PhD Positions to Investigate Aspects of Biogeochemistry, Biogeography, and Microbiology of Hadal Trench Systems and High-pressure Effects on Microbial Performance

Updated: 24 days ago
Deadline: 30 Jun 2021

The Danish Center for Hadal Research at the Department of Biology , University of Southern Denmark, would like to recruit four PhD students to investigate aspects of biogeochemistry, biogeography, and microbiology of hadal trench systems and high-pressure effects on microbial performance.

Hadal trenches are some of the most remote, extreme, and scantly explored habitats on Earth. They act as depocentres for organic material and are deep sea hotspots for largely unknown forms of life and for element cycling. Life at hadal depth is exposed to extreme hydrostatic pressure and the intensified biological activity and mineralization in these unique settings cannot be understood by simply extrapolating findings from the ambient ocean to the hadal realm. The four positions are all for three years, are interlinked, but have different research foci. The positions are embedded in the newly founded HADAL centre and will be part of a multidisciplinary and dynamic research team at SDU and collaborating institutions (University of Copenhagen, Danish Technical University, Aarhus University, Tokyo University of Marine Science and Technology). More details of the respective positions are provided below.

PhD position 1; Anaerobic mineralization of organic material at extreme hydrostatic pressure
Hadal sediments are sites of intensified mineralization of organic material and are characterized by relatively shallow O2 penetration depths. Anaerobic diagenetic pathways are therefore potentially important for the overturn of organic material and the cycling of e.g. nitrogen, iron, and sulfur. The aim of the current position is to quantify rates and controls of different anaerobic diagenetic pathways in hadal settings and explore how hydrostatic pressure affects the performance of the microbial communities involved in processes such as sulfate reduction, denitrification, anammox and nitrification. Candidates are expected to have an MSc degree in a field relevant to the mentioned project (aquatic biogeochemistry, microbiology or similar). 

PhD position 2; Hydrostatic Pressure, the viral loop and DOC turnover in hadal settings
Hydrostatic pressure affects thermodynamics of metabolic processes, enzymatic functions and efficiency, and microbial interactions such as viral infection and prophage induction in prokaryotic communities. The aim of the current position is to i) quantitatively explore how hydrostatic pressure influences specific enzymatic processes involved in DOC degradation ii) the importance of virus for DOC turn-over in the deepest parts of the global ocean. Candidates are expected to have an MSc degree in a field relevant to the mentioned project (microbiology, virology, biogeochemistry or similar).

PhD position 3; Deposition dynamics and distribution of trace metal and organic material in hadal trenches.
Two processes contribute to the intensified material deposition in hadal trenches, i) focusing of downward sinking material and ii) down slope martial transport stimulated by infrequent mass wasting events. Mass wasting results in highly disturbed vertical sediment profiles with irregular distribution of organic material from different sources, redox zonation, and presumably trace metals. The aim of the current position is to explore and quantify the sources and partway of material deposition in hadal trenches using material from moored sediment traps and detailed inspections of recovered sediment cores. Focus will mainly be on organic material and trace metals, but other materials such as pollutants could be considered. Candidates are expected to have an MSc degree in a field relevant to the mentioned project (marine science, geobiology, geology, biogeochemistry or similar). 

PhD position 4; Molecular diversity and biogeography of hadal meiofauna
Hadal trench sediment hosts a rich meiofauna, but the degree of endemism and environmental factors that govern distribution patterns remain largely unknown. The project will explore the molecular diversity and distribution of nematodes in hadal environments. The aim is to investigate the extent to which trenches host unique taxonomic groups and which factors might govern diversification in these settings. Taxonomic composition of nematodes within different trench systems will be compared to adjacent shallower settings, to investigate biogeographic patterns. Potential differences will be related to food availability, sediment texture and water depth. We envision to target some abundant and widespread nematodes genera (e.g. Acantholaimus and Halalaimus). The PhD project will be co-supervised by taxonomic (IFREMER/France) and molecular experts (ILVO & Ghent Uni./Belgium). Candidates are expected to have an MSc degree in a field relevant to the mentioned project (molecular biology and ecology, bioinformatics, marine science or similar).

Application deadline: 30 June 2021.

For further information please contact Ronnie N. Glud, tel.: +45 6550 2784, e-mail: .

Application, salary etc.
Appointment as a PhD Research Fellow is for three years. Employment stops automatically at the end of the period. The holder of the scholarship is not allowed to have other paid employment during the three-year period.

The successful applicant will be employed in accordance with the agreement on salaried PhD scholars between the Ministry of Finance and AC (the Danish Confederation of Professional Associations). Please check links for more information on salary  and taxation .

The successful candidate will be enrolled at this university in accordance with faculty regulations and the Danish Ministerial Order on the PhD Programme at the Universities (PhD order).

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

Application must be made in the form of a Declaration of Interest including the following:
• A research proposal/description of your approach to the above project (max one page excluding references)
• A letter stating your specific interest, motivation and qualifications for the project in question (max. two pages) (please attach this under box "Application form")
• Detailed CV, including personal contact information
• Copies of diplomas, Bachelor as well as Master’s degree, including transcript of notes/grades
• At least two signed reference letters. Should your referees wish to send their letters directly to us, please have them use e-mail: mentioning your name and the title of the position in the subject line. And please note that these also need to reach us before deadline.

Shortlisting may be used in the assessment process.

Further information about the PhD-study can be found at the homepage of the University .

Applications must be submitted electronically using the link "Apply online". Attached files must be in Adobe PDF or Word format. Each box can only contain a single file of max. 10 Mb. We strongly recommend that you read How to apply before you apply.

Incomplete applications and applications received after the deadline will neither be considered nor evaluated. This also applies to reference letters.

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