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Sökning: WFRF:(Nõges T.)

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1.
  • Moss, B, et al. (författare)
  • The determination of ecological status in shallow lakes - a tested system (ECOFRAME) for implementation of the European Water Framework Directive
  • 2003
  • Ingår i: Aquatic Conservation: Marine and Freshwater Ecosystems. - : Wiley. - 1052-7613. ; 13:6, s. 507-549
  • Tidskriftsartikel (refereegranskat)abstract
    • 1. The European Water Framework Directive requires the determination of ecological status in European fresh and saline waters. This is to be through the establishment of a typology of surface water bodies, the determination of reference (high status) conditions in each element (ecotype) of the typology and of lower grades of status (good, moderate, poor and bad) for each ecotype. It then requires classification of the status of the water bodies and their restoration to at least 'good status' in a specified period. 2. Though there are many methods for assessing water quality, none has the scope of that defined in the Directive. The provisions of the Directive require a wide range of variables to be measured and give only general guidance as to how systems of classification should be established. This raises issues of comparability across States and of the costs of making the determinations. 3. Using expert workshops and subsequent field testing, a practicable pan-European typology and classification system has been developed for shallow lakes, which can easily be extended to all lakes. It is parsimonious in its choice of determinands, but based on current limnological understanding and therefore as cost-effective as possible. 4. A core typology is described, which can be expanded easily in particular States to meet local conditions. The core includes 48 ecotypes across the entire European climate gradient and incorporates climate, lake area, geology of the catchment and conductivity. 5. The classification system is founded on a liberal interpretation of Annexes in the Directive and uses variables that are inexpensive to measure and ecologically relevant. The need for taxonomic expertise is minimized. 6. The scheme has been through eight iterations, two of which were tested in the field on tranches of 66 lakes. The final version, Version 8, is offered for operational testing and further refinement by statutory authorities.
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2.
  • Sagova-Mareckova, M., et al. (författare)
  • Expanding ecological assessment by integrating microorganisms into routine freshwater biomonitoring
  • 2021
  • Ingår i: Water Research. - : Elsevier. - 0043-1354 .- 1879-2448. ; 191
  • Forskningsöversikt (refereegranskat)abstract
    • Bioindication has become an indispensable part of water quality monitoring in most countries of the world, with the presence and abundance of bioindicator taxa, mostly multicellular eukaryotes, used for biotic indices. In contrast, microbes (bacteria, archaea and protists) are seldom used as bioindicators in routine assessments, although they have been recognized for their importance in environmental processes. Recently, the use of molecular methods has revealed unexpected diversity within known functional groups and novel metabolic pathways that are particularly important in energy and nutrient cycling. In various habitats, microbial communities respond to eutrophication, metals, and natural or anthropogenic organic pollutants through changes in diversity and function. In this review, we evaluated the common trends in these changes, documenting that they have value as bioindicators and can be used not only for monitoring but also for improving our understanding of the major processes in lotic and lentic environments. Current knowledge provides a solid foundation for exploiting microbial taxa, community structures and diversity, as well as functional genes, in novel monitoring programs. These microbial community measures can also be combined into biotic indices, improving the resolution of individual bioindicators. Here, we assess particular molecular approaches complemented by advanced bioinformatic analysis, as these are the most promising with respect to detailed bioindication value. We conclude that microbial community dynamics are a missing link important for our understanding of rapid changes in the structure and function of aquatic ecosystems, and should be addressed in the future environmental monitoring of freshwater ecosystems. (c) 2020 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/ )
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  • Björnerås, C., et al. (författare)
  • Widespread Increases in Iron Concentration in European and North American Freshwaters
  • 2017
  • Ingår i: Global Biogeochemical Cycles. - 0886-6236 .- 1944-9224. ; 31:10, s. 1488-1500
  • Tidskriftsartikel (refereegranskat)abstract
    • Recent reports of increasing iron (Fe) concentrations in freshwaters are of concern, given the fundamental role of Fe in biogeochemical processes. Still, little is known about the frequency and geographical distribution of Fe trends or about the underlying drivers. We analyzed temporal trends of Fe concentrations across 340 water bodies distributed over 10 countries in northern Europe and North America in order to gain a clearer understanding of where, to what extent, and why Fe concentrations are on the rise. We found that Fe concentrations have significantly increased in 28% of sites, and decreased in 4%, with most positive trends located in northern Europe. Regions with rising Fe concentrations tend to coincide with those with organic carbon (OC) increases. Fe and OC increases may not be directly mechanistically linked, but may nevertheless be responding to common regional-scale drivers such as declining sulfur deposition or hydrological changes. A role of hydrological factors was supported by covarying trends in Fe and dissolved silica, as these elements tend to stem from similar soil depths. A positive relationship between Fe increases and conifer cover suggests that changing land use and expanded forestry could have contributed to enhanced Fe export, although increases were also observed in nonforested areas. We conclude that the phenomenon of increasing Fe concentrations is widespread, especially in northern Europe, with potentially significant implications for wider ecosystem biogeochemistry, and for the current browning of freshwaters.
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  • Gyllström, Mikael, et al. (författare)
  • The role of climate in shaping zooplankton communities of shallow lakes
  • 2005
  • Ingår i: Limnology and Oceanography. - 1939-5590. ; 50:6, s. 2008-2021
  • Tidskriftsartikel (refereegranskat)abstract
    • We analyzed data from 81 shallow European lakes, which were sampled with standardized methods, for combined effects of climatic, physical, and chemical features of food-web interactions, with a specific focus on zooplankton biomass and community structure. Multiple-regression analysis showed that total phosphorus (TP) generally was the most important predictor of zooplankton biomass and community structure. Climate was the next most important predictor and acted mainly through its effect on pelagic zooplankton taxa. Benthic and plant-associated taxa (typically almost half the total zooplankton biomass) were, however, affected mainly by macrophyte coverage. Neither climate nor TP affected the relation between small and large taxa, and we found only a weak trend with increasing TP of increasing mean crustacean body mass. Dividing the data set into three climate zones revealed a pronounced difference in response to lake productivity between cold lakes, with long periods of ice cover, and the two warmer lake types. These ‘‘ice’’ lakes differed from the others with respect to the effect of TP on chlorophyll a, the zooplankton : chlorophyll a ratio, the chlorophyll a :TP ratio, and the proportion of cyclopoids in the copepod community. Our data suggest that bottom-up forces, such as nutrient concentration, are the most important predictors of zooplankton biomass. In addition, climate contributes significantly—possibly by affecting top-down regulation by fish—and may interact with productivity in determining the zooplankton standing biomass and community composition. Hence, the present study suggests that food-web dynamics are closely linked to climatic features.
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