Regional Risk Assessment addressing the impacts of climate change in the coastal area of the Gulf of Gabes (Tunisia)

Sound, cost efficient management strategies in developed coastal zones can be reinforced by a thorough understanding of risks associated with the combination of anthropogenic and natural drivers of change. A Regional Risk Assessment (RRA) methodology was developed for the assessment of the potential impacts of climate change in the Tunisian coastal zone of the Gulf of Gabes. It is based on the use of Multi-Criteria Decision Analysis techniques and Geographic Information Systems and is designed to support the development and prioritization of adaptation strategies. The RRA focuses on sea-level rise and storm surge flooding impacts for human and natural systems, i.e., beaches, wetlands, urban areas, agricultural areas, and terrestrial ecosystems. Results suggest that for both of the studied climate change impacts, i.e., sea-level rise and storm surge flooding, the area potentially exposed is limited to a narrow, low elevation region adjacent to the shoreline. However, the exposed areas showed a high relative risk score, obtained by the integration of exposure and susceptibility factors. Beaches have the lowest relative risk scores, while wetlands and terrestrial ecosystems have the higher relative risk scores. The final outputs of the analysis (i.e., exposure, susceptibility, and risk maps) can support end-users in the establishment of relative priorities for intervention and in the identification of suitable areas for human settlements, infrastructure, and economic activities, thus providing a basis for coastal zoning and land-use planning.     

Environmental monitoring and radioecology: a necessary synergy

Environmental monitoring primarily aims through sampling or by the use of direct detection equipment to quantify the levels of radioactive substances and ionising radiation resulting from human activities and natural sources in the different compartments of the environment. Its objectives are very practical and include the quantification of the environmental sources of ionising radiation and the verification of compliance with regulatory requirements and permit limits for industrial, research and medical activities, as stated by their specific licence. Radioecology is a multidisciplinary science, which attempts to understand and to quantify the behaviour of radionuclides in the environment and the processes ruling their transport through natural and agricultural ecosystems to various receptors such as plants, animals and humans. A second facet of this science covers the assessment of the radiological dose to and effects on man and its environment from present, past or future, even hypothetical, nuclear activities. Despite their different immediate objectives, environmental monitoring and radioecology are complementary. Many examples illustrate the connections between these two approaches. For instance, transfer parameters generated by radioecological studies are necessary to estimate through models the radiological exposure of population, derive from the contamination level measured in a bio-indicator the quantity of radioactivity released from a nuclear installation, or identify potentially important pathways to be monitored. On the other hand, monitoring data will confirm important pathways suggested by radioecological modelling and provide site-specific data for the estimation of model parameters or actual data sets for the validation of transfer models.     

Assessing and managing sediment contamination in transitional waters

Sediment contamination remains a global problem, particularly in transitional waters such as estuaries and coastal lagoons, which are the recipients of chemicals from multiple near- and far-field sources. Although transitional waters are highly productive ecosystems, approaches for assessing and managing their sediment contamination are not as well developed as in marine and fresh waters. Further, although transitional waters remain defined by their variable and unique natural water quality characteristics, particularly salinity, the biota inhabiting such ecosystems, once thought to be defined by Remane's “paradox of brackish water”, are being redefined. The purpose of the present paper is to build on an earlier but now dated (> 12 years old) review of methods to assess sediment contamination in estuaries, extending this to all transitional waters, including information on integrative assessments and on management decision-making. The following are specifically discussed: chemical assessments; bioindicators; biomarkers; and, biological surveys. Assessment and management of sediment contamination in transitional waters need to be focused on ecosystem services and, where appropriate and possible, be proactive rather than reactive when uncertainty has been suitably reduced.     

Does human activity impact the natural antibiotic resistance background? Abundance of antibiotic resistance genes in 21 Swiss lakes

Antibiotic resistance genes (ARGs) are emerging environmental contaminants, known to be continuously discharged into the aquatic environment via human and animal waste. Freshwater aquatic environments represent potential reservoirs for ARG and potentially allow sewage-derived ARG to persist and spread in the environment. This may create increased opportunities for an eventual contact with, and gene transfer to, human and animal pathogens via the food chain or drinking water. However, assessment of this risk requires a better understanding of the level and variability of the natural resistance background and the extent of the human impact. We have analyzed water samples from 21 Swiss lakes, taken at sampling points that were not under the direct influence of local contamination sources and analyzed the relative abundance of ARG using quantitative real-time PCR. Copy numbers of genes mediating resistance to three different broad-spectrum antibiotic classes (sulfonamides: sul1, sul2, tetracyclines: tet(B), tet(M), tet(W) and fluoroquinolones: qnrA) were normalized to copy numbers of bacterial 16S rRNA genes. We used multiple linear regression to assess if ARG abundance is related to human activities in the catchment, microbial community composition and the eutrophication status of the lakes. Sul genes were detected in all sampled lakes, whereas only four lakes contained quantifiable numbers of tet genes, and qnrA remained below detection in all lakes. Our data indicate higher abundance of sul1 in lakes with increasing number and capacity of wastewater treatment plants (WWTPs) in the catchment. sul2 abundance was rather related to long water residence times and eutrophication status. Our study demonstrates the potential of freshwater lakes to preserve antibiotic resistance genes, and provides a reference for ARG abundance from lake systems with low human impact as a baseline for assessing ARG contamination in lake water.     

Estimation of critical loads for radiocaesium in Fennoscandia and Northwest Russia

The application of the critical loads methodology for radioactive contamination of Arctic and sub-arctic ecosystems, where natural and semi-natural food products are important components of the diet of many people, is proposed and discussed. The critical load is herein defined as the amount of radionuclide deposition necessary to produce radionuclide activity concentrations in food products exceeding intervention limits. The high transfer of radiocaesium to reindeer meat gives this product the lowest critical load, even though the intervention limit is relatively high compared with other products. Ecological half-lives of radiocaesium in natural and semi-natural products are often very long, and it is therefore important to take account of contamination already present in the event of an accident affecting areas where such products are important. In particular, the long ecological half-life for radiocaesium in moose meat means that the critical load is highly sensitive to prior deposition. An example of the potential application of the method for emergency preparedness is given for the Chernobyl accident.     

Ozone and natural systems: understanding exposure,response, and risk

Research aimed at understanding the response of plants to ozone has been conducted for over four decades but little of it has addressed intact natural systems. Even so, there is sufficient scientific information at this time to support air quality standards that will protect natural terrestrial ecosystems from ozone. What is unknown is the risk associated with continued exposure of natural systems, including both above- and below-ground components, in combination with other stresses including changing temperature and precipitation, elevated carbon dioxide, pests and pathogens, invasive species, and other activities that may fragment the landscape. Research to support an assessment of the ecological risk associated with ozone as it exists, in a milieu of stresses, must include endpoints beyond those addressed in the past, primarily productivity and species composition. To estimate the risk to society of ozone impacts on natural systems, endpoints such as the integrity of soil food webs, the quantity and quality of water supplied from terrestrial ecosystems, wildlife and recreational values, and the transfer and fate of carbon, nutrients, and water within the systems must be quantified. Not only will this research provide the basis for a sound estimate of risk, but also it will improve our understanding of fundamental ecosystem processes.     

The impact of bacterial larvicidal agent and larvivorous fish on the preimaginal phases of bloodsucking mosquitoes in aquatic ecosystems of Southern Western Siberia

It has been shown that ecological prerequisites for the spread of bloodsucking mosquitoes from different aquatic ecosystems in the south of Western Siberia may be controlled by reducing the density of larval hemipopulations. The bacterial agent Bactiñide is most efficient in open water systems. In ecosystems overgrown with herb-shrub vegetation, an integrated approach should be used, which involves both stocking with belica (Leucaspius delineatus) and application of Bacticide. The development of larvivorous fish in the permanent water systems of the Karasuk-Burlinsk region and Teletskoye Lake basin contributes to elimination of mosquito larvae and, thus, to the improvement of natural environment.     

Linking Ecological Sustainability and World Food Needs

Ecological approaches to agriculture can provide useful guidelines for addressing world food needs, while avoiding adverse environmental and social impacts. Experiments in both natural and agricultural ecosystems suggest that systems with high plant diversity may be more productive, more stable and more resilient than species-poor systems. In addition, systems with high plant diversity support higher levels of biodiversity in other functional groups, which may enhance the productivity of the plant component. Given these benefits of diverse systems, various approaches for converting conventional high input agricultural systems to more sustainable systems are addressed. Andow and Hidaka's (1989) concept of production syndromes is considered in the context of conversion to sustainable agriculture.     

Ecological issues related to N deposition to natural ecosystems: research needs

There has and continues to be concern about the effects of elevated nitrogen (N) deposition on natural ecosystems. In this paper, research on natural ecosystems, including wetlands, heathlands, grasslands, steppe, naturally regenerated forests and deserts, is evaluated to determine what is known about nitrogen cycling in these ecosystems, the effects of elevated nitrogen on them and to identify research gaps. Aquatic ecosystems are not included in this review, except as they are part of the larger ecosystem. Research needs fall into several categories: (1) improved understanding and quantification of the N cycle, particularly relatively unstudied processes such as dry deposition, N fixation and decomposition/mineralization; (2) carbon cycling as affected by increased N deposition; (3) effects on arid ecosystems and other "neglected" ecosystems; (4) effects on complex ecosystems and interactions with other pollutants; (5) indicators and assessment tools for natural ecosystems.     

Soil-plant transfer of plutonium and americium in contaminated regions of Belarus after the Chernobyl catastrophe

Experimental data are presented for the soil to plant transfer of plutonium and americium into the main species of grass vegetation of Belarusian grasslands contaminated as a result of the Chernobyl catastrophe of 1986. The content of radionuclides in pore soil solutions and the total reserve of biologically available forms of plutonium and americium in rooting layers of different soil varieties have been established. The distribution coefficients of (239,240)Pu and 241Am between the solid phase and pore waters of soils have been evaluated. The migration ability and biological availability of radionuclides in soils with different structures of the absorbing complex have been analyzed for various landscape conditions. The dependence of soil to plant transfer of plutonium and americium on the content and composition of organic matter, and other characteristics of the soil complex has been studied. On the basis of these data, predictions of the contamination levels of the main grass species of natural and agricultural ecosystems by 241Am are presented.     

The use of the shanny Lipophrys pholis for pollution monitoring: a new sentinel species for the northwestern European marine ecosystems

The contamination of aquatic ecosystems by organic contaminants such as polycyclic aromatic hydrocarbons (PAHs) is a matter of great concern. Mussels have been extensively used as sentinel species in a large number of monitoring programs. However, the use of bivalves as the sole species has some limitations, because they are not as responsive as fish to Aryl Hydrocarbon Receptor agonists. Hence, for many marine areas, there is the need to validate new sentinel fish species that can be used in the assessment of pollution by organic contaminants. The shanny Lipophrys pholis is an intertidal fish that combines many characteristics required in a sentinel species: is abundant and easy to catch, has a wide geographical distribution and restrict home range. After larvae recruitment to the intertidal rocky shores, they remain in the same area for the rest of the life-cycle, thus reflecting local pollutants exposure. In order to evaluate the species sensitivity to organic contaminants under field conditions, L. pholis were collected at six sites reflecting different degrees of anthropogenic contamination. The induction of two biomarkers extensively validated in the assessment of PAHs contamination ethoxyresorufin-O-deethylase activity (EROD) and Fluorescent Aromatic Compounds (FACs) was evaluated. In parallel, mussels were collected at the same locations and levels of 16 PAHs and selected heavy metals determined. Overall, the specimens collected in the urban areas showed a significant induction of EROD and FACs (up to a six-fold induction) if compared with the reference sites. Additionally, a positive correlation was observed between the biomarkers and PAHs levels in mussel tissues. Even though further validation is currently in progress, the available data indicate that L. pholis is responsive to organic contaminants such as PAHs, suggesting its future integration in monitoring programmes designed to evaluate the presence of these contaminants in European marine ecosystems.     

Experience in establishing a natural standard for analyzing the dynamics of taiga ecosystems

Experience in organizing a natural reference area (standard) for studies on the functional dynamics of ecosystems in connection with paludification and forest-bog relationships is described. The essence of studies on ecosystem dynamics with the aid of natural standards and key plots is described using an example of the Yenisei region of Western Siberia. Arguments are presented for the necessity of using a differential approach to studies on the dynamics of nature and taking into account local ecological conditions while extrapolating the results of these studies to other geographic regions.     

The significance of agricultural vs. natural ecosystem pathways in temperate climates in assessments of long-term radiological impact

Recent developments in performance assessment biosphere models have begun to emphasise the importance of natural accumulation pathways. In contrast to the agricultural pathways, the database for natural ecosystem pathways is less well developed, leading to a mismatch in quality of representations of the two types of system. At issue is the lack of reliable soil-plant and animal ingestion transfer factors for key radionuclides in natural ecosystems. The relative importance of the agricultural vs. natural ecosystem pathways is investigated here, in the context of a temperate site in present day, Eastern France. The BIOMASS Candidate Critical Group (CCG) methodology has been applied to map a set of eight candidate critical groups derived from the present-day societal context onto physical locations within a simple model of a river catchment system. The overall assessment model has been implemented using the Aquabios code. Annual individual dose to each of the CCGs has been calculated for each of the key radionuclides (79Se, 94Nb, 99Tc, 129I, 135Cs and 237Np) released to the valley aquifer and river. In addition to the traditional agricultural pathways, lifestyle groups exploiting natural habitats are explicitly addressed. Results show the susceptibility of different candidate critical groups to different radionuclides. A reference database typical of those employed in long-term performance assessment models is employed. Doses from external exposure (94Nb) and dust inhalation (237Np) are shown to dominate agricultural food consumption by factors of more than six, but, with the reference data set, foodstuffs obtained from natural ecosystems do not contribute significantly to critical group dose and, at most, show similar exposures to the agricultural pathways. This may lead to the conclusion that natural food can be ruled out of consideration in performance assessment models. However, systematic parametric sensitivity studies carried out on soil-plant and animal ingestion transfer factors restrict the validity of this observation and demonstrate the limitations of existing databases. Remaining uncertainties can be reduced by improving structural models for performance assessment and by better characterisation of sources of locally obtained foods. Improved characterisation of radionuclide accumulation in natural ecosystems in temperate as well as alternative future climate states should complement the modelling approach.     

城市化对周边土壤资源与环境的影响

城市化快速发展对土壤资源产生巨大压力。因而对粮食安全与环境生态健康带来严峻挑战，作为一种非再生性自然资源，土壤的各种功能在城市化过程中强烈的人为活动影响下转化，演变和消失，那么，寻求城市化过程中土壤资源的可持续利用，在环境友好的模式下协调土壤自然生态与社会经济发展，最大限谋发挥土壤生态，生产和社会，经济功能，也是城市化快速发展的重要前提，也是最终实现可持续城市目标的基础。     

MUD: a Model to investigate the migration of 137Cs in the Urban environment and Drainage and sewage treatment systems

A model is presented for the migration of 137Cs in the urban environment, including the drainage systems and the sewage treatment plants, with flexibility to be adapted to different configurations common in urban areas. The dynamics of 137Cs is simulated both under natural evolution and in case of forced decontamination, which can have a direct impact on the radioactivity going to sewers. The model assesses the activity concentrated in sewage sludge and that discharged with the treated or untreated effluent to the receiving watercourse. Tests made for two post-Chernobyl contamination scenarios in Sweden show differences between model predictions and observed results within the range of the experimental uncertainties. An uncertainty and sensitivity analysis of the main model parameters indicates that some parameters may have a significant influence on the results of the model. Moreover, the model uncertainty is driven by a few parameters; therefore, additional research could be necessary into these parameters, aiming at simplifying the model without losing its predictive power.     

Stability of aquatic ecosystems and their variation under conditions of toxic pollution

The development of concepts concerning the stability of aquatic ecosystem and their variation under conditions of toxic pollution and after its reduction is considered. General trends in ecosystem transformation are explained in terms of theoretical ecology and thermodynamic mechanisms of energy ordering in living systems. Basic symptoms of disorganization in ecosystems under extreme loads and of their regenerative self-organization are discussed. It is shown that the development of a new modification of an aquatic ecosystem after a decrease in toxic pollution complies with the pattern of ecosystem succession: from a natural ecosystem, via the critical stage, to its more stable but structurally different modification.     

Aerial measurements of artificial radionuclides in Germany in case of a nuclear accident

Gamma-ray spectrometric systems carried by helicopters prove to be indispensable for the surveillance of environmental radioactivity. The aerial measurements are an important tool for rapid and large-scale nuclide specific determination of soil contamination after an accidental release of radionuclides from a nuclear facility. Furthermore this technique is also applied for the determination of anomalies of elevated radioactivity of natural radionuclides, the detection of lost radioactive sources and geological mapping. For the measurements the helicopters are equipped with a NaI(Tl)-detector array and a high purity germanium-semiconductor (HPGe) detector. Especially with the HPGe-detector it is possible to clearly identify individual radionuclides. To improve and to guarantee the quality of this method several exercises with different fields of interest have been carried out during the last years. Thereby the main focus is on the improvement of the instrumentation, data handling and data analysis. The results of the airborne radionuclide measurements from the Black Forest which was performed in co-operation with the Swiss National Emergency Operation Centre, are presented here. During this exercise the gamma dose rate, soil contamination due to 137Cs and the specific activities of natural radionuclides in soil were determined.     

From frontier economics to an ecological economics of the oceans and coasts

Ecological economics is a field of enquiry that has had, with a few exceptions, an almost entirely terrestrial focus. Given the fundamental ecological and economic importance of oceanic and coastal ecosystems, and the accelerating deterioration of these ecosystems, we argue that there is an urgent case to redress this imbalance. In so doing, the scope of ecological economics will be extended and compelling insights developed and applied to better understand and govern marine systems. Although we acknowledge that there is no unequivocal or unitary view of what might constitute an ecological economics of the oceans and coasts, we assert that it should consist of at least ‘four cornerstones’: (1) sustainability as the normative goal; (2) an approach that sees the socio-economic system as a sub-system of the global ecological system; (3) a complex systems approach; and (4) transdisciplinarity and methodological pluralism. Using these four cornerstones, we identify a future research agenda for an ecological economics of the oceans and coasts. Specifically, we conclude that ecological economists must work with other disciplines, especially those involved in marine policy and practice, to move from a ‘frontier economics’ (which has dominated marine management) to entrench an ‘ecological economics’ of the oceans and coasts as the dominant paradigm.     

Managing common pool resources without state support: insights from Shisholeka community in Central Zambia

Increasingly, emphasis is being placed on the role of indigenous or locally crafted natural resources management systems in sustainable natural resources management. While it is generally agreed that their potential to sustain and protect natural ecosystems exists in large measure, such systems are increasingly facing diverse internal and external pressures that threaten their viability. These pressures include demographic and economic change, land privatisation policies, renewable energy investment projects and large-donor-driven livelihood projects. Such pressures and their complexity raise the need to understand how local communities organise to protect resources they collectively value in the face of both internal and external pressures. Based on empirical data collected through interviews, participant observations, focus group discussions and a questionnaire survey conducted with local level actors in Shisholeka village of Central Zambia, this paper shows how local actors, in the absence of state support, react to internal and external pressures to develop robust and locally suited governance and institutional arrangements that best suit their interests in order to sustain their resource base.     

Linking health and ecology in the medical curriculum

Human health vulnerabilities to ecosystem degradation are well documented. Destabilization of natural ecosystems and the biosphere have posed an entirely new set of risks to human health and preclude any simple extrapolations from the past. Newly emerging diseases, increasing prevalence of many vector borne diseases, increased exposure to harmful UV radiation and a number of other transformations in the natural environment, have decidedly negative implications for the sustainability of human health. Curricula in medical schools are responding to these new realities by exposing the connections between health and ecology. The program in Ecosystem Health at the University of Western Ontario serves as one model for connecting these disciplines. This program has resulted in a perceptible shift in values and professional responsibilities of emerging physicians.