Nitrogen Losses and Nutrient Regeneration in Oxygen Minimum Zones
|Other Titles:||Stickstoffverluste und Nährstoffregeneration in Sauerstoffminimumzonen||Authors:||Kalvelage, Tim||Supervisor:||Kuypers, Marcel M. M.||1. Expert:||Kuypers, Marcel M. M.||2. Expert:||Bange, Hermann W.||Abstract:||
In the tropical oceans, coastal upwelling of nutrient-rich deep waters fuels high surface productivity. The decomposition of sinking algal biomass results in the formation of large oxygen-deficient water bodies at mid depths (~100 1,000 m). Although, these oxygen minimum zones (OMZs) amount to <1% of the global ocean volume, they account for ~30-50% of total oceanic nitrogen (N) loss. Anammox, the anaerobic oxidation of NH4 with NO2- to gaseous N2 is the major N-loss pathway in OMZs. The recirculation of N-deficient waters to the surface limits phytoplankton growth and thus carbon sequestration in large parts of the tropical oceans. Continuing ocean de-oxygenation is expected to result in significantly increasing N-losses, thereby reducing the ocean s capacity to attenuate rising atmospheric CO2. This thesis aimed to determine regulatory effects of O2 and organic matter availability on anammox and N-linked processes in OMZs to facilitate model-based assessments of future ocean changes.
|Keywords:||oxygen minimum zone, nitrogen loss, anammox, denitrification, nitrification, organic matter, export production, microbial respiration, nitrogen cycle, oxygen sensitivity, Benguela upwelling, Peruvian upwelling||Issue Date:||27-Jul-2012||URN:||urn:nbn:de:gbv:46-00102781-14||Institution:||Universität Bremen||Faculty:||FB5 Geowissenschaften|
|Appears in Collections:||Dissertationen|
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