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MSc defence: Sofie S. Mathiesen

Sofie S. Mathiesen defends her Masters thesis "Genetic diversity and connectivity within Mytilus spp. in the subarctic and Arctic"

2015.10.21 | Susanna Pakkasmaa

Date Mon 26 Oct
Time 12:00 16:00
Location Arctic Research Centre, Aarhus University, C. F. Møllers allé 8, bldg. 1110, auditorium 223

Arctic mussels. Photo Mikael Kristian Sejr

The abstract of Sofie's MSc thesis:

Future climatic changes are predicted to be more severe in the Arctic than anywhere else on Earth. To best predict arctic marine species responses to these changes, baseline studies of species diversity and population structure are needed. Mytilus mussels are widely distributed in subarctic and arctic regions. However, our understanding of their genetic diversity and connectivity in these regions remain incomplete. Mytilus mussels are habitat-forming species, and have a high commercial value. Furthermore, they are considered sensitive climate change indicators, as they have been proven to respond to climatic changes and were found to have recolonized Svalbard after being absent for a thousand years. However, their genetic diversity and connectivity needs to be elucidated to be able to infer distribution barriers and to predict impacts of climate change.

To determine the distribution of three species within the Mytilus edulis complex (M. edulis, M. trossulus and M. galloprovincialis) in subarctic and arctic regions, I analysed 81 single nucleotide polymorphisms (SNPs) in 509 individuals sampled throughout subarctic and arctic regions ranging from Baffin Bay in Canada to the Pechora Sea in Russia. For the first time, I can report the presence of M. trossulus in Northwest Greenland  (77°N). In Southwest Greenland, I found M. edulis (64°N) and in Midwest Greenland (72°N), I found the two species to coexist and hybridise. Also for the first time, M. galloprovincialis and/or M. galloprovincialis/M. edulis hybrids were found in Southwest Greenland, Svalbard and the Pechora Sea. When focusing on M. edulis populations, I found a clear split of populations on each side of the Atlantic, and found this species to be the most abundant in Svalbard (78°N to 80°N) with individuals resembling populations along the Norwegian and the Russian coast. Overall, this study reveals a high diversity of Mytilus mussels across subarctic and arctic regions. It further highlights the necessity of genetic tools when studying the ecology and physiology of Mytilus populations in these regions, especially in the light of future climate change

Tags: MSc thesis, Mytilus spp., genetic diversity and connectivity