Revived microalgae from the past - population changes through time
Nina Lundholm
The Natural History Museum of Denmark, University of Copenhagen
Marine anoxic sediments often have very well preserved and undisturbed sediment records with yearly layered sediments. The well-preserved assemblages in these sediments offer a unique opportunity to study long-term viability, and for species which remain viable many decades in the sediment it offers the possibility to study genetic variation over time, and potentially linking this to environmental change. This talk will present an overview of studies on cultures of microalgae established from individually isolated cysts from dated sediment cores obtained in Koljö Fjord on the west coast of Sweden. The cultures have been used to test for variability through time in morphology, gene sequences and physiology. Six polymorphic microsatellite loci have been developed for analyzing the population structure. Results from genotyping of strains revived from three discrete sediment layers spanning the past 100 years will be presented, revealing if there have been shifts in the population structure in the area. The genetic results will be compared to ecophysiological characters of selected strains from three different layers. Furthermore, the genetic variation will be linked to changes in environmental variables.
