Natural adaptive capability of coral reef islands to sea-level rise and implications for future human occupation

Primary supervisor: Professor Gerd Masselink (University of Plymouth)

Secondary supervisor: Dr Tim Scott (University of Plymouth)

Additional supervisors:

Professor Paul Kench, (Simon Fraser University/University of Auckland). Email:

Dr Robert McCall, (Deltares, Netherlands). Email:

Professor Steve Fletcher, (UN Environment World Conservation Monitoring Centre, UK). Email:

Project description 

It is a widespread expectation that sea-level rise will drown low-lying islands formed on coral reef platforms and that increased flooding will render them uninhabitable within the coming decades. 

Such projections are largely founded on assumptions that islands are geologically inert landforms, whereas in reality, they have the ability to morphologically respond to changing sea levels. 

Specifically, overwash processes can raise the island crest level, implying that islands are dynamic and will not drown in place. Such change in perception has implications for how reef island communities can adapt to climate change. 

This project will investigate the natural adaptation of coral reef islands to sea-level rise.

Small-scale laboratory experiments will be conducted in the COAST facility (University of Plymouth), which houses a variety of wave basins and flumes with state-of-the-art instrumentation, over two four-week periods to investigate how coral reef islands adapt to sea-level rise as a function of rate of sea-level rise, wave climate, sediment delivery and reef platform elevation. 

The physical model results will be used to validate the XBeach numerical model, which is capable of simulating overwash processes and island response, and the model will be used to further explore the relevant factors controlling island adaption. 

Based on field measurements of reef island and platform morphology, involving RTK-GPS and drone surveys, the numerical model will then be used to evaluate, for different sea-level and wave climate scenarios, the future trajectories of one or several actual coral reef islands (from Maldives, Kiribati or Marshall Islands). 

Finally, the implications of these trajectories for its inhabitants will be assessed and human adaptation strategies will be explored.

The successful candidate will be part of the Coastal Processes Research group, an internationally recognised group of researchers, specialising in field studies and numerical modelling of coastal processes. It is customary for all members of the group to participate in each other’s field campaigns, resulting in organic transference of data collection/analysis skills and subject-specific knowledge. 

More specifically, this PhD project provides the opportunity to gain a range of advanced skills as the project includes field surveys on a reef island, small-scale physical modelling in a state-of-the-art engineering laboratory and advanced numerical modelling. 

The PhD student will also spend a significant amount of time at the Case partner (United Nations Environment World Conservation Monitoring Centre) and also with the external partners, further augmenting their knowledge and skills.

We are seeking a PhD candidate with a background in marine science, physical geography, geology or coastal engineering, and with strong numeracy, communication and inter-personal skills, and with a strong affinity for the marine environment.

This proposal builds on existing collaboration between University of Plymouth and Auckland, as well as with Deltares in the Netherlands, whilst at the same time the student will be embedded within the Case partner, United Nations Environment World Conservation Monitoring Centre (UNEP-WCMC) in Cambridge. 

Work is also in progress to seek funding from NERC through a Large Grant, provisionally involving Universities of Plymouth, Exeter and Cambridge (outline submission February 2019). The topic of this project is the natural capability of coral reef islands to adapt to sea-level rise through roll-over induced by washover processes. 

As sea level rises, and during extreme storms, sediment is transferred from the front of the reef island to the top and the back of the island. This results in island retreat, but also an increase in the island elevation; therefore, the island does not automatically drown but may continue to provide space and conditions for human occupation.

The overall aim of the proposed research is to explore the extent to which coral reef islands roll-back as sea level rises and are able to maintain their elevation relative to the rising sea level, thereby ensuring that the islands can remain inhabitable. 

This natural capability of the coral reef islands to adjust to rising sea level will be investigated as a function of a range of key factors, including rate of sea-level rise, wave climate, island and platform morphology, sediment budget and reef platform response. Such an approach will resolve critical thresholds of island morphological behaviour relevant to human occupation. 

The implications of the research for coral reef island communities will be explored using different sea-level and wave forcing scenarios, and human adaptation strategies to deal with the island response will be investigated.

The successful PhD student will be provided with an excellent research environment, both in terms of supervision by experts in the field (coastal processes – Plymouth; coral reef dynamics – Auckland/Simon Fraser; numerical modelling; Deltares), an extremely supportive and collegiate research group (CPRG), the use of a state-of-the-art physical laboratory (COAST facility) and through spending three months at the Case partner, United Nations Environment World Conservation Monitoring Centre (UNEP-WCMC). 

Through the involvement of the Universities of Auckland/Simon Fraser, the PhD student will also benefit from a field visit to one or several coral reef islands in the Maldives, Kiribati or Marshall Islands, and interaction with coral reef island communities. 

The student will receive training in: numerical modelling, physical laboratory experiments, field data collection and analysis of large and complex data sets obtained from all these activities, and application of the new science for sustainable environmental management.


This project has been shortlisted for funding by the ARIES NERC Doctoral Training Partnership. Undertaking a PhD with ARIES will involve attendance at training events.

ARIES is committed to equality & diversity, and inclusion of students of any and all backgrounds. All ARIES Universities have Athena Swan Bronze status as a minimum.  

Applicants from quantitative disciplines who may have limited environmental science experience may be considered for an additional three-month stipend to take appropriate advanced-level courses.

Usually, only UK and EU nationals who have been resident in the UK for three years are eligible for a stipend. Shortlisted applicants will be interviewed on 26/27 February 2019.

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