Lead Supervisor: Theodore Henry (Heriot Watt University)
Stakeholder Supervisor: Isabella Gosetto (Joint Nature Conservation Committee (JNCC))
Co-Supervisor 1: Teresa Fernandes (Heriot Watt University)
Co-Supervisor 2: Alistair Boxall (University of York)
Co-Supervisor 3: Gisela Umbuzeiro (Faculdade de Technologia)
Project Description: This project will build on our foundation of knowledge of the ecotoxicology of P. hawaiensis from the development of the model (laboratory husbandry and testing, molecular biology, pathology, and behaviour) and responses to chemical toxicants (metals, natural and anthropogenic particles, and PAHs) to incorporate the critically important aspect of substance-particle interactions and consideration of application of science in policy or conservation advice. Our focus in the laboratory will be on investigating how particles (select natural colloids, plastic particles, and engineered nanoparticles) interact with toxicants (polycyclic aromatic hydrocarbons (PAHs), dissolved metals) and influence their bioavailability via sorption/desorption reactions and the effects of changes in salinity on these processes.  Our purpose-built particle dispersion chamber enables particles to remain suspended in the aqueous phase and manipulation of toxicant concentrations, application of UV light (for photo-induction), at the same time toxicological responses are measured in model aquatic organisms.  The model organism for this research is the circumtropical estuarine amphipod Parhyale hawaiensis which has emerged as a particularly useful organism for laboratory research with direct relevance to critically important aquatic ecosystems (e.g., mangrove wetlands).  Bioavailability of toxicants will be assessed by a combination of methods that include changes in target gene expression, immunotoxicology (blood cells), and behavioural ecotoxicology.  Opportunities will be available for field investigations to be conducted in either Brazil or Malaysia in which the project supervisors have existing research collaborations. 
The student to be selected for this project will need to have some experience in both laboratory and field research with some aptitude for both molecular biology and behavioural toxicology.  An interest in physical and analytical chemistry will be useful as will be an appreciation for the importance of tropical aquatic environments.  The student will become part of an established international team of researchers investigating ecotoxicology of tropical aquatic ecosystems.
What do you need to know: The aquatic toxicity of substances is controlled largely by factors that influence their bioavailability and among the most important of these are interactions with particles. Toxic substances sorb and desorb to particles in the aqueous phase and undergo transformation reactions mediated by photoactivation and microbial processes.  As particles with sorbed toxicants are transported to river mouths and mangrove wetlands, rapid changes in salinity can alter toxicant-particle associations and affect toxicant bioavailability.  Our established tropical amphipod model Parhyale hawaiensis and purpose-built particle-toxicant dispersion test chambers enable investigations into these critically important and understudied questions of environmental toxicology.  The lead supervisor has existing research projects and long-term research collaborations with colleagues working with this model organism within mangrove ecosystems, which will provide access to these sites for field investigations.
What expertise and skills will the student develop? 
The student will develop expertise in particle-substance interactions, assessment of toxicant bioavailability and toxicity, and ecotoxicology methods at multiple levels of biological organization including molecular biology (gene expression analyses), tissue (histopathology), and whole organism (behavioural toxicity). The student will also be able to develop competence in physical chemistry including aqueous-phase particles and analytical chemistry.  The main project supervisor has long established research collaborations with supervisor in Brazil (Prof GA Umbuzeiro) and a joint academic appointment at the University of Campinas (Campinas, Brazil), and close partnerships with colleagues in Malaysia in which some research opportunities in tropical ecotoxicology will be available.
Why is the project novel?
The importance of particle-substance interactions on the bioavailability of toxicants to aquatic organisms are recognised as among the most critical and poorly understood areas of ecotoxicology.  Our previous research has demonstrated the influence aqueous-phase particles on toxicant bioavailability, toxicant decomposition, and toxicant photo-induction and degradation/decomposition.  This project will employ state-of-the-art techniques to enhance understanding of particle-toxicant interactions relevant to mangrove wetlands which are among the most threatened ecosystems in the world. The project will inform ecological protection and identify areas of interest for international conventions such as Ramsar and UN Environment Programme for tackling pollution in mangroves.
What real-life challenge does it address? 
Mangrove ecosystems face mounting threats from the triple planetary crises of pollution, climate change and biodiversity loss. Particle-toxicant interactions result in complex scenarios in which toxicants are transformed and traditional ecotoxicity tests that do not include the influence of particles on toxicant bioavailability have limited ability to predict toxicity.  This project will move forward understanding of particle-toxicant interactions and enhance knowledge of multiple factors that affect toxicity in a critically important relevant model organism of mangrove ecosystems. Findings will inform environmental policy, enhance risk assessment frameworks, and support conservation strategies for mangroves, critical buffers against climate impacts and biodiversity decline.

Lead Supervisor: Richard Cross (UK Centre for Ecology & Hydrology)
Stakeholder Supervisor: Geoff Hilton (Wildfowl and Wetlands Trust)
Co-Supervisor 1: Annette Burden (UK Centre for Ecology & Hydrology)
Co-Supervisor 2: Joe Taylor (UK Centre for Ecology & Hydrology)
Co-Supervisor 3: Frances Orton (Heriot Watt University)
 
Project Description: This project is a unique opportunity to integrate new monitoring approaches to understand the emergent provision of ecosystem services whilst gaining insights into potential interacting stressors of pollution, pathogens and antimicrobial resistance as saltmarsh ecosystems are restored through managed realignment of the coastline. Restored saltmarshes represent an opportunity for significant accumulation of carbon, but these same processes may lead to the rapid accumulation of pollutants along with the influx of sediments into the newly established intertidal zones. Plastic litter and microplastics are concentrated in coastal zones and may well rapidly accumulate in restored saltmarshes. These not only present a pollutant threat in their own right to the newly establishing communities that take root in these restored saltmarshes, but there is emerging evidence that plastic (and microplastics) may act as reservoirs or preferential substrates for pathogenic bacteria to thrive, including the potential to carry and transfer antimicrobial resistance genes. The project will test the hypothesis that significant and rapid accumulation of plastics in restored saltmarshes may lead to interactions between these multiple stressors, increasing the cumulative risks. This will be looked at in newly realigned saltmarsh habitat, as well as the opportunity to sample a chronosequence of sites reflecting various time points since restoration, and differing estuarine contexts giving insights into potential differences over time and space. Alongside state-of-the-art monitoring methods utilising molecular ecology and analytical chemistry, ecosystem service provision will be monitored, for example with onsite eddy covariance to measure greenhouse gas flux, establishing a baseline from which trends over time can be investigated.

What do you need to know:
This project will be the first of its kind to integrate monitoring of both multiple stressors and ecosystem services in restored saltmarsh ecosystems, right from the beginning of the managed realignment of a new coastal saltmarsh. Focused on microplastics and their potential to serve as a reservoir for pathogens and antimicrobial resistance, and together acting as potential multiple stressors in restored saltmarsh systems, the supervisory team brings access to the state-of-the-art microplastics analysis facility at UKCEH as well as expertise in molecular ecology, environmental microbiology, saltmarsh restoration, and multiple stressor impacts.
The team collectively spans disciplines from microplastics and microbial source monitoring and tracking, as well as interactions of these multiple stressors, to blue carbon and habitat restoration. This offers the student an exceptional opportunity to work at the interface of environmental chemistry, ecology, and genomics. The student will also benefit from access to UKCEH’s high-performance sequencing and analytical infrastructure, as well as collaborations with restoration practitioners and conservation organisations involved in saltmarsh restoration schemes. This combination of facilities, expertise, and stakeholder partnerships provides an ideal environment to deliver an ambitious, interdisciplinary project with strong scientific and applied outcomes.

What expertise and skills will the student develop? 
The student will become experts in saltmarsh ecosystems and their biogeochemical and ecological functioning. They will learn about different approaches and designs to saltmarsh restoration and develop new methods for combined monitoring and integration of data across multiple stressors and assessment of the provision of ecosystem services. The student will gain hands on experience in field sampling, vibrational spectroscopy for plastic analysis, molecular ecology techniques, and multi-stressor statistical approaches.
The student will be able to apply their research findings to real-world restoration scenarios by working with the WWT, who manage, design and construct saltmarshes. They will also have the opportunity to work with WWT policy and communication teams, gaining valuable experience in translating scientific evidence into practical recommendations for habitat restoration, management, and policy engagement.

Why is the project novel? 
 The timing of this project provides a unique opportunity to investigate the accumulation of microplastics as new saltmarsh develops, as it coincides with restoration of saltmarsh along the coastline.  Through a unique combination of monitoring approaches, utilising the latest vibrational spectroscopy and molecular ecology techniques, the project will explore and evaluate the role of plastics (including microplastics) acting as a reservoir for pathogens and antimicrobial resistance in these emerging systems, in addition to quantifying key ecosystem services. It will therefore provide the first comprehensive framework for evaluating both the benefits and potential unintended consequences of large-scale coastal restoration schemes.

What real-life challenge does it address? 
This project directly addresses the real-world challenge of how to restore coastal habitats in ways that maximise ecological and climate benefits while minimising new environmental risks. It will evaluate the trade-offs between the benefits of saltmarsh restoration for a range of ecosystem services (carbon storage, biodiversity, flood protection), and the potential introduction of new stressors through sediment-borne contaminants and microbes. In doing so, it responds to an urgent policy and management need to understand the sustainability of nature-based solutions under the pressures of pollution, climate change, and coastal development. The findings will provide evidence to guide coastal restoration design, management, and national blue carbon accounting frameworks, ensuring that restoration interventions remain both effective and safe.