Sökning: "lake ecosystem"
Visar resultat 11 - 15 av 81 avhandlingar innehållade orden lake ecosystem.
11. The palaeolimnological record of regime shifts in lakes in response to climate change
Sammanfattning : Regime shifts in lake ecosystems can occur in response to both abrupt and continuous climate change, and the imprints they leave in palaeolimnological records allow us to investigate and better understand patterns and processes governing ecological changes on geological time scales. This thesis aims at investigating palaeolimnological records of regime shifts in lakes during the Holocene to explore how lake ecosystems responded to climate changes and anthropogenic activities and to identify thresholds or tipping points that produced regime shifts. LÄS MER
12. Element transport in aquatic ecosystems – Modelling general and element-specific mechanisms
Sammanfattning : Radionuclides are widely used in energy production and medical, military and industrial applications. Thus, understanding the behaviour of radionuclides which have been or may be released into ecosystems is important for human and environmental risk assessment. LÄS MER
13. Arctic Water System Change and its Interactions with Permafrost and Ecosystem Changes
Sammanfattning : Climate change and various changes in the landscape itself, such as permafrost thaw, may trigger and mediate substantial changes in the inland water system of the Arctic. Many climate change responses in the Arctic landscape and ecosystems are then related to alterations in the hydrological system. LÄS MER
14. Subarctic ecosystem responses to climate, catchment and permafrost dynamics in the Holocene
Sammanfattning : This thesis assesses aspects of the wetland development, permafrost dynamics and associated changes in carbon and nutrient cycling of the Stordalen Mire in northern Sweden. Various ecological and biogeochemical analyses of one peat and two lake sediment sequences were conducted, including analyses of organic matter and carbonate content, mosses, diatoms, testate amoebae, pigments, carbon and nitrogen and their stable isotopes, near infrared spectroscopy and biogenic silica. LÄS MER
15. The Invasion of the Zebra Mussel - Effects on Phytoplankton Community Structure and Ecosystem Function
Sammanfattning : Biological invasion has become a major threat to economy, ecology, global biodiversity and ecosystem function of aquatic ecosystems. The main aim of the thesis was to study the effects of the zebra mussel (Dreissena polymorpha), a versatile invasive species, on phytoplankton dynamics and ecosystem function of lakes. LÄS MER
