Trial lecture
The candidate will first give a trial lecture on the following topic: 'The ecology and evolution of parasitism'.
Main research findings
Pelagic copepods are possibly the most abundant group of animals on the planet, and are central in marine food webs. Copepods host numerous parasites with detrimental effects. However, these parasites have mostly been ignored since their discovery more than 100 years ago. In my thesis I have combined field sampling, experiments and modeling to investigate the occurrence of copepod parasites and their effects on individuals, populations and communities.
An initial modeling study showed that the population impact of copepod parasites may be large, and pinpointed important parasite traits for infection dynamics. Combining estimates based on the literature with new experiments we found that the release of parasite spores scales with host size, and that larger copepods experience higher infection pressure. We quantified mortality increase and behavioral change induced by the elusive Yellow-Hyphal Parasite, and found that infection was associated with an altered bacterial microbiome. Using a combination of molecular methods and biomass data, we found widespread parasitism year-round in the Oslofjord. Parasite prevalence reached a seasonal peak of 100%, and was often over 50%.
This thesis shows that the parasites of copepods are widespread and prevalent, and may play a larger role in plankton ecology than previously believed.
Adjudication committee
- Senior Lecturer Erik Selander, Department of Biology, University of Lund, Sweden
- Professor Fabrice Not, CNRS & Sorbonne University Station Biologique de Roscoff, France
- Associate Professor Adriana Lopes dos Santos, Department of Biosciences, University of Oslo, Norway
Chair of the defense
- Professor emeritus Stein Kaartvedt, Department of Biosciences, University of Oslo, Norway
Supervisors
- Professor Josefin Titelman, Department of Biosciences, University of Oslo, Norway
- Professor emeritus Tom Andersen, Department of Biosciences, University of Oslo, Norway
- Professor Lasse Riemann, Department of Biology, University of Copenhagen, Denmark