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Job Description: Four MSc’s, two PhD’s and one Post Doctorate opportunity in the SOCCO iron project

Introduction:

Introduction:There is now unequivocal evidence that the micronutrient iron and iron-light co-limitation are the primary limiting factors of phytoplankton production in the Southern Ocean. This effectively controls the strength of the efficiency of the 'biological carbon pump', which exports fixed carbon into the deep ocean and so influences atmospheric CO2 concentration. This is due to low dFe concentrations (<1.0nmol), low solubility in oxygenated seawater at normal pH and low inputs to the Southern Ocean from continental shelfs. Iron is an essential element for phytoplankton growth, as it occurs and is needed in different metabolic processes, such as in the photosynthetic and respiratory electron transport system, reduction of nitrates and phosphates, nitrogen and carbon dioxide fixation and the synthesis of chlorophyll. The net impact of Fe on overall primary productivity requires quantifying dFe supply and dFe demand on phytoplankton photosynthetic rates and on nitrogen uptake rates under variable light regimes also taking into consideration phytoplankton community structure. Clearly resolving this complex matrix of interdependent processes as a function of environmental variability (seasonal, regional and longer-term) necessitates a multi-disciplinary approach.

Study 1:One MSc project assisting with high depth resolution measurements of dFe in winter to characterize the dFe profile and high depth and time resolution dFe profiles in summer to investigate the sub-seasonal supply of Fe to surface waters through transient mixing and re-stratification events. The dFe supply and demand will be interpreted in conjunction with measurements of phytoplankton biomass, community structure and productivity.

Study 2:One PhD project that aims to understand how the Southern Ocean phytoplankton community adapts and responds to fluctuations of dFe and light over sub-seasonal time scales and across different regions based on their photo-physiological and nitrate uptake responses to dFe-light variability and on nitrate uptake. Achieving this aim will require simulated in-situ bioassay type incubation experiments and laboratory cultures of keystone Antarctic phytoplankton that test phytoplankton responses to variable light, dFe and macro-nutrient concentrations.

Study 3: The biogeochemistry of Iron in the Southern Ocean:1PhD and 1 MSc project tackling the following Key questions: 1. What sustains the stability of Fe2+ nanno-particles in the oxygenated waters of the Southern Ocean? 2. What is the speciation of Fe in the Southern Ocean and what new methods may be developed to better understand and model their role in limiting primary production?

Study 4:Two masters projects tackling the following Key question: 1. What new organic bio-markers can be used to observe past long term trends and variability of Sea Surface Temperature in the Southern Ocean?

We invite applications for a number of post-graduate study opportunities within the SOCCO Programme, which is a partnership between CSIR and a number of academic institutions. MSc and PhD applications are restricted to South African students but the Post-Docs are open. SOCCO is committed to supporting CSIR and partner-institutions in meeting the goals of national redress in science and engineering

Expression of Interest:Please send CV as expression of interest to: Dr Thato Mtshali at TMtshali@csir.co.za

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