Postdoc Positions in Hadal Biogeochemistry & Microbial Ecology

The Danish Center for Hadal Research (HADAL) at the Department of Biology University of Southern Denmark invites applicants for 7 postdoc positions in deep-sea biogeochemistry and microbial ecology. The positions are fully funded by the Danish National Research Foundation with complement from the Independent Research Fund Denmark. The respective projects are expected to be initiated during late summer or early autumn 2026.

HADALis a Center of Excellence that explores life and element cycling in the deepest oceanic realm. The Center was founded in 2020 engages about 35 students technicians and scientists and has a large international network of collaborators. We seek committed candidates that can work focused and independently but that flourish in an international team having a strong synergetic and multidisciplinary approach for solving new and important research challenges. The scientific approach is based on advanced theoretical and experimental studies but international deep-sea expeditions are critical for our scientific advances. Candidates for the positions should be willing to undertake several weeks long international voyages. The specific profiles for the 7 available positions are outlined below:

Position A Distribution and genomic potential of hadal microbial communities
Recent research has documented that hadal microbial communities are surprisingly diverse both functionally and taxonomically. Guided by biogeochemical insights the post doc will explore the diversity distribution and functional potential of microbial communities in hadal sediments using state of the art bioinformatic approaches (i.e. metagenomics comparative genomics). The aim being to provide insights into the specificities of hadal microbial life and its role in global biogeochemical cycles. The work will take advantage of large sediment repositories and databases that are established at the HADAL centre but also include new data from planned expeditions. Extensive experience with microbial bioinformatic pipelines would be an advantage and the candidate should closely synergize with biogeochemical researchers and students at HADAL.
The position is available for 36 months with the potential for further information please contactRonnie N. Glud or Mathias Middelboe.

Position B Biogeography of hadal microbial communities
We still only have limited insights into the biogeography of microbial communities in deep sea sediments. Using advanced bioinformatic tools (metagenomics fine-scale genetic diversity) this Postdoc will explore how the diversity and abundance of specific benthic microbial groups changes with increasing water depth and to what extent they differ among hadal environments. The insights generated should foster novel understanding on the sourcing and adaptation of microbial communities to extreme pressure and hadal sediments. The work will take advantage of large sediment repositories and databases that are established at the HADAL centre but also include new data from planned expeditions.
The position is available for 30 months with the potential for extension. For further information please contact Ronnie N. Gludor Mathias Middelboe.

Position CMicrobial utilization and transformation of particulate and dissolved organic matter in the deep ocean
Sinking marine snow particles experience increasing hydrostatic pressure that inhibit the microbial degradation of particulate organic matter and promote the leakage of dissolved organic matter. The Postdoc will study the microbial utilization and transformation of particulate and dissolved organic matter under high-pressure conditions. Field-collected microbial communities and particles will be used for laboratory and on-board pressure incubations that simulate deep-sea and hadal-trench conditions. Advanced particulate and dissolved organic matter analysis will be combined with biogeochemical rate measurements and molecular approaches for identification and enumeration of deep-sea with experimental biogeochemistry particulate and dissolved organic matter analysis and sea-going expeditions are position will have a prime focus on the pelagic realm but aspects of sedimentary processes could be considered.
The position is available for 24 months with the potential for further information please contactPeter Stief or Karl Attard.

Position D Vertical transport and overturn of particulate material at great depths
Hadal trenches are supplied with organic matter through vertical sinking lateral transport and episodic mass-wasting events yet the relative importance of the different transport mechanisms the origin of the organic matter and the fate of this material remains poorly constrained. This Postdoc project will investigate how particulate organic matter is transported and transformed to and within hadal trenches The work is anticipated to focus on resolving the origin transport pathways and biogeochemical transformation of organic material entering hadal systems. This includes quantifying the relative importance of vertical particle fluxes versus lateral inputs (e.g. nepheloid layers and mass-deposition events) and assessing whether organic matter is retained or rapidly remineralized. The work will combine in situ observations during expedition and moored instrumentation (e.g. sediment traps current meters and camera systems) to establish how transport and transformation processes vary across depth and time and whether ventilation of trenches leads to significant export of remineralized nutrients to the surrounding deep ocean. The position will be jointly hosted at the Alfred Wegener Institute (AWI) and the University of Southern Denmark (SDU) integrating expertise on in situ optical observations particle flux measurements and experimental biogeochemistry. Experience in marine biogeochemistry and biological oceanography along with a strong interest in field-based research and interdisciplinary collaboration is advantageous.
The position is available for 36 months with the potential for extension. For further information please contact Morten Iversen orRonnie N. Glud.

Position E Benthic biogeochemistry of hadal sediments
Sediments in hadal trenches are hotspots for the mineralization of organic matter a process that is mediated by diverse aerobic and anaerobic microbial communities. To understand the overturn and relative importance of different processes involved in carbon mineralization and nitrogen cycling at extreme pressure it is critical to quantify and gain insight on the defining biogeochemical processes in various hadal environments. The postdoc will determine substrate turnover by a combination of onboard investigations and situ incubations using different isotopically labelled substrates and reactants. Targeted processes could include denitrification anammox nitrification and sulfate reduction but indirect quantifications of iron- and manganese respiration could also be relevant. Research experience with sediment biogeochemistry tracer incubations and in situ technology would be an advantage.
The position is available for 30 months with the potential for extension. For further information please contactFrank WenzhöferorRonnie N. Glud.

Position F Deep-sea biogeochemistry and technology
Biogeochemical cycling in complex deep-sea habitats such as polymetallic nodules remains poorly understood despite these habitats being widespread in the deep ocean. The Postdoc will focus on biogeochemical cycling in abyssal settings with the aspiration of expanding the operational depth range of evolving in situ technologies to the hadal zone. The Postdoc will be working closely with other researchers mechanical engineers and technicians at SDU and AWI as well as with industry partners to develop and deploy in situ sensing technologies (e.g. chambers microprofilers and eddy covariance) on autonomous landers and ROV-deployed frames for studies of carbon cycling in deep-sea environments. Additional responsibilities include testing and calibration of underwater instrumentation quantification of biogeochemical fluxes in the laboratory sediment and porewater analyses. Experience with in situ and laboratory biogeochemical techniques sea-going expeditions and experimental/analytical biogeochemistry would be an advantage.
This position is available for 24 months with potential for extension. For further information please contact Karl Attard or Frank Wenzhöfer.

Position G Detrital food-web and meiofauna distribution in hadal settings
Most benthic fauna depend critically on the pulsed supply of organic material from the surface ocean. However little is known about the importance of different functional fauna groups for the overturn of freshly deposited phytodetritus at hadal depth. The postdoc will use lander experiments (Benthic chamber incubations) involving simulated food pulses of 13C- and 15N-labelled detritus material to track its uptake and incorporation into various size- and functional groups of organisms. With a focus on meiofauna the aim of the project is to identify key players in the detrital food chain that are involved in the initial decomposition of fresh deposits at these extreme depths. Furthermore the project will explore the biology ecology and biogeography of hadal meiofauna taking advantage of repositories and databases already established at the HADAL center as well on new sampling campaigns. Experience in genomic and/or classical taxonomic characterization of meiofauna and manipulative biogeochemical research would be an advantage.
The position is available for 30 months with the potential for extension. For further information please contactFrank WenzhöferorRonnie N. Glud.

If you are interested in one (or more) of these positions please provide a motivated application that outlines your research vision the expertise and competence that you could bring to HADAL. We encourage you to include relevant references. We offer an opportunity to join a highly motivated international team of researchers fascinated by biochemistry and microbiology in the deepest part of the global ocean.

Application deadline: 1 June 2026 andapplications will be assessed by an expert assessor/committee. Shortlisting may be used in the assessment applications and applications received after the deadline will neither be considered nor also applies to reference will be informed of their assessment by the information about the positions and the hadal center can be directed to Ronnie N. Glud.

E-mail list of contact people
Frank Wenzhöfer (/ )
Karl Attard ()
Mathias Middelboe ()
Morten Iversen ()
Peter Stief ()
Ronnie N. Glud()

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The University of Southern Denmark is Denmarksthird largest university with campuses across the country. As part of the Faculty of Sciencethe Department of Biologyis located in Odense the Universitys largest campus. Odense is the countrysthird largest city and is centrally located with easy commutes to Copenhagen and Aarhus (approximately 1½ hour).

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Application salary etc.
The successful applicant will be employed in accordance with the agreement between the Ministry of Finance and AC (the Danish Confederation of Professional Associations).Please check links for more information onsalary(only available in Danish)and taxation.

The application must include the following:

• A curriculum vitae including information on previous employment with start and end dates
• A full list of publications stating the scientific publications on which the applicant wishes to rely
• Copy of PhD diploma if PhD diploma has not yet been received please include statement from your supervisor

Shortlisting may be used in the assessment process. Incomplete applications and applications received after the deadline will neither be considered nor evaluated.

To qualify you must have passed a PhD or equivalent. Applications will be assessed by an expert assessor/committee. Applicants will be informed of their assessment by the university.

The University wishes our staff to reflect the diversity of society and thus welcomes applications from all qualified candidates regardless of personal background.

Applications must be submitted electronically using the link Apply now. Attached files must be in Adobe PDF format. We strongly recommend that you read How to apply for a position at SDUbefore you apply.
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About SDU
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