Abstract
A large number of Nordic lakes have during the last decades become invaded and dominated by the noxious microalgal species Gonyostomum semen. This phytoplankton species forms intense blooms and expels slimy threads that cause skin irritation to bathers as well as clogging of filters, thereby reducing the recreational value of lakes and water quality. Despite being classified as a nuisance alga, almost no research effort has to date been focused on this species, or invasion by phytoplankton in general. The aim of this project is two-fold: (1) To investigate the pattern of Gonyostomum invasion, and thereby determine if it has been spreading or simply become more abundant. (2) To experimentally test a hypothesis that could explain its dominance. The first part involves analyzing the invasion pattern of Gonyostomum using DNA fingerprinting techniques. A large number of single-cell cultures will be established from different lakes in Sweden, Finland, Norway, and the U.K. Intra- and interpopulation genetic differences can thus be determined, and patterns discerned. In the second part, I will test the hypothesis that Gonyostomum is largely unaffected by grazing, which could explain its dominance and success in invading new waters. The results will hopefully shed some light on the processes and pathway of Gonyostomum dominance dynamics and spreading, and eventually on the potential causes (such as climate change) and the species’ effect on biodiversity in aquatic communities.
Sweden