SIDE EFFECTS OF 58 YEARS OF COPPER SULFATE TREATMENT OF THE FAIRMONT LAKES,MINNESOTA1

The shallow Fairmont Lakes in southern Minnesota have been treated with copper sulfate for 58 years to reduce excessive algal growth. Copper sulfate was applied to five lakes at cumulative rates upo to 1647 kg/ha (1470 1b/acre), totaling 1.5 million kilograms. Data collected since treatment of the Fairmont Lakes began in 1921 provide alarming insights into lake responses to sustained chemical treatment with copper sulfate. Short-term and long-term effects have occurred. Short-term effects include: a) the intended temporary killing of algae, b) dissolved oxygen depletion by decomposition of dead algae, c) accelerated phosphorus recycling from the lake bed and recovery of the algal population within 7 to 21 days, and d) occasional fish kills due to oxygen depletion or copper toxicity or both. Long-term effects are shown to include: a) copper accumulation in the sediments, b) tolerance adjustments of certain species of algae to higher copper sulfate dosages, c) shift of species from green to blue-green algae and from game fish to rough fish, d) disappearance of macrophytes, and e) reductions in benthic macroinvertebrates. The conclusion is that while copper sulfate treatments enjoy great popularity because they kill and remove algae almost instantaneously, other immediate or cumulative side effects can be harmful to many other aquatic organisms.     

Computer-assisted navigation and the acquisition of route and survey knowledge

The incidental acquisition of spatial orientation knowledge when using a pedestrian navigation assistance system for wayfinding was compared to incidental learning during map-based wayfinding. First-time visitors to a real environment (a zoo) took a guided tour. In the navigation assistance conditions, users were provided with direction information and view-based pictures of the current intersection at each decision point, presented on a hand-held computer. In the map-based condition, participants derived route segments from a map (each segment comprising three or four intersections), and then walked the partial routes from memory. After walking, unexpected tests on route memory and survey knowledge were administered. Navigation assistance users showed good route knowledge and poor survey knowledge. In contrast, map users showed better survey knowledge and nearly perfect route knowledge. Variations of information presentation within navigation assistance conditions (auditory vs. visual direction command, additional presentation of allocentric spatial information) was not effective. Results are explained with an active encoding principle. Only information that is actually encoded, transformed, and/or memorized during the primary wayfinding activity, is incidentally learned. Since navigation assistance systems do not require users to encode, transform, and memorize spatial information, the spatial orientation knowledge of navigation assistance users is poor.     

The BG measurement system for hazardous substances (BGMG) and the exposure database of hazardous substances (MEGA).

German employers' liability insurance associations or Berufsgenossenschaften (BGs)--institutions for statutory accident insurance--maintain a measurement system for hazardous substances, the so-called BGMG. The aim of the BGMG is to determine and document valid results of measurements of exposure primarily for prevention purposes. The data are collected systematically, in parallel to the sampling in a company. Parameters which are supposed to have a visible effect on exposure levels are documented. The MEGA database (documentation of measurement data relating to workplace exposure to hazardous substances) holds 1,629 million measurement values, which have been compiled in since 1972. The database offers a host of selection possibilities for assessments depending on the evaluation strategy.     

Projected Climate Change Effects on Winterkill in Shallow Lakes in the Northern United States

2 was obtained from the output of the Canadian Climate Center General Circulation Model. To illustrate the effect of projected climate change on lake DO characteristics, we present herein DO information simulated, respectively, with inputs of past climate conditions (1961–1979) and with a projected 2 × CO₂ climate scenario, as well as differences of those values. Specific parameters obtained were minimum under-ice and lake bottom DO concentration in winter, duration of under-ice anoxic conditions (<0.1 mg/liter) and low DO conditions (<3 mg/liter), and percentage of anoxic and low DO lake volumes during the ice cover period. Under current climate conditions winterkill occurs typically in shallow eutrophic lakes of the northern contiguous United States. Climate warming is projected to eliminate winterkill in these lakes. This would be a positive effect of climate warming. Fish species under ice may still experience periods of stress and zero growth due to low DO (<3 mg/liter) conditions under projected climate warming.     

Modelling economic impacts and adaptation to extreme events: Insights from European case studies

Adaptation to climate change in Europe has only recently become a true policy concern with the management of extreme events one priority item. Irrespective of future climatic changes increasing the need for systematic evaluation and management of extremes, weather-related disasters already today pose substantial burdens for households, businesses and governments. Research in the ADAM project identified substantial direct risks in terms of potential crop and asset losses due to combined drought and heatwave, as well as flood hazards in Southern and Eastern Europe, respectively. This paper focuses on the indirect, medium to longer term economic risks triggered by the direct risks and mediated by policy responses. We present a selection of three economic impact and adaptation assessments and modelling studies undertaken on extreme event adaptation in Europe. Responding to a need for more economically based adaptation assessments, we address some relatively unresearched issues such as the understanding of past adaptation, the role of market response to impacts as well as government’s ability to plan for and share out extreme event risks. The first analysis undertakes an empirical exploration of observed impacts and adaptation in the agricultural sector in the UK comparing the impact of consecutive extreme events over time in order to determine whether adaptation has occurred in the past and whether this can be used to inform future estimates of adaptation rates. We find that farmers and the agricultural sector clearly have adapted to extreme events over time, but whether this rate can be maintained into the future is unclear, as some autonomous adaptation enacted seemed rather easy to be taken. Markets may mediate or amplify impacts and in the second analysis, we use an economic general equilibrium model to assess the economic effects of a reduction in agricultural production due to drought and heatwave risk in exposed regions in Spain. The analysis suggests that modelled losses to the local economy are more serious in a large-scale scenario when neighbouring provinces are also affected by drought and heatwave events. This is due to the supply-side induced price increase leading to some passing on of disaster costs to consumers. The simulation highlights the importance of paying particular attention to the spatial and distributional effects weather extremes and possibly changes therein induced by climate change may incur. Finally, we discuss how national governments may better plan their disaster liabilities resulting from a need to manage relief and reconstruction activities post event. We do so using a risk based economic planning model assessing the fiscal consequences associated with the coping with natural extremes. We identify large weather-related disaster contingent liabilities, particularly in the key flood hot spot countries Austria, Romania, and Hungary. Such substantial disaster liabilities (“hidden disaster deficits”) when interacting with weak fiscal conditions may lead to substantial additional stress on government budgets and reduced fiscal space for funding other relevant public investment projects. Overall, our paper suggests the importance of respecting the specific spatial and temporal characteristics of extreme event risk when generating information on adaptation decisions. As our adaptation decisions considered, such as using sovereign risk financing instruments are associated with a rather short time horizon, the analysis largely focuses on the management of today’s extreme events and does not discuss in detail projections of risks into a future with climate change. Such projections raise important issues of uncertainty, which in some instances may actually render future projections non-robust, a constraint to be kept in mind when addressing longer term decisions, which at the same time should account for both climate and also socioeconomic change.     

Climate change and financial adaptation in Africa. Investigating the impact of climate change on the robustness of index-based microinsurance in Malawi

This paper discusses the applicability of crop insurance for the case of Malawi and explores the potential impact of climate change on the viability of the Malawi weather insurance program making use of scenarios of climate change-induced variations in rainfall patterns. The analysis is important from a methodological and policy perspective. By combining catastrophe insurance modeling with climate modeling, the methodology demonstrates the feasibility, albeit with large uncertainties, of estimating the effects of climate variability and climate change on the near- and long-term future of microinsurance schemes serving the poor. By providing a model-based estimate of insurance back-up capital necessary to avoid ruin under climate variability and climate change, along with the associated uncertainties and data limitations, this methodology can quantitatively demonstrate the need for financial assistance to protect micro-insurance pools against climate-induced insolvency. This is of major concern to donors, NGOs and others supporting these innovative systems, those actually at-risk and insurers providing insurance. A quantitative estimate of the additional burden that climate change imposes on weather insurance for poor regions is of interest to organizations funding adaptation. Further, by linking catastrophe modeling to regionalized climate modeling, the analysis identifies key modeling inputs necessary as well as important constraints. We end with a discussion of the opportunities and limits to similar modeling and weather predictability for Sub-Saharan Africa beyond the case of Malawi.

Abschätzung des Beitrages kommunaler Kläranlagen an Schadstoffkonzentrationen in Oberflächengewässern

A number of products, such as washing agents or pharmaceuticals, enter the hydrosphere mainly with municipal wastewater. In this case the predicted environmental concentrations (PEC) of substances are largely determined by their elimination in municipal wastewater treatment plants and by the dilution ratio of wastewater in the rivers. In this article some rough estimates of the wastewater ratio in German rivers are presented and as a starting point for a more complex model for calculating the PEC more exactly, data on the fluctuation of river flow rates are shown.     

Add-on conservation benefits of marine territorial user rights fishery policies in central Chile.

To combine the rational use of marine benthic resources and economic development of small-scale fishers, Chile passed legislation in 1991 establishing a comanagement policy that grants exclusive territorial user rights for fisheries (TURFs) to artisanal fisher organizations in well-defined inshore coastal areas, known as Management and Exploitation Areas for Benthic Resources (MEABRs). In general the policy has been proclaimed a management and economic success because benthic resource abundances have increased inside MEABRs in comparison with open-access areas. However, there is a lack of studies assessing the impact of this management policy on nontargeted subtidal species and community assemblages and the policy's implications for biodiversity and conservation. This study starts to fill this gap and links the allocation of TURFs for benthic resources with add-on conservation benefits for species that are not directly linked with the fishery policy. Comparative subtidal surveys inside vs. outside MEABRs were used to assess the effects of three MEABRs on managed targeted benthic species, biodiversity (species richness), and community assemblages in central Chile. Surveys focused exclusively on subtidal kelp forest habitats dominated by Lessonia trabeculata, spanning 4-12 m in depth and with similar levels of habitat complexity. The study comprised: (1) quantification of kelp forest complexity, (2) understory survey of sessile species, (3) quantification of conspicuous benthic macroinvertebrates, including those under management, and (4) quantification of reef-fish species inside the kelp habitat. Results showed population enhancement of target-managed invertebrates inside MEABRs. Moreover, reef-fish species were significantly more diverse and abundant inside MEABRs, and community assemblages of nontarget benthic invertebrates and reef fish were significantly different inside vs. outside MEABRs. The comanagement of inshore benthic resources in Chile, through MEABRs aims for the sustainability of invertebrate and algae stocks. However, our study shows that this management tool, which in practice restricts access to the entire management area, provides important conservation add-on effects for species that are not the focus of the management policies. Therefore, in Chile, the hundreds of already established MEABRs could represent an important ancillary network, which complements the biodiversity objectives of fully protected areas such as no-take marine protected areas or others.     

Earthworms and legumes control litter decomposition in a plant diversity gradient

The role of species and functional group diversity of primary producers for decomposers and decomposition processes is little understood. We made use of the "Jena Biodiversity Experiment" and tested the hypothesis that increasing plant species (1, 4, and 16 species) and functional group diversity (1, 2, 3, and 4 groups) beneficially affects decomposer density and activity and therefore the decomposition of plant litter material. Furthermore, by manipulating the densities of decomposers (earthworms and springtails) within the plant diversity gradient we investigated how the interactions between plant diversity and decomposer densities affect the decomposition of litter belonging to different plant functional groups (grasses, herbs, and legumes). Positive effects of increasing plant species or functional group diversity on earthworms (biomass and density) and microbial biomass were mainly due to the increased incidence of legumes with increasing diversity. Neither plant species diversity nor functional group diversity affected litter decomposition, However, litter decomposition varied with decomposer and plant functional group identity (of both living plants and plant litter). While springtail removal generally had little effect on decomposition, increased earthworm density accelerated the decomposition of nitrogen-rich legume litter, and this was more pronounced at higher plant diversity. The results suggest that earthworms (Lumbricus terrestris L.) and legumes function as keystone organisms for grassland decomposition processes and presumably contribute to the recorded increase in primary productivity with increasing plant diversity.