Dr Simon Ussher, University of Plymouth
Dr Martha Gledhill, GEOMAR Helmholtz Centre for Ocean Research Kiel
Particulate matter (PM) is a key constituent involved in the cycling of elements that support marine life and control ocean productivity as part of the ocean’s ‘biological pump’. This cycling can impact the distribution and availability of essential trace nutrients to marine organisms, including iron. The availability of iron limits primary production in a third of the world’s oceans, impacting the efficiency of the biological pump so influencing earth’s climate.
Ocean PM consists of organic (humics, exopolymeric-substances) and inorganic material (clays, silicates, hydroxides). Important information about elemental cycling associated with PM can be garnered from elemental stoichiometry (their ratios) and factors that influence that stoichiometry. However, while there have been investigations relating to the stoichiometries of nitrogen and phosphorus associated with dissolved and particulate matter, the stoichiometries of trace elements are less studied.
The overall aim of this project is to assess trace elemental stoichiometry of PM from varied sources (e.g. open ocean, continental shelf) as well as the binding and/or release of those elements with any associated organic material. This project will provide in-depth understanding of element-particle dynamics for a deeper understanding of trace elemental cycling and spatial productivity.
Using clean-handling techniques, you will supplement existing PM samples by collecting PM from SW rivers and the Celtic Sea. You will also have the opportunity to participate in a research cruise to the Southern Ocean. You will subject collected PM to leach and digestion procedures. You will perform controlled incubations (e.g. changes in pH, ionic strength, element additions) to assess the binding and release of elements, and any subsequent element-complexation with organic matter. Samples to assess impacts on microbial communities will also be gathered to aid interpretation for incubations.
You will receive comprehensive training in clean-handling, both in land-based laboratories and at sea, and advanced analytical techniques which will be required to undertake the experiments and respective analyses. You will spend time in Germany developing skills to extract, analyse and interpret trace elements bound to organic matter.
We are looking for an individual with a degree in Chemistry or Earth, Ocean, or Environmental Science.