Sökning: "Gulf of bothnia"

Visar resultat 11 - 15 av 29 avhandlingar innehållade orden Gulf of bothnia.

  1. 11. Variation in age and size at maturation in two benthic crustaceans in the Gulf of Bothnia

    Författare :Kjell Leonardsson; J. Ekman; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Age at maturation; alternative prey; Bergmanris rule; cannibalism; growth; life-history theory; mortality; Mvoxocephalus quadricornis; poikilotherm; Pontoporeia affinis; population dynamics; risk- taking behaviour; Saduria entomon; size at maturation; temperature;

    Sammanfattning : The thesis deals with variation in age and size at maturation in Saduria entomon and Pontoporeia affinis along a depth gradient in the Gulf of Bothnia, Sweden. I have analysed at what sizes and ages animals should mature in relation to growth and mortality conditions. LÄS MER

  3. 12. Geochemistry of the Lule River, northern Sweden, before and after regulation

    Författare :Lisbeth Drugge; Luleå tekniska universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Applied Geology; Tillämpad geologi;

    Sammanfattning : The Lule River is the largest and most important river for hydropower production in Sweden. This river, situated in the northern part of the country, has been regulated since the beginning of the 20th century and is heavily regulated with 15 power stations. LÄS MER

  4. 13. Impact of hydropower regulation on river water geochemistry and hyporheic exchange

    Författare :Dmytro Siergieiev; Hjalmar Laudon; Luleå tekniska universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; regulated river; hyporheic zone; hydraulic conductivity; clogging layer; Applied Geology; Tillämpad geologi;

    Sammanfattning : Hydropower regulation of rivers exhibits a threat to the riverine ecosystems. Fragmentation of flow, landscape disturbances, and water retention are key features of regulated catchments, resulting in reduced floods and geochemical tr¬ansport, non-natural water level fluctuations, and thus disturbed exchange between the river and the aquifer. LÄS MER

  5. 14. Flipping the pyramid : lessons from converting top-down management of bleak-roe fishing

    Författare :Carl Rova; Luleå tekniska universitet; []
    Nyckelord :SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; Political Science; Statsvetenskap;

    Sammanfattning : The fishing of vendace (Coregonus albula), in the northern part of the Gulf of Bothnia, is a good illustration of the presumption that institutional arrangements which are too inflexible to cope with changing ecological conditions are unlikely to prosper. The aim of this thesis is to contribute to the development of a better understanding of governance in a relatively small and clearly defined, but complex common-pool resource system. LÄS MER

  7. 15. Properties of humic substances from groundwater and surface waters

    Författare :Catharina Pettersson; Linköpings universitet; []
    Nyckelord :SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; INTERDISCIPLINARY RESEARCH AREAS; TVÄRVETENSKAPLIGA FORSKNINGSOMRÅDEN;

    Sammanfattning : Humic substances play an important role in the environment. The aim of this thesis is to enhance the understanding of the behaviour of humic substances in natural waters and their importance for mobilizatiou/immobilization, redistribution, bioavailability and removal of metals and organic pollutants from aqueous systems. LÄS MER