Plant and Soil System Responses to Ozone After 3 Years in a Lysimeter Study with Juvenile Beech (Fagus sylvatica L.)

A lysimeter study was performed to monitor effects of elevated ozone on juvenile trees of Fagus sylvatica L. as well as on the plant–soil system. During a fumigation period over almost three growing seasons, parameters related to plant growth, phenological development and physiology as well as soil functions were studied. The data analyses identified elevated ozone to delay leaf phenology at early and to accelerate it at late developmental stages, to reduce growth, some leaf nutrients (Ca, K) as well as some soluble phenolics (hydroxycinnamic acid derivatives, total flavonol glycosides). No or very weak ozone effects were found in mobile carbon pools of leaves (starch, sucrose), and other phenolic compounds (flavans). Altered gene expression related to stress and carbon cycling corresponded well with findings from leaf phenology and chemical composition analyses indicating earlier senescence and oxidative stress in leaves under elevated ozone. Conversely in the soil system, no effects of ozone were detected on soil enzyme activities, rates of litter degradation and lysimeter water balances. Despite the fact that the three reported years 2003–2005 were climatically very contrasting including a hot and dry as well as an extremely wet summer, and also mild as well as cold winters, the influence of ozone on a number of plant parameters is remarkably consistent, further underlining the phytotoxic potential of elevated tropospheric ozone levels.     

Substance Flow Analyses of Organic Pollutants in Stockholm

This paper summarizes substance flow analyses for four organic substances in the City of Stockholm, Sweden: diethylhexyl phthalate (DEHP), alkylphenolethoxylates (APEO), polybrominated diphenylethers (PBDE) and chlorinated paraffins (CP). The results indicate that the stocks of APEO, PBDE and CP all are approximately 200–250 tonnes, whereas the DEHP stock is two orders of magnitude larger. Emissions can be linked to imported consumer goods such as electronics (PBDE) and textiles (APEO), and to construction materials (DEHP, CP). For several of the substances considerable amounts remain in the technosphere for a long time, even after use of the substance in new products has been eliminated. For example, the use of DEHP as plasticizer for PVC plastics in cables and floorings has more or less been phased-out, but still these applications make up a stock of some 20,000 tonnes (85% of the total DEHP stock in Stockholm) and emit 28 tonnes of DEHP annually (93% of overall emissions). Likewise, the use of chlorinated paraffins in sealants has been radically reduced, but there are 170 tonnes of CP in sealants in Stockholm making up 75% of the stock, and causing half of the emissions to water and air. These emissions are likely to continue for decades, and the stocks therefore have to be considered when analysing and managing the impact of urban substance flows on the environment.     

Sustainability, substance flow management and time. Part I Temporal analysis of substance flows

Flows of chemical substances need to be managed in a sustainable way. Sustainable development as a whole and the sustainable management of substance flows in particular are both time issues. These include the importance of the dynamics of substance flows and the way these interconnect with the use of resources, the avoidance of environmental pollution, and their effects on health and food production. Another prerequisite for the proper management of substance flows is justice within and between generations. This requires a systematic approach and a systematic analysis of the issues as well as of the actions to be taken. One tool for such a systematic approach is temporal analysis. It brings the temporal aspects of the substances themselves and of their intended use, as well as factors affecting the stakeholders, such as decision makers, producers and consumers, into focus. In the past, timing factors were rarely taken into account. Knowledge of the temporal dynamics of substance flows and their resultant outcomes, as well as of their interaction with ecological, economic and social systems, is a basic requirement for successful substance flow management. The need to include temporal aspects into substance flow management and how to do so is outlined here. Included are not only politicians but also practitioners and scientists who must explicitly take into account adequate time scales, points in time, breaks and other forms of time in planning and acting.     

A framework for valuing the health benefits of improved bathing water quality in the River Irvine catchment

A simple model predicting bathing water concentrations of Escherichia coli from livestock in the Irvine catchment in SW Scotland has been adapted for intestinal enterococci (IE). This has been used to predict risk of bather illness by extrapolation of published data on bather IE exposure vs incidence of gastro-enteritis. Simulated reduction in the risk of illness by reduced faecal loading was multiplied by a willingness to pay for risk reduction to estimate the annual benefits of mitigation. Health benefits of reducing loading by 75% at Irvine Beach were estimated by a willingness to pay method to be about pound 276k pa. Estimated annualised costs of diffuse pollution mitigation measures across the catchment were higher (> pound 1m), and it is very unlikely that 75% mitigation is achievable with current stocking rates. Further work should explore the influence of uncertainty of model parameters, and use emerging epidemiological information on specific zoonotic pathogens such as E. coli O157 and Cryptosporidium. Other components of the value of clean water should also be included to obtain a complete estimate of the cost:benefit of mitigation.     

Identification of key parameters controlling dissolved oxygen migration and attenuation in fractured crystalline rocks

In the crystalline rocks of the Canadian Shield, geochemical conditions are currently reducing at depths of 500-1000 m. However, during future glacial periods, altered hydrologic conditions could potentially result in enhanced recharge of glacial melt water containing a relatively high concentration of dissolved oxygen (O2). It is therefore of interest to investigate the physical and geochemical processes, including naturally-occurring redox reactions, that may control O2 ingress. In this study, the reactive transport code MIN3P is used in combination with 2k factorial analyses to identify the most important parameters controlling oxygen migration and attenuation in fractured crystalline rocks. Scenarios considered are based on simplified conceptual models that include a single vertical fracture, or a fracture zone, contained within a rock matrix that extends from the ground surface to a depth of 500 m. Consistent with field observations, Fe(II)-bearing minerals are present in the fractures (i.e. chlorite) and the rock matrix (biotite and small quantities of pyrite). For the parameter ranges investigated, results indicate that for the single fracture case, the most influential factors controlling dissolved O2 ingress are flow velocity in the fracture, fracture aperture, and the biotite reaction rate in the rock matrix. The most important parameters for the fracture zone simulations are flow velocity in the individual fractures, pO2 in the recharge water, biotite reaction rate, and to a lesser degree the abundance and reactivity of chlorite in the fracture zone, and the fracture zone width. These parameters should therefore receive increased consideration during site characterization, and in the formulation of site-specific models intended to predict O2 behavior in crystalline rocks.     

Downward Migration of Dense Bottom Currents

The focus of this paper is on the dynamics of a dense current flowing along the continental slope, and the frictionally induced downward motion it experiences. In particular, the movement of the lateral boundaries where the isopycnals meet the bottom are considered. The current is taken to be wide compared to the Rossby radius, which is in accordance with observations and makes the dynamics quasigeostrophic. The time development of the plume thickness is studied, using three different parameterisations for the bottom friction.Independently of the choice of parameterisation, the following results are obtained: In the central part of the plume friction acts as a diffusive process to minimise the curvature of the upper surface of the plume. At the upper edge the plume quickly approaches a state with small slope, i.e. small geostrophic velocity and small frictionally induced downward flow. At the lower edge a tongue of dense water shoots out creating a widening layer. The thickness of the migrating layer is approximately equal to the boundary layer depth and its downward speed is comparable to the along-slope geostrophic velocity. The downslope end of the migrating layer may form a steep front which requires some precautions in the numerical procedure.     

Biomonitoring zur wirkungsbezogenen Ermittlung der Schadstoffbelastung in terrestrischen Ökosystemen

Biomonitoring programmes provide relevant information, which may supplement ambient air pollution monitoring or modelling around emission sources. As a prerequisite, assessment scales for biomonitoring data have to be derived based on an objective evaluation of available data, as well as on a scheme of presentation, which is suggestive and easily understandable even for laymen. Based on an evaluation of numerous monitoring programmes, assessment scales for biomonitoring results are derived for plant biomonitoring, which also serve as a basis for the graphical presentation of monitoring results. This study is focussed on bioindicator plants like mosses (passive biomonitoring) and exposed lichens (active biomonitoring), in which 14 metal elements are investigated. As an example, data from a local biomonitoring network around a cement plant were used to demonstrate the use of the assessment scales derived and the presentation scheme developed. Data sets from about 15 moss and 24 lichen biomonitoring programmes, comprising more than 1000 specimens, were sorted by their pollutant characteristics in order to form the database. Data on the metal contents of species demonstrating similar values with respect to growth characteristics and habit, and representing background or low pollution levels, are aggregated and their statistical distributions are evaluated. Spacing of the assessment scales and their colour designations are derived from the 50-, 75-, 90- and 95-percentile values. Graphical presentation allows a comparison of the absolute values of metal contents and a relative association of measured values. Exemplary results from moss and lichen monitoring around a cement plant are generally below or slightly above the median values at background and low-pollution sites. Metal contents are higher in lichens compared to mosses for 7 elements (Cd, Cu, Hg, Pb, Sb, Sn, Zn), and are lower in lichens only for thallium. The assessment scheme presented is mainly aimed at the practitioner in the field of biomonitoring in order to provide a reliable and sound scale of assessment by comparison on an absolute scale rather than presenting the basis of ecological risk assessment. Differences in metal content of co-located samples of various moss species and possible correction procedures are briefly discussed- as well as the consequences of pooling monitoring data across various moss species for the quality of assessment scales. Further evaluations shall focus on species-specific rather than on pooled databases and will investigate the consequences of the use of correction factors when extrapolating metal data from one monitoring species to another.     

Growth of Antarctic krill Euphausia superba at South Georgia

 Antarctic krill Euphausia superba has a central role in the ecosystem of the Southern Ocean and knowledge of its growth rate is central to determining the factors influencing population dynamics. The length of Antarctic krill in the diet of Antarctic fur seals Arctocephalus gazella at South Georgia revealed a consistent increase in size between ca. 42 and ca. 54 mm over the period October–March, indicating growth rates much higher than predicted by existing models. Geographical variation in growth rate may result in 2-year-old krill at South Georgia attaining the same size as 3-year-old krill in the Antarctic Peninsula region. The effect of geographical variation in growth rate on the population structure of krill has important implications for comparing the fate of individual cohorts over large scales and in the interpretation of krill life-cycles. Received: 20 May 2000 / Accepted: 11 August 2000     

Anti-sense expression of putrescine N-methyltransferase confirms defensive role of nicotine in Nicotiana sylvestris against Manduca sexta

Summary. Several lines of evidence support the defensive function of nicotine production in the Nicotiana genus against a range of herbivores, but the evidence is largely correlative. To suppress nicotine production in planta and to test its defensive function, we expressed DNA of putrescine N-methyl transferase in an anti-sense orientation (AS-PMT) in N. sylvestris and fed leaf material from two lines of transformed and wild type plants to Manduca sexta larvae. Larvae consumed more leaf area and gained more mass on the foliage of plants with low PMT expression and low nicotine levels as compared to plants with high PMT expression and high nicotine levels and wild type plants. Overall, larval consumption and performance were negatively correlated with constitutive nicotine levels. We conclude that nicotine decreases the palatability of N. sylvestris leaves to the nicotine-resistant M. sexta larvae.