About this Research Topic
Oxygen plays a critical role for almost all life forms on Earth. The (sub) tropical Oxygen Minimum Zones (OMZs) are key regions of low-to-zero oxygen in today's ocean. Recent modelling results suggest that oceanic oxygen levels will decrease significantly over the next decades in response to climate change. Future Ocean nutrient cycling may experience major shifts triggered by the expansion and intensification of OMZs. The effects of oxygen-dependent nutrient cycling processes occurring in these relatively small regions are carried into the rest of the ocean by circulation. Hence, "small" OMZs can impact oceanic nutrient budgets, biological productivity, greenhouse gas formation and CO2 fixation on a global scale. When oceanic oxygen concentrations decrease below certain threshold levels, major changes to remineralization processes and associated sources and sinks of bio-essential elements such as nitrogen, phosphorus and iron occur in the water column and underlying sediments. Paleo-records give evidence for periods of dramatically reduced oceanic oxygen that had major consequences for marine ecosystems. Low oxygen levels can therefore be viewed as a "switch" for nutrient cycling. There are numerous feedbacks between oxygen, nutrient cycling and biological productivity; however existing knowledge is insufficient to fully understand past interactions or to accurately assess and confidently predict future changes, as well as regional and temporal patterns of ocean deoxygenation.
This research topic aims to gather most recent insights into the impacts of declining oceanic oxygen on nutrient turnover from various disciplines, which may include but are not restricted to biogeochemistry, ecology, climate modelling and paleo-oceanography.
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