Skip to main content

Green planet: the timeline of photosynthetic evolution and the habitability of the Earth


Key facts

Type of research degree
Application deadline
Friday 31 May 2024
Project start date
Tuesday 1 October 2024
Country eligibility
UK only
Source of funding
Research council
Dr Benjamin Mills
Additional supervisors
Khushboo Gurung, Patricia Sanchez-Baracaldo (Bristol), Andy Ridgwell (University of California, Riverside)
School of Earth and Environment
<h2 class="heading hide-accessible">Summary</h2>

This fully funded PhD place provides an exciting opportunity to pursue postgraduate research in Earth science and evolution.<br /> <br /> Primary producers (i.e. cyanobacteria, algae, plants) use photosynthesis to transform light energy from the sun into chemical energy in the form of sugars, typically producing oxygen as a byproduct. This fundamental process has underpinned the evolution of complex life om Earth. Once ancestral cyanobacteria evolved, they played a crucial role by facilitating the rise of atmospheric oxygen over two billion years ago. But the relationship between dominant primary producers, the global carbon cycle and the overall production of O2 remains unclear and is mostly neglected from the numerical simulations we use to reconstruct the history of our world. Perhaps unsurprisingly, these simulations do not yet provide a clear picture of the planet&rsquo;s past. In this project the researcher will build on the current state of the art in global biogeochemical models to add representations of primary producer evolution, and to test how this impacts the carbon cycle and changes atmospheric composition.

<h2 class="heading hide-accessible">Full description</h2>

<p>This project offers a unique opportunity to study the biological innovations that have underpinned changes in primary productivity over Earth history such as the shift from single-celled to filamentous bacteria, seafloor to water column habitats, then the evolution of eukaryotic algae and ultimately of plants. The following key questions will guide the research:</p> <p>- did the evolution of filamentous cyanobacteria alter the biological pump and drive the great oxidation event?<br /> - did a biosphere dominated only by microbial mats help explain why complex life took so long to evolve?&nbsp;<br /> - did the evolution of planktonic cyanobacteria and/or eukaryotes drive the later Neoproterozoic oxygenation?<br /> &nbsp;</p> <p><strong>Working environment</strong></p> <p>The research will be based in Mills&rsquo; Earth Evolution Modelling Group, which is part of the Earth Surface Science Institute (ESSI), within the School of Earth and Environment at the University of Leeds. ESSI is a medium sized and friendly research institute that includes analytical geochemists, biogeochemists, sedimentologists, palaeontologists and modellers of climate and biogeochemistry. The group holds several annual science and social events and weekly informal get-togethers. Project supervisor Mills has received multiple ESSI &lsquo;Star Supervisor&rsquo; awards. For more information on the research group, see&nbsp;<a href=""></a>.&nbsp;</p> <p><strong>Entry requirements</strong></p> <p>This project would suit somebody with a degree in one of the natural sciences, mathematics or computing, and the candidate should have a strong interest in Earth history and evolution of the biosphere. Formal training in numerical techniques is not essential, but enthusiasm for computing is advisable. All necessary training will be provided as part of the project.</p> <p><strong>Information about the Award</strong></p> <p>We are offering 1 full-time PHD scholarship in the School of Earth and Environment for one UK candidate, matching UKRI maintenance stipend and UK tuition fees for three and a half years, subject to satisfactory progress.&nbsp;</p> <p><strong>Duration of the Award</strong></p> <p>Full-time (3.5 years). The award will be made for one year in the first instance and renewable for a further period of up to two and a half years, subject to satisfactory academic progress.</p> <p><strong>Other Conditions</strong></p> <ul> <li>Applicants must not have already been awarded or be currently studying for a doctoral degree.</li> <li>Awards must be taken up by 1st October 2025.</li> <li>Applicants must live within a reasonable distance of the University of Leeds whilst in receipt of this scholarship.</li> </ul>

<h2 class="heading">How to apply</h2>

<p>Formal applications for research degree study should be made online through the&nbsp;<a href="">University&#39;s website</a>. Please state clearly in the research information section&nbsp;that the research degree you wish to be considered for is &ldquo;Green planet: the timeline of photosynthetic evolution and the habitability of the Earth&rdquo;&nbsp;as well as&nbsp;<a href="">Prof Benjamin Mills</a> as your proposed supervisor.</p> <p>If English is not your first language, you must provide evidence that you meet the University&#39;s minimum English language requirements (below).</p> <p><em>As an international research-intensive university, we welcome students from all walks of life and from across the world. We foster an inclusive environment where all can flourish and prosper, and we are proud of our strong commitment to student education. Across all Faculties we are dedicated to diversifying our community and we welcome the unique contributions that individuals can bring, and particularly encourage applications from, but not limited to Black, Asian, people who belong to a minority ethnic community, people who identify as LGBT+ and people with disabilities. Applicants will always be selected based on merit and ability.</em></p>

<h2 class="heading heading--sm">Entry requirements</h2>

Applicants to this scholarship in the School of Earth and Environment should normally have a First class or 2:1 Undergraduate degree (or international equivalent) AND/ OR a Distinction or Merit (or predicted Distinction or Merit) in their Masters degree (both in an appropriate discipline). Applicants who are uncertain about the requirements for a particular research degree are advised to contact the Postgraduate Research Admissions Team prior to making an application.

<h2 class="heading heading--sm">English language requirements</h2>

The minimum English language entry requirement for research postgraduate research study is an IELTS of 6.0 overall with at least 5.5 in each component (reading, writing, listening and speaking) or equivalent. The test must be dated within two years of the start date of the course in order to be valid. Some schools and faculties have a higher requirement.

<h2 class="heading">Funding on offer</h2>

<p>One full scholarship is available in the School of Earth and Environment from October 2024. This scholarship is open to UK applicants and covers fees plus UKRI maintenance stipend (currently &pound;19,237 in 2024/25).</p>

<h2 class="heading">Contact details</h2>

<p>Professor Mills can be reached at for any questions about this project. See for more information about the Earth Evolution Modelling Group.</p> <p>If you have any questions regarding the application process, please contact the Postgraduate Research Admissions team for the Faculty of Environment:;</p>

<h3 class="heading heading--sm">Linked research areas</h3>