Changing coastal seas
Coastal seas of the world are experiencing an unprecedented period of rapid change that is driven largely by human-induced alterations in climate and release of chemical contaminants into the environment. Polar areas appear particularly vulnerable as temperatures rise and toxicants accumulate suggesting that their synergistic effects could result in loss of fitness, recruitment, and survival in many species. However, life in general is very adaptable, with heritability and epigenetics as enduring mechanisms that shield future generations from effects of parental exposure to environmental stressors. To better understand adaptation and resilience in coastal keystone species, we propose to compare Antarctic and temperate sea urchins as models of molecular, genetic, epigenetic, and transgenerational effects. Understanding impacts from multiple stressors is critical to fully understand the environment which organisms are living in, and the impacts of changing those conditions.
Adapting to climate change and environmental pollutants across latitudes
Sea urchins are useful coastal sentinels for environmental stressors including climate change and contaminant exposure. These sentinels are ubiquitous in all the world’s oceans, enabling comparative experiments of closely related species from environmental extremes (Antarctic compared with temperate). In addition, they have been a model for cell biology, development, ecotoxicology research for decades. Sea urchins are a useful bio-indicator to understand short- and long-term impacts of complex multi-stressor future environmental conditions such as elevated temperature, reduced salinity, and presence of chemical contaminants. In early life stages (gametes, embryos, and larvae), resilience and sensitivity to environmental stressors can be influenced by preconditioning (and acclimation) of parents. Negative effects of some types of environmental stress can be ameliorated by acclimatisation of parents to stressors prior to release of gametes in some marine invertebrates. Despite the importance of parental acclimation and environmental conditions during gametogenesis, the extent of preconditioning on the response to multi-stressors is largely unknown. Comparing between closely-related species of sea urchin from the Antarctic and temperate regions (Scotland) will provide insight into future resilience and vulnerability across environmental extremes.
Eco-genotoxicology of sea urchins
Understanding combined effects from all stressor sources (the total ‘exposome’ concept) is most usefully achieved by consideration of combined modes of action or toxicity pathways in the target organism. This project proposes to focus on the combined genetic and epigenetic damage response system. The mechanism by which individual effects link to longer-term population and even species-level impacts is through heritable changes in either the genome or the epigenome: changes which can be beneficial for adaptation or negative through inherited genome instability. How organisms are susceptible to heritable changes, and their ability to respond, repair, or adapt to damaging environmental conditions is complex and largely unknown. Sea urchin research has recently shed some light on their responses to DNA damaging contaminants, and their ability to protect, respond, and repair DNA makes them ideal for eco-genotoxicological studies. How sea urchins protect and repair compromised DNA from genotoxic exposure has been investigated in some tropical and temperate species; however, the role of adult preconditioning and sensitivity in the very early stages of embryonic development, and in the involvement of epigenetic marks in determining early life stage responses is less known. Comparison of temperate species with Antarctic has not been carried out previously.
We hypothesise that acclimating adult sea urchins to end-century predicted elevations in water temperature will result in gametes and early embryonic sea urchin stages that are more resilient to subsequent exposures to multiple stressors (e.g. reduced salinity) and pollutants (metals and chemical contaminants). Combined genotoxic stressors will cause complex and additive responses in types of DNA lesions, multiple pathways of DNA repair with extensive energetic trade-offs, and the extent of susceptibility or resilience will differ in broadcast gametes, larvae, and adults.
The project
The overall aim of this project is to understand adult preconditioning impacts on spawning success and gamete/embryo sensitivity to multi-stressor impacts on DNA damage susceptibility and repair in sea urchin populations from latitudinal extremes. The project will take an eco-genotoxicological approach to address three specific objectives.
Objective 1: Precondition aquarium stocks of Antarctic (Sterechinus neumayeri, British Antarctic Survey), and co-familial temperate (e.g., Psammechinus miliaris) sea urchins to end-century elevated water temperatures (+2°C).
Objective 2: Spawn both Antarctic and temperature species after 1 and 2 years acclimation followed by acute multi-stress exposures (e.g., reduced salinity and chemical genotoxic pollutant) to investigate multi-stress response after preconditioning.
Objective 3: Assess adult, gamete, embryo, and larvae viability, development, and survival after acute multi-stress exposure; develop and assess DNA damage, DNA repair, and epigenetic regulation.
The start date of this project is: 2 October 2023
The 3½ year studentships cover:
- Tuition fees each year at Home (UK) rate. For International students, there may be funding available to cover the full international tuition fee and this will be discussed at interview.
- A maintenance grant each of around £15,000 per annum (for full-time study)
- Funding for research training
- Part-time study is an option, with a minimum of 50% of full-time effort being required.
Applicants should normally have, or be studying for:
- A postgraduate Master’s degree from a degree-awarding body recognised by the UK government, or equivalent, or
- A first or upper second class honours degree from a degree awarding body recognised by the UK government, or equivalent, or
- Other qualifications or experience that affords sufficient evidence of an applicant’s ability to work at the academic level associated with doctoral study.
The ideal candidate should have at least some experience of conducting experimental research with some knowledge of marine systems. The student will (1) be based within a dynamic and active marine science laboratory at SAMS with placements at BAS and Heriot Watt University (2) become part of a vibrant PhD community at SAMS/UHI which is embedded in a culture of research and higher education (3) become expert in experimental marine biology and organismal molecular toxicology. Therefore, skills and prior experience in the following would be highly beneficial: molecular biology, toxicology, developmental biology, practical aquarium-based experimental marine biology.
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