Quantificational reductionism as a risk in geography and cartography

A reductionistic concept is being pursued in the 125 000 geomorphological mapping of the Federal Republic of Germany. Complex landscape elements with a base length greater than 100 m are broken down into partial elements and re-interpreted in terms of quantificational or abstractly defined, theoretically neutral map symbols. The genetic aspect is expressed by areal colouring. In this way it aims to achieve an interdisciplinary utilization of such information. This reduction has proved to be too drastic insofar as it gives rise to irretrievable loss of information. The claim that use-oriented, ecologically relevant information would be derivable from the GMM-25 has not been substantiated. As ecologically justifiable evaluation must also consider as its most fundamental indicators the quality and distribution of biotopes. These are not even rudimentarily included in the GMM-25. The uncontextualized blending of information units which only make sense in heterogeneous contexts to produce a single map is antithetical to the principle of subject related selection of relevant characteristics and prevents comprehension of the systematic relationships.The underlying concept of the GMM-25, derived from an uncritical incorporation of physico-mathematical total predictability principles, leads to an irreversible renunciation of the necessarily complex constituents of a high geomorphological level of integration.     

Fifteen days of continuous activity survey at Stromboli volcano, Italy, in late September 2000: Doppler radar, seismicity, infrared, soil humidity, and mapping of the crater region

The intention of our study was to gain new insight into the complex interplay between different types of eruption of the Stromboli volcano by combining detailed field observation with different geophysical methods. We recorded more than 600 eruptions by use of continuous Doppler radar measurements. We detected the onset of the seismic precursor and the beginning of the visible eruption by use of seismic and infrared data. Two soil samples per day were used to monitor the effect of humidity on the eruptive style. We mapped the crater region as a reference base for the long-term morphological changes of the active region and for the exact positions of our measurement systems. Two distinct types of eruption were distinguished from each other on the basis of seismic and radar data - short, wide-angle Strombolian explosions and pulsating, sharp angle fountain-like eruptions. Data and visual observations imply that weather conditions significantly effect volcanic activity. We also interpret the intensification of eruptive activity during our field study as replenishment of the reservoir with a new batch of magma in late September 2000.     

Pleistocene/Holocene climate change, re-establishment of fluvial drainage network and increase in relief in the Swiss Alps

ABSTRACT Data are presented about modern sediment discharge of the Swiss rivers and related to the size of catchments. The information reveals that the Central Alps have experienced denudation rates of ≈0.15 mm yr⁻¹ in the foreland, and ≈0.5 mm yr⁻¹ in the Alpine core. Mapping, however, indicates that modern erosion only affects 30–50% of the Alpine surface, and that fluvial and associated hillslope processes have focused erosion in 50–200-m-deep valleys. These valleys are incised into the glacial surface. If this limited spatial extent of erosion is considered, then effective erosion rates are significantly higher than average denudation rates. These effective rates equal or locally exceed modern rates of rock uplift. This implies that the modification of erosional processes related to the Pleistocene/Holocene climate change has resulted in an increase in the relief at a local scale. At a drainage basin scale, however, the relief appears not to change at present.     

Investigating hydrological drivers of nitrate export dynamics in two agricultural catchments in Germany using high-frequency data series

In this study near-continuous time series of nitrate, electrical conductivity, and discharge were used to identify the dominating hydrological mechanisms that control nitrate export dynamics in two agricultural catchments. The main goal was to assess relationships between contrasting event based as well as long-term nitrate transport behaviour and catchment hydrology. Data records were obtained from online probes that allow field based high-frequency analyses over long time periods. The catchments of the Ammer River (southwestern Germany) and the Weida River (eastern Germany) are similar with respect to size (~100 km²), morphology, and climate and are dominated by agricultural use. Main differences are the stronger urbanization and the occurrence of karstic rocks in the Ammer catchment. Nitrate concentrations are high in water of both streams and range mostly between 20 and 50 mg l^?1. Nitrate export in the Ammer catchment is dominated by baseflow and a minor second, diluting runoff component generated in urbanized areas. In contrast, nitrate dynamics of the Weida catchment is governed by the interplay of at least three runoff components, while the largest amount of nitrate is mobilized intermittently by a delayed fast component generated in the catchment’s soils during wet conditions. These interpretations, derived with one online probe at the outlet of each catchment, are well in line with the former modeling results. This study shows that high-resolution data obtained by online techniques offers a large potential to improve the conceptualization of dominating flow and transport processes at catchment scales at relatively low costs and effort.     

Investigating suspended particulate matter in coastal waters using the fractal theory

Ocean Dynamics - Suspended particulate matters (SPM) in coastal waters were investigated with an approach combining suspended particulate matter concentrations (SPMCs) measured by an optical...     

Sub-lethal effects of metal exposure: physiological and behavioural responses of the estuarine bivalve Macoma balthica

Variation in glycogen concentration, condition index (CI) and filtration activity were measured in the bivalve Macoma balthica buried in sediment and experimentally exposed to cadmium (Cd). The stress due to elevated but sub-lethal concentrations (300 ppb Cd) affected the overall fitness of the organism as all parameters monitored responded significantly. Lower concentrations tested (10, 30 and 100 ppb) only induced a significant decrease in filtration activity, which may play a protective role, enabling the organism to slow down its metabolic activity and preserving the integrity of its reserves (reflected by stable CI and glycogen levels). Hence, the various endpoints selected show different thresholds. Our results also demonstrate that under high exposure, small individuals loose proportionally more glycogen per unit of weight than larger ones, thus confirming the higher sensitivity of small individuals to metal contamination. Furthermore, exposure to intermediate concentration (30 ppb) seems to be beneficial to the small individuals as indicated by their high CI values compared to the control. These results showed thus that non-sigmoidal concentration-response relationship and sizes of individuals should be considered in monitoring programmes and risk assessment.     

Multi‐method virtual electromagnetic experiments for developing suitable monitoring designs: A fictitious CO2 sequestration scenario in Northern Germany

We present a numerical study for 3D time‐lapse electromagnetic monitoring of a fictitious CO₂ sequestration using the geometry of a real geological site and a suite of suitable electromagnetic methods with different source/receiver configurations and different sensitivity patterns. All available geological information is processed and directly implemented into the computational domain, which is discretized by unstructured tetrahedral grids. We thus demonstrate the performance capability of our numerical simulation techniques. The scenario considers a CO₂ injection in approximately 1100 m depth. The expected changes in conductivity were inferred from preceding laboratory measurements. A resistive anomaly is caused within the conductive brines of the undisturbed reservoir horizon. The resistive nature of the anomaly is enhanced by the CO₂ dissolution regime, which prevails in the high‐salinity environment. Due to the physicochemical properties of CO₂, the affected portion of the subsurface is laterally widespread but very thin. We combine controlled‐source electromagnetics, borehole transient electromagnetics, and the direct‐current resistivity method to perform a virtual experiment with the aim of scrutinizing a set of source/receiver configurations with respect to coverage, resolution, and detectability of the anomalous CO₂ plume prior to the field survey. Our simulation studies are carried out using the 3D codes developed in our working group. They are all based on linear and higher order Lagrange and Nédélec finite‐element formulations on unstructured grids, providing the necessary flexibility with respect to the complex real‐world geometry. We provide different strategies for addressing the accuracy of numerical simulations in the case of arbitrary structures. The presented computations demonstrate the expected great advantage of positioning transmitters or receivers close to the target. For direct‐current geoelectrics, 50% change in electric potential may be detected even at the Earth's surface. Monitoring with inductive methods is also promising. For a well‐positioned surface transmitter, more than 10% difference in the vertical electric field is predicted for a receiver located 200 m above the target. Our borehole transient electromagnetics results demonstrate that traditional transient electromagnetics with a vertical magnetic dipole source is not well suited for monitoring a thin horizontal resistive target. This is due to the mainly horizontal current system, which is induced by a vertical magnetic dipole.     

The fusion crust of the Winchcombe meteorite: A preserved record of atmospheric entry processes

Fusion crusts form during the atmospheric entry heating of meteorites and preserve a record of the conditions that occurred during deceleration in the atmosphere. The fusion crust of the Winchcombe meteorite closely resembles that of other stony meteorites, and in particular CM2 chondrites, since it is dominated by olivine phenocrysts set in a glassy mesostasis with magnetite, and is highly vesicular. Dehydration cracks are unusually abundant in Winchcombe. Failure of this weak layer is an additional ablation mechanism to produce large numbers of particles during deceleration, consistent with the observation of pulses of plasma in videos of the Winchcombe fireball. Calving events might provide an observable phenomenon related to meteorites that are particularly susceptible to dehydration. Oscillatory zoning is observed within olivine phenocrysts in the fusion crust, in contrast to other meteorites, perhaps owing to temperature fluctuations resulting from calving events. Magnetite monolayers are found in the crust, and have also not been previously reported, and form discontinuous strata. These features grade into magnetite rims formed on the external surface of the crust and suggest the trapping of surface magnetite by collapse of melt. Magnetite monolayers may be a feature of meteorites that undergo significant degassing. Silicate warts with dendritic textures were observed and are suggested to be droplets ablated from another stone in the shower. They, therefore, represent the first evidence for intershower transfer of ablation materials and are consistent with the other evidence in the Winchcombe meteorite for unusually intense gas loss and ablation, despite its low entry velocity.