PhD Impact of climate change related coastal acidification on the sensitivity of the intertidal mangrove amphipod Parhyale hawaiensis to contaminant exposure in a multi-stressor context

This project is part of the NERC-funded Centre for Doctoral Training, ECOWILD.

For more details, and for a full list of projects offered under this programme, please visit: https://ecowild.site.hw.ac.uk/

Project Description

The project will examine the impact of exposure of the amphipod Parhyale hawaiensis to environmentally relevant pollutant mixtures with different climate change-related physical drivers under a multi-stressor regime.

Climate change is driving changes in the aquatic environment, particularly transitional waters such as wetlands, estuaries and intertidal systems. These include rising temperatures, fluctuating salinities, pH shifts and dissolved oxygen concentrations. These physical drivers will affect the physico-chemical properties of chemical pollutants influencing their behaviour in the aquatic environment and their bioavailability for exposed organisms. With the exception of spill events or point source discharge, environmental contaminants often occur in concentrations unlikely to induce an acute response. The changing conditions, however, are likely to impact the ability of chronically exposed organisms to respond to resulting oxidative stress and the multi-stressor approach will uncover potentiating effects of combinations of stressors at otherwise benign concentrations.

The project will optimise for P. hawaiensis well-established oxidative stress biomarker endpoints, including catalase (CAT), Superoxide dismutase (SOD), Glutathione-S-Transferase (GST), Glutathione Peroxidase (GPx), Reduced Glutathione (GSH), oxidised Glutathione (GSSG), GSH:GSSG and Glutathione Reductase (GR) as well as a comparison of different DNA damage techniques (Comet assay vs Fast Micromethod). The antioxidant response to a range of environmental contaminants and contaminant mixtures – as characterized through ‘hypenated’ techniques, including gas chromatography mass spectrometry (GC/MS) – will be assessed under varied physical drivers. With the optimisation of these antioxidant biomarkers currently lacking for Parhyale, ecotoxicological biomarker baselines will be generated and compared to the response sensitivity of the species to pollution in a climate-driven multi-stressor environment.

What do you need to know:

This is a laboratory based experimental project with the aim to optimise a range of ecotoxicological biomarker assays for Parhyale hawaiensis,to assess the sensitivity of the species to multi-stressor exposure.

The student will have a biology background, preferably with hands-on laboratory, hypothesis generating and statistical analytical experience, as well as a passion for experimentation. Particularly desirable is experience in aquatic invertebrate husbandry and an understanding of carbonate chemistry.

Collectively, the proposed supervisory team is highly experienced in the fields of ecotoxicology and environmental impact, particularly in the use of Parhyale hawaiensis and ecotoxicological assessment together with biomarker design and optimisation across a range of organisms and aquatic environments, as well as analytical chemistry.

What expertise and skills will the student develop?

The student will be based at Heriot-Watt (HWU) and integrated in vibrant ecotoxicology teams at HWU and SAMS, and develop skills in experimental design, data management and statistical analysis, hands-on handling and husbandry of the established colonies of P. hawaiensis (HWU), ecotoxicological biomarker techniques (HWU and SAMS) and chemical analysis (HWU and BGS).

Why is the project novel?

The novelty of the project lies in understanding the responses of intertidal amphipods to multi-stressors, which are still quite unknown, particularly the stressor of acidification. Ocean acidification is well known, but intertidal fluctuations are relatively understudied, and the variance and extremes are totally different from open ocean acidification. Intertidal species are usually very well adapted to extreme conditions, but molecular and biochemical mechanisms of stress resilience under multi-stressor exposure are less understood.

What real-life challenge does it address?

We are currently in a biodiversity crisis often a result of multi-stressor exposure, which is set to intensify with the effects of progressing climate change. Optimising the proposed biomarker endpoints for Parhyale, which are far more sensitive than conventional endpoints such as mortality or behaviour, and more economic to achieve than gene expression and associated bioinformatics, could be further developed and future-proofed for use in conservation strategies and management of coastal systems, in order to better link ecotoxicology methods to real-world contaminant situations in a climate change-related multi-stressor context.

Timelines

The closing date for applications is 17:00 BST Friday 9 January 2026, and applicants must be available to start in October 2026.