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Sökning: WFRF:(Kahlert Maria)

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1.
  • Kahlert, Maria, et al. (författare)
  • Kiselalger i Blekinge 2011
  • 2012
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • Sammanfattningsvis så visar kiselalgsfloran i de undersökta vattendragen i Blekinge län att närsaltshalten i dessa vatten är i överlag låg med undantag av Västra Orlundsån Ned Agerum (Möllebjörke). Detta vattendrag är troligtvis även organisk förorenat, vilket möjligtvis gäller även Fröjadalsbäcken Möllenäs. Angående surhet så visar kiselalgsmetoden att 13 undersökta lokaler hade nära neutrala eller alkaliska förhållanden medan de flesta andra var måttligt sura. Undantagen var Bäck fr Porsgölen nedstr. bron och Bäck fr. Skinsagylet Värhult, nedstr. bron samt Lyckebyån Kättilsmåla nedströms Lillåns tillflöde som var surare med risk för försurning. Andelen missbildningar var relativ höga i Mållebäcken Stensjömåla med 5,8 % deformerade skal och även i Bäck NV om Åkeholm, uppströms väg innan utflöde i Bäck NV om Åkeholm Uppstr väg innan utflöde i Mörrumsån med 2,6 %, vilket tyder på en trolig påverkan av metaller, eftersom en påverkan av lantbrukskemilarier verkar osannolik. Den vanligaste kiselalgstaxon räknat till antal räknade skal var Achnanthidium minutissimum grupp II (medelbredd 2,2-2,8µm)
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2.
  • Bighiu, Maria, et al. (författare)
  • Limited effects of pesticides on stream macroinvertebrates, biofilm nematodes, and algae in intensive agricultural landscapes in Sweden
  • 2020
  • Ingår i: Water Research. - : Elsevier BV. - 0043-1354 .- 1879-2448. ; 174
  • Tidskriftsartikel (refereegranskat)abstract
    • Pesticides are frequently detected in surface waters, sometimes at levels exceeding ecotoxicological guidelines. We screened for almost 100 pesticides in 32 streams from intense agricultural areas in Southern Sweden, in concert with water chemistry parameters. In addition, we investigated the communities of benthic macroinvertebrates, biofilm nematodes and algae and calculated multiple bioassessment metrics. The number of pesticides found in each stream ranged between 2 and 52, but the sum of Toxic Units (Sigma TU) for the mixtures was generally low, and exceeded the European Uniform Principles only in a single sample for algae and in 2% of the samples for Daphnia. Only nematode communities were significantly correlated with the Sigma TU, potentially due to their higher pesticide exposure in biofilms. Diatom metrics showed that most streams were impacted by eutrophication and macroinvertebrate metrics showed good status in most streams, whereas the SPEAR(pesticides) (SPEcies At Risk) index, specifically designed to indicate pesticide effects, showed that about half of the samples were at risk. Interestingly, SPEAR(pesticides) was not correlated to Sigma TUDaphnia and this discrepancy suggests that redefining the boundaries for quality classes might be necessary for this index. Moreover, SPEAR(pesticides) was positively correlated with the commonly used macroinvertebrate index ASPT, although disparate results were found for several streams. We argue that this questions the scaling of both metrics and the specificity of their responses. We discuss that the overall good/moderate status of the streams, despite the intense agriculture in the catchments, can be due to the fact that i) a sampling strategy with repeated grab samples did not capture peak pesticide concentrations, thus underestimating acute exposure, ii) pesticide run-off indeed was low, due to measures such as buffer strips, and iii) the nutrient-rich conditions and high sediment loads counteracted pesticide toxicity. We conclude that agricultural land use was the overriding stressor in the investigated streams, including strong effects of nutrients, less apparent effects of pesticides and likely impact of hydromorphological alterations (not specifically addressed in this study). (C) 2020 The Authors. Published by Elsevier Ltd.
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5.
  • Corcoll, Natàlia, 1981, et al. (författare)
  • Linking pesticide pollution with periphyton quality in agricultural streams: a fatty-acids approach
  • 2018
  • Ingår i: SETAC Europe 28th Annual Meeting 13−17 May 2018 | Rome, Italy. Abstract Book.. - 2309-8031.
  • Konferensbidrag (refereegranskat)abstract
    • Although the environmental risks associated with pesticide pollution in agricultural streams are quite well documented, little is know about its potential effects on periphyton quality. Periphyton provides many of the essential polyunsaturated fatty acids (PUFA) that are needed for organisms at higher trophic levels in river food webs. This study aims to assess the effects of pesticide mixtures on periphyton quality in situ. Three streams (Höje å, Skivarpsån and M42) located in the agriculturally dominated region of Skåne (SE Sweden) were sampled in September and October 2016. The effects of pesticide pollution were assessed by passive field sampling coupled with laboratory ecotoxicity tests, by mixture toxicity modelling to predict which chemical stressors were potentially driving the toxicity, and by examining the fatty acid profiles, pigment content and algal diversity of periphyton communities. Results from water chemical analyses clearly showed higher levels of nutrients and pesticide pollution in Skivarpsån and M42 than in Höje å. Ecotoxicity tests using the passive sampler extracts demonstrated that the pesticide mixtures ocurring at Skivarpsån and M42 were toxic for periphyton communities from Höje å, causing an inhibition of the photosynthetic activity up to 63% and 53%, respectively. Cluster and principal component analyses based on pigments content, algal diversity and fatty acid profiles, clearly separated the periphyton from the three river sites studied. Algal biomass from periphyton of pesticide polluted streams (Skivarpsån and M42) was higher than in Höje å. The nutritive quality of the periphyton differed among streams, and fatty acids considered high-quality such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were also more abundant in pesticide polluted streams (Skivarpsån and M42). Overal, even though results from the lab show that the mixture of pesticides pollution in the studied streams might be toxic for periphyton (i.e. inhibiting the photosynthetic activity), being herbicides the driving chemical stressors. Results from the field, indicate that when the levels of pesticide pollution are low and co-occur with high levels of nutrients pollution, nutrients migh mask pesticides effects on periphyton quantity and quality because compensatory effects from nutrients
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8.
  • Diehl, Sebastian, et al. (författare)
  • Inverse relationship of epilithic algae and pelagic phosphorusin unproductive lakes : Roles of N2 fixers and light
  • 2018
  • Ingår i: Freshwater Biology. - Chichester : Wiley-Blackwell Publishing Inc.. - 0046-5070 .- 1365-2427. ; 63:7, s. 662-675
  • Tidskriftsartikel (refereegranskat)abstract
    • 1. Phosphorus (P) often limits the biomass of primary producers in freshwater lakes. However, in unproductive northern lakes, where anthropogenic nitrogen (N) deposition is low, N instead of P can limit primary producers. In addition, light can be limiting to primary producers at high concentrations of coloured dissolved organic matter (cDOM), as cDOM is the major determinant of light penetration in these lakes.2. To address resource limitation of epilithic algal biomass, we repeatedly sampled epilithon (periphyton on stony substrata) in 20 lakes covering a large, correlated cDOM and N-deposition gradient across boreal and subarctic Sweden. Across these lakes, pelagic total N (TN) and total P (TP) were positively correlated, and benthic light supply was negatively correlated, with cDOM. Microscopically determined algal biovolume and epilithic carbon (C), N and P were subsequently regressed against benthic light supply and pelagic TN and TP.3. Patterns in epilithic biovolume were driven by N2-fixing cyanobacteria, which accounted for 2%–90% of total epilithic biovolume. Averaged over the growing season, epilithic algal biovolume, C and N were negatively related to TP and positively to TN, and were highest in the clearest, most phosphorus-poor lakes, where epilithon was heavily dominated by potentially N2-fixing cyanobacteria.4. A structural equation model supports the hypothesis that cDOM had two counteracting effects on total epilithic algal biovolume: a positive one by providing N to algae that depend on dissolved N for growth, and a negative one by shading N2-fixing cyanobacteria, with the negative effect being somewhat stronger.5. Together, these findings suggest that (1) light and N are the main resources limiting epilithic algal biomass in boreal to subarctic Swedish lakes, (2) epilithic cyanobacteria are more competitive in high-light and low-nitrogen environments, where their N2-fixing ability allows them to reach high biomass, and (3) epilithic N increases with N2 fixer biomass and is—seemingly paradoxically—highest in the most oligotrophic lakes. © 2018 John Wiley & Sons Ltd
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9.
  • Drakare, Stina, et al. (författare)
  • EuropaBON EBV workflow templates
  • 2024
  • Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
    • The information provided here represents the EBV workflow templates collected during the EuropaBON online workshop on Essential Biodiversity Variable (EBV) workflows from 22–24 February 2023. The templates were designed to capture comprehensive descriptions about the three workflow components (data collection and sampling, data integration, and modelling) that are typical for generating EBVs. Recognising the potential value of those EBV templates for European biodiversity monitoring, our objective is to share them for enhancing transparency, knowledge exchange and collaboration, and promoting the operationalisation of EBVs across Europe.EuropaBON (https://europabon.org/) is a Horizon 2020 research and innovation action funded by the European Commission that seeks to co-design a European Biodiversity Observation Network. This network aims to bridge the gap between the biodiversity data needs of policy-makers and authorities on the one hand and the existing reporting streams and available data sources on the other hand, considering both present obligations and forthcoming policy needs. Essential Biodiversity Variables (EBVs) are a central concept of EuropaBON as they provide a standardised framework for biodiversity monitoring and reporting. In 2023, EuropaBON had identified 70 EBVs (Junker et al., 2023) that are policy-relevant for the EU, and measurable with available and existing technologies and with a proven track record of feasibility in ongoing initiatives. EBVs require workflows to process the raw data (primary observations) through data integration and modelling into spatially-explicit EBV data products (Kissling et al., 2018; Schmeller et al., 2017). These workflows can be broken down into three main components (data collection and sampling, data integration, and modelling), with additional aspects of data interoperability and IT infrastructure being recognised as crucial for transnational data streams (Kissling & Lumbierres, 2023).To capture information about the EBV workflows, an online workshop was held on 22–24 February 2023 with 520 registered participants from 49 countries, covering a large range of expertise (Lumbierres & Kissling, 2023). Participants contributed information on EBV workflow components and advanced monitoring techniques, discussed initiatives, and identified tools and requirements for implementing 70 proposed EBVs. The information from the workshop participants was collected through pre-defined EBV workflow templates (provided as Google Docs). Templates were organised into rows representing the workflow components (‘Data collection and sampling’, ‘Data integration’, and ‘Modelling’) and columns reflecting the levels of maturity ('Current initiatives', 'Emerging tools and projects' or 'Future needs'). Prior to the workshop, some information on existing workflows was pre-filled based on previous EuropaBON deliverables, namely an assessment of the current biodiversity monitoring gaps in the EU (Santana et al., 2023) and an assessment of current EU monitoring workflows and bottlenecks (Morán-Ordóñez et al., 2023).After the workshop, the EBV workflow templates were processed to ensure the accuracy and relevance of the information. Each listed initiative was verified to be part of an active biodiversity monitoring scheme and pertinent to the specific EBV under consideration, cross-referencing with the initiative’s websites and other data collected by the EuropaBON deliverables (Morán-Ordóñez et al., 2023; Santana et al., 2023). Moreover, we ensured correct alignment of each initiative and listed requirements and needs with the appropriate workflow components and maturity levels.The EBV workflow templates provide insights into the current biodiversity monitoring landscape in Europe and how EBV production could be operationalized at the EU level. They offer detailed information about ongoing initiatives and projects, methodologies, and technologies that can be used to generate EBVs at a continental scale. Nevertheless, it is important to note that they do not encompass an exhaustive list of all ongoing or proposed initiatives of biodiversity monitoring in all member states of the EU. It is suggested to use them as a starting point and baseline for the further development of EBVs in a European context.
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10.
  • Drakare, Stina, et al. (författare)
  • Implementation options for DNA-based identification into ecological status assessment under the European Water Framework Directive
  • 2018
  • Ingår i: Water Research. - : Elsevier BV. - 0043-1354 .- 1879-2448. ; 138, s. 192-205
  • Forskningsöversikt (refereegranskat)abstract
    • Assessment of ecological status for the European Water Framework Directive (WFD) is based on “Biological Quality Elements” (BQEs), namely phytoplankton, benthic flora, benthic invertebrates and fish. Morphological identification of these organisms is a time-consuming and expensive procedure. Here, we assess the options for complementing and, perhaps, replacing morphological identification with procedures using eDNA, metabarcoding or similar approaches. We rate the applicability of DNA-based identification for the individual BQEs and water categories (rivers, lakes, transitional and coastal waters) against eleven criteria, summarised under the headlines representativeness (for example suitability of current sampling methods for DNA-based identification, errors from DNA-based species detection), sensitivity (for example capability to detect sensitive taxa, unassigned reads), precision of DNA-based identification (knowledge about uncertainty), comparability with conventional approaches (for example sensitivity of metrics to differences in DNA-based identification), cost effectiveness and environmental impact. Overall, suitability of DNA-based identification is particularly high for fish, as eDNA is a well-suited sampling approach which can replace expensive and potentially harmful methods such as gill-netting, trawling or electrofishing. Furthermore, there are attempts to replace absolute by relative abundance in metric calculations. For invertebrates and phytobenthos, the main challenges include the modification of indices and completing barcode libraries. For phytoplankton, the barcode libraries are even more problematic, due to the high taxonomic diversity in plankton samples. If current assessment concepts are kept, DNA-based identification is least appropriate for macrophytes (rivers, lakes) and angiosperms/macroalgae (transitional and coastal waters), which are surveyed rather than sampled. We discuss general implications of implementing DNA-based identification into standard ecological assessment, in particular considering any adaptations to the WFD that may be required to facilitate the transition to molecular data.
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11.
  • Drakare, Stina, et al. (författare)
  • Redundancy in the ecological assessment of lakes: Are phytoplankton, macrophytes and phytobenthos all necessary?
  • 2016
  • Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 568, s. 594-602
  • Tidskriftsartikel (refereegranskat)abstract
    • Although the Water Framework Directive specifies that macrophytes and phytobenthos should be used for the ecological assessment of lakes and rivers, practice varies widely throughout the EU. Most countries have separate methods for macrophytes and phytobenthos in rivers; however, the situation is very different for lakes. Here, 16 countries do not have dedicated phytobenthos methods, some include filamentous algae within macrophyte survey methods whilst others use diatoms as proxies for phytobenthos. The most widely-cited justification for not having a dedicated phytobenthos method is redundancy, i.e. that macrophyte and phytoplankton assessments alone are sufficient to detect nutrient impacts. Evidence from those European Union Member States that have dedicated phytobenthos methods supports this for high level overviews of lake condition and classification; however, there are a number of situations where phytobenthos may contribute valuable information for the management of lakes. (C) 2016 The Authors. Published by Elsevier B.V. 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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12.
  • Epp, Alexandra, et al. (författare)
  • Sialylation of IgG antibodies inhibits IgG-mediated allergic reactions
  • 2018
  • Ingår i: Journal of Allergy and Clinical Immunology. - : Elsevier BV. - 1097-6825 .- 0091-6749. ; 141:1, s. 8-402
  • Tidskriftsartikel (refereegranskat)abstract
    • In presence of high allergen dosis besides IgE also IgG antibodies can induce allergic reactions, whose severity is dependent on the induced type of IgG Fc glycosylation, what should be considered for new AIT protocols containing new adjuvants.
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13.
  • Feckler, Alexander, et al. (författare)
  • Blinded by the light: Increased chlorophyll fluorescence of herbicide-exposed periphyton masks unfavorable structural responses during exposure and recovery
  • 2018
  • Ingår i: Aquatic Toxicology. - : Elsevier BV. - 0166-445X .- 1879-1514. ; 203, s. 187-193
  • Tidskriftsartikel (refereegranskat)abstract
    • In surface waters within agricultural catchments, periphyton - i.e., biofilms containing algae, heterotrophs, and associated detritus - is subjected to multiple stressors including herbicides. Although herbicide effects on periphyton are frequently studied, the focus has been on photosynthesis-inhibiting herbicides while other modes of toxic action have received little attention. Against this background, a 21-days-lasting bioassay was conducted, during which mature periphytic communities were exposed to the carotenoid-biosynthesis-inhibiting herbicide diflufenican for 12 days (up to 10 mu g/L; n = 4), followed by a 9-days-lasting recovery phase in herbicide-free medium. Variables related to periphytic functioning (photosynthetic efficiency and non-photochemical quenching) and structure (pigment concentrations, biomass, and algal community structure) were quantified every third day during both experimental phases. Exposure to >= 0.2 mu g diflufenican/L resulted in 20-25% and 25-30% lowered carotenoid and chlorophyll a concentrations, respectively, likely explained by a reduced algal biovolume as well as diflufenican's mode of toxic action and thus a shift towards a higher heterotrophy of the communities. Despite these adverse effects on the photosynthetic apparatus, the photosynthetic efficiency increased by up to similar to 15% under diflufenican exposure judged on higher chlorophyll fluorescence. This may be explained by an up to similar to 60% reduced non-photochemical quenching as well as binding of diflufenican to the pigment-protein membrane complex of the photosystem II, two processes causing higher chlorophyll fluorescence. Additionally, phototrophs may have actively increased energy assimilation to cope with higher energy demands under chemical stress. Although periphyton showed some recovery potential following the exposure phase, observed as increasing chlorophyll a concentrations and non-photochemical quenching, periphyton may not be able to quickly recover from stress given the persistent increase in the photosynthetic efficiency. While the processes underlying the observed effects yet remain speculative, the results suggest a shift towards a higher degree of heterotrophy in periphytic communities ultimately increasing the importance of heterotrophic ecosystem functions at impacted sites over the long term.
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14.
  • Feckler, Alexander, et al. (författare)
  • Impacts of Contaminants on the Ecological Role of Lotic Biofilms
  • 2015
  • Ingår i: Bulletin of Environmental Contamination and Toxicology. - : Springer Science and Business Media LLC. - 0007-4861 .- 1432-0800. ; 95, s. 421-427
  • Forskningsöversikt (refereegranskat)abstract
    • Biofilms play a fundamental ecological role in freshwater ecosystems as they contribute to ecosystem function(s) such as autotrophic primary production, organic matter decomposition and the bottom-up directed energy transfer in the food web. The present focused review summarizes the scientific knowledge on how the roles of autotrophic and heterotrophic biofilms can be modulated as a response to chemical (i.e., pesticide) stress. We discuss how horizontal effects (alterations in the structure of biofilms) can affect the physiological fitness and life history strategy of the next trophic level (vertical effects), namely primary consumers. Since the literature indicates that heterotrophic biofilms are currently at risk as a result of pesticide stress, the protectiveness of environmental risk assessment in Europe as well as North America is questioned. By briefly outlining substantial knowledge gaps, we provide ideas on how the identified uncertainties may be empirically addressed.
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15.
  • Goedkoop, Willem, et al. (författare)
  • Biologisk karaktärisering av bäckar i typområden jordbruksmark
  • 2009
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • Projektet (kontraktnr. 222 0742) omfattar standardiserad provtagning av fastsittande kiselalger, bottenfauna och fisk (elfiske), taxonomiska analys och bedömning med nya bedömningsgrunderna för dessa kvalitetsfaktorer för vattendragen i typområden jordbruksmark (8 intensivområden). Även en bedömning av vattenkemi ingår i uppdraget. Syftet med uppdraget är att genom analys av påväxtalger, bottenfauna och fisksamhället och en bedömning med nya bedömningsgrunder för miljökvalitet göra en karaktärisering och analys av ekologisk status för vattendragen i typområden jordbruksmark (8 intensivområden).
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  • Goedkoop, Willem, et al. (författare)
  • CAFF Circumpolar Biodiversity Monitoring Program State of Arctic Freshwater Biodiversity Report
  • 2019
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • Arctic freshwater ecosystems (lakes, rivers, and associated wetlands) are threatened by climate change and human development that can affect freshwater biodiversity. Such effects will change not only the distributions and abundances of aquatic species, but also the lives of Arctic Peoples that are dependent on the ecosystem services supplied by lakes and rivers. Thus, the freshwater biodiversity program of the Circumpolar Biodiversity Monitoring Program (Freshwater-CBMP) focuses on lake and river ecosystems and has established a long-term monitoring framework for these Arctic freshwaters. Developed for the Conservation of Arctic Flora and Fauna (CAFF; the biodiversity Working Group of the Arctic Council), this framework facilitates more accurate and rapid detection, communication and response to significant trends in Arctic water quality and biodiversity. Freshwater-CBMP goals are addressed in the “Arctic Freshwater Biodiversity Monitoring Plan”, which describes an integrated, ecosystem-based approach for monitoring Arctic freshwaters.
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18.
  • Goedkoop, Willem, et al. (författare)
  • Undersökning av pesticidorsakade effekter på bentiska organismsamhällen i jordbrukspåverkade vattendrag
  • 2018
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • Under 2015 och 2016 provtogs sammanlagt 32 respektive 13 vattendrag i jordbruksbygder med avseende paett antal biologiska variabler (pavaxtalger, meiofauna och makroskopisk bottenfauna) bottenfauna och medavseende pa oorganisk vattenkemi (narsalter, metaller, alkalinitet, m.m.). Proverna togs och analyserades avackrediterad personal vid SLU. Backarna ingick i det screeninguppdrag som SLU fick av Naturvardsverket2015–2016, utom 4 som utgor del av det nationella miljoovervakningsprogrammet (M42, N34, O18, E21).Undersokningen en unik mojlighet att fa ett dataunderlag som innefattar bade kvantifieringar av exponeringenmed bekampningsmedel (beraknat som toxiska enheter, ΣTU, med akuta EC50-varden) och den biologiskaresponsen hos olika organismgrupper i jordbrukspaverkade vattendrag.Generellt var det svart att koppla analyser av de biologiska samhallena till exponeringen medbekampningsmedel (ΣTU). Det beror framst pa att toppar med kraftiga fororeningar med bekampningsmedelnoterades endast i enstaka fall. Analyserna visade att exponeringen for alger oftast overskred EU:s uniformprinciples, en regulatorisk koncentration for vilken inga effekter ska forekomma for enskilda substanser.Pavaxtalgerna har dock en kort generationstid och en snabb tillvaxt och torde visa en snabb aterhamtning efteren exponering.Analys av algssamhallena uppvisade en stor variation i biomassa och artsammansattning blandvattendragen. Tradformiga gronalger och tradformiga rodalger var vanligt forekommande, och kiselalger,framforallt arter som lever som enstaka celler, fanns pa alla lokaler. De flesta algtaxa ar typiska for naringsrikavattendrag och vatten med neutralt eller hogt pH. Forekomsten av rodalger tyder pa en mojlig begransningmed ljus i vissa backar, och forekomsten av kiselalgstaxon Diadesmis contenta var. contenta tyder pa starkavattenstandsforandringar i andra. Den ekologiska statusklassningen med fastsittande kiselalger bekraftade attde flesta vattendrag var naringsrika, framforallt rika pa fosfor, samt att nagra aven var mattligt eller starktpaverkade av organiska, syretarande fororeningar. De flesta av vattendragen klassades som mattlig ekologiskstatus. Andelen deformerade kiselalgsskal overskred 1% pa en tredjedel av lokalerna vilket kan tyda pa enpaverkan av miljogifter sasom metaller eller bekampningsmedel. Redundansanalys for kiselalger visade intepa en signifikant paverkan fran herbiciderna. Daremot paverkades kiselalgernas artsammansattning signifikantav aluminium-, jarn- och kvavekoncentrationerna i vattnet.Bottenfaunadata visade att alla vattendrag utom O18 uppnar hog eller god ekologisk status narbedomningen gors med ASPT. For SPEARpesticides-indexet lag samtliga varden utom fyra under 33, vilket i denvetenskapliga litteraturen anges som grans for god-mattlig status, utan att ha en formell sadan status iTyskland. SPEARpesticides visar med andra ord en helt annan bild an ASPT som ingar i de svenskabedomningsgrunderna. Bade ASPT och SPEARpesticides visar dock, liksom i tidigare analyser, ett starktstatistiskt samband (R2 = 0,62). Det starka sambandet tyder pa att de bada indexen i stort satt mater sammapaverkan, fast i olika skalor. Tidigare analyser har ocksa visat att bada indexen visar ett starkt samband medandelen jordbruksmark i vattendragens avrinningsomrade. Varken ASPT eller SPEARpesticides visar ett tydligtsamband med den maximalt uppmatta ΣTUDaphnia under sasongen, vilket kan beror pa de generellt laga vardenfor ΣTUDaphnia.Redundansanalys visade att ΣTUDaphnia inte paverkade bottenfaunasamhallena signifikant. Daremot fannvi att meiofaunasamhallen i biofilmerna pa stenarna signifikant paverkades av ΣTUDaphnia. Resultatet kan beropa att denna mindre fauna lever mer exponerat och att vissa bekampningsmedel kan ackumulera i biofilmerna.Nematodfaunan i biofilmerna visade pa nema-SPEAR-varden under gransen for god status i Kavlingean,Segea och M42. Atta vattendrag hade en sa pass rik nematodfauna med manga fororeningskansliganematodarter att Nema-SPEAR indikerade hog ekologisk status.Analysen visar att vattendrag som erfar en stark jordbrukspaverkan och fysisk paverkan haller enoverraskande god status med avseende pa pavaxtalger och bottenfauna. En kombination av hoganasaltskoncentrationer, en god syresattning som foljd av stromforhallandena, samt en god tillgang till fodakan bidra till att vattendragen far en rik bottenfauna och forhallandevist hoga indexvarden. Aven det faktumatt provtagning gors pa de sparsamma steniga bottnarna (dar mojligt) i de annars sand/lerbottendomineradevattendragen kan bidra till att de visar forhallandevis hog status.
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19.
  • Goncalves, Sara, et al. (författare)
  • A freshwater diatom challenged by Zn: Biochemical, physiological and metabolomic responses of Tabellaria flocculosa(Roth) Kutzing
  • 2018
  • Ingår i: Environmental Pollution. - : Elsevier BV. - 0269-7491 .- 1873-6424. ; 238, s. 959-971
  • Tidskriftsartikel (refereegranskat)abstract
    • Freshwater ecosystems are under threatening anthropogenic pressures worldwide, namely by metals. Diatoms are used as water quality indicators, but the influence of micronutrients such as Zn and its impacts are poorly understood. Thus, our study aimed to elucidate the tolerance level, the cellular targets and the responses to counteract Zn toxicity of freshwater diatoms by exposing Tabellaria flocculosa, isolated from a Zn contaminated stream. Biochemical, physiological and metabolomic approaches were used. It was demonstrated that Zn is toxic to T. flocculosa at concentrations occurring in contaminated environments. At low stress (30 mu g Zn/L) few alterations in the metabolome were observed, but the enzymatic (SOD, CAT) and molecular (GSH, GSSG) antioxidant systems were induced, protecting cells from oxidative stress. At moderate stress (500 mu g Zn/L) the main changes occurred in the metabolome (increases in fatty acids, amino acids, terpenoids, glycerol and phosphate, decreases in sucrose and lumichrome) with a moderate increase in cell damage (LPO and PC). The concerted action of all these mechanisms resulted in a non-significant decrease of growth, explaining the survival of this T flocculosa strain in an environment with this Zn concentration. At the highest stress level (1000 mu g Zn/L) the metabolome was identical to 500 mu g Zn/L, and the induction of antioxidant systems and extracellular ion chelation (exopolysaccharides, frustulins) were the main responses to the increase of Zn toxicity. However, these mechanisms were unable to effectively abrogate cellular damage and growth reduction was observed. Moreover, the decrease in sucrose and especially in lumichrome should be tested as new specific markers of Zn toxicity. The information obtained in this study can assist in environmental risk assessment policies, support the prediction of diatom behaviour in highly impacted Zn environments, such as mining scenarios, and may help develop new indices, which include alterations induced by metals. (C) 2018 Elsevier Ltd. All rights reserved.
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20.
  • Goncalves, Sara, et al. (författare)
  • Assessing Cu impacts on freshwater diatoms: biochemical and metabolomic responses of Tabellaria flocculosa (Roth) Kutzing
  • 2018
  • Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 625, s. 1234-1246
  • Tidskriftsartikel (refereegranskat)abstract
    • Metals are a recognised threat to aquatic organisms but the impact of metals such as copper (Cu) on benthic freshwater diatoms is poorly understood, even if diatoms are commonly used as water quality indicators. Our study aimed to elucidate the cellular targets of Cu toxicity and the mechanisms cells resort to counteract toxicity and to increase tolerance to Cu. A concerted approach analysing the biochemical, physiological and metabolome alterations in diatom cells was conducted by exposing the freshwater diatom Tabellaria flocattosa to 0, 0.3, 6 and 10 mu g Cu/L. Cu was already toxic to T. flocculosa at concentrations common in environments and which are not usually considered to be contaminated (0.3 mu g Cu/L). Under Cu impact, the metabolome of T. flocculosa changed significantly, especially at high concentrations (6 and 10 mu g Cu/L). Cu toxicity was counteracted by increasing extracellular immobilization (EPS, frustulins), antioxidant (SOD, CAT) and detoxifying (GSTs) enzymes activity and low molecular weight antioxidants (GSH). These mechanisms were fuelled by higher energy production (increased ETS activity). At the highest Cu concentration (10 mu g/L), these processes were specially enhanced in an attempt to restrain the oxidative stress generated by high intracellular Cu concentrations. However, these mechanisms were not able to fully protect cells, and damage in membranes and proteins increased. Moreover, the decrease of hydroxylamine and unsaturated fatty acids and the increase of saturated fatty acids, 2-palmiloylglycerol, glycerol and diterpenoid compounds should be tested as new specific markers of Cu toxicity in future studies. This information can support the prediction of diatom behaviour in different Cu contamination levels, including highly impacted environments, such as mining scenarios, and may assist in environmental risk assessment policies and restoration programs. (C) 2018 Elsevier B.V. All rights reserved.
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21.
  • Goncalves, Sara, et al. (författare)
  • Valve teratologies and Chl c in the freshwater diatom Tabellaria flocculosa as biomarkers for metal contamination
  • 2019
  • Ingår i: Ecological Indicators. - : Elsevier BV. - 1470-160X .- 1872-7034. ; 101, s. 476-485
  • Tidskriftsartikel (refereegranskat)abstract
    • Freshwater benthic diatoms, routinely used for bioassessment, are potential metal indicators because of their known capacity to reflect changes in water chemistry. Nevertheless, the effect of metals on benthic freshwater diatoms is still poorly understood. Metals, such as Zn and Cu, are not only essential as micronutrients, but also one of the main anthropogenic pressures in aquatic ecosystems. However, metal stress cannot be detected with the current European standard methods using bioindicators for environmental assessment, so new tools need to be developed. We studied the effects of Zn and Cu on the freshwater diatom Tabellaria flocculosa. This diatom isolated from a Zn and Cu contaminated stream, was exposed to different concentrations of Zn and Cu, and the metal effects were assessed by measuring physiological ((growth, fluorescence, pigments' content (Chl a, c, carotenoids)) and morphological parameters (teratological forms). We found that at environmental concentrations occurring in European streams, Zn and Cu showed toxic effects on T. flocculosa. Toxic effects induced by Zn were only observed at high concentrations (500 and 1000 mu g/L), resulting in fluorescence changes, an increase of Chl c cellular content and an increase of teratological forms (with an increase of more heavily deformed valves with increasing metal concentrations). Increasing Cu exposure induced several changes, such as increasing the cellular content of Chl a and c, while carotenoids' cellular content decreased. Cu also increased the number of T. flocculosa frustule deformations. Cu did not affect the cellular fluorescence. Our results thus show that the frequency of diatom teratologies could potentially be used to assess metal stress for the studied metals Zn and Cu. Additionally, the analysis of algal pigments could potentially separate the effects of different metals.
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22.
  • Gottschalk, Steffi, et al. (författare)
  • Comparing aspirations: intercalibration of ecological status concepts across European lakes for littoral diatoms
  • 2014
  • Ingår i: Hydrobiologia. - : Springer Science and Business Media LLC. - 0018-8158 .- 1573-5117. ; 734, s. 125-141
  • Tidskriftsartikel (refereegranskat)abstract
    • Eleven European countries participated in an exercise to harmonise diatom-based methods used for status assessment in lakes. Lakes were divided into low, medium and high alkalinity types for this exercise. However, it was not possible to perform a full intercalibration on low alkalinity lakes due to the short gradient and confounding factors. Values of the Trophie Index were computed for all samples in order that national datasets could all be expressed on a common scale. Not all participants had reference sites against which national methods could be standardised and, therefore, a Generalised Linear Modelling approach was used to control the effect of national differences in datasets. This enabled the high/good and good/moderate status boundaries to be expressed on a common scale and for deviations beyond +/- 0.25 class widths to be identified. Those countries which had relaxed boundaries were required to adjust these to within +/- 0.25 class widths whilst the intercalibration rules allowed those countries with more stringent boundaries to retain these. Despite biogeographical and typological differences between countries, there was broad agreement on the characteristics of high, good and moderate status diatom assemblages, and the exercise has ensured consistent application of Water Framework Directive assessments around Europe.
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23.
  • Gottschalk, Steffi, et al. (författare)
  • Shifts in taxonomical and guild composition of littoral diatom assemblages along environmental gradients
  • 2012
  • Ingår i: Hydrobiologia. - : Springer Science and Business Media LLC. - 0018-8158 .- 1573-5117. ; 694, s. 41-56
  • Tidskriftsartikel (refereegranskat)abstract
    • Diatoms are commonly and frequently used as water quality indicators, but only a few studies have been done to evaluate the importance of littoral, contemporary diatoms as bioindicators. This study aims to determine the main predictors of diatom community composition from 73 Swedish lakes. Canonical correspondence analysis (CCA) revealed pH, phosphate, nitrite/nitrate levels, longitude and percentage of forest in the catchment to be the most important factors of 51 environmental variables for structuring diatom assemblages. Cluster analysis separated the lakes into three groups based on the diatom community composition. Lakes belonging to these groups were characterised as: (1) acidic, nutrient-poor; (2) circumneutral, nutrient-poor and (3) alkaline, nutrient-rich, according to the results of a discriminant function analysis and dominant diatom taxa revealed by similarity percentage analysis. Ecological guilds according to growth morphology and the ability of nitrogen-fixation were assigned to all diatom taxa. All three lake groups exhibited a distinct guild composition. Nitrogen-fixing diatoms were found in nutrient-rich lakes, only. Our results indicate that taxonomical composition of littoral diatom assemblages can be applied in the assessment of nutrient and acidity status of Swedish lakes. Differences in distribution of the ecological guilds were connected to several environmental factors such as nutrients, light and grazing; their application in assessment of trophic status of lakes is therefore precarious.
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24.
  • Göthe, Emma, et al. (författare)
  • Headwater biodiversity among different levels of stream habitat hierarchy
  • 2014
  • Ingår i: Biodiversity and Conservation. - : Springer Science and Business Media LLC. - 0960-3115 .- 1572-9710. ; 23, s. 63-80
  • Tidskriftsartikel (refereegranskat)abstract
    • With the current loss of biodiversity and threats to freshwater ecosystems, it is crucial to identify hot-spots of biodiversity and on which spatial scale they can be resolved. Conservation and management of these important ecosystems needs insight into whether most of the regional biodiversity (i.e. gamma-diversity) can be found locally (i.e. high alpha-diversity) or whether it is distributed across the region (i.e. high beta-diversity). Biodiversity patterns of benthic macroinvertebrates and diatoms were studied in 30 headwater streams in five Swedish catchments by comparing the relative contribution of alpha- and beta-diversity to gamma-diversity between two levels of stream habitat hierarchy (catchment and region level). The relationship between species community structure and local environmental factors was also assessed. Our results show that both alpha- and beta-diversity made a significant contribution to gamma-diversity. beta-diversity remained relatively constant between the two levels of habitat hierarchy even though local environmental control of the biota decreased from the catchment to the region level. To capture most of headwater gamma-diversity, management should therefore target sites that are locally diverse, but at the same time select sites so that beta-diversity is maximized. As environmental control of the biota peaked at the catchment level, the conservation of headwater stream diversity is likely to be most effective when management targets environmental conditions across multiple local sites within relatively small catchments.
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25.
  • Hasselquist, Eliza Maher, et al. (författare)
  • Contrasting effects of geomorphic complexity on diversity of three aquatic organism groups after stream restoration
  • Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
    • Ecological theory states that greater habitat heterogeneity should support higher biodiversity. Many stream restoration projects aim to increase geomorphic complexity, assuming that this increases habitat heterogeneity and, thus, biodiversity. However, little evidence has been published that supports this theory, especially with respect to stream restoration and aquatic organisms.Previous assessments of stream habitat restoration have suffered from four major limitations: (1) incomplete quantification of habitat complexity metrics, (2) assessment of the responses of only one organism group, most often macroinvertebrates, (3) mismatch between scale of restoration and scale of disturbance, and (4) limited number of restoration measures applied.We used 12 metrics of geomorphic complexity spanning five dimensions of complexity (sediment grain size distribution, longitudinal profile, cross section, planform, and instream wood) to evaluate if the diversity, abundance and community composition of three aquatic organism groups (benthic macroinvertebrates, diatoms and macrophytes) relate positively to complexity along near-natural, restored and channelised stream reaches in rural northern Sweden where disturbance to the streams has been primarily reach-scale channelisation to facilitate timber floating.We found that the variation in biodiversity and abundance within each of the three organism groups could be described by multiple regression models that included only geomorphic complexity metrics, but the variation within an organism group could rarely be described by only one metric of complexity in isolation. Rather, three metrics were needed on average to describe the variation in biodiversity and abundance, and rarely did all metrics relate positively to diversity. Sediment grain size distribution metrics were most often significant as explanatory variables, but were inconsistent in the direction of influence. The other four dimensions of complexity were less consistently significant but were nearly all positively related to our diversity metrics.Most of the variation in these metrics was driven by advanced restoration techniques and to a lesser extent older best practice techniques. Three complexity metrics were most often included in multiple regression models as well as described community composition in ordinations:  a metric quantifying heterogeneity of small sediment sizes, a metric that represents the variation in stream depth along the longitudinal profile, and instream wood metrics. Therefore, specifically these metrics could be targets for future restoration. The organism groups were not concordant in their patterns of diversity, abundance, or community composition; thus, none can be used as a surrogate in monitoring biodiversity of these sites.Synthesis and applications. Geomorphic complexity should be measured in multiple dimensions, and ideally in all five dimensions, to understand the full breadth of restoration impacts to which organisms could be responding. More than one organism group should be used in monitoring to ensure biodiversity goals are met. Finally, even though the scale of the restorations matched the scale of the disturbance at the reach scale, the older best practice methods of restoration rarely restored the large-scale features necessary to bring the sites up to their potential levels of complexity as these elements (large boulders, bedrock, log jams) had been destroyed or removed from the system. Although the advanced restoration sites were the youngest, advanced restoration techniques that added big boulders, coarse gravel and instream wood increased complexity to a level that elicited a biological response. Finally, the complexity level needed to elicit a biological response could be difficult to understand for a given system, so we suggest doing restoration work in an experimental way in collaboration with geomorphologists to determine what level of complexity is needed.
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26.
  • Hasselquist, Eliza Maher, et al. (författare)
  • Contrasting Responses among Aquatic Organism Groups to Changes in Geomorphic Complexity Along a Gradient of Stream Habitat Restoration : Implications for Restoration Planning and Assessment
  • 2018
  • Ingår i: Water. - : MDPI. - 2073-4441. ; 10:10
  • Tidskriftsartikel (refereegranskat)abstract
    • Many stream restoration projects aim to increase geomorphic complexity, assuming that this increases habitat heterogeneity and, thus, biodiversity. However, empirical data supporting these linkages remain scant. Previous assessments of stream restoration suffer from incomplete quantification of habitat complexity, or a narrow focus on only one organism group and/or one restoration measure, limiting learning. Based on a comprehensive quantification of geomorphic complexity in 20 stream reaches in northern Sweden, ranging from streams channelized for timber floating to restored and reference reaches, we investigated responses of macroinvertebrates, diatoms, and macrophytes to multiple geomorphic metrics. Sediment size heterogeneity, which was generally improved in restored sites, favored macroinvertebrate and diatom diversity and macroinvertebrate abundance. In contrast, macrophyte diversity responded to increased variation along the longitudinal stream profile (e.g., step-pools), which was not consistently improved by the restoration. Our analyses highlight the value of learning across multiple restoration projects, both in identifying which aspects of restoration have succeeded, and pinpointing other measures that might be targeted during adaptive management or future restoration. Given our results, a combination of restoration measures targeting not only sediment size heterogeneity, but also features such as step-pools and instream wood, is most likely to benefit benthic biota in streams.
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27.
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28.
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29.
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30.
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31.
  • Kahlert, Maria (författare)
  • A comparison of national approaches to setting ecological status boundaries in phytobenthos assessment for the European Water Framework Directive: results of an intercalibration exercise
  • 2009
  • Ingår i: Hydrobiologia. - : Springer Science and Business Media LLC. - 0018-8158 .- 1573-5117. ; 621, s. 169-182
  • Tidskriftsartikel (refereegranskat)abstract
    • The European Union (EU)'s Water Framework Directive (WFD) requires that all Member States participate in intercalibration exercises in order to ensure that ecological status concepts and assessment levels are consistent across the EU. This paper describes one such exercise, performed by the countries in the Central/Baltic Geographical Intercalibration Group stretching from Ireland in the west to Estonia in the east and from the southern parts of Scandinavia to the northern regions of Spain and Italy (but excluding alpine regions, which were intercalibrated separately). In this exercise, methods used to measure ecological status of rivers using benthic diatoms were compared. Ecological status is estimated as the ratio between the observed value of a biological element and the value expected in the absence of significant human impact. Approaches to defining the 'reference sites', from which these 'expected' values were derived, varied from country to country. Minimum criteria were established as part of the exercise but there was still considerable variation between national reference values, reflecting typological differences that could not be resolved during the exercise. A simple multimetric index was developed to compare boundary values using two widely used diatom metrics. Boundary values for high/good status and good/moderate status set by each participant were converted to their equivalent values of this intercalibration metric using linear regression. Variation of +/- 0.05 EQR units around the median value was considered to be acceptable and the exercise provided a means for those Member States who fell significantly above or below this line to review their approaches and, if necessary, adjust their boundaries.
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32.
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33.
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34.
  • Kahlert, Maria (författare)
  • Analys av kiselalger LKAB, Kiruna 2011
  • 2012
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • Sammanfattningsvis så visar kiselalgsfloran i de undersökta vattendragen inte på någon störning. Både referenser skiljer sig ej mycket från lokalerna nedströms. Den ganska rika diversiteten, det medelstora taxaantalet, det låga andelen deformerade skal och den höga statusklassningen tyder alla på att kiselalgsfloran i de undersökta vattendragen mår bra. Det verkar inte heller finnas en övergödning- eller försurningsproblem och lokalerna är inte kalkade. Det nya utloppet från sjön öppnades den 11 juli 2011 och proverna togs den 25 augusti, vilket innebär att lokalerna exponerats under ca 1,5 månad. Vattenkemidata visar dock att inga förändringar i t.ex. metallhalten hade skett under denna tid, vilket gör det osannolikt att kiselalgerna exponerades för någon toxiskt påverkan. Undersökningen kan därför anses vara ett underlag vid bedömningen av kommande undersökningar.
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35.
  • Kahlert, Maria, et al. (författare)
  • Analys av Kiselalger LKAB, Kiruna 2012
  • 2013
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • Pahtajoki/Rautasälven. Sammanfattningsvis visar kiselalgsfloran i de undersökta vattendragen i Pahtajoki/Rautasälven inte på någon störning bortsett från andelen störningstoleranta skal, vilket dock är ett osäkert tecken på en störning eftersom de kan finnas där naturligt. Referenserna skiljer sig inte mycket från lokalerna nedströms. Den ganska rika diversiteten, det medelstora antalet taxa, den låga andelen deformerade skal, den höga statusklassningen och den surhetsklassningen som nära neutralt tyder alla på att kiselalgsfloran i de undersökta vattendragen är ett samhälle som inte påverkas nämndvärd av mänskliga aktiviteter. Det verkar inte heller finnas ett övergödnings- eller försurningsproblem, surheten verkar vara naturligt för regionen, och lokalerna verkar inte vara kalkade. Det nya utloppet från sjön öppnades den 11 juli 2011, fortfarande tyder inget på att kiselalgerna är påverkade. Luossajoki, Tuollujoki och Pahtajoki söder om Kiruna. Kiselalgsfloran i de undersökta lokalerna i Luossajoki och Pahtajoki (Pa1), men inte Tuollujoki, verkar vara delvis påverkad. Troligen kommer påverkan i Luossajoki från Kiruna reningsverk (KVA135 och KVA136). I Pahtajoki (Pa1) verkar det ske en påverkan från verksamhet vid eller längre uppströms Kiruna flygplats. Det finns möjligtvis en diffus påverkan av miljögifter, t.ex. metaller, eftersom IPS är något lägre än förväntat vilket inte kan förklaras med stödparametrarna TDI eller %PT. Istället tyder den nya metoden med screeningsindex för miljögifter på en påverkan i Luossajoki på lokalerna KEP31, och möjligen i KEP32 och KVA136. I Pahtajoki tyder det på en påverkan i lokal Pa1. Angående surheten så tyder kiselalger på alla av Luossajoki lokaler på en alkalisk pH regim, vilket troligtvis inte är den naturliga surheten som borde vara lägre för detta geografiska område. Detta får stöd i vattenkemin eftersom pH är förhöjt i hela bäcken med knappt en pH-enhet, vilket beror på vittringsprodukter från gråbergsupplagen i Luossajokis och Luossajärvis avrinningsområde.
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36.
  • Kahlert, Maria (författare)
  • Application of high-throughput sequencing (HTS) metabarcoding to diatom biomonitoring: Do DNA extraction methods matter?
  • 2017
  • Ingår i: Freshwater Science. - : University of Chicago Press. - 2161-9549 .- 2161-9565. ; 36, s. 162-177
  • Tidskriftsartikel (refereegranskat)abstract
    • Current freshwater biomonitoring with diatoms is based on microscopic examination of the morphology of their silica skeleton. This standardized approach is time consuming and requires a high degree of taxonomic expertise. Metabarcoding combined with high-throughput sequencing (HTS) has great potential for next-generation biomonitoring applications but requires standardization. Molecular inventories are strongly influenced by the DNA extraction method used, but the effect of extraction protocols has not been tested to enable selection of the best DNA extraction method for HTS metabarcoding. We used 5 DNA extraction methods combining various types of cell lysis and DNA purification to extract DNA from 8 pure diatom cultures and 8 samples from streams and lakes with differing water quality. We compared the methods based on: 1) quality and purity of the extracted DNA, 2) community inventories obtained from HTS targeting the ribulose-1, 5-bisphosphate carboxylase (rbcL) barcode, and 3) similarity between molecular and microscopy-based inventories of community composition and the Specific Pollution sensitivity Index [SPI]. A method based on GenEluteTM-LPA had higher extraction efficiency than the 4 commercial kits but had the highest polymerase chain reaction inhibition level. All 5 methods were efficient for HTS, and method did not affect operational taxonomic unit richness. We observed variations in the relative abundance of some taxa within Nitzschia, Amphora, Encyonerna, Gomphonema, and Navicula between 2 of the 5 methods, but method did not affect global diatom community composition or SPI values. SPI values calculated from microscopy-based inventories and molecular inventories based on all 5 extraction methods were strongly correlated. For convenience purposes (high DNA quantity and low cost), we encourage standardization of FITS diatom biomonitoring based on the SA-Gen method.
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37.
  • Kahlert, Maria (författare)
  • Applied use of taxonomy: lessons learned from the first German intercalibration exercise for benthic diatoms
  • 2015
  • Ingår i: Acta Botanica Croatica. - : Walter de Gruyter GmbH. - 0365-0588. ; 74, s. 211-232
  • Tidskriftsartikel (refereegranskat)abstract
    • The first German intercalibration exercise for benthic diatoms was conducted to improve the application of the implementation of the European Water Framework Directive for running waters and lakes in Germany. The intercalibration exercise revealed several taxonomic problems. Among others, considerable problems occurred with identifying and differentiating species of the following four groups: (I) Amphora indistincta Levkov and A. pediculus (Kutzing) Grunow, (II) Cocconeis placentula var. euglypta Ehrenberg and C. placentula var. lineata (Ehrenberg) Van Heurck, (III) Navicula cryptotenella Lange-Bertalot and N. cryptotenelloides Lange-Bertalot and (IV) N. reichardtiana Lange-Bertalot and N. caterva Hohn & Hellermann. The taxonomic problems that emerged occurred due to both insufficient use of given taxonomic details (by limnologists) and ambiguous species descriptions and documentation (by taxonomists). Thus, we recommend to the applied limnologist to use the mandatory identification literature and to document any ambiguous valves during routine counts. Also, it would be desirable to further investigate certain species by taxonomists and, in general, to provide more basic data with species descriptions or in identification manuals. These measures will improve the use of diatoms as bioindicators and consequently benefit both applied limnologists and taxonomists.
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38.
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39.
  • Kahlert, Maria, et al. (författare)
  • Benthic Diatom Communities in Urban Streams and the Role of Riparian Buffers
  • 2020
  • Ingår i: Water. - : MDPI AG. - 2073-4441. ; 12
  • Tidskriftsartikel (refereegranskat)abstract
    • Urbanization impacts stream ecosystems globally through degraded water quality, altered hydrology, and landscape disturbances at the catchment and riparian scales, causing biodiversity losses and altered system functioning. Addressing the "urban stream syndrome" requires multiple mitigation tools, and rehabilitation of riparian vegetation may help improve stream ecological status and provide key ecosystem services. However, the extent to which forested riparian buffers can help support stream biodiversity in the face of numerous environmental contingencies remains uncertain. We assessed how a key indicator of stream ecological status, benthic diatoms, respond to riparian habitat conditions using 10 urban site pairs (each comprising of one unbuffered and one buffered reach), and additional urban downstream and forest reference upstream sites in the Oslo Fjord basin. Diatom communities were structured by multiple drivers including spatial location, land use, water quality, and instream habitat. Among these, riparian habitat condition independently explained 16% of variation in community composition among site pairs. Changes in community structure and indicator taxa, along with a reduction in pollution-tolerant diatoms, suggested tangible benefits of forested riparian buffers for stream biodiversity in urban environments. Managing urban impacts requires multiple solutions, with forested riparian zones providing a potential tool to help improve biodiversity and ecosystem services.
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40.
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41.
  • Kahlert, Maria (författare)
  • Benthic diatoms in streams and lakes
  • 2016
  • Ingår i: Ecological Assessment of Swedish Water Bodies; development, harmonisation and integration of biological indicators. Final report of the research programme WATERS. Deliverable 1.1-4. - 9789163920981 ; 2016:10:2016:10, s. 44-50
  • Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
    • The Water Framework Directive was incorporated into Swedish legislation in 2004. Its aim is to develop sustainable management of European surface- and groundwater and with the implementation of the directive there was a need for development of monitoring programmes and tools for assessing water quality. In response to these needs the Swedish Environmental Protection Agency opened a call for research on "Biological assessment criteria in aquatic environments". As a result of this call, a consortium of 11 partners, was granted a total budget of 47 million SEK funded by the Swedish Environmental Protection Agency's Environmental Research Grant, to pursue the research programme WATERS during 5 years. WATERS has developed better indicators and methods for classification and references in Swedish lakes, streams and coastal waters. This provides a valuable basis for a new generation of biological assessment criteria to be defined by the authorities. WATERS has also developed general methods for assessing and reducing uncertainty in classification of ecological status, as well as harmonised and transparent methods for integrated assessment. In combination, these results are expected to improve and simplify future status assessments according to the Water Framework Directive. Several teams of ecologists specialised in limnic and marine waters have contributed, led by Jacob Carstensen, Aarhus university, Richard Johnson, Swedish university of agricultural sciences, Leif Pihl, University of Gothenburg and Sofia A Wikström, Stockholm university. The programme has been coordinated by Mats Lindegarth at the Swedish institute for the marine environment. We wish to express our sincere gratitude to everyone that has contributed to the success of the programme. WATERS steering group has consisted of the coordinator, team leaders and responsible contacts at the Swedish Agency for Marine and Water Management and the Swedish Environmental Protection Agency. These have been represented by Mats Svensson and Cecilia Lindblad respectively. The authors alone are responsible for the content of this report.
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42.
  • Kahlert, Maria, et al. (författare)
  • Biodiversity patterns of Arctic diatom assemblages in lakes and streams: Current reference conditions and historical context for biomonitoring
  • 2022
  • Ingår i: Freshwater Biology. - : Wiley. - 0046-5070 .- 1365-2427. ; 67, s. 116-140
  • Tidskriftsartikel (refereegranskat)abstract
    • Comprehensive assessments of contemporary diatom distributions across the Arctic remain scarce. Furthermore, studies tracking species compositional differences across space and time, as well as diatom responses to climate warming, are mainly limited to paleolimnological studies due to a lack of routine monitoring in lakes and streams across vast areas of the Arctic. The study aims to provide a spatial assessment of contemporary species distributions across the circum-Arctic, establish contemporary biodiversity patterns of diatom assemblages to use as reference conditions for future biomonitoring assessments, and determine pre-industrial baseline conditions to provide historical context for modern diatom distributions. Diatom assemblages were assessed using information from ongoing regulatory monitoring programmes, individual research projects, and from surface sediment layers obtained from lake cores. Pre-industrial baseline conditions as well as the nature, direction and magnitude of changes in diatom assemblages over the pastc.200 years were determined by comparing surface sediment samples (i.e. containing modern assemblages) with a sediment interval deposited prior to the onset of significant anthropogenic activities (i.e. containing pre-1850 assemblages), together with an examination of diatoms preserved in contiguous samples from dated sediment cores. We identified several biotypes with distinct diatom assemblages using contemporary diatom data from both lakes and streams, including a biotype typical for High Arctic regions. Differences in diatom assemblage composition across circum-Arctic regions were gradual rather than abrupt. Species richness was lowest in High Arctic regions compared to Low Arctic and sub-Arctic regions, and higher in lakes than in streams. Dominant diatom taxa were not endemic to the Arctic. Species richness in both lakes and streams reached maximum values between 60 degrees N and 75 degrees N but was highly variable, probably reflecting differences in local and regional environmental factors and possibly sampling effort. We found clear taxon-specific differences between contemporary and pre-industrial samples that were often specific to both ecozone and lake depth. Regional patterns of species turnover (beta-diversity) in the pastc.200 years revealed that regions of the Canadian High Arctic and the Hudson Bay Lowlands to the south showed most compositional change, whereas the easternmost regions of the Canadian Arctic changed least. As shown in previous Arctic diatom studies, global warming has already affected these remote high latitude ecosystems. Our results provide reference conditions for future environmental monitoring programmes in the Arctic. Furthermore, diatom taxa identification and harmonisation require improvement, starting with circum-Arctic intercalibrations. Despite the challenges posed by the remoteness of the Arctic, our study shows the need for routine monitoring programmes that have a wide geographical coverage for both streams and lakes.
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43.
  • Kahlert, Maria (författare)
  • Biomass and Nutrient Status of Benthic Algae in Lakes
  • 2001
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • For a complete picture of the lake ecosystem, it is necessary to understand the mechanisms regulating biomass and nutrient status (nutrient limitation, optimal supply, or surplus) of benthic algae, which are important primary producers and a food resource for grazers. This thesis gives an overview of the natural variation of benthic algae at different scales of space and time and on different substrates, and unravels some of the underlying factors. Algal nutrient status was assessed using the C:N:P (carbon:nitrogen:phosphorus) ratio of the entire natural benthic community. A review, observations, and experiments confirmed that a C:N:P ratio of about 158:18:1 (molar basis) represented an optimal nutrient supply, and that substantially higher C:N, N:P, or C:P ratios reflected algal growth limitation caused by an N or P nutrient deficiency. Horizontal variation of benthic algal biomass and nutrient status was patchy, of similar amount for all investigated distances, substrates, and lakes, and constituted a dominant proportion of the total variation. For example, patches of nutrient limited algae were found within only 10 m distance from patches with a nutrient surplus. Thus, horizontal variation should not be neglected when sampling benthic algae in lakes. Field observations suggested an impact of wind, nutrients, and grazers on the horizontal variation. Light and nutrients might have caused the observed vertical and temporal variation. Field experiments confirmed a simultaneous control of benthic algal biomass by nutrients and grazing, mediated by light and temperature. Grazing effects were larger than nutrient effects, but the comparison of natural communities in lakes of different trophy suggested that benthic algal biomass was controlled by nutrients in the long run. An important nutrient supply was animal excretions, causing a low C:N:P ratio of epizoon on zebra mussels, and algal communities associated with macrograzers. A field experiment revealed that 15N circulated one week longer in epizoon associated with a sessile caddisfly than in surrounding epilithon. In conclusion, the regulation of benthic algal biomass and nutrient status in lakes is complex, and benthic animals should be looked at not only as grazers, but also as a nutrient source.
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44.
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45.
  • Kahlert, Maria (författare)
  • Co-occurrence, ecological profiles and geographical distribution based on unique molecular identifiers of the common freshwater diatoms Fragilaria and Ulnaria
  • 2022
  • Ingår i: Ecological Indicators. - : Elsevier BV. - 1470-160X .- 1872-7034. ; 141
  • Tidskriftsartikel (refereegranskat)abstract
    • Diatom taxonomy has evolved in recent years, with many new species described and new approaches such as molecular genetics showing the existence of cryptic diversity within currently accepted species. This cryptic diversity is not well understood even for common freshwater genera such as Fragilaria and Ulnaria. The purpose of our study was to define taxon-specific ecological profiles and geographical distributions for unique molecular identifiers (amplicon sequence variants, ASVs) linked to curated taxonomy for these genera. Our goal is to contribute to the development of ecological assessment methods, and to the understanding why we often observe so many diatom species co-occurring in a single sample. We filtered a large (770 samples) metabarcoding dataset with linked environmental data covering several countries in Europe for genetic variants (ASVs) assigned to currently accepted species of our target genera. We studied the geographical distribution of the ASVs, and tested for ASV-pair co-occurrence. We modelled ASV-specific preferences for pH, alkalinity, total nitrogen, total phosphorus and conductivity, and analysed their preference for lakes or streams as habitat. Our study confirmed that there seems to be no general geographical barrier for the distribution of freshwater benthic diatom ASVs in Europe, but that dispersal is not rapid enough to hide historical events. The Fragilaria and Ulnaria ASVs in our study showed considerable overlap in geographical distribution, habitat and ecological preferences. We found evidence that only large differences in preferences for the analysed water chemistry variables prevented the cooccurrence of ASVs at the same sites. Instead, Fragilaria and Ulnaria ASVs co-occurred frequently in samples. We found subtle differences in ecological preferences for some ASV pairs, which might in part explain the cooccurrence by the avoidance of direct competition. However, the great overlap in distribution and ecological preferences suggests that other factors not studied here were also responsible for the observed co-occurrences and high richness of ASVs found at many sites. To our knowledge, we are the first to use ASVs in combination with a curated taxonomy to understand co-occurrence, specific ecological profiles and large-scale geographical distribution for unique identifiers not biased by the quality of reference databases, clustering methods, or non-harmonized morphological identification. Thus, our results can now be used in subsequent projects to interpret ASV occurrences, e.g. for development of ecological assessment methods.
  •  
46.
  • Kahlert, Maria, et al. (författare)
  • Comparing new and conventional methods to estimate benthic algal biomass and composition in freshwaters
  • 2014
  • Ingår i: Environmental Science: Processes and Impacts. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 16, s. 2627-2634
  • Tidskriftsartikel (refereegranskat)abstract
    • We compared conventional microscope-based methods for quantifying biomass and community composition of stream benthic algae with output obtained for these parameters from a new instrument (the BenthoTorch), which measures fluorescence of algal pigments in situ. Benthic algae were studied in 24 subarctic oligotrophic (1.7-26.9, median 7.2 mu g total phosphorus L-1) streams in Northern Sweden. Readings for biomass of the total algal mat, quantified as chlorophyll a, did not differ significantly between the BenthoTorch (median 0.52 mu g chlorophyll a cm(-2)) and the conventional method (median 0.53 mu g chlorophyll a cm(-2)). However, quantification of community composition of the benthic algal mat obtained using the BenthoTorch did not match those obtained from conventional methods. The BenthoTorch indicated a dominance of diatoms, whereas microscope observations showed a fairly even distribution between diatoms, blue-green algae (mostly nitrogen-fixing) and green algae (mostly large filamentous), and also detected substantial biovolumes of red algae in some streams. These results most likely reflect differences in the exact parameters quantified by the two methods, as the BenthoTorch does not account for variability in cell size and the presence of non-chlorophyll bearing biomass in estimating the proportion of different algal groups, and does not distinguish red algal chlorophyll from that of other algal groups. Our findings suggest that the BenthoTorch has utility in quantifying biomass expressed as jig chlorophyll a cm(-2), but its output for the relative contribution of different algal groups to benthic algal biomass should be used with caution.
  •  
47.
  • Kahlert, Maria, et al. (författare)
  • Connecting the morphological and molecular species concepts to facilitate species identification within the genus Fragilaria (Bacillariophyta)
  • 2019
  • Ingår i: Journal of Phycology. - : Wiley. - 0022-3646 .- 1529-8817. ; 55, s. 948-970
  • Tidskriftsartikel (refereegranskat)abstract
    • This paper explores the diversity and taxonomy of species within Fragilaria sensu stricto, an abundant and ecologically important diatom genus, taking advantage of cultured and DNA-barcoded material. The goal is to facilitate the identification of European taxa within this complex, providing a unified view on morphological and molecular diversity. There is a general agreement that the separation of species within the group of Fragilaria is difficult because morphological descriptions of species are not consistent between authorities, ongoing taxonomic revisions have resulted in species described with standards of the late 20th and 21st centuries alongside descriptions based on 19th century (light microscopical) criteria, and because not all diagnostic characters can be seen in all specimens encountered in routine analyses. Consequent confusion could blur potentially important ecological distinctions between species. Our study demonstrated that some species defined on morphological criteria could be confirmed using the rbcL chloroplast gene as a genetic marker, for example, Fragilaria gracilis, Fragilaria tenera, Fragilaria perminuta, and Fragilaria subconstricta. However, even for those species, preliminary identifications based on morphology often differed from identifications based on phylogenetic clustering combined with detailed morphological study. Clades were well-defined by rbcL, but based on morphology, the terminal taxa of these clades did not match the currently described Fragilaria species. To clarify recognition of these taxa, we describe three new species: Fragilaria agnesiae, Fragilaria heatherae, and Fragilaria joachimii.
  •  
48.
  • Kahlert, Maria (författare)
  • Delimitation of Some Taxa of Ulnaria and Fragilaria (Bacillariophyceae) Based on Genetic, Morphological Data and Mating Compatibility
  • 2023
  • Ingår i: Diversity. - : MDPI AG. - 1424-2818. ; 15
  • Tidskriftsartikel (refereegranskat)abstract
    • Fragilaria and Ulnaria are two closely related diatom genera for which the delimitation and circumscription of several species is unclear. We studied strains isolated from Lake Baikal and compared them with the species from freshwater reservoirs in Europe and Asia using phylogenetic and species delimitation methods, microscopy and interclonal crossing experiments. The results of the phylogenetic analyses of the fragments of rbcL and 18S rRNA genes revealed that baikalian F. radians clade was independent from the representatives of the genus from other localities. Among Ulnaria we found the following 18S rRNA phylogenetic tree groups at species level: U. acus, U. ulna and U. danica. Genetic distance between genera varied between 3.9-10.2% substitutions in rbcL gene and 3.2-11.5% in 18S rRNA. The boundary between intraspecies and interspecies polymorphism for studied species of Ulnaria and Fragilaria in these marker genes was around 0.8% substitutions. Morphometric characters of individual strains showed their variability and division into F. radians, U. acus and U. ulna together with U. danica. Strains of U. acus and U. danica from different localities of Europe and Asia were sexually compatible inside the species. Sexual reproduction has never been observed in monoclonal cultures, either between this species or with strains of the Fragilaria.
  •  
49.
  • Kahlert, Maria, et al. (författare)
  • Diatom DNA metabarcoding for ecological assessment: Comparison among bioinformatics pipelines used in six European countries reveals the need for standardization
  • 2020
  • Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 745
  • Tidskriftsartikel (refereegranskat)abstract
    • Ecological assessment of lakes and rivers using benthic diatom assemblages currently requires considerable taxonomic expertise to identify species using light microscopy. This traditional approach is also time-consuming. Diatom metabarcoding is a promising alternative and there is increasing interest in using this approach for routine assessment. However, until now, analysis protocols for diatom metabarcoding have been developed and optimised by research groups working in isolation. The diversity of existing bioinformatics methods highlights the need for an assessment of the performance and comparability of results of different methods. The aim of this study was to test the correspondence of outputs from six bioinformatics pipelines currently in use for diatom metabarcoding in different European countries. Raw sequence data from 29 biofilm samples were treated by each of the bioinformatics pipelines, five of them using the same curated reference database. The outputs of the pipelines were compared in terms of sequence unit assemblages, taxonomic assignment, biotic index score and ecological assessment outcomes. The three last components were also compared to outputs from traditional light microscopy, which is currently accepted for ecological assessment of phytobenthos, as required by the Water Framework Directive. We also tested the performance of the pipelines on the two DNA markers (rbcL and 185-V4) that are currently used by the working groups participating in this study. The sequence unit assemblages produced by different pipelines showed significant differences in terms of assigned and unassigned read numbers and sequence unit numbers. When comparing the taxonomic assignments at genus and species level, correspondence of the taxonomic assemblages between pipelines was weak. Most discrepancies were linked to differential detection or quantification of taxa, despite the use of the same reference database. Subsequent calculation of biotic index scores also showed significant differences between approaches, which were reflected in the final ecological assessment. Use of the rbcL marker always resulted in better correlation among molecular datasets and also in results closer to these generated using traditional microscopy. This study shows that decisions made in pipeline design have implications for the dataset's structure and the taxonomic assemblage, which in turn may affect biotic index calculation and ecological assessment. There is a need to define best-practice bioinformatics parameters in order to ensure the best representation of diatom assemblages. Only the use of similar parameters will ensure the compatibility of data from different working groups. The future of diatom metabarcoding for ecological assessment may also lie in the development of new metrics using, for example, presence/absence instead of relative abundance data. (C) 2020 The Authors. Published by Elsevier B.V.
  •  
50.
  • Kahlert, Maria, et al. (författare)
  • Diatom teratologies as biomarkers of contamination: are all deformities ecologically meaningful?
  • 2017
  • Ingår i: Ecological Indicators. - : Elsevier BV. - 1470-160X .- 1872-7034. ; 82, s. 539-550
  • Tidskriftsartikel (refereegranskat)abstract
    • Contaminant-related stress on aquatic biota is difficult to assess when lethal impacts are not observed. Diatoms, by displaying deformities (teratologies) in their valves, have the potential to reflect sub-lethal responses to environmental stressors such as metals and organic compounds. For this reason, there is great interest in using diatom morphological aberrations in biomonitoring. However, the detection and mostly the quantification of teratologies is still a challenge; not all studies have succeeded in showing a relationship between the proportion of abnormal valves and contamination level along a gradient of exposure. This limitation in part reflects the loss of ecological information from diatom teratologies during analyses when all deformities are considered. The type of deformity, the severity of aberration, species proneness to deformity formation, and propagation of deformities throughout the population are key components and constraints in quantifying teratologies. Before a metric based on diatom deformities can be used as an indicator of contamination, it is important to better understand the "ecological signal" provided by this biomarker. Using the overall abundance of teratologies has proved to be an excellent tool for identifying contaminated and non-contaminated environments (presence/absence), but refining this biomonitoring approach may bring additional insights allowing for a better assessment of contamination level along a gradient. The dilemma: are all teratologies significant, equal and/or meaningful in assessing changing levels of contamination? This viewpoint article examines numerous interrogatives relative to the use of diatom teratologies in water quality monitoring, provides selected examples of differential responses to contamination, and proposes solutions that may refine our understanding and quantification of the stress. This paper highlights the logistical problems associated with accurately evaluating and interpreting teratologies and stimulates more discussion and research on the subject to enhance the sensitivity of this metric in bioassessments.
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