8 documents found

Dissertation

Biogeochemical cycling of iron and phosphorus under low oxygen conditions

Benthic release of the key nutrients iron (Fe) and phosphorus (P) is enhanced from sediments that are impinged by oxygen-deficient bottom waters due to its diminished retention capacity for such redox sensitive elements. Suboxic to anoxic and sometimes even euxinic conditions are recently found in open...
Dissertation

Efficiency of the Benthic Microbial Methane Filter under Varying Fluid...

Abstract: Marine sediments all over the world bear methane, generated from organic matter and deposited at the seafloor. By diffusion or ascending fluids the methane is transported to the sediment surface and emitted into the oceans and further into the atmosphere, where it acts as greenhouse gas. However,...
Dissertation

Mineralogical and isotope geochemical investigations of high Mg-calcites...

Within the framework of this thesis investigations on formation and dissolution processes of Mg-calcites have been carried out. Based on the results of mineralogical and isotope geochemical investigations it was possible to reconstruct the formation processes of authigenic high Mg-calcite concretions...
Dissertation

Quantification of methane fluxes and authigenic carbonate formation at...

This thesis represent stand-alone articles which have been published or will be submitted for publication in peer-reviewed scientific journals. Each of the Chapters II, III and IV contains a separate introduction, description of methods, presentation of data, results and discussion as well as a separate...
Dissertation

Bacterial methane formation and distribution in marine environments : case...

(Keine Zusammenfassung in englischer Sprache vorhanden.) (No summary in English language.)
Dissertation

Anthropogenic emissions of greenhouse gases from the seafloor into the...

The present thesis provides the first methane (CH4) emissions measurements from offshore abandoned wells in the North Sea and found that boreholes constitute unrecognized, but important conduits for the release of biogenic CH4 originating from shallow gas accumulations (<1,000 m sediment depth) in the...
Dissertation

Langzeiteffektivität und Funktionalität von Fe°-Reaktionswänden : Untersuchung...

Reaktionswände zur passiven in-situ Grundwassersanierung gelten zunehmend als Stand der Technik und insbesondere Fe0-Reaktionswände wurden in den letzten Jahren zunehmend eingesetzt. Trotz der rasanten Entwicklung im Bereich der Forschung und Implementierung gelten noch einige Fragen etwa im Zusammenhang...
Dissertation

Stability of mixed gas hydrates and mass transfer during formation, accumulation...

Gas hydrates are fascinating ice-like compounds made of water cages that retain various types of guest molecules. Natural gas hydrates on Earth form below the seafloor and permafrost and contain mainly methane (CH4). Methane from hydrate deposits could be considered as an energy resource. One possible...