Sökning: "nitrogen budget"

Visar resultat 6 - 10 av 17 avhandlingar innehållade orden nitrogen budget.

1. 6. Agricultural nutrient budgets in Europe: data, methods, and indicators

   Författare :Rasmus Einarsson; Chalmers tekniska högskola; []
   Nyckelord :LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; phosphorus; nutrient budget; EU; nutrient balance; nitrogen; Europe; indicators; environment; agriculture;

   Sammanfattning : Agricultural production systems feed humanity but also cause a range of adverse environmental effects, including climate change, loss of biodiversity, and pollution of air and water. A main cause of these effects is the emissions of nitrogen (N) and phosphorus (P) that occur as a side effect of nutrient cycling in agriculture. LÄS MER

3. 7. Carbon dynamics in spruce forest ecosystems - modelling pools and trends for Swedish conditions

   Författare :Magnus Svensson; Per-Erik Jansson; Dan Berggren Kleja; Keith Paustian; KTH; []
   Nyckelord :boreal; climate; CoupModel; net ecosystem production; nitrogen; process-based model; soil carbon; NATURAL SCIENCES; NATURVETENSKAP;

   Sammanfattning : Carbon (C) pools and fluxes in northern hemisphere forest ecosystems are attracting increasing attention concerning predicted climate change. This thesis studied C fluxes, particularly soil C dynamics, in spruce forest ecosystems in relation to interactions between physical/biological processes using a process-based ecosystem model (CoupModel) with data for Swedish conditions. LÄS MER

4. 8. Distribution and activity of nitrogen-fixing bacteria in marine and estuarine waters

   Författare :Hanna Farnelid; Lasse Riemann; Jonathan Zehr; Linnéuniversitetet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; 454-pyrosequencing; diazotrophs; heterotrophic bacteria; marine bacteria; marine microbial ecology; microbiology; nifH; nitrogenase; nitrogen fixation; PCR; qPCR; Mikrobiologi; Microbiology;

   Sammanfattning : In aquatic environments the availability of nitrogen (N) generally limits primary production. N2-fixing prokaryotes (diazotrophs) can convert N2 gas into ammonium and provide significant input of N into the oceans. Cyanobacteria are thought to be the main N2-fixers but diazotrophs also include a wide range of heterotrophic bacteria. LÄS MER

5. 9. Regional Nutrient Budgets in Forest Soils in a Policy Perspective

   Författare :Cecilia Akselsson; Avdelningen för kemiteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; pedology; cartography; climatology; Fysisk geografi; geomorfologi; marklära; kartografi; klimatologi; geomorphology; Physical geography; Miljökemi; Environmental chemistry; skogsteknik; skogsbruk; Skogsvetenskap; forestry technology; forestry; Silviculture; Näringslära; Nutrition; Växtekologi; policy-making; Plant ecology; regional scale; deposition; eutrophication; carbon sequestration; acidification; Nutrient budget;

   Sammanfattning : Sweden's forests are one of its most important natural resources, as well as being important from ecological and social perspectives. Nutrient sustainability is essential to maintain the production capacity and reduce the effects of acidification and eutrophication. LÄS MER

7. 10. Environmental conditions governing the distributions of symbiotic and free-living diazotrophic cyanobacteria in two tropical open oceans

   Författare :Marcus Stenegren; Rachel Foster; Bethany Jenkins; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Nitrogen fixation; Diazotroph; Cyanobacteria; Symbiosis; DDA; Richelia; Marine Ecology; marin ekologi;

   Sammanfattning : Di-nitrogen (N2) fixation plays a crucial role in oceanic carbon and nitrogen cycles and is important for marine biogeochemistry on regional and global scales. N2-fixing (diazotrophs) cyanobacteria are considered to contribute the most to marine nitrogen fixation, and thereby fuel the surrounding phytoplankton communities with bioavailable ammonia. LÄS MER