Sökning: "Christian Bigler"

Visar resultat 1 - 5 av 7 avhandlingar innehållade orden Christian Bigler.

1. 1. Diatoms as indicators of Holocene climate and environmental change in northern Sweden

   Författare :Christian Bigler; Ingemar Renberg; Roland Hall; N. John Anderson; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physical geography and sedimentology; diatoms; Holocene; paleolimnology; climate change; lake sediments; transfer functions; quantitative environmental reconstructions; northern Sweden; Abisko; Naturgeografi och sedimentologi; Physical geography; Naturgeografi; naturgeografi; Physical Geography;

   Sammanfattning : The objective of the thesis was to explore the potential of diatoms (Bacillariophyceae) as indicators of Holocene climate and environmental change in northern Sweden (Abisko region, 68°21'N, 18°49'E). A modern surface-sediment calibration set including 100 lakes was developed and lake-water pH, sedimentary organic content (assessed by loss-on-ignition) and temperature were identified as most powerful environmental variables explaining the variance within the diatom assemblages. LÄS MER

3. 2. Metals take flight : Transport and effects across ecosystems

   Författare :Johan Lidman; A. M. M. Berglund; Micael Jonsson; Christian Bigler; Brendan Mckie; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Metals; aquatic subsidies; passerines; aquatic insects; environmental science; miljövetenskap; ekotoxikologi; Ecotoxicology;

   Sammanfattning : Metal contamination can have severe toxic effects in the ecosystems, resulting in loss of biodiversity, reduced abundance of organisms, and loss of ecosystem services. Traditionally, aquatic ecosystems have been regarded as a sink of metal contamination. LÄS MER

4. 3. Combining limnology and paleolimnology : a refined understanding of environmental sediment signal formation in a varved lake

   Författare :Dominique Béatrice Maier; Christian Bigler; Sebastian Diehl; Jasmine E. Saros; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; varved lake sediments; diatom sediment signal formation; sequential sediment trap; seasonal process timing; ice thinning; varve compaction; climate impact; catchment properties; Earth Sciences with Specialization Environmental Analysis; geovetenskap med inriktning mot miljöanalys;

   Sammanfattning : Paleoclimatic archives, such as lake sediments, extend our understanding of terrestrial and aquatic ecosystem dynamics in relation to climate variability beyond the period covered by instrumental data. In this context, annually laminated (i.e. LÄS MER

5. 4. Long-term development of subalpine lakes : effects of nutrients, climate and hydrological variability as assessed by biological and geochemical sediment proxies

   Författare :Manuela Milan; Christian Bigler; Monica Tolotti; Richard Bindler; Krystyna Szeroczyńska; Atte Korhola; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Paleolimnology; diatoms; Cladocera; sub-fossil pigments; geochemistry; wavelengthdispersive X-ray fluorescence spectroscopy; Lake Garda; Lake Ledro; reference conditions; nutrient enrichment; climate change; hydrological regime.;

   Sammanfattning : Sediment records of two Italian subalpine lakes (Lake Garda and Lake Ledro) were analyzed in order to reconstruct their ecological evolution over the past several hundred years. A multi-proxy and multi-site approach was applied in order to disentangle the effects of local anthropogenic forcings, such as nutrients, and climate impacts on the two lakes and their catchments. LÄS MER

7. 5. Lake sedimentary archives of medieval mining and smelting in Sweden : tracking environmental changes from site to landscape

   Författare :Erik Myrstener; Richard Bindler; Christian Bigler; Elinor Andrén; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; environmental science; miljövetenskap;

   Sammanfattning : While the environmental impact of the industrial age is massive, including climate change, pollution, microplastics and habitat loss, our influence reaches further back than many recognize. In Sweden, an early and important activity with large potential impact was the mining and smelting of iron, copper and silver ores over the last ~800 years. LÄS MER