Integrated Rhaetian foraminiferal and conodont biostratigraphy from the Slovenian Basin, eastern Southern Alps

Conodonts and re-deposited shallow-water benthic foraminifera co-occur in the Upper Norian-Rhaetian Slatnik Formation of the Slovenian Basin (Southern Alps). The Mt. Kobla and Mt. Slatnik sections were investigated in order to give the first direct correlation between these two groups. The Norian-Rhaetian boundary (NRB) is placed at the First Appearance Datum of the conodont Misikella posthernsteini and is approached with the First Occurrence of the foraminifer Involutina turgida. An association of Trocholina turris with duostominids is a good marker for the Rhaetian. Careful revision of literature combined with our data culminated in reambulation of stratigraphical ranges for several foraminiferal species. The foraminiferal Triassic-Jurassic boundary (TJB) can be defined with the Last Occurrence of Galeanella tollmanni, ??Sigmoilina?? schaeferae or duostominids. The absence of the uppermost Rhaetian Misikella ultima conodont zone and the close coincidence of foraminiferal and conodont TJB could point to the presence of hiati in the upper part of the Slatnik Formation. Consequently, the exact pattern of disappearance of Late Triassic foraminifera at the boundary could not be observed. It is clear, however, that the foraminiferal assemblage was decimated for reef-dwelling foraminifera, duostominids and most of the platform-dwelling foraminifera. Biotic changes at the TJB are best explained as a result of a biocalcification crisis.     

Comments on Lowe et al. “Otolith Microchemistry Reveals Substantial Use of Freshwater by Southern Flounder in the Northern Gulf of Mexico”

Lowe et al. (Estuaries and Coasts, 34:630–639, 2011) hypothesized that juvenile southern flounder Paralichthys lethostigma (Jordan and Gilbert 1884) would migrate from the Gulf of Mexico into the Mobile-Tensaw River Delta (AL, USA) and use low-salinity (oligohaline/freshwater) habitats during, at least, a portion of their first year of life. Thus, they analyzed the Sr/Ca ratio profiles along the sagittal otoliths of southern flounder collected in the Mobile-Tensaw River Delta and observed that one third of the flounders had low Sr/Ca levels in the otoliths’ core and throughout the otolith, suggesting that these fishes hatched in freshwater or low-salinity habitats where they spend the majority of their life. The other two thirds of southern flounder showed high levels of Sr/Ca ratio in the otoliths’ core following a marked decline of Sr/Ca ratio, which then maintained along the remainder of the otolith. This pattern was interpreted as larvae hatched in higher salinity waters before entering the Mobile-Tensaw River Delta; however, in this paper, I list several arguments to support an alternative interpretation for this pattern. I suggest that the high levels of Sr/Ca ratios in the otoliths’ core of southern flounder does not reflect the saline conditions where larvae hatched, instead it reflects the location where the female progenitor hydrated the eggs. Thus, adding my interpretation on the data of Lowe et al. (Estuaries and Coasts, 34:630–639, 2011), it seems that southern flounder might hatch in or near freshwater habitats and the migration of southern flounder into an estuarine ecosystem to spawn might exist.     

Risk of water pollution due to ash–sludge mixtures: column trials

The purpose of this work was to study the risks of water pollution due to the use of mixtures containing wood ash and sewage sludge. Mixtures including sludge and ash may be recycled as fertilizers, and they are economical as they do not integrate commercial limes, but Escherichia coli counts may keep significantly high in such mixtures, because their pH is not alkaline enough. In view of that, it seems interesting to study the E. coli survival in lixiviate from ash?Csludge mixtures including limes rather than from ash?Csludge mixtures alone. Two kinds of experiments were performed using laboratory column trials under saturated flow conditions. The first experiment investigated the chemical leaching behaviour of a mixture of 70% timber-industry wood ashes and 30% urban sewage sludge (% dry weight) at doses equivalent to 10 and 30?Mg/ha. The second experiment studied the survival of E. coli in lixiviates generated from 30?Mg/ha of a mixture consisting in 75% wood ash, 20% sewage sludge and 5% quicklime (% dry weight). In the first experiment, admixture of the ash and sludge achieved a stabilization of elements such as aluminium, iron, magnesium, nickle, carbon monoxide, cadmium, chromium and molybdenum that reduced their solubility compared with that in the ash or sludge alone. Significant solubilisation of heavy metals was not observed, with overall minor risk of chemical water pollution. In the second experiment, although including quicklime E. coli counts were still detected in the lixiviate, indicating risk of water contamination.     

Coupling hydrogeological with surface runoff model in a Poltva case study in Western Ukraine

This paper presents the hydrological coupling of the software framework OpenGeoSys (OGS) with the EPA Storm Water Management Model (SWMM). Conceptual models include the Saint Venant equation for river flow, the 2D Darcy equations for confined and unconfined groundwater flow, a two-way hydrological coupling flux in a compartment coupling approach (conductance concept), and Lagrangian particles for solute transport in the river course. A SWMM river–OGS aquifer inter-compartment coupling flux is examined for discharging groundwater in a systematic parameter sensitivity analysis. The parameter study involves a small perturbation (first-order) sensitivity analysis and is performed for a synthetic test example base-by-base through a comprehensive range of aquifer parametrizations. Through parametrization, the test cases enables to determine the leakance parameter for simulating streambed clogging and non-ocillatory river-aquifer water exchange rates with the sequential (partitioned) coupling scheme. The implementation is further tested with a hypothetical but realistic 1D river–2D aquifer model of the Poltva catchment, where discharging groundwater in the upland area affects the river–aquifer coupling fluxes downstream in the river course (propagating feedbacks). Groundwater contribution in the moving river water is numerically determined with Lagrangian particles. A numerical experiment demonstrates that the integrated river–aquifer model is a serviceable and realistic constituent in a complete compartment model of the Poltva catchment.     

Uncertainties of geochemical modeling during CO<Subscript>2</Subscript> sequestration applying batch equilibrium calculations

One of the uncertainties in the field of carbon dioxide capture and storage (CCS) is caused by the parameterization of geochemical models. The application of geochemical models contributes significantly to calculate the fate of the CO₂ after its injection. The choice of the thermodynamic database used, the selection of the secondary mineral assemblage as well as the option to calculate pressure dependent equilibrium constants influence the CO₂ trapping potential and trapping mechanism. Scenario analyses were conducted applying a geochemical batch equilibrium model for a virtual CO₂ injection into a saline Keuper aquifer. The amount of CO₂ which could be trapped in the formation water and in the form of carbonates was calculated using the model code PHREEQC. Thereby, four thermodynamic datasets were used to calculate the thermodynamic equilibria. Furthermore, the equilibrium constants were re-calculated with the code SUPCRT92, which also applied a pressure correction to the equilibrium constants. Varying the thermodynamic database caused a range of 61% in the amount of trapped CO₂ calculated. Simultaneously, the assemblage of secondary minerals was varied, and the potential secondary minerals dawsonite and K-mica were included in several scenarios. The selection of the secondary mineral assemblage caused a range of 74% in the calculated amount of trapped CO₂. Correcting the equilibrium constants with respect to a pressure of 125 bars had an influence of 11% on the amount of trapped CO₂. This illustrates the need for incorporating sensitivity analyses into reaction pathway modeling.     

Evaluation of the water resource reproducible ability on Tarim River Basin in south of Xinjiang,northwest China

With the over-exploitation of water resources, water pollution and poor management of water infrastructures are exacerbated. Ecosystem degradation is apparent at the basin level. The Tarim River Basin in northwest China has seen intensive confrontation between environmental protection and economic development over the past five decades. Ambitious agricultural development and land reclamation projects implemented by the Chinese government in the early 1960s led to several influences. For example, the construction of dams like the Daxihaizi Reservoir disrupted the stream-flow to the lower reaches. Water resource reproducible ability (WRRA) refers to the ability of water resources to be continually added by the natural water cycle. It includes the supplementation of water quantity and the self-purification of water quality in the natural cycle of water resources. This study discusses the WRRA index and introduces the computational method for calculating the WRRA index for the Tarim River Basin. The following conclusions are observed: (1) from 1956 to 2005, the indices of WRRA in the Hotan River Basin, Yarkand and Aksu River Basin are 0.26, 0.55, 0.58, respectively, which are between 0 and 1. The results indicate that the hydrological cycle in these three sub-basins is in a reproducible state. (2) The WRRA index in the Kaidu-Kong River Basin is 1.23 > 1, which indicates that floods may occur in the Kaidu-Kong River Basin. (3) The index of WRRA in the main stream is 0, which indicates that the WRRA is very weak at this location, and zero-flow may occur. Calculating the WRRA of a basin can provide a basis for corresponding basin water resources management.     

Challenges of an integrated water resource management for the Distrito Federal, Western Central Brazil: climate, land-use and water resources

Land-use/cover change (LUCC) and climate change are major controlling factors for water resources in the Distrito Federal in Western Central Brazil. Dynamic LUCC in the region has severe impacts on water resources, while climate changes during the last three decades is thought to have only moderate effects. LUCC affects water quantity mostly during base flow conditions. River basins with substantial expansion of agriculture since the end 1970s show a dramatic decrease of base flow discharge by 40?C70%, presumably due to irrigation. In contrast, the effects of urbanization on runoff are less distinct, since factors controlling runoff generation might be more variable. For water quality, we found urban areas to have a strong influence on the parameters CSB, NH₄ ⁺, and suspended solids. In addition, we assume emerging pollutants, e.g. organic (micro)pollutants, might play a major role in the future. The project IWAS-áGUA DF focuses on creating the scientific base to face these problems in frame of an IWRM concept for the region. Results of our study will be a contribution to an IRWM concept for the Distrito Federal and will help to maintain high standards in water supply for the region.     

Electrical resistivity response due to variation in embankment shape and reservoir levels

The safety of the center-core type of fill dam structure was assessed by examining the effects of the distortion of electrical response verified in terms of two-dimensional (2D) apparent resistivity and its inverted sections from three-dimensional (3D) modeling for the embankment. The distortion effect is due to 2D interpretation of the 3D structure of the embankment. From the analysis, it was found that water level was correctly described by the resistivity section around the middle part rather than each side at the end of the embankment. This is due to the 3D terrain effect when the material of the embankment is assumed to be horizontally uniform. In addition, when the slope of the outer rock-fill section is set as uniform, the resistivity section is more similar for sharper center-core slopes. On the other hand, when the rock-fill slope is steep, the resistivity section shows the water level at a lower position than the real one, and the 3D distortion effect at the end of the embankment is enhanced.