Der "International Bodenseetag" vom 2.Dezember 1967, an dem praktisch die ganze Bevölkerung um den Bodensee zur See-Putzete antrat, gestaltete sich zu einer eindrücklichen Willenskundgebung der gesamten Seeanwohner, das Ihre zu tun, um den bedrohten See, von dem in mancher Hinsicht ihre Existenz abhängt, einer Sanierung entgegenzuführen.

Special Issue: Abstracts of the XXIX International Congress of Psychology

A kinetic model of the contact stabilization process has been developed and experimentally verified with the aid of bench-scale activated sludge units treating domestic sewage. The model provides information on the relationship between the design parameters (process loading, temperature, residence time distribution) and process performance (sludge, production, oxygen uptake, COD-removal, organic nitrogen conversion, nitrification and effluent suspended solids). An oxygen equivalence mass balance equation, which is applicable to all activated sludge process modifications is proposed and may be used in the design and operation of these processes.

Under laboratory conditions, the availability of cadmium, lead and copper in an Orthic Luvisol was investigated when applied to the soil at various initial concentrations. The metals were applied separately or concurrently with the other two heavy metal ions in order to bring about competition for the adsorption sites.<br/> The presence of competing metals increased the general availability especially of cadmium in the soil. Lead and copper were to a lesser extent also affected by the competition of other ions.<br/> On the basis of our ion-competition results we developped two models, namely a chemical equilibrium model and a convective—dispersive model. The models, suitable to predict the consequences of regular heavy metal loading (e.g., in the form of sewage sludge), take into consideration the annual precipitation and the relevant physical parameters of the soil. The conclusions reached by both models are essentially the same and imply that the threshold values for heavy metals in the sewage sludge regulation (Switzerland) are too high.

The partition of Cu and Zn between the particulate and dissolved phases has been investigated in the Carnon River and Restronguet Creek, England; a system contaminated by acid mine drainage. It is shown that binding to the surfaces of amorphous Fe oxyhydroxides regulates Cu and Zn concentrations in solution, in both fresh and saline waters. The sorptive process is pH dependent and is in general agreement with laboratory studies of trace metal adsorption on amorphous Fe oxyhydroxides.

Fluvio-glacial gravel deposits make up most of the groundwater reservoir in Switzerland. At the outcrop scale these deposits display a complex pattern of sedimentary structures. A minor part of these deposits is made up of stringer gravels without any fine fraction. The degree of interconnection of these layers and their extent determine the easiest flow path. Deterministic numerical models help visualize the influence of sedimentary structures on groundwater circulation at different scales.

The derailment of a petrol cistern train at Zürich-Affoltern followed by several explosions caused, a damage of about 10 million Swiss Francs to the sewer system. In the following, the paper describes the measures taken after the desaster and it tries to reconstruct the events in the sewer system that took place after the petrol had entered the system. And finally it looks into potential hazards to sewer systems and plants in general and outlines the measures which must be taken.

This paper investigates whether siphon weight limits the elongation of the siphon of deposit-feeding benthic bivalves under natural conditions. Were this to be so, it would imply that foraging and predator avoidance place conflicting demands on these animals, since an increase in the feeding radius on the surface would be associated with a decrease in the burying depth, and vice versa. The paper presents methods with which to measure siphon length and equations to transform siphon weight to siphon length in two benthic bivalves, <I>Scrobicularia plana</I> and <I>Macoma balthica</I>. Relatively heavy siphons are longer, but also thicker, than lightweight ones. We conclude that most individual bivalves stretch their siphons fully while feeding. However, bivalves with heavy siphons keep part of the siphon in reserve within the shell. Siphon cropping therefore results in an immediate reduction in siphon length, unless the siphon is heavy and a reserve is available. The feeding radius of <I>M. balthica</I> and <I>S. plana</I> is a linear function of shell size. <I>S. plana</I> use half of their siphon length to feed on the surface and the other half to bury themselves, but if the siphon weight is below average, the proportion extended over the surface decreases with siphon size. However, among the animals with a short siphon, those with a good body condition take no risks and live as deeply as possible. A comparison between species reveals that the weight of the extended inhalant siphon per cm amounts, on average, to 0.6% of the total body weight.

A simple, one reactor vessel system, called a fill-and-draw system, was developed for the study of enhanced biological phosphate removal under defined conditions. Sludge was grown in a medium with acetate and glucose as sole energy and carbon sources. The sludge was exposed to cycles with three distinct, consecutive periods; first an anaerobic period, then an aerobic period and finally a settlement period. In the period of settlement one third of the liquid was replaced with fresh medium. Sludge grown under this regime became considerably enriched with polyphosphate-accumulating bacteria. The polyphosphate content reached up to 110 mg P/g dry weight. The amount of polyphosphate in the cells during steady state depended on the acetate:glucose ratio, the nitrate and phosphate concentration in the medium. Highest phosphate accumulation was obtained with an acetate:glucose ratio of 9:1. Intracellular polyphosphate was formed during the aerobic period and was anaerobically hydrolysed and released as phosphate into the medium. In the absence of oxygen and in the presence of 2g acetate-COD/l, 80-90% of phosphate was released by sludge containing 100 mg P/g dry weight. In the absence of acetate only 2-19% of the accumulated phosphate was excreted.

The nickel(II) ion in factor F₄₃₀ pentacarboxylic acid, both in the native form and in the 12,13-di-epimer, in solution can be reversibily in a one-electron to the monovalent state by the action of titanium-(III) citrate. The 3d⁹ Ni(I) is quantitatively detected by EPR spectroscopy as a tetragonally distorted octahedral system with the in the d(<I>x</I>²-<I>y</I>²) orbital resulting in an <I>S</I> = ¹/₂ spin with <I>g</I>_∥ = 2.244, <I>g</I>_⊥ = 2.061, (<I>g</I>_∥ = 2.238, <I>g</I>_⊥ = 2.057 for the di-epimer), subject to isotropic superhyperfine interaction from the four in-plane nitrogen ligand with <I>A</I> = 1.0 mT. The UV-visible spectrum of the reduced native F₄₃₀ has peaks (extinction coefficients in mM^-1 cm^-1) at 268 (24.0), 378 (34.7), and 715 nm (2.3), In the reduced di-epimer these values are 265 (23.7), 376 (27.6), and 710 nm (1.6). Complete reduction is achieved only at alkaline pH; the process an apparent p<I>K</I> of 8.9 (native) or 9.4 (di-epimer). The Ni(II)/Ni(I) in <I>F</I>₄₃₀ has a reduction <I>E</I>_m,10.4 = -0.65 (native) or -0.62 V(diepimer). Three-pulse stimulated ESEEM spectroscopy on the reduced complexes reveals a single, near isotropic proton at ≈13 MHz. In ²H₂O solution this line is replaced by a quadrupole-split deuterium resonance around ≈2 MHz, indicating that the Ni(I) in and 12,13-di-epimeric F₄₃₀ is weakly coordinated by water. The absence of a strong axial bond with water would leave the ability of the d(<I>z</I>²) pair for nucleophilic attack on substrate carbon largely intact.

Although the proclamation of “water as an economic good” has been generally accepted among water resources managers, there are still some debates on the explanation of this topic. In this paper it is argued that different water forms or uses have different kinds of economic value. Even for the same form or use, water economic value can be transferred from one kind to another by interventions.<br/> If water is an economic good, water pricing should be recognized as one of the important incentive measures for water demand management. Although the increased block tariffs (IBTs) have become the tariff structure of choice in many developing countries, it still deserves more careful examination. The traditional IBT-con cannot achieve the initial objectives of IBTs for its incorrect designed structure.<br/> This paper is intent to critically examine the use of IBT-con and to strongly promote a new tariff structure, IRT-cap. The case study of Weinan City shows that IRT-cap is an effective tariff to achieve the objectives of equity, simplicity, transparency and implement as well. Also IRT-cap seems easier to achieve cost recovery than the traditional IBT-con taking the ability to pay of water consumers into account. Pilot projects are necessary to be formulated for verification of this new tariff.

The identification of unknown compounds is essential in a wide variety of research areas and especially so in environmental analysis. Combining liquid chromatography with tandem mass spectrometry today allows the identification of substances that were not amenable to classical techniques.Environmental toxicologists and chemists increasingly focus on chemicals that can potentially cause adverse effects in organisms and humans. Since effect concentrations are often very low, but also because the matrix can affect the sensitivity, selective enrichment has become a popular tool for sample clean-up and lowering the limit of detection. Advances in environmental analysis, including techniques based on molecular recognition for selective enrichment or effect-oriented research were presented in this session.

Adaptive radiations (ARs) frequently show remarkable repeatability where single lineages undergo multiple independent episodes of AR in distant places and long-separate time points. Genetic variation generated through hybridization between distantly related lineages can promote AR. This mechanism, however, requires rare coincidence in space and time between a hybridization event and opening of ecological opportunity, because hybridization generates large genetic variation only locally and it will persist only for a short period. Hence, hybridization seems unlikely to explain recurrent AR in the same lineage. Contrary to these expectations, our evolutionary computer simulations demonstrate that admixture variation can geographically spread and persist for long periods if the hybrid population becomes separated into isolated sub-lineages. Subsequent secondary hybridization of some of these can reestablish genetic polymorphisms from the ancestral hybridization in places far from the birthplace of the hybrid clade and long after the ancestral hybridization event. Consequently, simulations revealed conditions where exceptional genetic variation, once generated through a rare hybridization event, can facilitate multiple ARs exploiting ecological opportunities available at distant points in time and space.

Temporal genetic variation was studied within the cyclic parthenogenetic <i>Daphnia galeata-cucullata</i> species complex in Lake Tjeukemeer (The Netherlands). During three successive years, three allozyme loci were studied in order to compare the level of genetic variation in <i>D. galeata</i> (G), <i>D. cucullata</i> (C) and their interspecific hybrid (C × G). This data set was used to investigate: whether C × G hybrids are regularly produced by the parental species and to what extent backcrossing takes place in this species complex. G and C × G were the most abundant taxa, whereas C was only abundant in late summer and autumn. Genetic diversity was highest in C, lowest in G, and intermediate in C × G. <i>pgm</i> and <i>pgi</i> allele frequencies of C × G were not intermediate to those of the parental species but were more similar to G than to C. In addition, almost no significant deviations from Hardy-Weinberg were observed. An UPGMA analysis of Nei's genetic distances showed that C × G hybrids are more closely related to G (difference <0.04), than to C (difference 0.30). My data suggest, in accordance with other studies, that C × G hybrids are probably still formed by the parental species, though not necessarily every year. Furthermore, my data suggest that backcrossing occurred frequently, and led to introgression of C alleles into G.

The Activated Sludge Model No. 2d (ASM2d) presents a model for biological phosphorus removal with simultaneous nitrification-denitrification in activated sludge systems. ASM2d is based on ASM2 and is expanded to include the denitrifying activity of the phosphorus accumulating organisms (PAOs). This extension of ASM2 allows for improved modeling of the processes, especially with respect to the dynamics of nitrate and phosphate.

We studied population extinction of the locally abundant fen plant <I>Swertia perennis</I> in Switzerland and used up to 127-year old herbarium records to relocate 63 sites that had once hosted this species. We recorded current site characteristics and related them to the absence or abundance of populations. Fifty-four sites (86%) were still traditionally used (extensively mown or grazed). Fifteen populations (24%) had gone extinct. Extinction was more likely at lower altitude, in the peripheral distribution range of <I>S. perennis</I> (58% peripheral, 9% central populations extinct). on the smallest fens (75% extinct on fens < 400 m²) and on fens with intensified land use. However, even on traditionally managed wetlands 18.5% of the populations had gone extinct. Moreover, 40% of all remaining populations were smaller than 250 flowering plants. We conclude that both intensified agricultural practice and habitat fragmentation contributed to local extinction of <I>S. perennis</I>. Small populations, especially, may not be able to persist in the long term.

We assessed the effects of habitat fragmentation on the demography of the locally abundant, long-lived fen plant <I>Swertia perennis</I> L., by examining population structure, components of fitness and herbivory of 17 populations in Switzerland. We distinguished between large MAIN, small, barely isolated NEAR and small, geographically isolated DISTANT habitat islands. Large isolation distance of small sites significantly affected the transition from sub-adult to adult age states: the mean population density was reduced by 30%, the density of vegetative adults by 60% and the density of reproductive adults by 78% on DISTANT compared with NEAR islands. Seedling survivorship decreased significantly from MAIN to NEAR to DISTANT islands. Moreover, several vegetative components of fitness were significantly reduced on DISTANT islands, i.e. the length and number of leaves and the stern height. Finally, leaf herbivory was highest on small NEAR islands. Our results indicate that population viability of <I>S. perennis</I> is reduced on small, isolated fens, possibly because of arrested individual adult growth due to inbreeding. In contrast, environmental influences such as higher productivity through increased nutrient influx on small sites may be responsible for changed plant-herbivore interactions.

Animals have evolved a number of ways to protect themselves from the harmful effects of ultraviolet-B (UV-B) radiation, but little is known about the relative importance of different mechanisms protecting amphibian embryos from UV-B radiation. Using enzymatic removal of gelatinous coats (jelly envelope) surrounding the eggs of <I>Rana temporaria</I>, we tested the hypothesis that the jelly envelope acts as a sunscreen that protects embryos from harmful effects of UV-B radiation. We conducted two independent factorial laboratory experiments employing three different UV-B (no UV-B, normal, and enhanced) levels and jelly removal (control, modified, and completely removed) treatments. We found no UV-B X jelly removal treatment interactions in survival rates or in frequency of abnormal individuals, suggesting that jelly removal did not increase susceptibility of embryos to UV-B radiation. These results support the contention that the jelly envelope is not the most important means of protecting <i>R. temporaria</I> embryos from UV-B radiation. Other factors (e.g., melanin pigments, other sunscreen compounds, effective DNA-repair mechanisms) must be responsible for the high UV-B radiation tolerance of embryos.

Domestic water use is generally the most important component of urban water consumption. In this paper, the relatively new technique of artificial neural network (ANN) is proposed to model and forecast the water demand in urban areas. Results indicate that the WDF-ANN (water demand forecast using artificial neural network) model offers an effective way to formulate domestic water demand in Weinan City in China. The model evaluation shows that the correlation coefficients are more than 90% both for the training data and the testing data.

Effects of free-air carbon dioxide enrichment (FACE, 60 Pa pCO₂) on plant growth as compared with ambient pCO₂ (36 Pa) were studied in swards of <em>Lolium perenne</em> L. (perennial ryegrass) at two levels of N fertilization (14 and 56 g m⁻² a⁻¹) from 1993 to 2002. The objectives were to determine how plant growth responded to the availability of C and N in the long term and how the supply of N to the plant from the two sources of N in the soil, soil organic matter (SOM) and mineral fertilizer, varied over time. In three field experiments, ¹⁵N-labelled fertilizer was used to distinguish the sources of available N.<br/> In 1993, harvestable biomass under elevated pCO₂ was 7% higher than under ambient pCO₂. This relative pCO₂ response increased to 32% in 2002 at high N, but remained low at low N. Between 1993 and 2002, the proportions and amounts of N in harvestable biomass derived from SOM (excluding remobilized fertilizer) were, at high N, increasingly higher at elevated pCO₂ than at ambient pCO₂. Two factorial experiments confirmed that at high N, but not at low N, a higher proportion of N in harvestable biomass was derived from soil (including remobilized fertilizer) following 7 and 9 years of elevated pCO₂, when compared with ambient pCO₂.<br/> It is suggested that N availability in the soil initially limited the pCO₂ response of harvestable biomass. At high N, the limitation of plant growth decreased over time as a result of the stimulated mobilization of N from soil, especially from SOM. Consequently, harvestable biomass increasingly responded to elevated pCO₂. The underlying mechanisms which contributed to the increased mobilization of N from SOM under elevated pCO₂ are discussed. This study demonstrated that there are feedback mechanisms in the soil which are only revealed during long-term field experiments. Such investigations are thus, a prerequisite for understanding the responses of ecosystems to elevated pCO₂ and N supply.

Whether interspecific hybridization is important as a mechanism that generates biological diversity is a matter of controversy. Whereas some authors focus on the potential of hybridization as a source of genetic variation, functional novelty and new species, others argue against any important role, because reduced fitness would typically render hybrids an evolutionary dead end. By drawing on recent developments in the genetics and ecology of hybridization and on principles of ecological speciation theory, I develop a concept that reconciles these views and adds a new twist to this debate. Because hybridization is common when populations invade new environments and potentially elevates rates of response to selection, it predisposes colonizing populations to rapid adaptive diversification under disruptive or divergent selection. I discuss predictions and suggest tests of this hybrid swarm theory of adaptive radiation and review published molecular phylogenies of adaptive radiations in light of the theory.

The research on commons dilemmas is characterized by innumerable published findings, each standing relatively isolated from the other. To date there is little integration of the findings under a unified concept. The present contribution aims to integrate already existing findings in a general dynamic model of cooperative behavior in resource crises by means of computer simulation. The model postulates that people base their decisions regarding resource use on both ecological and social information. Whether or not ecological or social information will dominate, however depends on people's social values, attributions, and their perceptions of the state of the resource. The advantage of the simulation method used is that successful integration of the findings can be shown explicitly, as the simulation then replicates the experimental data. With the model presented here, it is also possible to let variables work together whose interaction has not yet been investigated in real experiments. For instance, the simulation model allows us to hypothesize that people, in dependence upon their resource uncertainty and in dependency upon their attributions, utilize a resource completely differently if the resource is in an optimal or sub-optimal condition.

The evaluation of toxicological effects at the cellular and molecular levels in organisms are often used to determine sites subjected to contamination problems that pose a threat to the long-term survival of organisms. However, the integration of multiple measurements on the health status of organisms into a model for site discrimination is challenging. This study compares two discrimination methods which are based on rule inference: rough sets (RS) analysis and classification trees (CT) with classical multivariate discriminant analysis (DA). Site classification was attempted with six biomarkers of effects: metallothionein levels, lipid peroxidation, DNA damage, levels of lipophosphoproteins (i.e., vitellins), phagocytosis activity and haemocyte cell viability on clam (<I>Mya arenaria</I>) populations from the Saguenay River fjord (Quebec, Canada). Rule based methods have the advantage of complete independence from data distribution constraints in contrast to the classification methods from multivariate analysis that are more commonly used in ecotoxicology. Results show that RS and CT gave better classifications than DA because they do not require strong distributional assumptions. Moreover, RS provided classification rules that could identify the most important biomarker(s) for site discrimination. RS and CT were shown to be simple and efficient methods for classifying multivariable ecotoxicological data. This methodology would be especially useful when freedom from distributional assumptions is required.