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Hydraulic characterisation of the Stuttgart formation at the pilot test site for CO2 storage, Ketzin, Germany

The paper presents an approach for the interpretation of hydraulic tests of a CO₂ storage reservoir. The sandstone reservoir is characterised by a fluviatile channel structure embedded in a low-permeability matrix. Pumping tests were carried out in three wells, with simultaneous pressure monitoring in each well.The hydraulic parameters (permeability and storativity) and the boundary configurations were calibrated using three different approaches: (i) parameter calibration and type curve interpretation for single-hole tests, (ii) calibration of the entire build-up phase for cross-hole tests, and (iii) calibration of the initial pressure response for cross-hole pumping tests. In addition, the arrival time of the pressure response was determined and provides additional information about the pathways of hydraulic connection.The measured pumping test permeabilities of the formation were much lower than those measured on the cores, which is very unusual. The pumping test permeabilities are mainly between 50 mD and 100 mD (millidarcy), while core samples show a mean aquifer permeability of 500–1100 mD. Based on this it was concluded that some kind of continuous low-permeability structure exists, which was supported by core material. Three possible aquifer configurations were considered. The first and second were derived from traditional pumping test analysis and were conceptualised using flow boundaries. Each of the analyses provides a different result. A method was developed in which these differences were resolved by interpreting the pressure response with respect to its spatial and temporal sensitivity. This solution lead to a third configuration which was mainly based on spatially-variable permeabilities. Taking into account the pumping test results, the geological background and the behaviour of injected CO₂, we consider only the third configuration to be realistic. The results are in good agreement with modelled CO₂ arrival times and pressure history.     

Genetic and color morph differentiation in the Caribbean sea anemone<Emphasis Type="Italic"> Condylactis gigantea</Emphasis>

The distribution of phenotypic and genetic variation across environments can provide insights into local adaptation. The tropical sea anemone Condylactis gigantea inhabits a broad spectrum of coral-reef habitats and displays a variety of phenotypes, particularly with respect to color. At the coast of Discovery Bay, Jamaica, individuals with either pink or green tentacle tips show distinct distributions. Pink morphs are more abundant in the lagoon and in deeper areas, while green morphs are more abundant in the forereef and in shallower areas. We use DNA sequence data (ITS1-5.8S) to investigate if variation in color is associated with genetic differentiation in lagoon and forereef habitats about 5 km apart. Population genetic analyses reveal two distinct ITS1-5.8S variants, which differ in relative frequency. The two variants are present in both habitats, but a dearth of intermediates suggests reduced gene flow. In the lagoon, but not the forereef, ITS variants show an association with color. In order to address the potential ecological significance of color, we study UV absorbance and UV acclimatization capacities of pink and green color morphs in the lagoon. Color morphs differed significantly in UV-B absorbance. These results suggest genetic and ecological differentiation in the face of gene flow over short distances.Communicated by O. Kinne, Oldendorf/Luhe