Investigations on CO2 storage capacity in saline aquifers: Part 1. Dimensional analysis of flow processes and reservoir characteristics

The CO₂ storage capacity of geological reservoirs is of great interest for the selection of potential storage sites in carbon capture and storage (CCS) projects. A detailed analysis essentially requires a thorough understanding of the interaction of forces acting within the system. By defining characteristic quantities for length, time, pressure and velocity, the governing multiphase flow equations can be non-dimensionalised. This allows for the definition of physically sound dimensionless numbers, resembling the ratios of acting forces like viscous, capillary and gravitational forces. An analysis of the relation of forces in reservoirs with different parameter setups allows their intercomparison with respect to their CO₂ storage capacity potential. To back up the analysis, a comprehensive reservoir parameter database with more than 1200 reservoirs is analysed and statistical characteristics are derived. Effects of reservoir parameters like depth, temperature, absolute and relative permeability, as well as capillary pressure are investigated. It is shown that dimensionless numbers can be used to qualitatively order reservoirs with respect to the forces acting in the reservoir. Moreover, it is shown that the relative permeability relations together with the residual saturations have a great influence on the balance of forces.     

Veränderung von Biokonzentration und Wirkung vom PSM in Anwesenheit von Huminstoffen

Humic substances, in aqueous bodies primarily fulvic acids, may demonstrate an inhibitory as well as an activating influence on organisms. We present evidence with bacteria-containing algal cultures and with cultures of the nematodeCaenorhabditis elegans. Structural elements of the fulvic acids which may be responsible for such effects are not yet known. Furthermore, the presence of fulvic acids may lead to increases in bioconcentration of xenobiotics. Increase in the toxicity of xenobiotics in the presence of humic substances have also been described. We present studies applying lethal as well as sublethal toxicity endpoints.     

The effect of nitrogen enrichment on the carbon sink in coniferous forests: Uncertainty and sensitivity analyses of three ecosystem models

Estimates of the global carbon sink induced by nitrogen enrichment range vary widely, from nearly zero to 2.3 Gt C year^?1. It is necessary to reduce this uncertainty if we are to make accurate predictions of the future magnitude of the terrestrial carbon sink. Here, we present a Monte Carlo approach to uncertainty and sensitivity analysis of three ecosystem models, Century, BGC and Hybrid. These models were applied to a coniferous forest ecosystem in Sweden. The best estimate of the change in total carbon content of the ecosystem with the cumulative change in nitrogen deposition over 100 years, ΔC_total/ΔN_deposition was 20.1 kg C (kg N)^?1 using the pooled mean, with a pooled standard deviation of 13.8 kg C (kg N)^?1. Variability in parameters accounted for 92% of the total uncertainty in ΔC_total/ΔN_deposition, and only 8% was attributable to differences between models. The most sensitive parameters were those which controlled the allocation of assimilate between leaves, roots and stem. In particular, an increase in allocation to fine roots led to a large reduction in ΔC_total/ΔN_deposition in all models, because the fine roots have a very high turnover rate, and extra carbon allocated there is soon lost through mortality and decomposition.     

Intra- and inter-annual variability of VOC emissions from natural and semi-natural vegetation in Europe and neighbouring countries

Biogenic VOC emission estimates from the earth's surface are crucial input parameters in air quality models. Knowledge accumulated in the last years about BVOC source distributions and chemical compound species emission profiles in Europe as well as the demand of air quality modellers for a finer resolution in space and time of BVOC estimates have led to the set-up of new emission modelling systems. An updated fast BVOC emission modelling platform explicitly considering the seasonality of emission potentials and leaf temperature gradients in forest canopies by the semi-empirical emission module (seBVOC) will be proposed and used for estimating hourly values of chemical compound-specific emissions in Europe (33–68° north; 10° west to 40° east) in the years 1997, 2000, 2001, and 2003. Spatial resolution will be 10 km by 10 km. The database used contains latest land and forest distributions, updated foliar biomass densities, leaf area indices (LAI), and plant as well as chemical compound-specific emission potentials, if available. Meteorological input parameters for the respective years will be generated using the non-hydrostatic meteorological model MM5. Highest BVOC emissions occur in daytime hours around noon from the end of May to mid-August in the Mediterranean area and from the mid of June to the end of July in the boreal forests. Comparison of 3 BVOC model approaches will reveal that for July 2003, the European isoprene and monoterpene totals range from 1124 Gg to 1446 Gg and from 338 Gg to 1112 Gg, respectively. Small-scale deviations may be as high as ±0.6 Mg km^?2 for July 2003, reflecting the current uncertainty range for BVOC estimates. Key sources of errors in inventories are still insufficiently detailed land use data for some areas and lacking chemically speciated plant-specific emission potentials in particular in boreal, south-eastern, and northern African landscapes. The hourly emissions of isoprene, speciated terpenes, and oxyVOC have been made available by the NatAir database.     

The Influence of Place Attachment and Experience Use History on Perceived Depreciative Visitor Behavior and Crowding in an Urban National Park

Research on recreational place attachment suggests that place identity, or the emotional/symbolic ties people have to places, and place dependence, which describes a functional attachment to a specific place, influence the perception of social and environmental site conditions. Recent research, however, has found that place attachment is not always a predictor of such perceptions. This study investigated the influence of place attachment and experience use history on the perception of depreciative visitor behavior, recreation impacts and crowding in an urban national park. In 2006, 605 on-site visitors to the heavily-used Viennese part of the Danube Floodplains National Park were asked about past experience, place attachment, perceptions of depreciative visitor behavior, crowding, changes in visitor numbers during the past ten years, and recreation impacts on wildlife. Confirmatory factor analysis confirmed the two dimensions of place attachment. Linear regression analyses found that place identity and place dependence were related to some perceived depreciative visitor behaviors and visitor number changes but not to crowding, while experience use history additionally related to perceived crowding. Visitors with higher place attachment and past experience were more sensitive to social and environmental site conditions. Management implications of the findings are discussed.     

On the Curing of ESO/MTHPA/DEH 35 and ESO/MTHPA/DEH 35/TIN

Journal of Polymers and the Environment - Epoxidized soybean oil (ESO) compounds were cured with methyl tetrahydrophthalic anhydride (MTHPA) as hardener and 2,4,6-tris (dimethylaminomethyl) phenol...     

Polybrominated diphenyl ethers (PBDEs) and alternative brominated flame retardants in air and seawater of the European Arctic

The spatial distribution of polybrominated diphenyl ethers (PBDEs) and several alternative non-PBDE, non-regulated brominated flame retardants (BFRs) in air and seawater and the air-seawater exchange was investigated in East Greenland Sea using high-volume air and water samples. Total PBDE concentrations (Ó₁₀PBDEs) ranged from 0.09 to 1.8 pg m⁻³ in the atmosphere and from 0.03 to 0.64 pg L⁻¹ in seawater. Two alternative BFRs, Hexabromobenzene (HBB) and 2,3-dibromopropyl-2,4,6-tribromophenyl ether (DPTE), showed similar concentrations and spatial trends as PBDEs. The air-seawater gas exchange was dominated by deposition with fluxes up to −492 and −1044 pg m⁻² day⁻¹ for BDE-47 and DPTE, respectively. This study shows the first occurrence of HBB, DPTE and other alternative flame retardants (e.g., pentabromotoluene (PBT)) in the Arctic atmosphere and seawater indicating that they have a similar long-range atmospheric transport potential (LRAT) as the banned PBDEs.