PhD student in Assessing Marine Sediments as Georeactors for Modifying Bottom-Ocean Chemistry: Natural Analogues and Human Interventions

Stockholms universitet · Stockholm, Sweden

No Swedish requiredPosted 16 days ago

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The Department of Geological Sciences is part of the Faculty of Science at Stockholm University. It consists of approximately 80 teachers, researchers, doctoral students, and technical/administrative staff. The department conducts a wide range of fundamental and applied research within marine geology and geophysics, geochemistry and classical geology.

More information about us, please visit: The Department of Geological Sciences.

Project description

Degradation of ocean conditions, including acidification and deoxygenation, can have profound impacts on climate, biodiversity, and ecosystem functioning. In marginal and semi-enclosed seas, including the Baltic Sea and many coastal ocean regions, human activities can accelerate environmental degradation, potentially leading to changes that are difficult or impossible to reverse. Geoengineering has therefore been proposed as a potential strategy to mitigate deteriorating ocean conditions. However, before any large-scale intervention is considered, its effectiveness, risks, and unintended consequences must be evaluated through studies of natural analogues and carefully controlled experiments.

This project investigates the potential of marine sediments to function as georeactors that enhance ocean resilience in both a eutrophication and climate perspective. Specifically, it will examine

(1) the potential of restoring diagenetic iron–phosphorus (Fe–P) formation through oxygen additions (as CaO2, calcium peroxide) to the anoxic coastal sediments outside Stockholm. Amounts of oxygen needed for both the biological and chemical oxygen demand, as well as the available pool of Fe, are critical parameters to be investigated for a successful increase of the surface sediment P binding capacity. Furthermore, based on lab results, a full-scale treatment of anoxic sediments with granulated oxygen in the Björnöfjärden bay should be performed in 2027.
(2) the capacity of marine silicate minerals to naturally buffer ocean acidification from marginal oceans such as Ulleung Basin (East/Japan Sea). The acidity generated by rapid organic matter degradation is proposed to induce dissolution of primary silicate minerals that are either delivered via rivers and/or volcano activities. As a result, total alkalinity increases in porewater and potentially bottom seawater due to the release of various cations from marine silicate weathering. The project aims to reproduce such a process in a controlled laboratory environment under in-situ conditions.

By reproducing relevant natural conditions in laboratory experiments, the project will evaluate how both natural processes and targeted human interventions influence the biogeochemical coupling between surface sediments and overlying seawater. Ultimately, the project aims to determine whether sediment-based processes can help mitigate environmental degradation while preserving the integrity and functioning of the sediment–ocean system.

Qualification requirements

In order to be admitted to postgraduate education, the applicant must have the general and specific entry requirements. The qualification requirements must be met by the deadline for applications.

You meet general entry requirements if you have completed a second-cycle degree, or completed courses equivalent to at least 240 higher education credits, of which 60 credits must be in the second cycle, or have otherwise acquired equivalent knowledge in Sweden or elsewhere.

Specific entry requirements are described in the general syllabus for doctoral studies in the field of geochemistry:

At least 90 credits in geosciences
At least 30 credits in mathematics, physics, chemistry and/or biology depending on the chosen subject area within geochemistry or biogeochemistry
In addition, at least 60 credits at the advanced level, including 30 credits of independent work in geosciences.

Selection

The selection among the eligible candidates will be based on their capacity to benefit from the training. The following criteria will be used to assess this capacity:

experiences in conducting long-term laboratory incubation
experiences in laboratory analytical methods and instruments, including IC, ICP-OES, titration, spectrophotometry, etc
experiences in geochemical sampling during research cruises
programming ability, especially in processing time-series data
written and oral proficiency in English
ability to collaborate
creativity, initiative, and independence
the candidate’s potential to succeed, demonstrated through a brief research proposal (max 2 pages) submitted with the application, outlining how they would approach the project

Assessment will be based on previous experience and grades, the quality of the degree project, references, relevant laboratory or field experience, interviews, and the candidate’s written motivation for seeking the position. The successful candidate is expected to start as soon as possible.

Admission Regulations for Doctoral Studies at Stockholm University.

About the employment

We offer a fixed-term employment as a doctoral student according to Chapter 5 of the Higher Education Ordinance (1993:100). The period of employment may not be longer than what corresponds to full-time doctoral education for four years. As a doctoral student, you should primarily devote yourself to your own doctoral education, but the employment may include work with education, research and administration to a limited extent (maximum 20 %).

A new employment as a doctoral student is for a maximum of one year, the employment is then renewed for a maximum of two years at a time.

Stockholm University strives to be a workplace free from discrimination and with equal opportunities for all.

Contact

For more information, please contact Associate professor in geochemistry, Dr. Wei-Li Hong, wei-li.hong@geo.su.se

Application

Apply for the PhD student position at Stockholm University's recruitment system. Attach a personal letter and CV as well as the attachments requested in the application form. It is the responsibility of the applicant to ensure that the application is complete in accordance with the instructions in the job advertisement, and that it is submitted before the deadline.

The instructions for applicants are available at: How to apply for a position.

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