Marine Ecology: Understanding the Welsh Seascape: Critical Coastal Habitats for Blue Carbon and Fish

Funding Providers: NRW, Swansea University, EVMT ProgRess Ltd (Dr Mark Townley and Heather Townley), Project Seagrass

Subject Area: Marine and Coastal Ecology 

Project Start Dates: October 2026 

** (Please see the note below regarding potential later start dates.) 

Supervisors:

• Dr Nicole Esteban 
• Dr Richard Unsworth
• Dr Penny Neyland

Aligned programme of study: 

PhD in Biological Sciences 

Mode of study: Full-time 

Place of study: Swansea University (Singleton Campus) 

Project description:
Saltmarshes and seagrasses are renowned for numerous ecosystem services including coastal defence, carbon sequestration, nutrient cycling, and water filtration (McKinley et al., 2018; Unsworth et al. 2022). The role of this coastal seascape as important blue carbon and fish habitats is widely cited in the literature but, in reality, is poorly understood and only a few European studies have described factors influencing saltmarsh and seagrass environments for blue carbon and fish (Laffaille et al., 2000; Veiga et al., 2006; Ribeiro et al., 2012; Stamp et al., 2023; O’Neill et al. 2024; Shute et al. 2025). Increasingly saltmarsh and seagrass restoration efforts are focusing on the need to maximise design to improve habitats to enhance ecosystem services such as marine biodiversity and productivity but the means of doing so is limited by significant knowledge gaps. To guide restoration efforts, data-driven studies are needed to explore the ecological drivers of the Welsh Seascape with a focus on saltmarsh and seagrass, including provision of food, shelter or migratory pathways for fish communities and considering blue carbon storage. This PhD will seek to build an understanding of the pivotal factors influencing blue carbon and fish assemblages within saltmarsh and seagrass habitats in South Wales (including niche habitats, predation risk, connectivity, abiotic factors). These findings will be used to inform and optimise the design of restoration initiatives to maximise ecosystem services of saltmarsh and seagrass. 

The PhD research will build on the current understanding of drivers of blue carbon and fish populations (e.g., abundance, diversity) in shallow water habitat by first reviewing environmental drivers including salinity, bathymetry, tide and temperature. After key abiotic factors are identified to inform experimental design and site selection, a series of studies will focus on learning about how fish use saltmarshes and seagrass in South Wales. Research findings will extend our understanding beyond what is known about fish in saltmarshes and seagrass across the intertidal and at high tide (when historic sampling has been conducted) to include microhabitats and lower tidal or deeper creeks. Investigations will include controlled laboratory experiments (e.g. in the Centre of Sustainable Aquatic Research at Swansea University) and saltmarsh and seagrass sampling to quantify the influence of biotic and abiotic factors (such as saltmarsh or seagrass meadow size, presence of pools/creeks, water quality, carbon storage) within the seascape. Emerging data will answer questions such as “how does vegetation composition, grazing intensity and topography affect blue carbon and overall fish assemblage?” The PhD findings will inform enhance our understanding of environmental drivers of blue carbon and fish assemblages in saltmarsh and seagrass with a focus on South Wales. 

Funding Duration: 3 years  

Applicants who are Welsh, female or from disadvantaged backgrounds are particularly encouraged to apply 

**In exceptional circumstances, and subject to the discretion of the University and/or the relevant funding body, a deferral of offer may be granted to the next available enrolment period. Such deferral will typically not exceed a duration of three calendar months from the originally stipulated commencement date. Please note that only one deferral may be considered, and any such deferral is not guaranteed. 

Applications may be submitted in Welsh and any application submitted in Welsh will be treated no less favourably than an application submitted in English. Please refer to the University’s Welsh Language Policy on Awarding Grants. Please see our website for more information on the selection process.