The Department of Biology at the University of Southern Denmark invites applications for Ph.D. position in aquatic biogeochemistry and microbial ecology, available for 3 years from spring 2026. The position is associated to the ERC Synergy project RECLESS (Recycling versus loss in the marine nitrogen cycle: controls, feedbacks, and the impact of expanding low oxygen regions). RECLESS aims to predict how ongoing ocean deoxygenation impacts microbial nitrogen transformations and thereby the future availability of nitrogen to support oceanic primary production and carbon sequestration. The project involves researchers from the universities of Southern Denmark, Gothenburg, and Vienna, as well as Carnegie Science, and synergistically integrates innovative oceanographic, biogeochemical, ecophysiological, and model-based investigations.

The candidate will explore and quantify how benthic processes influence the exchange of matter between sediment and water column in oxygen-depleted coastal waters, thereby ultimately influencing pelagic nitrogen cycling in these systems. This involves studies of microbial processes and fluxes within the sediment as well as in the benthic boundary layer, which is a poorly understood component of these systems. As oxygen depletion is spreading in coastal waters worldwide, the project will address knowledge gaps of both local and global significance.

With the aim of obtaining a mechanistic understanding of benthic-pelagic coupling, key tasks may include biogeochemical sediment analyses, measurement of benthic exchange rates, experimental studies of microbial processes in the sediment and benthic boundary layer, and implementation of the results in reaction-transport models. The project is tightly integrated with investigations of pelagic processes in RECLESS, and participation in international research cruises is an integral part of the position.

We seek a candidate with a background and strong interest in experimental (bio-)geochemistry, microbial ecology, or related fields, and with experience in and aptitude for field work. Experience with one or more of the above-mentioned approaches is desirable. The selected candidate will be associated to Bo Thamdrup’s research group as part of the diverse and international Nordcee section at the department, and will work closely together with associates from all RECLESS institutions.

About the Department of Biology
The Department of Biology (approximately 200 employees) conducts a wide range of research within the broad and diverse field of biology. Our research is organized in 5 research groups; focusing on more specific, but still diverse, disciplines and biological focus areas.

About Nordcee
At Nordcee, six key research areas are explored, Microbes and Element cycles; Deep-sea research, Co-evolution of Life and Earth, Oxygen, Greenhouse gases and climate, Sustainability and biotechnology: How microorganisms interact with their environment with a particular focus on how microbes influence the biogeochemical cycling of elements, even in the deepest places on Earth, the abyssal plains and hadal trenches; How life and Earth co-evolved over billions of years and how microbial life gave rise to oxygen creating beneficial conditions for the emergence of complex lifeforms; How microbes in the Anthropocene act as sinks or sources of various greenhouse gases. Finally, how to harness microbial microorganisms for sustainable technologies of the future with geo- and bio-engineering strategies.