Search for dissertations about: "stable nitrogen isotopes"

Showing result 1 - 5 of 33 swedish dissertations containing the words stable nitrogen isotopes.

  2. 1. Nitrogen Cycling at Cold Climate Mine Sites in Northen Sweden

    Author : Lino Nilsson; Anders Widerlund; Anders Lundqvist; Luleå tekniska universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Nitrogen; Mining; Cycling; nutrients; Isotopes; Nitrogen-model; modelling; numerical-modelling; Isotope-tracing; Tracing; Isotope; geochemistry; Applied Geology; Tillämpad geologi;

    Abstract : High nitrogen discharge from mining sites has been an environmental issue that has been closely studied in the recent years. The environmental effects of high nitrogen discharge are mainly eutrophication, but can also lead to changed species composition and algae blooms. READ MORE

  4. 2. Nitrate stable isotopes and major ions in snow and ice from Svalbard

    Author : Carmen Paulina Vega Riquelme; V. A. Pohjola; R. Pettersson; E. Isaksson; C. E. Bøggild; Kumiko Goto-Azuma; Uppsala universitet; []
    Keywords : nitrate stable isotopes; nitrate; NOx proxies; ice cores; percolation; ion relocation; Svalbard; stabila isotoper av nitrat; nitrat; indikator för kväveoxider; iskärnor; perkolation; joniska omlokalisering; Svalbard; Earth Science with specialization in Physical Geography; Geovetenskap med inriktning mot naturgeografi;

    Abstract : Increasing atmospheric reactive nitrogen (Nr), as consequence of human activities, has generated accumulation of nitrate (NO3-) in Arctic regions. The Arctic has fragile nitrogen limited ecosystems that can be altered by increases of dry or wet deposition of Nr. READ MORE

  5. 3. Effects of heavy metal contamination on carbon and nitrogen cycling : An ecological approach to assess risks to soil functions

    Author : Ingrid Rijk; Alf Ekblad; Dan Berggren Kleja; Erik Karltun; Örebro universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; heavy metals; soil contamination; stable isotopes; N cycling microbial guilds; 13C; 15N; nitrification; denitrification; biochar; soil respiration; microbial activity; bioavailability;

    Abstract : Soil contamination with heavy metals may disrupt soil microorganisms with important roles in carbon (C) and nitrogen (N) cycling. However, there is a lack of understanding on how microorganisms are affected in soil, which may lead to a mismatch when assessing risks of contaminants to field soils. READ MORE

  6. 4. Varved lake sediments and diagenetic processes

    Author : Veronika Gälman; Ingemar Renberg; Daniel Conley; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Varved annually laminated lake sediment; diagenesis; varve appearance; iron; sulfur; chemical speciation; iron cycling; carbon; nitrogen; stabile isotopes; δ13C; δ15N; Earth sciences; Geovetenskap;

    Abstract : Varved (annually laminated) sediments are of great interest for inference of past environmental conditions, as they provide dated records with high time resolution. After deposition, the sediment varves are affected by diagenesis; i.e., chemical, physical and biological changes that occur within the sediment. READ MORE

  7. 5. Gradients of time and complexity : understanding how riparian and instream ecosystems recover after stream restoration

    Author : Eliza Maher Hasselquist; Christer Nilsson; Stewart Rood; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; bioassessment; biodiversity; boreal; bryophyte; chronosequence; complexity; diatom; geomorphology; habitat heterogeneity; hydromorphological; macroinvertebrate; macrophyte; nitrogen cycling; river restoration; riparian buffer; stable isotopes; succession; Sweden; Environmental Science; miljövetenskap;

    Abstract : Why evaluations of the ecological outcomes of stream and river restoration have largely reported inconclusive or negative results has been the subject of much debate over the last decade or more. Understanding the reasons behind the lack of positive results is important for bettering future restoration efforts and setting realistic expectations for restoration outcomes. READ MORE