Citation link:
https://doi.org/10.26092/elib/45
OpenAccess

Transformation processes of nitrogen, phosphorus and iron in sub-euphotic waters and surface sediments
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00103576-1.pdf | 11.28 MB | Adobe PDF | View/Open |
Other Titles: | Transformationsprozesse von Stickstoff, Phosphor und Eisen in sub-euphotischem Wasser und Oberflächensedimenten | Authors: | Sokoll, Sarah ![]() |
Supervisor: | Kuypers, Marcel M. M. | 1. Expert: | Kuypers, Marcel M. M. | 2. Expert: | Zabel, Matthias ![]() |
Abstract: | In the ocean, concentrations and ratios of nitrogen (N), phosphorus (P) and iron (Fe) determine primary production. In upwelling regions, nutrient-rich deep waters fuel this primary production. Knowledge of nutrient transformation processes in deep waters is still scarce. Therefore N-removal via denitrification and anaerobic ammonium oxidation (anammox) as well as P and Fe transformation processes were investigated. In the Arabian Sea up to 50% of N-loss was due to benthic N-removal, emphasizing the high potential of sediments to contribute to the N-deficit in the water column. In sandy permeable sediments off Mauritania, denitrification rates correlated with sediment grain size, indicating a strong relationship between benthic denitrification rates and advective porewater transport. On the shelf off Mauritania and Namibia, P-uptake was investigated in sub-euphotic waters and found to be largely biologically driven. In conclusion, transformation processes determine concentration and bioavailability of nutrients in the sub-euphotic water column and sediments and may eventually have an impact on the primary production in the surface ocean. |
Keywords: | nitrogen loss; phosphate uptake; nutrient cycling; sediment; benthic boundary layer; upwelling regions; oxygen minimum zones; stable isotopes; radiotracers; nirS functional genes | Issue Date: | 20-Nov-2013 | Type: | Dissertation | DOI: | 10.26092/elib/45 | URN: | urn:nbn:de:gbv:46-00103576-18 | Institution: | Universität Bremen | Faculty: | FB5 Geowissenschaften |
Appears in Collections: | Dissertationen |
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