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Visar resultat 1 - 5 av 66 avhandlingar som matchar ovanstående sökkriterier.
1. Beyond carbon-limitation : A re-evaluation of the ecological role of photorespiration and direct oxygen photoreduction in seagrasses
Sammanfattning : Seagrasses living in shallow coastal waters are regularly subjected to changes in environmental conditions including the two essential factors for photosynthesis: dissolved inorganic carbon (DIC) and irradiance. This thesis focuses on the photosynthetic responses of seagrasses to carbon limitation induced by community metabolism and/or high light intensities. LÄS MER
2. Factors regulating the origin and magnitude of carbon dioxide emissions from high-latitude lakes
Sammanfattning : Lake ecosystems receive, transmit and process terrestrial carbon and thereby link terrestrial, aquatic and global carbon cycles. Most lakes evade CO2 to the atmosphere, but the annual magnitude of CO2 evasion, as well as sources and mechanisms underpinning CO2 evasion from lakes are still largely unresolved. LÄS MER
3. Impacts of global change on primary production in northern lakes
Sammanfattning : Algae are primary producers, a major component of the aquatic foodweb, and changes in primary production affect aquatic ecology in general. Global changes such as warming, recovery of acidification and changes in land-use have caused warming and browning of northern lakes. LÄS MER
4. Allochthonous and autochthonous carbon sources of lake bacterioplankton
Sammanfattning : Organic substrates for pelagic bacteria are derived from dissolved organic carbon (DOC) in the water column that originates either from primary production from within the lake itself (autochthonous), or import of organic matter from the terrestrial watershed (allochthonous production). This thesis addresses the utilization of allochthonous versus autochthonous carbon (C) sources by lake bacterioplankton. LÄS MER
5. Productivity and carbon transfer in pelagic food webs in response to carbon, nutrients and light
Sammanfattning : Some of the major problems we face today are human induced changes to the nitrogen (N), phosphorus (P) and carbon (C) cycles. Predicted increases in rainfall and temperature due to climate change, may also increase dissolved organic matter (DOM) inflows to freshwater ecosystems in the boreal zone. LÄS MER