New Unstructured Mesh Water Quality Model for Cooling Water Biocide Discharges

A new unstructured mesh coastal water and air quality model has been developed that includes species transport, nonlinear decay, by-product formation, and mass-exchange between sea and atmosphere. The model has been programmed with a graphical user interface and is applicable to coastal seawater, lakes, and rivers. Focused on species conversion and interaction with the atmosphere, the water and air quality model follows a modular approach. It is a compatible module which simulates distributions based on fluid dynamic field data of underlying existing hydrodynamic and atmospheric simulations. Nonlinear and spline approximations of decay and growth kinetics, by-product formation, and joint sea–atmosphere simulation have been embedded. The Windows application software includes functions allowing error analysis concerning mesh and finite volume approximation. In this work, a submerged residual chlorine cooling water discharge and halogenated matter by-product formation has been simulated. An error analysis has been carried out by varying vertical meshing, time-steps and comparing results based on explicit and implicit finite volume approximation. The new model has been named 3D Simulation for Marine and Atmospheric Reactive Transport, in short 3D SMART.     

Tracking the legacy of early industrial activity in sediments of Lake Zurich,Switzerland: using a novel multi-proxy approach to find the source of extensive metal contamination

Environmental Science and Pollution Research - Historical industrial activities at the Horn Richterwil, on the shore of Lake Zurich (Switzerland), caused widespread metal contamination on land and...     

Measuring eddy covariance fluxes of ozone with a slow-response analyser

Ozone (O₃) fluxes above a temperate mountain grassland were measured by means of the eddy covariance (EC) method using a slow-response O₃ analyser. The resultant flux loss was corrected for by a series of transfer functions which model the various sources of high- and, in particular, low-pass filtering. The resulting correction factors varied on average between 1.7 and 3.5 during night and daytime, respectively. A cospectral analysis confirmed the accuracy of this approach. O₃ fluxes were characterised by a comparatively large random uncertainty, which during daytime typically amounted to 60%. EC O₃ fluxes were compared against O₃ flux measurements made concurrently with the flux-gradient (FG) method. The two methods generally agreed well, except for a period between sunrise and early afternoon, when the FG method was suspected of being affected by the presence of photochemical sources/sinks. O₃ flux magnitudes and deposition velocities determined with the EC method compared nicely with the available literature from grassland studies. We conclude that our understanding of the causes and consequences of various sources of flux loss (associated with any EC system) has sufficiently matured so that also less-than-ideal instrumentation may be used in EC flux applications, albeit at the cost of relatively large empirical corrections.     

Wirkungsorientierte Umweltanalytik Kombination des pHstat-Verfahrens mit dem Biolumineszenz-Hemmtest Mobilisationsverhalten von Schwermetallen aus Feststoffen

The pH_stat-procedure is a method to examine the pH-dependent mobilisation of heavy metals and other pollutants from solids. The metals in such extracts are usually determined by atomic absorption (AAS) or by emission spectrometry (ICP-OES). The obtained values present the total amount of mobilized metals. A statement concerning the effect-oriented true toxicity of the extract, respective of the examined solid, is not possible. A combined effect-oriented procedure, such as a the bioaluminescence-inhibition test with luminescence bacteria enables a precise statement about the ecotoxicity of solids. A variation of the inhibition test (addition of EDTA) indicates the main binding forms of heavy metals and the part of inhibition caused by organic material.     

An unintended experiment in fisheries science: a marine area protected by war results in Mexican waves in fish numbers-at-age

Marine protected areas (MPAs) are attaining increasing importance in the management of marine ecosystems. They are effective for conservation in tropical and subtropical areas (mainly coral and rocky reefs), but it is debated whether they are useful in the management of migratory fish stocks in open temperate regions. World War II created a large marine area within which commercial fishing was prevented for 6 years. Here we analyse scientific trawl data for three important North Sea gadoids, collected between 1928 and 1958. Using statistical models to summarise the data, we demonstrate the potential of MPAs for expediting the recovery of over-exploited fisheries in open temperate regions. Our age-structured data and population models suggest that wild fish stocks will respond rapidly and positively to reductions in harvesting rates and that the numbers of older fish in a population will react before, and in much greater proportion, than their younger counterparts in a kind of Mexican wave. Our analyses demonstrate both the overall increase in survival due to the lack of harvesting in the War and the form of the age-dependent wave in numbers. We conclude that large closed areas can be very useful in the conservation of migratory species from temperate areas and that older fish benefit fastest and in greater proportion. Importantly, any rise in spawning stock biomass may also not immediately result in better recruitment, which can respond more slowly and hence take longer to contribute to higher future harvestable biomass levels.     

Variations in the Epiphytic Invertebrate Community Structure on Potamogeton Perfoliatus L. in Traunsee (Austria): Patchiness versus Impacts by Industrial Tailings

The epiphytic invertebrates found on Potamogetonperfoliatus L. in Traunsee, an oligotrophic Alpine lake inAustria, were investigated in August and October 1998 in orderto study the impact of industrial tailings discharged into thelake. 113 taxa were found, 54 could be identified to thespecies level. Their total abundance varied between ca.190,000 and 1,138,000 ind. m^-2 lake bottom area. Thisepiphytic assemblage was dominated by Dreissenapolymorpha and Sida crystallina, which resulted in avery low overall species diversity. Multivariate statisticalanalyses revealed significant differences in the communitystructure between three sites, each of them was located at adifferent distance from the site of industrial waste emission.These differences were interpreted as variations which reflectthe patchiness within highly structured habitats rather thanas being the result of the industrial pollution.