Abstract
We will study genetic changes of diatoms in eutrophicated environments over time. From two fjords, with well-documented hydrographic history, we will collect sediment cores and establish S. marinoi populations spanning the age from 0-120 years old. We have recently sequenced the genome and we will use this as a back-bone for our analyses. We will resequence random individuals from recent, 20, 40 and 120 year old sediments. From the resequenced genomes possible candidate genes with a high degree of polymorphism between the old and the young strains will be identified. The populations will be phenotyped, and individual fitness in response to pre-industrial and ambient nutrient conditions will be determined. The candidate genes will be sequenced from all the old and young individuals. With this approach we will likely find variation in specific genes that are correlated with phenotypic trait values, and in this way infer links between genotype and phenotype. The link will be experimentally verified by RNAi based technology. Recent populations exposed to different degree of eutrophication will be analysed to confirm the correlation between genetic divergence in specific loci and divergence in stress. This research is important for increasing the scope of ecological risk assessment to include the effects of evolutionary response, for defining a genetic baseline for eutrophication, and for identifying markers which can be used to detect diffuse signals of eutrophication.
Sweden