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This study examines the relative contribution of algae and vascular plant litter to the food chains of freshwater marshes. Twelve enclosures (5 m diam.) were deployed in a nutrient-poor marsh of the Interlake region of Manitoba. Algae levels in six of the enclosures were increased by fertilizing the water column. In addition, the hardstem bulrush (Scirpus lacustris glaucus (Sm.) Hartm) litter present was replaced with a non-nutritive artificial substrate in half of the fertilized and unfertilized enclosures. Fertilization did not affect the dry weight loss of bulrush litter, but N and P concentrations were higher in the decomposing litter of the fertilized treatments. Dominant taxa of nektonic herbivores-detritivores responded to fertilization but were not affected by the replacement of plant litter by a non-nutritive substrate. Epiphytic herbivores-detritivores responded to changes in both detritus and algal food sources. Fertilization resulted in early peaks of emergence for the Chironominae, Tanypodinae and Orthocladiinae. Emergence data late in the study period suggest that the importance of litter as a food source may increase as decomposition progresses.

Nitrogen and sulfur deposition and water table level fluctuations have the potential to influence the C biogeochemistry in peatlands. Processes in peatland mesocosms were examined under steady state and dynamic conditions at different rates of N and S deposition, and water table levels. Net turnover rates were calculated from diffusive-advective mass-balances of pore water constituents. The limitations of the approach were tested with tracer experiments, which showed that diffusive-advective transport adequately described the flow of dissolved substances in peat columns. Incubation experiments quantified potential CO2, CH4, DOC, H2S and Fe 2+ production rates. / The vegetation assimilated most of the deposited nitrogen and sulfate when water table levels were high. Lowered water table levels resulted in seepage of sulfate to the water table, reduced the rates of photosynthesis, and increased the soil respiration rates. The potential for sulfate reduction was fairly large, despite small in situ sulfate concentrations, and the CO2 production could not be fully accounted for by known processes. Potential rates of sulfate reduction were large both in samples taken from the field site and from the controlled experiments. SO42- addition resulted partly in stimulation, partly in reduction of potential CH4 production rates suggesting that the relationship between sulfate reduction and methanogenesis is not exclusively competitive. / Changes of the water table level had in situ effects on CO2 and CH4 production rates not explainable by a distinction in aerobic/anaerobic conditions. Anaerobic in situ rates at greater depths were much lower when the water table was at the surface of the mesocosms than when it was at greater depths. This might have been due to in situ accumulation of CO2 and CH 4 in the deeper peat, which lowers the energy gain of anaerobic C mineralization. Flooding and draining of peat soil resulted in a delayed onset of CH 4 production, in increased anaerobic CO2 production and decreased CH4 production rates, and in the decoupling of gas exchange from production rates. These results document that fluctuations of environmental variables on short time scales have an impact on rates of C turnover in peat soils, and also limit the predictability of fluxes by statistical models.

Bakomliggande intresset för denna uppsats utgår ifrån frågan vilka motiv kommuner har för regionalt turismsamarbete. Samarbete har uppmärktsammats inom turismutveckling för att konkurrensen mellan destinationer har blivit global. Teorier om motiv för regionalt turismsamarbete har verklighetsprövats och jämförts mellan kommunerna Karlskrona och Karlshamn. Intervjuer med respektive turistchef genomfördes och teorierna som valts som utgångspunkt skiljde sig inte i allt för stor utmärkelse från resultatet. Resultat för motiv till regionalt turismsamarbete uppvisade att främsta motiven var; ekonomiska besparingar, utöka regionen med fler attraktioner samt för att skapa konkurrensfördelar gentemot andra regioner. Några av de valda teorierna stämde inte med kommunernas perspektiv till motiv och ett var motivet om kunskapsutbyte. Ett motiv som inte nämndes i någon vald teori men som Karlshamn nämnde var att se det regionala turismsamarbetet som en fördel för turisten.

Thesis (MAppSc in Physiotherapy) -- University of South Australia, 1994

Figure 5.13 is folded and in plastic pocket inside back cover. / Bibliography: leaves 147-168. / xiv, 184, [14] leaves, [35] leaves of plates : ill. (chiefly col.), maps ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Geology and Geophysics, 1998

Verdedigd als proefschrift Universität Zürich.

Thesis (M.A. - Anthropology)--University of Arizona. / Bibliography: leaves 107-109.

Thesis (M.A. - Anthropology)--University of Arizona. / Bibliography: leaves 164-167.

Thesis (M.A. in anthropology)--Washington State University, May 2008. / Includes bibliographical references (p. 123-133).