Sökning: "Per Hall"
Visar resultat 1 - 5 av 24 avhandlingar innehållade orden Per Hall.
1. Empirical Essays on Education and Social Insurance Policies
Sammanfattning : This thesis consists of four self-contained essays. Essay 1: This paper evaluates the effects of the introduction of a more comprehensive upper secondary school system in Sweden in the 1990s. LÄS MER
2. Role of manganese redox cycling for trace metals in the Baltic Sea
Sammanfattning : Redox zones are defined by steep gradients of changing concentrations and changing redox potential. They form a transition zone between oxic and anoxic/sulfidic conditions, where nitrate, manganese and iron reduction occurs. These redox zones can be situated in the sediment as well as in the water column. In the Baltic Sea both types are found. LÄS MER
3. Control factors of the marine nitrogen cycle : The role of meiofauna, macrofauna, oxygen and aggregates
Sammanfattning : The ocean is the most extended biome present on our planet. Recent decades have seen a dramatic increase in the number and gravity of threats impacting the ocean, including discharge of pollutants, cultural eutrophication and spread of alien species. LÄS MER
4. Benthic fluxes of biogenic elements in the Baltic Sea : Influence of oxygen and macrofauna
Sammanfattning : This thesis investigates how benthic fluxes of phosphorus (P), nitrogen (N), and silicon (Si) change upon oxygenation of anoxic soft bottoms in the brackish, eutrophicated Baltic Sea. Direct measurements in situ by benthic landers demonstrated that fluxes of dissolved inorganic P (DIP) from anoxic bottom sediments in the Eastern Gotland Basin are higher than previously thought (Paper I). LÄS MER
5. On benthic fluxes of phosphorus in the Baltic Sea proper – drivers and estimates
Sammanfattning : This Thesis focuses on the exchange of phosphorus (P) across the sediment–water interface in the Baltic Sea proper, with particular attention to the influence of bioturbating macrofauna and benthic redox conditions. Benthic P fluxes have major influence on P availability in the water column, which in turn regulates growth conditions for dinitrogen fixating cyanobacteria in the Baltic proper. LÄS MER