This fully funded PhD position at the Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, offers an exciting opportunity to investigate the effects of climate change and invasive species on blue mussels (Mytilus edulis) in the Wadden Sea, a UNESCO World Heritage Site. Blue mussels are key ecosystem engineers, supporting the intertidal ecosystem by providing substrate and protection for benthic organisms and serving as a vital resource for coastal and migratory birds. The introduction of the invasive Pacific Oyster has dramatically altered the composition of reef-forming structures in the Wadden Sea, with significant ecological consequences. The project aims to unravel how environmental pressures, such as increased competition and rising temperatures, impact the genetic diversity and resilience of blue mussel populations. The successful candidate will employ advanced sequencing technologies and computational approaches to generate and analyze genomic datasets, enabling genotype-by-environment analyses and environmental modeling under various climate change scenarios. The research will involve designing and conducting fieldwork, laboratory experiments, and bioinformatic analyses, with the goal of informing management strategies for the long-term sustainability of the Wadden Sea ecosystem. The position is embedded in the Ecological Genomics Lab led by Dr. Tom Oosting and Prof. Sancia van der Meij, and the candidate will actively contribute to both the lab and the Marine Biology cluster. The University of Groningen is renowned for its international research environment and commitment to diversity. The PhD appointment is for 48 months (1.0 FTE), with a competitive salary, holiday allowance, year-end bonus, and enrollment in the Graduate School of Science and Engineering. Applicants should have a Master's degree in ecology, genetics, or a related field, with experience or motivation to learn population genetics and computational skills (R, Python, Linux). Strong English proficiency and effective communication and collaboration skills are required. Applications must include a motivation letter, CV, academic transcripts, references, and proof of English proficiency. The application deadline is 1 December 2025, and the position will remain open until filled, with the latest possible start date of 1 March 2026.