Sökning: "Total institution"

Visar resultat 16 - 20 av 60 avhandlingar innehållade orden Total institution.

1. 16. Land-atmosphere interaction of a subarctic palsa mire

   Författare :Marcin Jackowicz-Korczynski; Institutionen för naturgeografi och ekosystemvetenskap; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; eddy covariance; chamber; methnaol; isoprene; nonmethane hydrocarbons; methane; carbon dioxide; carbon; mire; permafrost; subarctic; palsa; greenhouse gas;

   Sammanfattning : The main objective of this thesis was to quantitatively estimate the gaseous exchange of carbon dioxide (CO2) and methane (CH4) between a subarctic wetland ecosystem and the atmosphere. Additionally some initial estimates of the carbon input to the atmosphere of nonmethane hydrocarbons (NMHCs) were also obtained by combining different techniques in a joint setting. LÄS MER

3. 17. Semi-natural grasslands: landscape, history and plant species diversity

   Författare :Lotten Jönsson; Institutionen för naturgeografi och ekosystemvetenskap; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; aerial photographs; Land-use history; cadastral maps; habitat continuity; fragmentation; landscape context; habitat connectivity;

   Sammanfattning : This thesis explores the impact of past and present landscape and habitat structure on present levels of vascular plant species diversity within fragmented semi-natural grasslands. Within the Jordtorp-area, a mosaic agricultural landscape on the island of Öland (Sweden), historical land-use changes and the development of semi-natural grasslands was characterized, over a time-period of almost 300 years, using historical maps, aerial photographs and a high-resolution imagery. LÄS MER

4. 18. Hydrothermal alteration of organic matter at spreading centers

   Författare :Eva Andersson; Bernd R.T. Simoneit; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Chemistry; Kemi; Biogeochemistry; biogeokemi;

   Sammanfattning : Alteration of organic matter, mainly amino acids, at sub-seafloor hydrothermal conditions has been investigated by performing laboratory experiments and by studying deep-sea sediments from hydrothermally active areas on the northern Juan de Fuca Ridge, northeast Pacific Ocean.Quaternary sediments from Middle Valley and the eastern flank of the Juan de Fuca Ridge recovered during the Ocean Drilling Program Legs 139 and 168 have been analyzed for total hydrolyzable amino acid concentrations, individual amino acid abundances and stereochemistry in order to evaluate the effects of hydrothermal stress on the decomposition of sedimentary amino acids. LÄS MER

5. 19. The origin of the marine Lockne impact structure, Jämtland

   Författare :Erik Sturkell; Christian Keoberl; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Lockne; Jämtland; Earth sciences; Geovetenskap; allmän och historisk geologi; General and Historical Geology;

   Sammanfattning : The Lockne impact structure in Jämtland (63o00'20"N, 14o49'30"E), formed in the Middle Ordovician at approximately 455 Ma. The structure is a concentric crater with a total diameter of 13.5 km. The impact took place in a marine environment. LÄS MER

7. 20. The role of sediments in the biogeochemical cycles of nutrients in the Gulf of Riga

   Författare :Juris Aigars; Matti Perttilä; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Biogeochemistry; biogeokemi;

   Sammanfattning : The sediment biogeochemistry of C, N, P and biologic silica (BSi) plays an important role in cycling of these elements in aquatic ecosystems. In shallow coastal and estuarine systems, water-sediment nutrient dynamics can influence biological processes (e.g., primary production) in overlying waters. LÄS MER