Biogeochemical processes in sediments associated to cold-water coral ecosystems: From living reefs to ancient mounds
|Other Titles:||Biogeochemische Prozesse in Sedimenten assoziiert mit Kaltwasserkorallenriffen||Authors:||Wehrmann, Laura Mariana||Supervisor:||Jorgensen, Bo Barker||1. Expert:||Jorgensen, Bo Barker||2. Expert:||Zabel, Matthias||Abstract:||
Syn- to post-depositional microbially-mediated diagenetic processes in cold-water coral reef associated sediments are addressed here to assess the coupling between sulfur and iron cycles, and carbonate formation and dissolution. Organic carbon mineralization at cold-water coral reefs on the Norwegian margin occurred in: a) the reef surface framework consisting of living and dead coral thickets and b) the underlying sediments. Several cold-water coral mounds in the Gulf of Cadiz were influenced by ascending hydrocarbon-rich fluids and the diagenetic imprint of a sulfate-methane transition zone (SMTZ) was evidenced. Carbonate preservation in the cold-water coral reef associated sediments was controlled by the availability of reactive iron. The interplay of low rates of sulfate reduction and the input of terrigenous Fe-rich material led to a buffering of the pore-water carbonate system in the Norwegian reef sediments. Conversely, processes that led to a scavenging of Fe-oxides such as the production of hydrogen sulfide facilitated carbonate dissolution. This was manifested in distinct layers of dissolved corals in Gulf of Cadiz mound sediments.
|Keywords:||cold-water coral reefs, coral mounds, early diagenesis, marine biogeochemistry||Issue Date:||5-Mar-2010||URN:||urn:nbn:de:gbv:46-diss000119834||Institution:||Universität Bremen||Faculty:||FB5 Geowissenschaften|
|Appears in Collections:||Dissertationen|
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