Download Evolution and diversity of novel marine nitrogen

GW4 Training Partnership
Evolution and diversity of novel marine nitrogen-fixing organisms
and their impact on global climate
University Supervisor:
Dr Fanny Monteiro & Dr Patricia Sanchez-Baracaldo (University of
Bristol)
Dr Andy Rees
PML Supervisor:
Scientific background/rationale and significance: Ocean phytoplankton are key in regulating the
marine ecosystem and climate. Particularly important are phytoplankton which can fix atmospheric N2
into a bio- available source of nitrogen such as ammonium. Because nitrogen is the dominant limiting
nutrient in the ocean, nitrogen fixers are crucial in supporting marine productivity and thus regulating our
climate via the uptake and sequestration of atmospheric CO2. Unicellular N2 fixers have been shown to
play a key role and within this group new symbiotic species have been discovered. Interestingly these
micro-organisms have undergone genome reduction as a result of establishing symbiotic associations
with unicellular algae hosts. A trend in genome reduction likely reflects adaptation of the host to grow in
nutrient-poor environments such as the mid-ocean gyres which are geographically dominant. These
findings offer an exciting opportunity to study the evolution of nitrogen fixers and their impact on past and
present marine life, global nutrient cycles and climate.
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Research methodology: This project aims to study how genomic differences of newly discovered
nitrogen fixers and their closest relatives, and how these differences are reflected into their ecological
niches (e.g., coastal versus open ocean). The student will mainly employ comparative analyses using
genomic data to determine how genetic differences (e.g., gene structure, gene content) relate to
ecological differences, geographical distribution and past climatic events. The student will also have the
opportunity to use the already developed MIT-Darwin model [Monteiro et al., 2010] to perform numerical
investigations of the diversity and importance of these novel organisms to fuelling life in the ocean. This
project stands out for its inter-disciplinary nature, novelty and expert supervisory panel, and is a great
opportunity for any students interested in marine biology, evolution and climate.
Training: The student will be mostly based at Bristol University and she/he will do a rotation in the
Plymouth Marine Laboratory (one month per year). The successful candidate will learn skills from two
different highly-complementary fields:
1) She/he will learn about bioinformatics to generate new and uniquely integrated datasets of
phytoplankton and to analyze applying comparative methods. This includes the basics of computer
programming (Shell scripting and either PERL or Python). All these skills are highly transferable to
industry. We have budgeted for the following training opportunity: • International School on
Computational Molecular Evolution, Greece
2) She/he will have the potential to learn to use and develop complex marine ecosystem models using
the innovative and successful MIT-Darwin model (http://darwinproject.mit.edu/). This model represents
the diversity of the marine ecosystem by letting the ocean environment directly selects for the marine
species. The student will be training in computer programming (Fortran, Matlab and Python) and in
parallel computing on high-performance computers (using NERC and University of Bristol HPCs).
We have budgeted for the following training opportunity: • Earth System Science Spring School in the UK
This project will also involve a visit to Prof Jon Zehr laboratory at the University of California in Santa
Cruz (USA). His internationally recognised research team has led to the discovery some of the latest
marine species of nitrogen fixers. The student will have the opportunity to discuss the ecology and
modern distribution of nitrogen fixers with the Zehr lab as well as learn about the techniques needed to
analyse marine organisms in situ (flow cytometry, metagenomics and molecular ecology). This visit will
assist with both the genomics and modelling aspects of this interdisciplinary project.