Jón Tomas Magnússon
PhD
Supervisors: Albert Pessarrodona & Thomas Wernberg

My research aims to better understand the diversity of kelp-associated species and how it is impacted by disturbances such as storms, climate change and other anthropogenic stressors. Specifically, it will investigate biodiversity at different recovery stages after harvesting, providing insight into commercial harvesting long-term effects. Furthermore, it will compare biodiversity across different habitat states to understand how species abundance, distribution and composition vary when kelp forests change. Another key objective is to evaluate how to best assess biodiversity in kelp canopies and the effectiveness of various methods, including SCUBA diving surveys, environmental DNA (eDNA), and other remote sensing. In addition, the project will explore how kelp-associated biodiversity responds to environmental changes using Arctic ecosystems as a proxy. Finally, the project will include a conceptual review and/or modelling exercise evaluating biodiversity metrics and…
Qualifications
2021: MSc Marine Biology (1st class with distinction), University of Iceland, Iceland. Thesis: Mobile predators on the Ascophyllum nodosum dominated shores of Breiðafjörður, Iceland.
2018: BSc Environmental Biology, Autonomous University of Barcelona, Spain.
Achievements and awards
2021: Erasmus + Traineeship Scholarship. Exchange at the University of Lisbon
2017: Erasmus + Mobility Scholarship. Exchange at the University of Bergen
2017: MOBINT Undergraduate International Mobility Scholarship. Generalitat de Catalunya
Publications
Magnússon, J. T., Hawkins, S. J., Gunnarsdóttir, L., Svavarsson, J., & Gunnarsson, K. (2024). Range extension of invasive Cancer irroratus and native Carcinus maenas polewards in the Ascophyllum-dominated intertidal zone in north-west Iceland. Journal of the Marine Biological Association of the United Kingdom, 104, e3. https://doi.org/10.1017/S0025315423000905
Magnússon, J. T., Silva, A., Hawkins, S. J., Paula, J. P., Marques, T. A., & Boaventura, D. (2025). Spatial distribution of the intertidal limpet Patella depressa Pennant, 1777: Patterns across wave exposure and season. Journal of Experimental Marine Biology and Ecology, 582, 152073. https://doi.org/10.1016/j.jembe.2024.152073
Magnússon, J. T., Hawkins, S. J., Gunnarsdóttir, L., Svavarsson, J., & Gunnarsson, K. (2025). Icelandic intertidal fish communities and effects of knotted wrack (Ascophyllum nodosum) harvesting. Journal of the Marine Biological Association of the United Kingdom, 105, e75. https://doi.org/10.1017/S0025315425100301
