Geomicrobiology of oceanic oxygen deficiency zones, GOODZ

Geomicrobiology of oceanic oxygen deficiency zones, GOODZ

Associate professor Bo Thamdrup, Ph.D., Institute of Biology, University of Southern Denmark

While the availability of oxygen permits the existence of multi-cell organisms in most of the oceans, there are also extensive areas of open seas where there is a persistent deficiency of oxygen and where only microorganisms are able to live. These oxygen deficiency zones (ISZ) absorb only approximately 2 per cent of the area of the oceans. However, they play a disproportionately significant role in the Earth’s cycle of material, with a high primary production, great burial of organic matter and a large absorption/removal of nitrogen. The extent of ISZ is highly influenced by the circulation in the sea and, for instance, global warming may cause changes that have potentially significant consequences. Although ISZs are key localities in the biogeochemical cycle of the sea, we have limited knowledge of the structure and function of the microbial communities that dominate these systems, and new discoveries have caused questions to be asked concerning the existing paradigm for the cycles of material in the ISZs. As part of the Galathea 3 expedition, we shall carry out an extensive study of the ISZ regions in the Arabian Sea and off the coast of Peru, with the following aims:

·        Researching the structure and function of the microbial communities, with identification of the organisms that play the main roles in the turnover, and with studies on the ways in which virus impacts the structure and turnover of the community,

·        Determination of turnover rates for the significant processes and the contribution of these to the biogeochemical cycles at the local level and on a global scale, and

·        Identification and interpretation of chemical and biological markers of the variation in the level of oxygen deficiency under the ISZ through the ages.