Muhammed Fatih Sert will publicly defend his PhD thesis entitled, “Biogeochemistry of dissolved organic matter in Arctic Ocean waters charged with methane” on November 25th 2022 at UiT – The Arctic University of Norway. This work was funded by the Centre for Arctic Gas Hydrate, Environment, and Climate (CAGE) at UiT.
The trial lecture and public defense will take place at Naturfagbygget and it will also be streamed online.
Popular scientific abstract
Dissolved organic matter (DOM) is defined as organic matter that is smaller than a nominal pore size filter (e.g., 0.7 µm) that passes through during the filtration of aquatic samples. It comprises the largest reservoir of reduced carbon (700 Pg C) in the oceans. The DOM pool is in close interaction with all the elemental cycles and food chains in the ocean and is an essential component in the marine microbial loop. Methane is seeping from numerous geological sources in the Arctic Ocean associated with multiple mechanisms that elevate methane production and release. Independent of the mechanism, however, liberated methane is predominantly consumed in the water column by methanotrophic bacteria (MOB), which use methane as a source of carbon and energy during an aerobic enzymatic reaction called methane oxidation (MOx). In sedimentary fluid flow systems such as cold seeps or hydrothermal vents, the amount of methane release and subsequent MOx would be substantial and further trigger other ecosystem processes such as bacterial growth and heterotrophic consumption and consequent mechanisms that alter DOM composition in the water column. Since methane is one of the most potent greenhouse gasses in the atmosphere and due to its subsequent effect on global warming, it has been quantified extensively in the oceanic environments and its fate in the water column has been investigated in different types of geological settings. However, the effects of methane emanation and methane-driven processes on DOM dynamics in the water column have been merely constrained. The main objective of this thesis was to unravel the modifications of DOM composition in relation to methane release in the Arctic Ocean cold seeps and hydrothermal vents.
The plan for Muhammed Fatih Sert’s public defense for the PhD degree in Science, on November 25th 2022, is as follows:
Trial lecture at 10:15 on the following topic:
‘The fate of anthropogenic CO2 in the ocean’
PhD thesis defense at 12:15:
‘Biogeochemistry of dissolved organic matter in Arctic Ocean waters charged with methane’
PhD Thesis is published and available here.
Supervisors:
- Researcher Dr. Anna Silyakova, Department of Geosciences, UiT (main supervisor)
- Researcher Dr. Friederike Gründger, Department of Biology, Aarhus University, Denmark
- Professor Helge Niemann, NIOZ Royal Institute for Sea Research, the Netherlands
Evaluation Committee:
- Professor Thorsten Dittmar, ICBM, Universität Oldenburg, Germany (1. opponent)
- Dr Jeffrey Hawkes, Department of Chemistry, University of Uppsala, Sweden (2. Opponent)
- Professor Giuliana Panieri, Department of Geosciences, UiT (internal member and leader of the
committee)
To read more about the findings of this research:
Sert, M.F., D’Andrilli, J., Gründger, F., Niemann, H., Granskog, M.A., Pavlov, A.K., Ferré, B. & Silyakova, A. (2020). Compositional Differences in Dissolved Organic Matter Between Arctic Cold Seeps Versus Non-Seep Sites at the Svalbard Continental Margin and the Barents Sea. Frontiers in Earth Sciences, 8, 552731. Also available in Munin at https://hdl.handle.net/10037/20176. https://doi.org/10.3389/feart.2020.552731
Sert, M.F., Niemann, H., Reeves, E.P., Granskog, M.A., Hand, K.P., Kekäläinen, T., … Gründger, F. (2022). Composition of dissolved organic matter in the ice-covered water column above hydrothermal vents at the Aurora Seamount, Gakkel Ridge, Arctic Ocean. Biogeosciences, 19, 2101–2120. Also available in Munin at https://hdl.handle.net/10037/24913. https://doi.org/10.5194/bg-19-2101-2022
