Seafloor Iron Mobilization Across The Deep-Water Redox Gradients Of The Black Sea And The Sea Of Marmara

Alımlı, Nimet
Iron is one of the key elements in the ocean which has wide interconnections with other essential elements (i.e., C, N, P, O, Mn, S) and fundamental mechanisms (i.e., photosynthesis, respiration, chemosynthesis). The critical role of iron, since the beginning of life until the modern oceans, was increasing with biogeochemical evolution creating new niches for iron. Despite iron is ubiquitous on land, its trace level presence in the ocean creates difficulties for iron studies. Hence, the complex cycle of iron still has many gaps and filling the gaps is crucial to understand the past, present and the future of oceans and moreover Earth. In this thesis work, benthic dissolved iron patterns in the Black Sea and for the first time in the Sea of Marmara was studied in the comparison of recent redox changes and well-established redox environments. High amounts of dissolved iron were measured, and high benthic fluxes estimated for the Sea of Marmara showing that, in terms of iron source, it is comparable to other oxygen minimum zones. The potential connection between the organic complexation and porewater size fractions is examined with comparison of more established iron fraction species. The results from seawater and porewater size fractionations indicated that the nature of the seawater and porewater species are different at least to the extent of different influences by sample handling. In summary, the iron patterns in the Sea of Marmara indicates the recent hypoxia have already cause iron to be mobilized at the seafloor and the sedimentary colloidal andvi soluble phases needs a more detailed attention to understand the effective scale of benthic iron species.


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Citation Formats
N. Alımlı, “Seafloor Iron Mobilization Across The Deep-Water Redox Gradients Of The Black Sea And The Sea Of Marmara,” M.S. - Master of Science, Middle East Technical University, 2022.