Title of thesis:

Calanus in the North Atlantic: species identification, stress response, and population genetic structure.

Title of trial lecture:

"Ecological and evolutionary consequences of dispersal"

Time for trial lecture:  Oct 16, 10:15-11:15
Time for dissertation: Oct 16, 12:15-15:30
 
Main supervisor: Galice Hoarau

Members of the comittee:
- Research Fellow Katja Peijnenburg, Institute for Biodiversity and Ecosystem Dynamics, University  
of Amsterdam, Netherlands
- Researcher Ricardo Pereyra, Centre for Marine Evolutionary Biology, University of Gothenburg, 
Sweden
- Professor Ketil Eiane, Faculty of Biosciences and Aquaculture, University of Nordland, Bodø, 

PhD trial lecture and defence are open for the public. The thesis is available, contact Jeanett Kreutzmann, jeanett.kreutzmann@uin.no, tel +47 75 51 74 49.  

About the thesis:

"It is hard to imagine that such minute animals could be of such importance in the economy of a country", said Norwegian naturalist A. Boeck already in 1871 about Calanus finmarchicus, a tiny crustacean (ca. 3 mm) drifting in the ocean. Indeed Calanus species are likely the most numerous animals in the world and are central in marine food webs. Calanus eat phytoplankton and are at the same time an important food source for many marine organisms, including herring, sardine, cod and salmon. Since the 1950s, due to increase of sea temperature in the North Atlantic, Calanus species have moved northwards, affecting the abundance of several species of fish, and, potentially leading to ecosystem changes.

            In her thesis, Irina Smolina has used state-of-the-art genomics methods to study Calanus. So-called Next Generation Sequencing technologies allow us to sequence large amount of DNA and RNA quickly and cheaply. Partial sequencing of the genome of Calanus was used to design new tools to reliably identify species.

Calanus species look very similar but differ in their amount of energy-rich lipids and, thus, support different food webs. Species identification is crucial and needed to predict how species responds to climate change. Furthermore, looking at the genes responding to temperature stress revealed striking differences between the boreal C. finmarchicus and the Arctic C. glacialis that seems to lack the molecular mechanisms to deal with elevated temperature. This, combined with other information, suggests that the Arctic C. glacialis is likely vulnerable to climate change.