Population structure in the red calcifying alga Corallina officinalis in the North Atlantic: implications in a time of global climate change

In 2018 Henry Glynn conducted a masters research project using SNP markers to analyse population genetic patterns of Corallina officinalis in the Northeast Atlantic. This is a follow-up to a previous project.


The intertidal zone consists of a variety of habitats providing shelter and resource for a wide array of wildlife including commercial species. Red coralline algae are an important component of these habitats as ecosystem engineers, primary producers and links in the carbon and carbonate cycles. Global climate change leading to increased sea surface temperatures and oceanic acidification threatens the survival of coralline algae through complex interactions affecting the production of their calcite skeletons. Much research has been undertaken investigating the effects of this on small scales, but very little is known about the potential impacts on population or species scales. On these scales genetic differentiation, connectivity between populations, and available genetic diversity enabling adaptation needs to be considered. For the first time, this paper uses population genetic analyses on single nucleotide polymorphisms identified in the red calcifying alga Corallina officinalis across the North Atlantic to determine how these factors may influence this species under a changing climate. C. officinalis showed significant population structuring over fine and large scales and demonstrated strong isolation by distance. Discriminant analysis of principal components identified 7 genetic clusters which broadly corresponded to geographical regions and highlighted that Icelandic and Spanish populations were the most isolated. However gene flow was observed between most populations. The highest levels of diversity were observed around the British Isles particularly around the Irish Sea. This indicates that the British Isles may be a goldilocks zone: a hotspot for adaptation to climate change, and highlights the importance of protecting the intertidal zone to facilitate the spread of adaptive genes across the wider population.


Glynn H (2018) Population structure in the red calcifying alga Corallina officinalis in the North Atlantic: implications in a time of global climate change. Thesis project for the MRes in Biodiversity , Evolution and Conservation at University College London. Supervised by Prof Juliet Brodie & Dr Chris Yesson with the assistance of Steve Russell (PDF)


Genetic cluster assignment for populations of Corallina officinalis.


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