Pan-tropical analysis of peat hydraulic conductivity

Peatlands are organic-rich wetlands, where waterlogged conditions allow carbon-rich plant detritus to accumulate over thousands of years. The ability of tropical peats to retain water, particularly in the face of climatic and land-use change, is of central importance to determining the fate of these ecosystems and their carbon stocks in the coming decades, but their hydrological functions are poorly understood. This study will address an important knowledge gap in tropical peatland hydrology, analysing a large database of peat hydraulic properties and other measurements to establish the controls on saturated hydraulic conductivity in tropical peats. Hydraulic conductivity is a measure of how permeable peat is to the flux of water, and thus plays an important role in determining water loss and retention, but the hydraulic properties of tropical peats are severely understudied. This study will combine and analyse datasets of peat hydraulic conductivity and other properties, collected by the supervisors from sites across the tropics, to address this knowledge gap.

<h2 style="margin-top: 21px; margin-bottom: 21px;">Background</h2> <p style="margin-top: 21px; margin-bottom: 21px;">Important concentrations of tropical peat swamp forests can be found in humid regions of South America, central Africa and Southeast Asia, and are thought to store more than one hundred billion tons of soil carbon (Crezee et al., 2022; Page et al., 2022). The slow accumulation and long-term persistence of peat-carbon at the Earth’s surface requires saturated soil surface conditions for much of the year, meaning that peatland carbon budgets are closely tied to peatland water budgets (Baird et al., 2016). If allowed to dry, tropical peatlands can lose huge amounts of carbon in a few years through aerobic decomposition and wasting (Roucoux et al., 2017; Prananto et al., 2020; Garcin et al., 2022). A deeper understanding of these ecosystems’ hydrological functions is urgently needed.</p> <p style="margin-top: 21px; margin-bottom: 21px;">This study will address an important knowledge gap in tropical peatland hydrology, by developing a large database of peat hydraulic properties and other measurements to establish the controls on saturated hydraulic conductivity (<em>Ksat</em>) in tropical peats. <em>Ksat </em>is a measure of how permeable peat is to the flux of water, and thus plays an important role in determining water loss and retention (e.g., Baird et al., 2016). In higher-latitude northern peatlands that are common across Canada, Russia and northern Europe, pedotransfer functions have begun to be developed: equations that allow the confident prediction of hydraulic properties, including <em>Ksat</em>, from other, simpler measurements, such as dry bulk density and degree of decomposition (e.g., Morris et al., 2022). However, the hydraulic properties of tropical peats are severely understudied in comparison, and it is unclear if similar relationships exist as in northern peats. This study will take advantage of existing datasets of <em>Ksat </em>and other peat properties, collected by the supervisors, from sites in Costa Rica, the central Congo Basin and Malaysia.</p> <h2 style="margin-top: 21px; margin-bottom: 21px;">Objectives</h2> <p style="margin-top: 21px; margin-bottom: 21px;">This desk-based project will develop and analyse a large database of existing measurements from multiple locations in the tropics, to understand the controls on peat saturated hydraulic conductivity. More specifically, the project has the following objectives:</p> <ol> <li style="margin-top: 21px; margin-bottom: 21px;">Scrutinise and harmonise the three datasets from across the tropics, so that they can be combined into the first pan-tropical database of peat hydraulic property measurements.  </li> <li style="margin-top: 21px; margin-bottom: 21px;">Develop statistical models, known as pedotransfer functions, from the combined database that can be used to establish the relationships between tropical peat <em>Ksat</em> and likely predictors such as dry bulk density, degree of humification, and peat floristic composition. </li> <li style="margin-top: 21px; margin-bottom: 21px;">Disseminate the findings in international outlets, including submitting a journal article for publication, and possibly also presenting at a major conference.<br />  </li> </ol> <h2 style="margin-top: 21px; margin-bottom: 21px;">Training</h2> <p>You will work under the supervision of <a href="https://environment.leeds.ac.uk/geography/staff/1078/dr-paul-morris" target="_blank">Dr. Paul Morris</a>, <a href="https://environment.leeds.ac.uk/geography/staff/997/professor-andy-baird" target="_blank">Prof. Andy Baird</a> and <a href="https://environment.leeds.ac.uk/geography/staff/1062/professor-simon-lewis" target="_blank">Prof. Simon Lewis</a> in the School of Geography, where you will become a member of two research clusters: <a href="https://environment.leeds.ac.uk/geography-research-river-basin-processes-management" target="_blank">River Basins</a>, and <a href="https://environment.leeds.ac.uk/geography-research-ecology-global-change" target="_blank">Ecology and Global Change</a>. Additionally, external supervision will be provided by <a href="https://www.nottingham.ac.uk/Biosciences/People/sofie.sjogersten" target="_blank">Prof. Sofie Sjögersten</a> (U. Nottingham), <a href="https://www.cranfield.ac.uk/people/dr-nick-girkin-26264651" target="_blank">Dr. Nick Girkin</a> (Cranfield U.) and <a href="https://www.rothamsted.ac.uk/our-people/hannah-cooper" target="_blank">Dr. Hannah Cooper</a> (Rothamsted Research), and you will become a member of the <a href="https://congopeat.net/" target="_blank">CongoPeat</a> consortium, an international, multi-institution network of scientists studying the tropical peat swamp forests of the central Congo Basin. The project will provide you with high-level training in (i) hydrological processes in tropical peatlands; (ii) advanced statistical techniques (e.g., generalised linear mixed models); (iii) interpretation of data describing soil and peat hydraulic properties; and (iv) research-level skills in writing, literature review and data visualisation. Training needs will be assessed at the beginning of the project and at key stages throughout. You will be encouraged to participate in the numerous training and development courses run by the university to support postgraduate research students, including statistics training (e.g. R, Python), academic writing, time management, and other relevant skills (see <a href="https://tinyurl.com/5djfk49y">https://tinyurl.com/5djfk49y</a>). Guidance at all stages of the project will involve regular meetings with internal and external supervisors. You will also be able to attend CongoPeat consortium meetings in the UK, providing opportunities for networking and feedback from a group of subject-leading experts.</p> <h2>Student profile                                                                                                    </h2> <p>Applicants should have a keen interest in physical hydrological processes. Applicants must hold, or be soon to receive, an undergraduate degree in physical geography, environmental science, or a related discipline. Some prior knowledge of tropical peatlands would be advantageous, but is not essential. The project will involve the use of advanced data analysis techniques; although full training will be provided by the supervisors, applicants should be numerate, and confident in manipulating and curating data. Towards the end of the project, you will be expected to submit an article describing their findings for publication in an international journal, under the supervisors’ guidance. As such, you should be ambitious, motivated and organised; the project would provide excellent preparation for an individual seeking a subsequent career in research, including PhD study.</p> <h2>References</h2> <p>Baird AJ, et al. (2016) High permeability explains the vulnerability of the carbon store in drained tropical peatlands. Geophysical Research Letters, 44, 1333–1339.</p> <p>Crezee B., et al. (2022) Mapping peat thickness and carbon stocks of the central Congo Basin using field data. Nature Geoscience, 15: 639–644.</p> <p>Garcin Y., et al. (2022) Hydroclimatic vulnerability of peat carbon in the central Congo Basin. Nature, 612: 277–282.</p> <p>Morris PJ, et al. (2022) Saturated hydraulic conductivity in northern peats inferred from other measurements. Water Resources Research, 58, e2022WR033181.</p> <p>Page S.E., et al. (2022) Anthropogenic impacts on lowland tropical peatland biogeochemistry. Nature Reviews Earth & Environment, 3: 426–443.</p> <p>Roucoux, K.H., et al. (2017) Threats to intact tropical peatlands and opportunities for their conservation. Conservation Biology, 31: 1283–1292.</p>

<p>Formal applications for research degree study should be made online through the <a href="https://www.leeds.ac.uk/research-applying/doc/applying-research-degrees">University's website</a>. Please state clearly in the research information section that the research degree you wish to be considered for is Pan-tropical analysis of peat hydraulic conductivity as well as <a href="https://environment.leeds.ac.uk/geography/staff/1078/dr-paul-morris" target="_blank">Dr. Paul Morris</a> as your proposed supervisor. The start date is highly flexible, and does not have to coincide with the University term dates. Please get in touch for more information: <a href="mailto:p.j.morris@leeds.ac.uk?subject=Pan-tropical%20analysis%20of%20peat%20hydraulic%20conductivity">P.J.Morris@leeds.ac.uk</a>  </p> <p>If English is not your first language, you must provide evidence that you meet the University'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>

Applicants to research degree programmes should normally have at least a first class or an upper second class British Bachelors Honours degree (or equivalent) in an appropriate discipline. The criteria for entry for some research degrees may be higher, for example, several faculties, also require a Masters degree. Applicants are advised to check with the relevant School prior to making an application. Applicants who are uncertain about the requirements for a particular research degree are advised to contact the School or Graduate School prior to making an application.

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.

<p>For further information please contact the lead supervisor, Dr. Paul Morris, <a href="mailto:p.j.morris@leeds.ac.uk?subject=Pan-tropical%20analysis%20of%20peat%20hydraulic%20conductivity">P.J.Morris@Leeds.ac.uk</a></p>