Dynamic Green Ocean Project

Laboratory based biological oceanography
TITLE: Iron-light colimitation.

SUPERVISOR
Erik Buitenhuis (UEA, UK)
External collaborator: Richard Geider (U.Essex, UK)

PROJECT DESCRIPTION

Iron limitation affects primary productivity in large regions of the ocean. Low irradiance greatly decreases the efficiency of iron utilisation (Sunda & Huntsman 1997), consistent with the high iron requirement for photosynthetic electron transfer (PET) (Raven 1990). Thus, light-limitation and iron-limitation should be viewed as end members of a continuum that includes varying degrees of co-limitation. There is strong evidence for both iron-limitation (Martin et al. 1990; de Baar et al. 1995) and light-limitation (Mitchell et al. 1991) of phytoplankton photosynthesis in the Southern Ocean.

In this project we will:
:-) derive taxonomic specific parameterisations for the major phytoplankton groups.
:-) test the physiological model of Buitenhuis and Geider (2010) of iron-light co-limitation.
:-) test the parameterisation in a global ocean biogeochemical model with an explicit representation of Phytoplankton Functional Types (at present 3), which includes the above physiological model (Buitenhuis and Le Quéré, submitted).

General background
We are a modelling group who investigate the feedback between climate and the oceanic carbon cycle through the structure of the marine ecosystem. The most recent climate models include representations of ecosystem processes, both on land and in the oceans. Ecosystem processes are now seen as vital to a better understanding of the various climate feedbacks. Here we propose to investigate the feedback between climate and the oceanic carbon cycle through iron biogeochemistry and the structure of the phytoplankton community. Currently, our group has 5 laboratory based PhD students who do experimental work (~75%), data synthesis (~15%) and modelling (~10%) to improve the representation of physiological characteristics of specific plankton groups. This work will be undertaken in the framework of the Dynamic Green Ocean Project, an international project aimed at developing a community model of ocean biogeochemistry for applications to Earth system problems.

Work plan
During the laboratory work the incumbent will cultivate ~ 10 species of phytoplankton and determine their physiological parameters under iron-light colimitation. This will constitute the main part of the project. There will be the opportunity to use the results of the experiments in our model. The incumbent will work as part of a small but dynamic and highly international group and in collaboration with a worldwide network of marine ecologists and ocean modelers.

Profile of the candidate: Both an MSc and a PhD student are sought. Experience with class 100 clean bench techniques, with low trace metal concentration seawater and/or with culturing of microorganisms is highly desirable.

Funding: An MSc student can apply for a Nuffield grant, a PhD student can apply for full funding from the School of environmental sciences.

How to apply: If you are interested in this project, please contact Erik Buitenhuis See also the extra guidance notes for PhD students.

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