A master’s research project is available to look at population genetics in the green and pale sea urchins, Strongylocentrotus droebachiensis and S. pallidus along the Norwegian coast and Svalbard. The master’s project may involve fieldwork to collect animals but will primarily be working with existing samples in the molecular lab.
Understanding marine population connectivity is critical for sustainable management of marine resources. The degree to which populations of marine organisms exchange migrants determines whether they function as one large metapopulation or many independent units and thus influences their response to potential disturbance from harvesting, habitat destruction or climate change. As such, knowledge of connectivity directly impacts management decisions and addresses the question of whether fisheries management and the design of marine protected areas should be tailored to variation in coastal geography and regional oceanographic conditions.
It is often assumed that marine species with long-lived planktonic larvae disperse great distances in ocean currents and will thus exhibit low levels of genetic differentiation. However, recent evidence shows that significant population-genetic subdivision may occur even in species with a long larval duration and that variability in ocean currents can influence the spatial genetic structure of marine populations.
In many marine fish, both adults and larvae contribute to migration among populations. Sea urchins have benthic adults with relatively little mobility, and population genetic structure will be determined by the interaction of regional oceanographic conditions and life-history traits. As such, the sea urchin system provides a proxy for dispersal of other commercially important organisms with pelagic larvae along the Norwegian coast and Svalbard. This study contributes knowledge of sea urchin population structure that is critical in managing natural populations of urchins and kelp forests and prerequisite for a sustainable commercial urchin fishery developing in Norway today.
We are presently working to determine the population genetic structure of the sea urchins Strongylocentrotus droebachiensis and Strongylocentrotus pallidus along the Norwegian coast and Svalbard, using a fragment of the cytochrome c oxidase I gene (COI) of the mitochondrion and microsatellite assays. This project will specifically examine if there is genetic differentiation of separate populations, or clinal variation within genetically continuous populations. If time allows, the project can be extended to include populations from Greenland, the eastern Pacific and western Atlantic oceans.
The student will work in a well-equipped modern molecular lab with ABI 3730 sequencing machines and numerous PCR machines, ensuring fast and effective genotyping. Molecular training will be provided but studentswith previous lab experience are desirable. This project is part of the larger "sea urchin project" described above and results are expected to lead to publishable data. The project will involve genotyping about 10 populations for several microsatellite loci and subsequent population-genetic analysis. Training in these methods will also be provided.
Fig. 1.Patterns of divergence in mitochondrial DNA and the nuclear gene for sperm bindin in S. droebachiensis. Pacific and Northwest Atlantic populations group together, while Arctic and Northeast Atlantic populations show greater similarity. We see a similar trend in bindin divergence in S. pallidus, but here mtDNA is monomorphic. From Marks et al. 2008.
Relevant publications
Marks, J.A., Biermann, C.H., Earnes, W.F. and H. Kryvi. 2008. Sperm polymorphism within the sea urchin strongylocentrotus droebachiensis: Divergence between Pacific and Atlantic oceans. Biol. Bull. 215: 115-125. pdf
Biermann, C. H. and J. A. Marks. 2000. Geographic divergence of gamete recognition systems in two species of the sea urchin genus Strongylocentrotus. Zygote 8 (S):86-87. pdf
Marks, J. A. and Aarset, B. 2004. Kr?keboller – fra pest til gullgruve? Norsk Fiskeoppdrett 29(4):32-34. pdf
Supervisors:
S?tre, Glenn-Peter(formal advisor), Jessica Marks, Claudia Junge (NIVA),; collaborator, G. Dahle(IMR)