Student Opportunities

PhD student on Fe-Mn colimitation of Antarctic phytoplankton, University of Bremen, Germany

The working group Ecotrace embedded in the Marine Botany Department at the University Bremen offers the position of a PhD Researcher in Antarctic phytoplankton ecophysiology for the duration of 3 years starting from September/October 2018. Salary will be according to the German Federal pay scale (TV-L 13).

Job Description:
The Southern Ocean (SO) exerts a disproportional control on the global carbon cycle, thus affecting climate at a global scale. Southern Ocean phytoplankton are major drivers of global carbon cycling accounting for 20% of the global annual primary production. In the SO, the biological uptake of carbon dioxide is mainly controlled by the availability of the trace metal iron (Fe) and light, both being essential for photosynthesis. Whereas most studies so far focused on disentangling how Fe and light influence SO phytoplankton growth and productivity, almost nothing is known whether other trace metals such as manganese (Mn) also act as limiting or co-limiting nutrient in the SO. Mn is required for various cellular processes in phytoplankton cells and has been suggested to be (co-)limiting with Fe in some parts of the SO such as the Drake Passage. Currently, we lack information on growth, photosynthesis, oxidative stress and Mn and Fe requirements under Fe-Mn limitation for SO phytoplankton species. This research project aims to improve our understanding about the potential effects of Fe-Mn co-limitation on SO phytoplankton physiology and their implications for the ecology and biogeochemistry in the present and future SO. To this end, the responses of SO phytoplankton will be studied in response to altered Fe and Mn availabilities under different light conditions, simulating different climate change scenarios. A multidisciplinary approach will be followed that integrates biology and marine chemistry and combines laboratory and field work. Laboratory experiments with ecologically and biogeochemically important phytoplankton species of the SO will provide a mechanistic understanding on physiological processes such as photosynthesis and trace metal requirements. Shipboard manipulation experiments with natural SO phytoplankton assemblages of different regions of the SO will further reveal the occurrence of Fe-Mn co-limitation and will help to identify phytoplankton species in the field, which are particularly sensitive, but also tolerant towards altered trace metal and light availabilities. All together this research project will help to assess an ecophysiological explanation for the spatial distribution of SO key phytoplankton species in the present and the future SO. Improved knowledge on the functioning and the sensitivity of the SO ecosystem is pivotal to improve our existing predictive tools (e.g. modelling) and increase our understanding on the mechanisms, by which the SO affects climatic processes at global scale.

The successful candidate should hold a Master’s degree (or comparable) in biology, marine biology, marine chemistry or environmental sciences. Ideally the candidate is experienced in:
- applying methods in plant physiology

- trace metal clean working techniques
- culturing marine phytoplankton
- trace metal chemistry

The candidate should be highly motivated and able to work in a small, closely cooperating team. The international nature of the project requires fluency in spoken and written English and good presentation and publication skills. In addition, the successful candidate should have good team spirit. The successful candidate will be embedded in the working group Ecotrace, headed by Prof. Dr. Scarlett Trimborn.

Conditions of employment:
The position is limited to 3 years and will start in October 2018, if possible. As the University of Bremen intends to increase the proportion of female employees in science, women are particularly encouraged to apply. In case of equal personal aptitudes and qualification, disabled persons will be given priority. Applicants with a migration background are welcome.

How to Apply & What to Do in Case of Questions:
Applications should comprise a motivation letter, complete CV including any achievements, degree certificates (including list of courses and grades), names and contact details of at least two referees, and a list of your publications.

Please send your application until August 31 as a single pdf-file not exceeding 10 MByte via e-mail to: Prof. Dr. Scarlett Trimborn, scarlett.trimborn at


MS/PhD Position available in Chemical Oceanography at USF, Florida, USA

MS/PhD Position available in Chemical Oceanography at USF College of Marine Science to begin Fall or Spring 2019

Project Area: Iron isotope biogeochemistry (MarMITE group)

Advisor: Dr. Tim Conway

The MarMITE group at the University of South Florida focuses on using trace metal isotope tracers in order to better understand the integral role of trace metals in modern carbon cycling and biogeochemical cycles. We also focus on how we can use these tracers to better understand the ocean system in the geological past and future climate. Iron is perhaps the most important of these metals and is an essential micronutrient in biogeochemical systems. In recent years iron isotopes have been used in order to constrain cycling and sources of iron to natural waters, including the ocean. We are looking for a highly motivated graduate student (PhD or MS) to join our group at USF, focusing one one of the projects below:

1) Investigating how Fe is released from atmospheric dust in the oceans. This NSF-funded project in collaboration with Oregon State will involve experimental lab work and field studies investigating the mechanisms by which different organic molecules enhance dissolution of metals from dust in seawater. This project involves funded fieldwork at Bermuda and in the Gulf of Mexico.

2) Sources, cycling and sinks of Fe throughout the oceans. This project will make use of samples from GEOTRACES section cruises from different areas of the Pacific and Atlantic to further our understanding of how Fe enters the oceans from sediments, hydrothermal vents and atmospheric dust in these regions. Future cruise participation is possible.

The student will measure trace metal concentrations and isotopes in USF's new Tampa Bay Plasma Facility, which includes an ISO-6 Clean lab dedicated for seawater processing, a SeaFast system, Thermo HR ICPMS Element XR and Thermo MC-ICPMS Neptune. Candidates must have a strong undergraduate background in chemical, earth or physical science. Laboratory experience in geochemistry is desirable, but not required. 

A minimum of 2 years of salary+tuition is available, with opportunities for extension through a wide range of college endowed fellowships or further grant funding, and research costs for the projects are fully funded. There will be opportunities for local and international cruises, and to present at national and international conferences.

The USF College of Marine Science is located on the water in sunny St Petersburg, Florida, and hosts a vibrant community of graduate students and faculty undertaking world class research in a range of oceanographic disciplines. For more information about the college please visit We strongly encourage diverse applications and equal opportunities.

Contact Tim Conway ( for more information and details on how to apply. The deadline for Fall admissions is Jan 15th, but earlier applications are encouraged! For spring admission please contact asap.

PhD position in Mercury Biogeochemistry in Oxygen Minimum Zones 

PhD position in Mercury Biogeochemistry in Oxygen Minimum Zones 

Mediterranean Institute of Oceanography (MIO) & Geosciences Environment Toulouse (GET

Fully-funded PhD Position 

The Marseille Marine Mercury Laboratory at the Mediterranean Institute of Oceanography (MIO) and the Mercury Isotopes Group at Geosciences Environment Toulouse (GET) are seeking to recruit a scientist for a fully-funded 3-year PhD position to work at at the frontiers of trace metal oceanography, analytical sciences, stable isotopes biogeochemistry, and ecology. This PhD position is funded via the ANR (Agence Nationale de la Recherche) MERTOX project (2017-21) “Unraveling the origin of methylMERcury TOXin in marine ecosystems” (PI David Point, GET). 

Mercury is global pollutant and a neurotoxin with a serious health risk for humans, mainly via the consumption of marine fish. Anthropogenic Hg emissions have largely altered natural Hg levels. Bacteria feeding on sinking marine organic matter in the mesopelagic zone are thought to produce the toxic methylmercury species (MMHg) that bioaccumulates along the marine trophic chain to harmful levels. This main goal of this PhD project to study mercury biogeochemistry in oxygen minimum zones (OMZ), and to develop new stable isotope tools for a better understanding of the marine biogeochemical Hg cycle. The MERTOX case study will be conducted in the Peruvian Humboldt OMZ, which is very productive, exhibits extreme redox gradients, and is known to enhance in situ MeHg production. This region accounts for 15% of worldwide commercial fisheries while representing 0.1% of the global ocean surface. Peruvian anchovy fisheries contribute to more than half of world landings used for fishmeal production and then fuels a critical portion of world aquaculture production. The MERTOX field campaigns are planned for April and August 2019, along several cruise transects covering the strong inshore/offshore organic matter gradients and steep shallow redox fronts. The cruises will be performed on board of IMARPE’s R/V Olaya and will be supported by bi-annual transect surveys. Complementary physical (salinity, temperature,..), chemical (macronutrients, Fe, Mn, CH4, HS-), microbiological (diversity, HgcAB methylating genes) and ecological (phytoplankton speciation, Chl-a,…) data will be gathered. The main field tasks of the PhD student is to sample and measure the full suite of Hg species (MMHg, DMHg, Hg°, Hg2+, pHg, pMMHg), perform isotopically labelled incubation experiments, and contribute to the isotopic measurement of both the Carbon (δ13C), and Hg (δ202Δ199Hg) atoms of the MeHg (CH3Hg) molecule, along the trophic chain (seawater, phyto-, zooplankton,…). 

The PhD student will be based at the MIO (Lars-Eric Heimbürger, Sophie Bonnet, Marseille, France) and will closely collaborate with the GET laboratory (David Point, Jeroen Sonke, Toulouse, France) for stable isotopic analysis, the LMD/IPSL (Laurent Bopp, Paris, France) for biogeochemical modeling, the LEMAR (Anne Lorrain, Brest, France) for ecological/trophic web investigations, and the IMARPE (Michelle Graco, Lima, Peru) for the specifics of the biogeochemistry of the Humboldt OMZ and field work . 

MIO is a joint research unit of AMU, CNRS, Institute of Research for Development (IRD) and University of Toulon (UTLN). MIO’s objectives are to better understand the ocean system and its response to global change, with expertise in chemical, physical and (micro-)biological oceanography. MIO has infrastructures at 5 sites: AMU Luminy, UTLN, the IFREMER marine base in La Seyne-sur-Mer and the IRD Centre in Nouméa, New Caledonia. MIO is structured in 5 disciplinary teams, with 6 cross-thematic research areas and 6 analytical platforms, a marine monitoring service supported by its own research vessel Antedon II, which will be used for method development. 

The Marseille Marine Mercury Laboratory at MIO is fully equipped for basic and advanced Hg analysis: cold vapor atomic fluorescence spectrometry (3x CV-AFS Brook Rand), an automated total Hg analyzer purge & trap CV-AFS (Brooks Rand MERX-T), an automated methylHg analyzer purge & trap GC-CV-AFS (Brooks Rand MERX-M, an automated combustion atomic absorption spectrometry AAS (Leco AMA 254), and a brand-new gas chromatography (Thermo Trace 1300) coupled to the HR-ICPMS (Thermo Element XR) for Hg speciation by isotope dilution. One fulltime dedicated technician manages daily operations and maintenance of these facilities. 

The PhD student will be trained in ultra-trace clean techniques, participate in several field campaigns, help with the validation and interpretation of all acquired data, help with the implementation of the data into numerical models and contribute to the publication of the findings. The PhD student will be lead author of at least 2 publications. 

The PhD student will potentially be involved in another Pacific Ocean cruise in November-December 2019, as part of the submitted ANR proposal TONGA (PIs Sophie Bonnet, MIO, Cecile Guieu, LOV, Villefranche sur Mer) as part of the international GEOTRACES program. A qualification comparable to a Master's degree or Diploma in chemistry, environmental chemistry, (chemical) oceanography or related field is required. Experience in analytical chemistry and / or marine biogeochemistry is desirable. An essential requirement for selection for the PhD projects is a top-quality MSc or equivalent 4–5 year degree. We also expect good English language skills, and that the candidate is willing and able to participate in sea-going expeditions. Most importantly, we are looking for a creative and curious mind. Applications including a letter of motivation, CV and contact details of 2 referees should be sent to as a single pdf file, using as email subject "PhD OMZ Hg". 

PhD supervisors Dr. Lars-Eric Heimbürger, Dr. Sophie Bonnet (HDR) Mediterranean Institute of Oceanography, Aix Marseille University, CNRS/INSU, Université de Toulon, IRD, Marseille, France 

Dr. David Point Geosciences Environment Toulouse, Observatoire Midi-Pyrénées, CNRS/IRD/Université Paul-Sabatier, Toulouse, France 

 Data Product (IDP2017)


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