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871.
Climate and land-use changes affecting river sediment and brown trout in alpine countries—a review 总被引:1,自引:1,他引:0
Karin Scheurer Christine Alewell Dominik Bänninger Patricia Burkhardt-Holm 《Environmental science and pollution research international》2009,16(2):232-242
Background, aim, and scope
Catch decline of freshwater fish has been recorded in several countries. Among the possible causes, habitat change is discussed. This article focuses on potentially increased levels of fine sediments going to rivers and their effects on gravel-spawning brown trout. Indications of increased erosion rates are evident from land-use change in agriculture, changes in forest management practices, and from climate change. The latter induces an increase in air and river water temperatures, reduction in permafrost, changes in snow dynamics and an increase in heavy rain events. As a result, an increase in river sediment is likely. Suspended sediment may affect fish health and behaviour directly. Furthermore, sediment loads may clog gravel beds impeding fish such as brown trout from spawning and reducing recruitment rates. To assess the potential impact on fine sediments, knowledge of brown trout reproductive needs and the effects of sediment on brown trout health were evaluated.Approach
We critically reviewed the literature and included results from ongoing studies to answer the following questions, focusing on recent decades and rivers in alpine countries.Results
Rising air temperatures have led to more intensive precipitation in winter months, earlier snow melt in spring, and rising snow lines and hence to increased erosion. Intensification of land use has supported erosion in lowland and pre-alpine areas in the second half of the twentieth century. In the Alps, however, reforestation of abandoned land at high altitudes might reduce the erosion risk while intensification on the lower, more easily accessible slopes increases erosion risk. Data from laboratory experiments show that suspended sediments affect the health and behaviour of fish when available in high amounts. Point measurements in large rivers indicate no common lethal threat and suspended sediment is rarely measured continuously in small rivers. However, effects on fish can be expected under environmentally relevant conditions. River bed clogging impairs the reproductive performance of gravel-spawning fish.Discussion
Overall, higher erosion and increased levels of fine sediment going into rivers are expected in future. Additionally, sediment loads in rivers are suspected to have considerably impaired gravel bed structure and brown trout spawning is impeded. Timing of discharge is put forward and is now more likely to affect brown trout spawning than in previous decades.Conclusions
Reports on riverbed clogging from changes in erosion and fine sediment deposition patterns, caused by climate change and land-use change are rare. This review identifies both a risk of increases in climate erosive forces and fine sediment loads in rivers of alpine countries. Increased river discharge and sediment loads in winter and early spring could be especially harmful for brown trout reproduction and development of young life stages. Recently published studies indicate a decline in trout reproduction from riverbed clogging in many rivers in lowlands and alpine regions. However, the multitude of factors in natural complex ecosystems makes it difficult to address a single causative factor.Recommendations and perspectives
Further investigations into the consequences of climate change and land-use change on river systems are needed. Small rivers, of high importance for the recruitment of gravel-spawning fish, are often neglected. Studies on river bed clogging are rare and the few existing studies are not comparable. Thus, there is a strong need for the development of methods to assess sediment input and river bed clogging. As well, studies on the effects to fish from suspended sediments and consequences of gravel beds clogging under natural conditions are urgently needed. 相似文献872.
Jarkko V. Niemi Sanna Saarikoski Minna Aurela Heikki Tervahattu Risto Hillamo Douglas L. Westphal Päivi Aarnio Tarja Koskentalo Ulla Makkonen Hanna Vehkamäki Markku Kulmala 《Atmospheric environment (Oxford, England : 1994)》2009,43(6):1255-1264
The frequency, strength and sources of long-range transport (LRT) episodes of fine particles (PM2.5) were studied in southern Finland using air quality monitoring results, backward air mass trajectories, remote sensing of fire hot spots, transport and dispersion modelling of smoke and chemical analysis of particle samples (black carbon, monosaccharide anhydrides, oxalate, succinate, malonate, SO42?, NO3?, K+ and NH4+). At an urban background site in Helsinki, the daily WHO guideline value (24-h PM2.5 mean 25 μg m?3) was exceeded during 1–7 LRT episodes per year in 1999–2007. The 24-h mean maximum concentrations varied between 25 and 49 μg m?3 during the episodes, which was 3–6 times higher than the local mean concentration (8.7 μg m?3) in 1999–2007. The highest particle concentrations (max. 1-h mean 163 μg m?3) and the longest episodes (max. 9 days) were mainly caused by the emissions from open biomass burning, especially during springs and late-summers in 2002 and 2006. During the period 2001–2007, the satellite remote sensing of active fire hot spots and transport and dispersion modelling of smoke indicated that approximately half of the episodes were caused partly by the emissions from wildfires and/or agricultural waste burning in fields in Eastern Europe, especially in Russia, Belarus and Ukraine. Other episodes were mainly caused by the LRT of ordinary anthropogenic pollutants, e.g. from energy production, traffic, industry and wood combustion. During those ‘other episodes’, air masses also arrived from Eastern Europe, including Poland. The highest concentrations of biomass-burning tracers, such as monosaccharide anhydrides (levoglucosan + mannosan + galactosan) and K+, were observed during open biomass-burning episodes, but quite high values were also measured during some winter episodes due to wood combustion emissions. Our results indicate that open biomass burning in Eastern Europe causes high fine particle concentration peaks in large areas of Europe almost every year. 相似文献
873.
B. Reidy J. Webb T.H. Misselbrook H. Menzi H.H. Luesink N.J. Hutchings B. Eurich-Menden H. Döhler U. Dämmgen 《Atmospheric environment (Oxford, England : 1994)》2009,43(9):1632-1640
Six N-flow models, used to calculate national ammonia (NH3) emissions from agriculture in different European countries, were compared using standard data sets. Scenarios for litter-based systems were run separately for beef cattle and for broilers, with three different levels of model standardisation: (a) standardized inputs to all models (FF scenario); (b) standard N excretion, but national values for emission factors (EFs) (FN scenario); (c) national values for N excretion and EFs (NN scenario). Results of the FF scenario for beef cattle produced very similar estimates of total losses of total ammoniacal-N (TAN) (±6% of the mean total), but large differences in NH3 emissions (±24% of the mean). These differences arose from the different approaches to TAN immobilization in litter, other N losses and mineralization in the models. As a result of those differences estimates of TAN available at spreading differed by a factor of almost 3. Results of the FF scenario for broilers produced a range of estimates of total changes in TAN (±9% of the mean total), and larger differences in the estimate of NH3 emissions (±17% of the mean). The different approaches among the models to TAN immobilization, other N losses and mineralization, produced estimates of TAN available at spreading which differed by a factor of almost 1.7. The differences in estimates of NH3 emissions decreased as estimates of immobilization and other N losses increased. Since immobilization and denitrification depend also on the C:N ratio in manure, there would be advantages to include C flows in mass-flow models. This would also provide an integrated model for the estimation of emissions of methane, non-methane VOCs and carbon dioxide. Estimation of these would also enable an estimate of mass loss, calculation of the N and TAN concentrations in litter-based manures and further validation of model outputs. 相似文献
874.
Ulla Sellström Anna-Lena Egebäck Michael S. McLachlan 《Atmospheric environment (Oxford, England : 1994)》2009,43(10):1730-1736
PCDD/F contamination of the Baltic Sea has resulted in the European Union imposing restrictions on the marketing of several fish species. Atmospheric deposition is the major source of PCDD/Fs to the Baltic Sea, and hence there is a need to identify the source regions of the PCDD/Fs in ambient air over the Baltic Sea. A novel monitoring strategy was employed to address this question. During the winter of 2006–2007 air samples were collected in Aspvreten (southern Sweden) and Pallas (northern Finland). Short sampling times (24 h) were employed and only samples with stable air mass back trajectories were selected for analysis of the 2,3,7,8-substituted PCDD/F congeners. The range in the PCDD/F concentrations from 40 samples collected at Aspvreten was a factor of almost 50 (range 0.6–29 fg TEQ/m3). When the samples were grouped according to air mass origin into seven compass sectors, the variability was much lower (typically less than a factor of 3). This indicates that air mass origin was the primary source of the variability. The contribution of each sector to the PCDD/F contamination over the Baltic Sea during the winter half year of 2006/2007 was calculated from the average PCDD/F concentration for each sector and the frequency with which the air over the Baltic Sea came from that sector. Air masses originating from the south–southwest, south–southeast and east segments contributed 65% of the PCDDs and 75% of the PCDFs. Strong correlations were obtained between the concentrations of most of the PCDD/F congeners and the concentration of soot. These correlations can be used to predict the PCDD/F concentrations during the winter half year from inexpensive soot measurements. 相似文献
875.
Bärbel Langmann Bryan Duncan Christiane Textor Jörg Trentmann Guido R. van der Werf 《Atmospheric environment (Oxford, England : 1994)》2009,43(1):107-116
Gaseous and particulate emissions from vegetation fires substantially modify the atmospheric chemical composition, degrade air quality and can alter weather and climate. The impact of vegetation fire emissions on air pollution and climate has been recognised in the late 1970s. The application of satellite data for fire-related studies in the beginning of the 21th century represented a major break through in our understanding of the global importance of fires. Today the location and extent of vegetation fires, burned area and emissions released from fires are determined from satellite products even though many uncertainties persist. Numerous dedicated experimental and modeling studies contributed to improve the current knowledge of the atmospheric impact of vegetation fires. The motivation of this paper is to give an overview of vegetation fire emissions, their environmental and climate impact, and what improvements can be expected in the near future. 相似文献
876.
877.
Katja Kangas Anne Tolvanen Tarja Kälkäjä Pirkko Siikamäki 《Environmental management》2009,44(3):408-419
Outdoor recreation and nature-based tourism represent an increasingly intensive form of land use that has considerable impacts
on native ecosystems. The aim of this paper is to investigate how revegetation and management of ski runs influence soil nutrients,
vegetation characteristics, and the possible invasion of nonnative plant species used in revegetation into native ecosystems.
A soil and vegetation survey at ski runs and nearby forests, and a factorial experiment simulating ski run construction and
management (factors: soil removal, fertilization, and seed sowing) were conducted at Ruka ski resort, in northern Finland,
during 2003–2008. According to the survey, management practices had caused considerable changes in the vegetation structure
and increased soil nutrient concentrations, pH, and conductivity on the ski runs relative to nearby forests. Seed mixture
species sown during the revegetation of ski runs had not spread to adjacent forests. The experimental study showed that the
germination of seed mixture species was favored by treatments simulating the management of ski runs, but none of them could
eventually establish in the study forest. As nutrient leaching causes both environmental deterioration and changes in vegetation
structure, it may eventually pose a greater environmental risk than the spread of seed mixture species alone. Machine grading
and fertilization, which have the most drastic effects on soils and vegetation, should, therefore, be minimized when constructing
and managing ski runs. 相似文献
878.
Sabine Gärtner 《Environmental Sciences Europe》1998,10(3):154-156
The purpose of medicinal products is to act effectively on living organisms. If they reach environmental compartments it should be taken into account that they may have effects on biota in these compartments. Legislation on medicinal products has given little consideration to the risk that medicinal products may pose to the environment. In the near future there will be some progress according to amendments to the relevant legislative provisions. 相似文献
879.
Manfred Niecke Andreas Krüger Peter Hauff Hermann Ellenberg Ralph Labes Susanne Niecke 《Environmental Sciences Europe》1998,10(1):3-14
With the aid of the Hamburg proton micro-probe, we examined the concentration of mercury in sea eagle feathers collected over the course of several decades in the Mecklenburg-Vorpommern area. Based on the sites where these feathers were collected and the data of these findings, it is possible to get a differential picture of mercury contamination related both temporally and regionally to the mercurial pollution of seed mordants used agriculturally. We compared the concentrations found with a basic “geogenic” contamination which was also to be seen in the feather samples from the last century as detected in museum animal specimens. 相似文献
880.
Determining the Chernobyl impact on sediments of a pre-Alpine lake with a very comprehensive set of data 总被引:2,自引:0,他引:2
Erlinger Ch Lettner H Hubmer A Hofmann W Steinhäusler F 《Journal of environmental radioactivity》2008,99(8):1294-1301
Man-made and natural radionuclides in Lake Wallersee were determined in the pre-Alpine environment at the northern slope of the Alps, which was heavily affected by the Chernobyl fallout in May 1986. The objective of this study was to get knowledge of location and quantity of man-made radionuclide input (especially (137)Cs) generated in the Chernobyl accident to lake sediments. Eleven sediment cores were sampled and activity depth profiles of (137)Cs and (210)Pb were determined with 5mm depth-resolution. The Chernobyl fallout produced an extreme (137)Cs peak in the sediment cores providing an excellent time marker. The chronological interpretation of deeper sediment layers was done by radiochemical analysis of (90)Sr and (239+240)Pu, which were released during atmospheric weapons' tests in the 1950s and 1960s. This allowed a complete chronological analysis of the sediment cores with a very compact set of data. 相似文献