The U.S. cruise along the GEOTRACES GP15 section in the Pacific Ocean will depart soon

The U.S. GEOTRACES GP15 cruise will be conducted in the Pacific Ocean along 152° W between Alaska and Tahiti (see map below) from 18 September to 24 November 2018. It aims at examining the influence of strong margin fluxes, atmospheric dust deposition, and the distal ends of hydrothermal plumes from the Juan de Fuca Ridge and East Pacific Rise as well as oxygen minimum zones, equatorial upwelling, and some of the lowest-nutrient waters in the world’s oceans in the South Pacific gyre at 20°S. The cruise will be the first meridional section of the U.S. GEOTRACES programme, and indeed, this transect would allow to explore virtually all of the processes and fluxes known to introduce trace elements to the ocean.

GP15 cruise trackThis project would also provide baseline measurements of trace elements in the Clarion-Clipperton fracture zone (~7.5°N-17°N, ~155°W-115°W) where large-scale deep sea mining is planned. Environmental impact assessments are underway in partnership with the mining industry, but the effect of mining activities on trace elements in the water column is one that could be uniquely assessed by the GEOTRACES community.

This cruise will support a large variety of individual science projects to study the chemical and biological interactions of trace elements, with some research being conducted on board the ship, and additional research at participating academic laboratories (please see the GP15 collaborators web page). In total, 45 researchers will participate in this cruise.

Want to learn more about this cruise?


Postdoctoral Scholar in Experimental Chemical Thermodynamics of Seawater, Scripps Institution of Oceanography, USA

Postdoctoral Scholar in Experimental Chemical Thermodynamics of Seawater (Scripps Institution of Oceanography)

The postdoctoral scholar will participate in laboratory measurements involved in better defining marine ‘pH’, and in quantifying chemical speciation in seawater media, including measurement of thermodynamic properties of aqueous solutions using both established reference methods (Harned Cells), and new approaches (using a differential scanning calorimeter). The majority of the postdoctoral scholar's effort will focus on making thermodynamic measurements in salt solutions that are needed to provide well-constrained parameters for a chemical speciation model for natural waters based upon the "Pitzer" equations. The overall aim of this project and its co-funded element in the U.K. is to create a step change in the capability of scientists to measure, interpret, and predict chemical speciation and pH in natural waters of varying composition. The activities of the project as a whole are closely related to those of SCOR Working Group 145 Modelling Chemical Speciation in Seawater to Meet 21st Century Needs.

For more information, please contact Andrew Dickson.

Postdoc in Marine Metals Science, University of Southern California, USA

The John Lab at the University of Southern California is seeking a Postdoctoral Researcher to study metal biogeochemistry in the North Pacific Subtropical Gyre. There is significant flexibility in the specific topic of research…what seems most exciting to you? Potential areas of study include the impact of metals on viral infection dynamics, molecular biology techniques to decipher in situ biological influences on metal and metal isotope cycling, and modeling metal-biological interactions in the North Pacific and beyond. More information about ongoing research is available online at Applicants may send a CV and brief discussion of research interests to

Catherine Jeandel, IPO science director, elected AGU Fellow

We are really very pleased to announce that Catherine Jeandel, GEOTRACES IPO Science Director, has been elected as AGU Fellow!

Congratulations Catherine!!!

GEOTRACES papers are amongst the most highly cited in Limnology and Oceanography: Methods

The journal Limnology and Oceanography: Methods published by the Association for the Sciences of Limnology and Oceanography (ASLO) is celebrating its 15th year of publication. To celebrate this event, they have published a collection of the most highly cited or downloaded papers – two from each year of publication (2002 to 2017):

Significantly, two of the 30 papers are GEOTRACES-related and appeared in L&O Methods’ special issue, Intercalibration in Chemical Oceanography (, that was based on the 2008-2009 GEOTRACES Intercalibration Cruises:

  • Cutter, G.A. and K. W. Bruland. 2012. Rapid and non-contaminating sampling system for trace elements in global ocean surveys. Limnol. Oceanogr. Methods, 10: 425-436.
  • Morton, P. et al. 2013. Methods for the sampling and analysis of marine aerosols: results from the 2008 GEOTRACES aerosol intercalibration experiment. Limnol. Oceanogr. Methods, 11: 62-78.

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


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