comprises a low velocity domain between the Arabian Plate and the Caspian Block. This is in agreement with global tomographic models, and also tectonic models, in which active Iranian plateau is trapped between the stable Turan plate in the north and the Arabian shield in the south. Our results show clear evidence of the mainly aseismic subduction of the oceanic crust of the Oman Sea underneath the Iranian Plateau. However, along the Zagros suture zone, the subduction pattern is more complex than at Makran where the collision of the two plates is highly seismic.     

Effects of groundwater extraction from crystalline hard rock on water chemistry in an acid forested catchment at Gårdsjön,Sweden

Atmospheric deposition of S in Sweden has decreased by some 80% over the last 15 a, resulting in a general reduction of SO₄ concentrations in ground and surface water. This project, however, shows that artificial hydrological alteration in an acid wetland can reverse this trend and increase acidity and SO₄ concentrations. The experiment involved the monitoring of two catchments in relatively virgin conditions. In one of the catchments, an experiment with intensive groundwater extraction from the bedrock was carried out. During the experiment, the runoff from the catchment decreased by 50%. Furthermore, the extraction of groundwater resulted in increased seasonal aeration of the centrally located wetland, leading to oxidation of reduced S bound to the soil layers of the wetland. The S changed to solute SO₄, with a subsequent SO₄ surge. Thus, the experiment resulted in an induced acidification of the wetland and runoff waters. The extraction of groundwater significantly increased the recharge of water from the overburden, glacial till and organic soils to groundwater in the bedrock, which in turn reduced the retention time in the bedrock aquifer. These changes resulted in the chemical signature of the groundwater in the bedrock becoming similar to those of the wetland. The findings revealed deterioration in the water quality in the bedrock due to increased concentrations of dissolved organic C and SO₄, as well as a decrease in pH.     

Distribution and abundance of Daphnia pulicaria, a large Daphnia of the “pulex group”, in Lake Constance (Lower Lake)

The population dynamics and distribution of Daphnia pulicaria were studied in Lake Constance (Lower Lake). This Daphnia was absent in the year 2004, absent during most part of the year 2005 and absent in spring 2007 but present from November 2005 to July 2006. Abundance was high from January to late May of the year 2006; maximum abundance was 95,000 ind. m⁻² (30 May). Males and ephippial females were observed in January and late May. Ovigerous females constituted between 30% and 70% of adult females from November 2005 to April 2006; in June and July their percentage decreased to <20%. Mean number of eggs per egg-bearing female ranged between 2 (in November 2005) and 9.8 (in April 2006) and maximum egg number was 20. Birth and growth rates were low (generally <0.15); death rate was highest in June (0.275). Females of D. pulicaria were larger than females of Daphnia galeata/hyalina but carried somewhat fewer eggs. D. pulicaria generally preferred the deep cool water layers. The species was abundant in the northern parts of the Lower Lake (Gnadensee and Zeller See), rare in the southern parts (Rheinsee) and absent in the Upper Lake. We conclude that the life history and occurrence of large-bodied D. pulicaria in Lake Constance can be governed by fish predation pressure. This suggestion is supported by analyses of stomach contents from Coregonus lavaretus; stomachs contained high proportions of D. pulicaria in the first half of the year 2006. The disappearance of D. pulicaria in early summer and the comparatively low proportion of adults for most part of the investigation period also indicate that fish predation is involved in the dynamics of this Daphnia. The preference for deep cool water can be strategy to reduce predation risk. The low density of D. pulicaria in the southern basin of Lower Lake (Rheinsee) may be explained by the influence of the Rhine River which flows through this basin.