Ändra sökning
Avgränsa sökresultatet
1 - 22 av 22
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Träffar per sida
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
Markera
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 1.
    Cornelissen, Johannes H C
    et al.
    Vrije Universiteit.
    Van Bodegom, Peter M
    Vrije Universiteit.
    Aerts, Rien
    Vrije Universiteit.
    Callaghan, Terry V
    University of Sheffield.
    Van Logtestijn, Richard S.P.
    Vrije Universiteit.
    Alatalo, Juha
    VINNOVA.
    Chapin, Stuart F.
    University of Alaska.
    Gerdol, Renato G
    Università degli Studi di Ferrara Dipartimento delle Risorse Naturali e Cultural.
    Gudmundsson, Jon
    Agricultural University of Iceland.
    Gwynn-Jones, Dylan
    University of Wales.
    Hartley, Anne E
    Florida International University.
    Hik, David S
    University of Alberta.
    Hofgaard, Annika
    Norwegian Institute for Nature Research.
    Jónsdóttir, Ingibjörg S.
    Agricultural University of Iceland.
    Karlsson, Staffan
    Vetenskapsrådet.
    Klein, Julia A
    Colorado State University.
    Laundre, Jim
    Marine Biological Labratory.
    Magnusson, Borgthor
    Icelandic Institute of Natural History.
    Michelsen, Anders
    University of Copenhagen.
    Molau, Ulf
    Göteborgs Universitet.
    Onipchenko, Vladimir G.
    Moscow State University.
    Quested, Helen M.
    Stockholms Universitet.
    Sandvik, Sylvi M
    Agder University College.
    Schmidt, Inger K.
    Royal Veterinary and Agricultural University Denmark.
    Shaver, Gus R.
    Marine Biological Labratory.
    Solheim, Bjørn S
    University of Tromsø.
    Soudzilovskaia, Nadejda A
    Vrije Universiteit, Moscow State University.
    Stenström, Anna
    Länsstyrelsen Västra Götaland.
    Tolvanen, Anne
    Finnish Forest Research Institute.
    Totland, Ørjan T
    Norwegian University of Life Sciences.
    Wada, Naoya W
    University of Toyama.
    Welker, Jeffrey M
    University of Alaska Anchorage.
    Zhao, Xinquan
    Chinese Academy of Sciences.
    Brancaleoni, Lisa
    Brancaleoni, Laura
    De Beus, Miranda A.H
    Cooper, Elisabeth J.
    Dalen, Linda
    Harte, John
    Hobbie, Sarah E
    Hoefsloot, Gerlof
    Jägerbrand, Annika K
    Göteborg University.
    Jonasson, Sven
    Lee, John A
    Lindblad, Karin
    Melillo, Jerry M
    Neill, Christopher
    Press, Malcolm C
    Rozema, Jelte
    Zielke, Matthias
    Global negative vegetation feedback to climate warming responses of leaf litter decomposition rates in cold biomes2007Ingår i: Ecology Letters, ISSN 1461-023X, E-ISSN 1461-0248, Vol. 10, nr 7, s. 619-627Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Whether climate change will turn cold biomes from large long-term carbon sinks into sources is hotly debated because of the great potential for ecosystem-mediated feedbacks to global climate. Critical are the direction, magnitude and generality of climate responses of plant litter decomposition. Here, we present the first quantitative analysis of the major climate-change-related drivers of litter decomposition rates in cold northern biomes worldwide.

    Leaf litters collected from the predominant species in 33 global change manipulation experiments in circum-arctic-alpine ecosystems were incubated simultaneously in two contrasting arctic life zones. We demonstrate that longer-term, large-scale changes to leaf litter decomposition will be driven primarily by both direct warming effects and concomitant shifts in plant growth form composition, with a much smaller role for changes in litter quality within species. Specifically, the ongoing warming-induced expansion of shrubs with recalcitrant leaf litter across cold biomes would constitute a negative feedback to global warming. Depending on the strength of other (previously reported) positive feedbacks of shrub expansion on soil carbon turnover, this may partly counteract direct warming enhancement of litter decomposition.

  • 2.
    Danielsson, Sara
    et al.
    Utförare miljöövervakning, Naturhistoriska riksmuseet, NRM.
    Odsjö, Tjelvar
    Utförare miljöövervakning, Naturhistoriska riksmuseet, NRM.
    Bignert, Anders
    Utförare miljöövervakning, Naturhistoriska riksmuseet, NRM.
    Remberger, Mikael
    Utförare miljöövervakning, Naturhistoriska riksmuseet, NRM.
    Organic Contaminants in Moose (Alces alces) and Reindeer (Rangifer tarandus) in Sweden from the past twenty years: Comments Concerning the National Swedish Contaminant Monitoring Programme in Terrestrial Biota2008Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Föreliggande rapport är resultatet av ett uppdrag från Naturvårdsverket (Överenskommelse 221 0730) som syftar till att ta fram en aktuell bild av förekomsten av ett antal pesticider eller ofullständigt kända föroreningar i svensk terrestrisk natur där alltså osäkerhet om ämnenas spridning och ackumulation i landlevande organismvärlden råder. Som matris i detta fall har vävnader och organ av älg och ren från mellersta respektive norra Sverige valts. Matriserna finns tillgängliga i Miljöprovbanken vid Naturhistoriska riksmuseet Valet av ämnen har vägletts av tidigare resultat från övervakningen av föroreningar i svensk natur samt av resultat från screeningundersökningar av ofullständigt kända ämnen som tagits fram i Naturvårdsvekets regi. Listan över analyserade ämnen innehåller enskilda substanser samt närbesläktade substanser tillhörande bl. a. följande grupper: klorbensen, HCBD, oktaklorstyren, PCB, DDT, klordan, HCH, PBDE, dioxiner, furaner, endosulfan, heptaklor, pentaklorfenol och PAH. Från Grimsö i Västmanland har vävnadsprover av årskalvar av älg insamlats till Miljöprovbanken och använts för analys av innehåll av miljögifter i denna studie. Med några få undantag är de provtagna individerna av hankön. Skillnader i halter av kadmium mellan könen har i tidigare studier visat sig icke existera. De utvalda proven av älg representerar perioden 1986-2005. Ett homogenat av muskel har beretts per år under perioden baserat på 10 g av tio individer per år. På samma sätt har prover av ren från sommarbetet S Abisko årligen insamlats i Rensjön NV Kiruna i samband med första höstslakten i mitten av september. Vävnadsprover har tagits av handjur av en ålder mellan 2 och 4 år, mestadels av 3-åriga djur. 1998 uppsköts den ordinarie slakten från första halvan av september till första halvan av november, vilket bör uppmärksammas vid tolkningen av analysresultaten. På samma sätt sköts slakten 2004 fram till mitten av december. Det förhållandet att renen förflyttas avsevärda sträckor under höstvandringen, från sommarbetet i de västra delarna av fjällkedjan till det mellansvenska skogslandet under vintern medför en ändring av föda, vilket kan inverka på exponering och bioackumulation av de studerade substanserna. Ju längre avvikelse från normal slakttid desto längre exponering via lavar som är stapelföda i skogslandet under vintern och som innehåller högre koncentrationer av många ackumulerade ämnen. För den aktuella studien valdes hanrenar av tre års ålder härrörande från Gabna, Lævas and Girjas samebyar vilka bildar ett sammanhängande område i norra Lappland. Provserien omfattar perioden 1987-2006. Ett homogenat per år bereddes baserat på 12 g muskel från tio individer per år. Många av de analyserade ämnena förekommer i koncentrationer under detektionsnivån (LOD) under alla eller de flesta av de undersökta åren (Tabell 2). Halterna funna i älg och ren är i många fall lägre än de nivåer som observerats i fisk från såväl limniska som marina områden. Som exempel har PBDE och HBCD inte ens detekterats i vare sig älg eller ren men finns närvarande i både insjöfisk och havsfisk (Bignert et al 2008). Penta- och hexaklorbensen, oktaklorstyren, polyklorerade bifenyler, - och -hexaklor-cyklohexan och polycykliska aromatiska kolväten förekommer samtliga i halter över LOD under samtliga eller större delen av åren under den undersökta perioden. Koncentrationerna av dessa ämnen har sjunkit med undantag för PAH där koncentrationerna är ungefär desamma under hela perioden. Den genomsnittliga årliga nedgången ligger mellan 3% och 10% med undantag för -HCH som visar den mest uttalade minskningen med 22% i älg och 17% i ren. Dessa resultat är samstämmiga med vad som observerats i biota från insjöar och marina områden i Sverige (Bignert et al. 2008, Bignert 2001). De sjunkande halterna i landanknuten biota under de gångna 20 åren är sannolikt orsakade av regleringar och ansträngningar för att minimera utsläpp av kända persistenta, bioackumulerande och toxiska ämnen till miljön. Ämnen hörande till PAHerna är huvudsakligen oavsiktligt spridda genom ofullständig förbränning av organiska ämnen. Källorna är många och varierande och till följd därav svåra att åtgärda med förbättringar. Detta är troligtvis förklaringen till avsaknaden av nedgående tendens för PAHer. Koncentrationerna av PFCs i både älg och ren var i allmänhet låga. Samtliga analyserade prover hade koncentrationer under LOQ. Närvaro av PFOSA, PFOS och PFOA kunde emellertid detekteras vissa år men inte i nivåer tillräckligt höga för att kvantifieras

  • 3.
    Hein, Catherine L.
    et al.
    Umeå universitet, Institutionen för ekologi, miljö och geovetenskap.
    Öhlund, Gunnar
    Umeå universitet, Institutionen för ekologi, miljö och geovetenskap.
    Englund, Göran
    Umeå universitet, Institutionen för ekologi, miljö och geovetenskap.
    Fish introductions reveal the temperature dependence of species interactions2014Ingår i: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 281, nr 1775, s. 20132641-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A major area of current research is to understand how climate change will impact species interactions and ultimately biodiversity. A variety of environmental conditions are rapidly changing owing to climate warming, and these conditions often affect both the strength and outcome of species interactions. We used fish distributions and replicated fish introductions to investigate environmental conditions influencing the coexistence of two fishes in Swedish lakes: brown trout (Salmo trutta) and pike (Esox lucius). A logistic regression model of brown trout and pike coexistence showed that these species coexist in large lakes (more than 4.5 km(2)), but not in small, warm lakes (annual air temperature more than 0.9-1.5 degrees C). We then explored how climate change will alter coexistence by substituting climate scenarios for 2091-2100 into our model. The model predicts that brown trout will be extirpated from approximately half of the lakes where they presently coexist with pike and from nearly all 9100 lakes where pike are predicted to invade. Context dependency was critical for understanding pike-brown trout interactions, and, given the widespread occurrence of context-dependent species interactions, this aspect will probably be critical for accurately predicting climate impacts on biodiversity.

  • 4.
    Jantunen, Liisa
    et al.
    Environment Canada, Canada.
    Wong, Fiona
    Stockholm University.
    Gawor, Anya
    Environment Canada.
    Kylin, Henrik
    Linköpings universitet, Tema Miljöförändring.
    Helm, Paul
    Ontario Ministry of the Environment, Canada.
    Stern, Gary
    University of Manitoba, Canada.
    Strachan, William
    Environment Canada, Canada.
    Burniston, Deborah
    Environment Canada, Canada.
    Bidleman, Terry
    Umeå University.
    20 Years of Air-Water Gas Exchange Observations for Pesticides in the Western Arctic Ocean2015Ingår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 49, nr 23, s. 13844-13852Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Arctic has been contaminated by legacy organochlorine pesticides (OCPs) and currently used pesticides (CUPs) through atmospheric transport and oceanic currents. Here we report the time trends and air−water exchange of OCPs and CUPs from research expeditions conducted between 1993 and 2013. Compounds determined in both air and water were trans- and cis-chlordanes (TC, CC), trans- and cis-nonachlors (TN, CN), heptachlor exo-epoxide (HEPX), dieldrin (DIEL), chlorobornanes (ΣCHBs and toxaphene), dacthal (DAC), endosulfans and metabolite endosulfan sulfate (ENDO-I, ENDO-II, and ENDO SUL), chlorothalonil (CHT), chlorpyrifos (CPF), and trifluralin (TFN). Pentachloronitrobenzene (PCNB and quintozene) and its soil metabolite pentachlorothianisole (PCTA) were also found in air. Concentrations of most OCPs declined in surface water, whereas some CUPs increased (ENDO-I, CHT, and TFN) or showed no significant change (CPF and DAC), and most compounds declined in air. Chlordane compound fractions TC/(TC + CC) and TC/(TC + CC + TN) decreased in water and air, while CC/(TC + CC + TN) increased. TN/(TC + CC + TN) also increased in air and slightly, but not significantly, in water. These changes suggest selective removal of more labile TC and/or a shift in chlordane sources. Water−air fugacity ratios indicated net volatilization (FR > 1.0) or near equilibrium (FR not significantly different from 1.0) for most OCPs but net deposition (FR < 1.0) for ΣCHBs. Net deposition was shown for ENDO-I on all expeditions, while the net exchange direction of other CUPs varied. Understanding the processes and current state of air−surface exchange helps to interpret environmental exposure and evaluate the effectiveness of international protocols and provides insights for the environmental fate of new and emerging chemicals.

  • 5.
    Kassel, Marlene
    Umeå universitet, Institutionen för ekologi, miljö och geovetenskap.
    Effects of climate change on freezing damage in three subarctic bryophyte species2017Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Climate change is expected to have a strong impact on subarctic ecosystems. Increased temperatures as well as altered precipitation and snow cover patterns are predicted to change species distribution and affect biogeochemical processes in the subarctic tundra. Bryophytes are an essential vegetational component in northern ecosystems, due to their high abundance and importance in many ecological processes. In this study the effects of elevation and altered snow cover on the temporal dynamics of freezing damage in three subarctic bryophyte species (Hylocomium splendens, Ptilidium ciliare, and Sphagnum fuscum) were studied in a snow manipulation field experiment in Abisko, during early spring. Soil temperature and field moisture of moss shoots were collected. A freeze-thaw incubation experiment was conducted to investigate the freeze-thaw cycle resistance of H. splendens and P. ciliare originating from habitats with two differing snow-cover thicknesses. Freezing damage differed significantly between the bryophytes species with P. ciliare experiencing the least and S. fuscum the highest damage. Damage was higher at the low elevation, possibly attributable to acclimation effects. Snow removal led to higher damage in moss shoots, but no interactions of the different snow cover treatments with elevation, species or time were found. Freezing damage increased over time and no recovery occurred, likely due to temporal patterns in soil freeze-thaw cycles during early spring. Soil freeze-thaw cycles were the main factor influencing damage in bryophytes after snow melt. Measured environmental parameters could not explain the entire variation in damage. Damage might additionally be attributable to increased UV radiation or disturbances by herbivores.

  • 6.
    Kuhn, McKenzie
    et al.
    Umeå universitet, Institutionen för ekologi, miljö och geovetenskap.
    Lundin, Erik J
    Umeå universitet, Institutionen för ekologi, miljö och geovetenskap.
    Giesler, Reiner
    Umeå universitet, Institutionen för ekologi, miljö och geovetenskap.
    Johansson, Margareta
    Karlsson, Jan
    Umeå universitet, Institutionen för ekologi, miljö och geovetenskap.
    Emissions from thaw ponds largely offset the carbon sink of northern permafrost wetlands2018Ingår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, artikel-id 9535Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Northern regions have received considerable attention not only because the effects of climate change are amplified at high latitudes but also because this region holds vast amounts of carbon (C) stored in permafrost. These carbon stocks are vulnerable to warming temperatures and increased permafrost thaw and the breakdown and release of soil C in the form of carbon dioxide (CO2) and methane (CH4). The majority of research has focused on quantifying and upscaling the effects of thaw on CO2 and CH4 emissions from terrestrial systems. However, small ponds formed in permafrost wetlands following thawing have been recognized as hotspots for C emissions. Here, we examined the importance of small ponds for C fluxes in two permafrost wetland ecosystems in northern Sweden. Detailed flux estimates of thaw ponds during the growing season show that ponds emit, on average (±SD), 279 ± 415 and 7 ± 11 mmol C m−2 d−1 of CO2 and CH4, respectively. Importantly, addition of pond emissions to the total C budget of the wetland decreases the C sink by ~39%. Our results emphasize the need for integrated research linking C cycling on land and in water in order to make correct assessments of contemporary C balances.

  • 7. Lueck, Jenna
    et al.
    Dickhut, Rebecca
    Cochran, Michele
    Falconer, Renee
    Kylin, Henrik
    Persistent organic pollutants in the Atlantic and southern oceans and oceanic atmosphere2017Ingår i: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 583, s. 64-71Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    Persistent organic pollutants (POPs) continue to cycle through the atmosphere and hydrosphere despite banned or severely restricted usages. Global scale analyses of POPs are challenging, but knowledge of the current distribution of these compounds is needed to understand the movement and long-term consequences of their global use. In the current study, air and seawater samples were collected Oct. 2007- Jan. 2008 aboard the Icebreaker Oden en route from Göteborg, Sweden to McMurdo Station, Antarctica. Both air and surface seawater samples consistently contained α-hexachlorocyclohexane (α-HCH), γ-HCH, hexachlorobenzene (HCB), α-Endosulfan, and polychlorinated biphenyls (PCBs). Sample concentrations for most POPs in air were higher in the northern hemisphere with the exception of HCB, which had high gas phase concentrations in the northern and southern latitudes and low concentrations near the equator. South Atlantic and Southern Ocean seawater has a high ratio of α-HCH to γ-HCH, indicating persisting levels from technical grade sources. The Atlantic and Southern Ocean continue to be net sinks for atmospheric α-, γ-HCH, and Endosulfan despite declining usage.

  • 8. Mastromonaco, Michelle G. Nerentorp
    et al.
    Gardfeldt, Katarina
    Assmann, Karen M.
    Langer, Sarka
    Delali, Tulasi
    Shlyapnikov, Yaroslav M.
    Zivkovic, Igor
    Horvat, Milena
    Speciation of mercury in the waters of the Weddell, Amundsen and Ross Seas (Southern Ocean)2017Ingår i: Marine Chemistry, ISSN 0304-4203, E-ISSN 1872-7581, Vol. 193, s. 20-33Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Despite the distance from large anthropogenic emission sources, toxic mercury is transported via the atmosphere and oceans to the Southern Ocean. Seawater samples were collected at selected stations and were analysed for total mercury (HgT) (8 stations), dissolved gaseous mercury (DGM) (62 stations) and methylmercury (12 stations) during winter (Weddell Sea), spring (Weddell Sea) and summer (Amundsen and Ross Seas) in the Southern Ocean. The HgT distribution in water columns was found to not vary significantly with depth. In the Weddell Sea the average column concentration was higher in spring (2.6 +/- 1.3 pM, 2 stations) than in winter (2.0 +/- 1.0 pM, 6 stations). We hypothesize that the seasonal HgT increase is due to atmospheric deposition of particulate Hg(II) formed during atmospheric mercury depletion events (AMDEs), as well as the addition of inorganic mercury species from melting sea ice and snow. Furthermore, HgT concentrations found in this study were significantly higher than previously measured in the Southern Ocean (Cossa et al., 2011), which was hypothesized to be due to seasonal variations in atmospheric deposition. The average water column DGM concentration in the Weddell Sea was 454 +/- 254 fM in winter and 384 +/- 239 fM in spring. The lowest average DGM concentration was found in summer in the Amundsen and Ross Seas (299 +/- 137 fM). The highest observed concentration in winter was hypothesized to be caused by the larger sea ice coverage, which is known to reduce the evasion of Hg(0) from the sea surface. The average monomethylmercury (MMHg) concentration in the Weddell Sea was 60 +/- 30 fM in winter (6 stations) and 95 +/- 85 fM in spring (2 stations), showing no significant seasonal difference. In the Amundsen and Ross Seas the summer average concentration of MeHg (MMHg and dimethylmercury; DMHg) was 135 +/- 189 fM (4 stations). The highest MeHg concentration was found in modified circumpolar deep water, which is known to have high primary production. 2017 Elsevier B.V. All rights reserved.

  • 9. Mastromonaco, Michelle G. Nerentorp
    et al.
    Gardfeldt, Katarina
    Langer, Sarka
    Mercury flux over West Antarctic Seas during winter, spring and summer2017Ingår i: Marine Chemistry, ISSN 0304-4203, E-ISSN 1872-7581, Vol. 193, s. 44-54Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    For the first time elemental mercury in air and surface seawater was measured continuously in the remote seas of western Antarctica. A major contributor to atmospheric emissions of the toxic and globally dispersed pollutant mercury is the re-evasion from water surfaces, due to a supersaturation of dissolved gaseous mercury (DGM) in surface water. In this study the degree of saturation and mercury flux at the air-sea surface interface have been estimated from continuous measurements of gaseous elemental mercury (GEM) or total gaseous mercury (TGM) in air, DGM in surface water and meteorological parameters. The measurements were performed during winter and spring (2013) in the Weddell Sea and during summer (2010/2011) in the Bellingshausen, Amundsen and Ross Seas, and show spatial and seasonal variations. The average DGM concentration in surface water in open sea was highest during spring (12 +/- 7pg L-1) and lowest during summer (7 +/- 6.8 pg L-1), resulting in a net evasion of mercury during spring (1.1 +/- 1.6 ng m(-2)h(-1)) and a net deposition during summer (-0.2 +/- 1.3 ng m(-2)h(-1)). In open sea, higher average concentrations of GEM (or TGM) and DGM were found close to the Drake Passage compared to in the Bellingshausen and Weddell Seas. Emission sources from the South American continent, identified with back trajectories, were suggested to explain the observed variations. The yearly mercury evasion from open sea surfaces in the Southern Ocean was estimated to 30 ( -450-1700) tons, using the average (and min and max) flux rates obtained in this study. Higher DGM was measured under sea ice (19-62 pg L-1 compared to in open sea due to a capsuling effect, resulting in a theoretical prevented evasion of 520 (0-3400) tons per year. Diminishing sea ice and higher water temperatures in polar regions could result in increased mercury evasion to the atmosphere. However, the contribution of the Southern Ocean to the global modeled annual emissions of mercury from sea surfaces would probably only be a few percent. (C) 2016 Elsevier B.V. All rights reserved.

  • 10.
    Monteux, Sylvain
    Umeå universitet, Institutionen för ekologi, miljö och geovetenskap.
    A song of ice and mud: Interactions of microbes with roots, fauna and carbon in warming permafrost-affected soils2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Permafrost-affected soils store a large quantity of soil organic matter (SOM) – ca. half of worldwide soil carbon – and currently undergo rapid and severe warming due to climate change. Increased SOM decomposition by microorganisms and soil fauna due to climate change, poses the risk of a positive climate feedback through the release of greenhouse gases. Direct effects of climate change on SOM decomposition, through such mechanisms as deepening of the seasonally-thawing active layer and increasing soil temperatures, have gathered considerable scientific attention in the last two decades. Yet, indirect effects mediated by changes in plant, microbial, and fauna communities, remain poorly understood. Microbial communities, which may be affected by climate change-induced changes in vegetation composition or rooting patterns, and may in turn affect SOM decomposition, are the primary focus of the work described in this thesis.

    We used (I) a field-scale permafrost thaw experiment in a palsa peatland, (II) a laboratory incubation of Yedoma permafrost with inoculation by exotic microorganisms, (III) a microcosm experiment with five plant species grown either in Sphagnum peat or in newly-thawed permafrost peat, and (IV) a field-scale cold season warming experiment in cryoturbated tundra to address the indirect effects of climate change on microbial drivers of SOM decomposition. Community composition data for bacteria and fungi were obtained by amplicon sequencing and phospholipid fatty acid extraction, and for collembola by Tullgren extraction, alongside measurements of soil chemistry, CO2 emissions and root density.

    We showed that in situ thawing of a palsa peatland caused colonization of permafrost soil by overlying soil microbes. Further, we observed that functional limitations of permafrost microbial communities can hamper microbial metabolism in vitro. Relieving these functional limitations in vitro increased cumulative CO2 emissions by 32% over 161 days and introduced nitrification. In addition, we found that different plant species did not harbour different rhizosphere bacterial communities in Sphagnum peat topsoil, but did when grown in newly-thawed permafrost peat. Plant species may thus differ in how they affect functional limitations in thawing permafrost soil. Therefore, climate change-induced changes in vegetation composition might alter functioning in the newly-thawed, subsoil permafrost layer of northern peatlands, but less likely so in the topsoil. Finally, we observed that vegetation encroachment in barren cryoturbated soil, due to reduced cryogenic activity with higher temperatures, change both bacterial and collembola community composition, which may in turn affect soil functioning.

    This thesis shows that microbial community dynamics and plant-decomposer interactions play an important role in the functioning of warming permafrost-affected soils. More specifically, it demonstrates that the effects of climate change on plants can trickle down on microbial communities, in turn affecting SOM decomposition in thawing permafrost.

  • 11.
    Newton, Seth
    Stockholms universitet, Institutionen för miljövetenskap och analytisk kemi.
    Occurrence and fate of emerging and legacy flame retardants: from indoor environments to remote areas2015Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Persistent organic pollutants (POPs) are toxic chemicals that can be found in various matrices in all corners of the planet, including remote areas such as the Arctic.  Several POPs are known and monitored but given the abundance of new chemicals in commerce about which little is known, chemicals that may be new POPs are constantly being screened for. The use of flame retardants, particularly brominated flame retardants (BFRs), has been increasing for decades. PBDEs and HBCDDs are two types of BFRs that have historically been used in large volumes but recently faced legislative restrictions. However, in order to meet fire safety standards, these BFRs have been replaced by a variety of emerging flame retardants (EFRs) about which little is known especially concerning their toxicity, production volumes, and environmental behavior. The main purpose of this thesis was to investigate the occurrence and fate in indoor and outdoor environments of several EFRs and compare them with PBDEs, HBCDDs, and legacy POPs.

    Several indoor environments in the city of Stockholm, Sweden were sampled for dust, indoor air, and ventilation system air (Paper II).  Results from these samples revealed a number of EFRs that humans are exposed to and that are emitted from buildings through ventilation systems. These included DDC-CO, DBE-DBCH, PBT, HBB, EHTBB, and BEH-TEBP. PBDE levels seem to be declining compared to previous studies in Stockholm.  Outdoor air and soil were sampled across transects of Stockholm (Paper II) and Birmingham, United Kingdom (Paper III).  Results from these samples showed the presence of many of the same EFRs in the outdoor environment that were found in indoor environments.  Urban pulses in air were discovered for PBDEs in both cities and for some EFRs in Stockholm, indicating that the cities are sources of EFRs to the outdoor environment.  Atmospheric deposition samples were taken at two sites in northern Sweden (Paper I).  Three EFRs (DDC-CO, DBE-DBCH, and BTBPE) and two current-use pesticides (trifluralin and chlorothalonil) were identified, indicating these compounds’ potential for long range transport and global contamination.  Other legacy POPs such as HCH, PCBs, and PBDEs were measured in the deposition samples as well.  The bulk of deposition was comprised of HCH and PCBs with only minor contributions from PBDEs, chlordanes, and emerging compounds.  Finally, passive and active air sampling methods were compared for BFRs in offices in Beijing, China.  Some EFRs were identified in indoor air from China; however, BDE-209 was the most predominant compound found (Paper IV).  Air samples collected with passive samplers generally had measured FR concentrations within a factor of 2-3 of those collected with active samplers. The use of a GFF in the passive samplers resulted in concentrations of particle-bound contaminants such as BDE-209 that were more comparable to those in active samples. The positioning of the PUF in the passive samplers affected the sampling rates for gaseous compounds and particle retention on PUFs was shown to be a large source of uncertainty in passive sampling.

  • 12.
    Pihl Karlsson, Gunilla
    et al.
    Utförare miljöövervakning, IVL Svenska Miljöinstitutet AB.
    Blomgren, Håkan
    Utförare miljöövervakning, IVL Svenska Miljöinstitutet AB.
    Petersson, Kjell
    Utförare miljöövervakning, IVL Svenska Miljöinstitutet AB.
    Svensson, Annika
    Utförare miljöövervakning, IVL Svenska Miljöinstitutet AB.
    Sjöberg, Karin
    Utförare miljöövervakning, IVL Svenska Miljöinstitutet AB.
    Nationell miljöövervakning av luft och nederbördskemi 20022003Rapport (Övrigt vetenskapligt)
  • 13. Pokrovsky, Oleg S.
    et al.
    Karlsson, Jan
    Umeå universitet, Institutionen för ekologi, miljö och geovetenskap.
    Giesler, Reiner
    Umeå universitet, Institutionen för ekologi, miljö och geovetenskap.
    Freeze-thaw cycles of Arctic thaw ponds remove colloidal metals and generate low-molecular-weight organic matter2018Ingår i: Biogeochemistry, ISSN 0168-2563, E-ISSN 1573-515X, Vol. 137, nr 3, s. 321-336Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    High-latitude boreal and arctic surface/inland waters contain sizeable reservoirs of dissolved organic matter (DOM) and trace elements (TE), which are subject to seasonal freezing. Specifically, shallow ponds and lakes in the permafrost zone often freeze solid, which can lead to transformations in the colloidal and dissolved fractions of DOM and TE. Here, we present results from experimental freeze-thaw cycles using iron (Fe)- and DOM-rich water from thaw ponds situated in Stordalen and Storflaket palsa mires in northern Sweden. After ten cycles of freezing, 85% of Fe and 25% of dissolved organic carbon (DOC) were removed from solution in circumneutral fen water (pH 6.9) but a much smaller removal of Fe and DOC (< 7%) was found in acidic bog water (pH 3.6). This removal pattern was consistent with initial supersaturation of fen water with respect to Fe hydroxide and a lack of supersaturation with any secondary mineral phase in the bog water. There was a nearly two- to threefold increase in the low-molecular-weight (LMW) fraction of organic carbon (OC) and several TEs caused by the repeated freeze-thaw cycles. Future increases in the freeze-thaw frequency of surface waters with climate warming may remove up to 25% of DOC in circumneutral organic-rich waters. Furthermore, an increase of LMW OC may result in enhanced carbon dioxide losses from aquatic ecosystems since this fraction is potentially more susceptible to biodegradation.

  • 14. Rodriguez, Patricia
    et al.
    Ask, Jenny
    Umeå universitet, Institutionen för ekologi, miljö och geovetenskap.
    Hein, Catherine L.
    Jansson, Mats
    Umeå universitet, Institutionen för ekologi, miljö och geovetenskap.
    Karlsson, Jan
    Umeå universitet, Institutionen för ekologi, miljö och geovetenskap.
    Benthic organic carbon release stimulates bacterioplankton production in a clear-water subarctic lake2013Ingår i: Freshwater Science, ISSN 2161-9549, E-ISSN 2161-9565, Vol. 32, nr 1, s. 176-182Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We carried out a set of experiments in a small clear-water lake in northern Sweden during summer 2010 to assess the effect of organic C (OC) released from epipelic algae on pelagic bacterial production (BP). The release rate of OC (dissolved and particulate) from epipelic algae was similar to 45.4 ng C m(-2) h(-1) Bacterioplankton uptake of dissolved OC was P-limited, and pelagic primary production (PP) was colimited by N and P. Pelagic BP (3.2 +/- 6 mu g C L-1 h(-1)) exceeded pelagic PP (0.012 +/- 0.008 mu g C L-1 h(-1)). Pelagic BP was higher in lake water in contact with sediments and the epipelic algae growing on their surface than in water separated from the sediments. Epipelic algae release OC to lake water and potentially stimulate pelagic BP. However, exploitation of benthic OC probably is suboptimal because of nutrient limitation (primarily by inorganic P) of BP.

  • 15. Rousk, Kathrin
    et al.
    Sorensen, Pernille L.
    Lett, Signe
    Umeå universitet, Institutionen för ekologi, miljö och geovetenskap.
    Michelsen, Anders
    Across-Habitat Comparison of Diazotroph Activity in the Subarctic2015Ingår i: Microbial Ecology, ISSN 0095-3628, E-ISSN 1432-184X, Vol. 69, nr 4, s. 778-787Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Nitrogen (N) fixation by N-2-fixing bacteria (diazotrophs) is the primary N input to pristine ecosystems like boreal forests and subarctic and arctic tundra. However, the contribution by the various diazotrophs to habitat N-2 fixation remains unclear. We present results from in situ assessments of N-2 fixation of five diazotroph associations (with a legume, lichen, feather moss, Sphagnum moss and free-living) incorporating the ground cover of the associations in five typical habitats in the subarctic (wet and dry heath, polygon-heath, birch forest, mire). Further, we assessed the importance of soil and air temperature, as well as moisture conditions for N-2 fixation. Across the growing season, the legume had the highest total as well as the highest fraction of N-2 fixation rates at habitat level in the heaths (> 85 % of habitat N-2 fixation), whereas the free-living diazotrophs had the highest N-2 fixation rates in the polygon heath (56 %), the lichen in the birch forest (87 %) and Sphagnum in the mire (100 %). The feather moss did not contribute more than 15 % to habitat N-2 fixation in any of the habitats despite its high ground cover. Moisture content seemed to be a major driver of N-2 fixation in the lichen, feather moss and free-living diazotrophs. Our results show that the range of N-2 fixers found in pristine habitats contribute differently to habitat N-2 fixation and that ground cover of the associates does not necessarily mirror contribution.

  • 16.
    Selberg, Cecilia
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM).
    Konsumenters köpvilja och inställning till ekologiska livsmedel: En jämförelse av konsumtionsmönster i storstad och landsbygd2016Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Försäljningen av ekologiska livsmedel utgör endast 6 procent av Sveriges totala livsmedelsförsäljning. Om konsumtionsmönster och inställning till ekologiska livsmedel skiljer sig åt beroende på om konsumenten bor i storstad eller landsbygd undersöktes genom en enkätstudie. Totalt delades 1 200 enkäter ut i Stockholm, Gnesta, Älvdalen och Abisko varav 246 svar inkom.

    Respondenterna var positivt inställda till ekologiska livsmedel och köpte gärna dessa även om de lika gärna köpte vanliga livsmedel framför allt de med god smak, bra kvalité samt svenskproducerade. Ekologiska livsmedel valdes främst för hälsans skull då de var fria från gifter och tungmetaller, för djurens- och arbetarnas bästa och för miljöns skull. Bidragande orsaker till att inte köpa ekologiskt var att livsmedlen var för dyra men även gamla invanda köpvanor samt svårigheter att hitta ekologiska alternativ bidrog.

    Studien visade att skillnader finns i konsumtionsmönstret mellan storstad och landsbygd. Landsbygdsborna tänkte mer på miljön och sin egen hälsa och köpte ekologiskt därav. De ansåg det viktigare med ekologiska livsmedelsinköp, närodlat och svenskproducerat och handlade mer frekvent ekologiskt än storstadsborna. Bidragande demografiska orsaker till den högre försäljningen av ekologiska livsmedel på landsbygden kan vara att från landsbygden fanns fler kvinnor och fler familjer med barn som svarade än från storstaden.

  • 17.
    Sjöberg, Karin
    et al.
    Utförare miljöövervakning, IVL Svenska Miljöinstitutet AB.
    Svensson, Annika
    Utförare miljöövervakning, IVL Svenska Miljöinstitutet AB.
    Pihl Karlsson, Gunilla
    Utförare miljöövervakning, IVL Svenska Miljöinstitutet AB.
    Blomgren, Håkan
    Utförare miljöövervakning, IVL Svenska Miljöinstitutet AB.
    Nationell miljöövervakning inom EMEP och Luft och Nederbördskemiska nätet 2004 & 20052006Rapport (Övrigt vetenskapligt)
  • 18.
    Svensson, Sören
    Utförare miljöövervakning, Lunds universitet, biologiska institutionen.
    Bevakning av häckningsframgången hos staren. Årsrapport för 20092010Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    (1) Antal starar som skrider till häckning i bevakningsområdena och som således ligger till grund för analys av häckningens förlopp och produktionen av ungar samt möjliggör provtagning för miljögiftsanalyser är efter uppsättning av kompletteringsholkar i vissa av områdena nu helt tillfredsställande i Grimsö, Kvismaren, Tiveden, Svartedalen, Fleringe, Ottenby och Revinge. I Berg har antal häckningar minskat och om trenden inte vänder kan en kompletterande holkgrupp komma att behövas. För Tyresta behövs ett kompletterings- eller ersättningsområde. (2) Den genomsnittliga äggkullstorleken var hög 2009, men andelen flygga ungar var däremot låg i förhållande till vad som gällt under senare delen av 1990-talet och 2000-talet. Den var dock högre än många år under 1980-talet och första delen av 1990-talet. Långsiktigt över hela bevakningsperioden sedan början av 1980-talet finns inga övergripande negativa trender. (3) Äggläggningen startade 2009 tidigare än någonsin i flera av områdena och nytt tidighetsrekord slogs i en holk i Fleringe där första ägget lades 16 april. Starens häckningsstart och häckningsframgång är känsliga för vårens väder och därför indikatorer på effekter av klimatförändringar.

  • 19. Svensson, Sören
    Fågelinventeringar i Norrbottens län 1981-1996 inom Naturvårdsverketsmiljökvalitetsprogram (PMK)2011Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Inom ramen för naturvårdsverkets program för miljökvalitetsövervakning (PMK) genomfördes fågelinventeringar i Norrbottens län åren 1981–1996. Tre s.k. referensområden låg helt inom (Abisko, Muddus och Reivo) och ett fjärde (Sorsele) berörde delvis länet.

    Inventeringarna bedrevs dels med punkt- och linjetaxeringar (s.k. milrutter) över större områden, dels med revirkartering i mindre provytor. Antalet milrutter var femton i Abisko, nitton i Muddus, åtta i Reivo och sexton i Sorsele. Milrutter inventerades i Abisko 1981–1995, i Muddus 1983–1984 och 1994–1995, i Reivo 1987–1994 och i Sorsele 1982–1984. Det sammanlagda antalet inventerade mil var 129 i Abisko, 55 i Muddus, 54 i Reivo och 45 i Sorsele. Antalet provytor var tre i Abisko, två i Muddus samt en vardera i Reivo och Sorsele.

    De inventerades ungefär samma år som milrutterna. Materialet från Abisko, som omfattar björkskog, kalfjäll och myrmark, är stort och av hög kvalitet och utgör en utmärkt bas för jämförelse vid en eventuell återinventering. Materialen från Muddus, Reivo och Sorsele, områden som domineras av barrskog och myrmark, är mindre bra eftersom antalet rutter och år med inventeringar är färre. Tillsammans representerar emellertid dessa tre områden ett stort stickprov om 43 olika rutter, en period om fjorton år och totalt 154 inventerade mil. Såväl tätheter som artsammansättning var inbördes lika i de tre områdena i skogslandet och de kan tillsammans betraktas som ett homogent stickprov i Norrlands inre skogsland. Vid en återinventering bör därför de tre områdena tillsammans utgöra jämförelsematerialet.

    Förändringar i fågelfaunan kunde med tillförsikt endast analyseras med det mångåriga materialet från Abisko. Där skedde en svag men signifikant nedgång av både artantal och antalet fåglar. I Muddus och Reivo var också negativa förändringar fler än positiva.

    Totalbilden för länet verkar således ha varit negativ under perioden, vilket innebär att fågelfaunans utveckling Norrland liknade den i södra Sverige under samma period.

    I Muddus gjordes en jämförelse mellan ruttsträckor som löpte innanför och utanför nationalparkens gräns. Den totala fågeltätheten var densamma innanför och utanför och de

    skillnader som fanns på artnivå var inte entydiga.

    En jämförelse mellan milrutterna och angränsande standardrutter, inventerade på 2000-talet, gjordes. De skillnader i fågeltätheter som observerades kan ge vissa antydningar om förändringar i fågelfaunan, men tolkningen är mycket osäker eftersom mil- och standardrutter inte är identiska utan har olika biotopsammansättning.

    Rekommendationen inför återinventering är att i första hand välja milrutterna i Abisko och i andra hand milrutterna i de tre barrskogsomårdena. Provytorna har lägre prioritet. Abisko ges prioritet både för att materialet är så gediget och för att fågelarterna i björk- och lågfjällszonerna länge varit betydligt sämre övervakade än arterna i skogslandet.

  • 20.
    Thompson, Megan Shera
    et al.
    Umeå universitet, Institutionen för ekologi, miljö och geovetenskap.
    Giesler, Reiner
    Umeå universitet, Institutionen för ekologi, miljö och geovetenskap.
    Karlsson, Jan
    Umeå universitet, Institutionen för ekologi, miljö och geovetenskap.
    Klaminder, Jonatan
    Umeå universitet, Institutionen för ekologi, miljö och geovetenskap.
    Size and characteristics of the DOC pool in near-surface subarctic mire permafrost as a potential source for nearby freshwaters2015Ingår i: Arctic, Antarctic and Alpine research, ISSN 1523-0430, E-ISSN 1938-4246, Vol. 47, nr 1, s. 49-58Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Subarctic peatlands are rich sources of organic carbon for freshwater ecosystems. Where those peatlands are underlain by permafrost, permafrost thaw may cause an initial release of bioavailable dissolved organic carbon (DOC) to surrounding freshwaters. In this study, we measured icebound and potentially leachable (extracted) DOC quantities and indices of DOC quality in active layer and permafrost layers from two subarctic peat mires, Stord-alen and Storflaket. Most of the permafrost layers did not contain more organic matter or exportable DOC (as g kg(-1) dry soil) than the overlying active layer, and there was no difference in aromaticity, molecular weight, or the ratio between labile and recalcitrant DOC extracted from the permafrost and active layer. However, DOC held in segregated ice of the near-surface permafrost had relatively low aromaticity compared to extracted DOC from the same depth. Total icebound and potentially leachable DOC in the Stordalen mire permafrost that is predicted to experience active layer deepening during each of the next 50 years corresponded to about 0.1% of the current annual aquatic export of DOC from the mire. We conclude that the pool of potentially leachable DOC currently stored in permafrost layers is small. We also highlight differences in permafrost organic material between the two studied mire systems, which has an effect on the pool and properties of leachable DOC that is potentially available for export during thaw. Moreover, the geomorphological form of permafrost thaw will influence future hydrological connectedness and DOC production, in turn determining future DOC export from the mires.

  • 21. Veen, G. F. (Ciska)
    et al.
    Sundqvist, Maja K.
    Umeå universitet, Institutionen för ekologi, miljö och geovetenskap.
    Metcalfe, Daniel
    Wilson, Scott D.
    Umeå universitet, Institutionen för ekologi, miljö och geovetenskap.
    Above-ground and below-ground plant responses to fertilization in two subarctic ecosystems2015Ingår i: Arctic, Antarctic and Alpine research, ISSN 1523-0430, E-ISSN 1938-4246, Vol. 47, nr 4, s. 693-702Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Soil nutrient supply is likely to change in the Arctic due to altered process rates associated with climate change. Here, we compare the responses of herbaceous tundra and birch forest understory to fertilization, considering both above-and below-ground responses. We added nitrogen and phosphorus to plots in both vegetation types for three years near Abisko, northern Sweden, and measured the effect on above-and below-ground plant community properties and soil characteristics. Fertilization increased ground-layer shoot mass, the cover of grasses, and tended to enhance total root length below-ground, while it reduced the cover of low statured deciduous dwarf-shrubs. The only statistically significant interaction between vegetation type and fertilization was for grass cover, which increased twofold in forest understory but sixfold in tundra following fertilization. The lack of interactions for other variables suggests that the ground layers in these contrasting vegetation types have similar responses to fertilization. The nutrient-driven increase in grass cover and species-specific differences in productivity and root characters may alter ecosystem dynamics and C cycling in the long-term, but our study indicates that the response of birch forest understory and tundra vegetation may be consistent.

  • 22.
    Wik, Martin
    et al.
    Stockholms universitet, Institutionen för geologiska vetenskaper.
    Crill, Patrick M.
    Stockholms universitet, Institutionen för geologiska vetenskaper.
    Varner, Ruth K.
    Bastviken, David
    Stockholms universitet, Institutionen för geologiska vetenskaper.
    Multiyear measurements of ebullitive methane flux from three subarctic lakes2013Ingår i: Journal of Geophysical Research - Biogeosciences, ISSN 2169-8953, E-ISSN 2169-8961, Vol. 118, nr 3, s. 1307-1321Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ebullition (bubbling) from small lakes and ponds at high latitudes is an important yet unconstrained source of atmospheric methane (CH4). Small water bodies are most abundant in permanently frozen peatlands, and it is speculated that their emissions will increase as the permafrost thaws. We made 6806 measurements of CH4 ebullition during four consecutive summers using a total of 40 bubble traps that were systematically distributed across the depth zones of three lakes in a sporadic permafrost landscape in northernmost Sweden. We identified significant spatial and temporal variations in ebullition and observed a large spread in the bubbles' CH4 concentration, ranging from 0.04% to 98.6%. Ebullition followed lake temperatures, and releases were significantly larger during periods with decreasing atmospheric pressure. Although shallow zone ebullition dominated the seasonal bubble CH4 flux, we found a shift in the depth dependency towards higher fluxes from intermediate and deep zones in early fall. The average daily flux of 13.4mg CH4 m(-2) was lower than those measured in most other high-latitude lakes. Locally, however, our study lakes are a substantial CH4 source; we estimate that 350kg of CH4 is released via ebullition during summer (June-September), which is approximately 40% of total whole year emissions from the nearby peatland. In order to capture the large variability and to accurately scale lake CH4 ebullition temporally and spatially, frequent measurements over long time periods are critical.

1 - 22 av 22
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf