Sökning: "Other earth sciences"
Visar resultat 21 - 25 av 3042 avhandlingar innehållade orden Other earth sciences.
21. Of seagrass and society : Exploring contributions of tropical seagrass meadows to food security
Sammanfattning : Conserving biodiversity while simultaneously feeding a growing population is one of the grand challenges of the Anthropocene. Recently, global assessments have shone a light on the importance of the marine environment for the supply of food (often termed blue food), as well as the diverse and many livelihood opportunities associated to it. LÄS MER
22. Social-ecological dynamics in a highly regulated fisheries system - Sources of resilience and limits to command-and-control management
Sammanfattning : Sustainable governance of natural resources is challenged by the poor understanding of complex human-nature couplings. Major advancements in resilience theory, acknowledging the importance of social-ecological linkages and the self-organizing capacity of social-ecological systems, provides a new perspective on research in sustainability science. LÄS MER
23. Mixture toxicity of pesticides and biological effects in agricultural streams : field and laboratory studies
Sammanfattning : The main objective of this thesis was to examine pesticide mixture toxicity and its effects on aquatic biota in agricultural streams. This was accomplished by (1) calculating the ΣTUs for algae and Daphnia magna and a pesticide toxicity index (PTI) based on water quality standards (WQS) for long-term monitoring data (2002-2010), (2) by performing algal inhibition tests with Pseudokirchneriella subcapitata, using both collected in situ water samples and reconstituted water spiked with field-observed pesticide mixtures, and (3) by studying seasonal changes in macroinvertebrate and diatom communities during 2008 in four agricultural streams and determine a set of community-based metrics such as species richness, diversity, ASPT, SPEAR and IPS. LÄS MER
24. Freshwater methane and carbon dioxide fluxes : Spatio-temporal variability and an integrated assessment of lake and stream emissions in a catchment
Sammanfattning : Freshwater bodies such as lakes and streams release the greenhouse gases methane (CH4) and carbon dioxide (CO2) into the atmosphere. Global freshwater CH4 and CO2 emissions have been estimated to be of a similar magnitude to the global land or ocean carbon sink, and are thus significant components of global carbon budgets. LÄS MER
25. Origin of organic compounds in fluids from ultramafic-hosted hydrothermal vents of the Mid-Atlantic Ridge
Sammanfattning : Natural gas, primarily methane (CH4), is produced in substantial amounts in ultramafic-hosted hydrothermal systems. These systems could also generate oil (heavier hydrocarbons) and the first building blocks of life (prebiotic molecules). In the presence of iron bearing minerals, serpentinisation reactions generate H2. LÄS MER
