Phytoplankton provide the basis for the whole marine food chain. These microscopic organisms are common in coastal areas, all the way from the polar regions to the Equator, and multiply through cell division.
If cells are present in the water mass in large numbers an algal blood develops – a recurrent problem in Swedish seas and along Swedish coasts. Researchers at the Department of Marine Ecology of the University of Gothenburg have long been interested in the development and causes of algal blooms.
The doctoral student Karolina Härnström has focused in her thesis on diatoms, which are the largest single group of phytoplankton, and their occurrence in the eutrophicated Mariager Fjord in Jutland. The results show that different populations of a diatom species may have different growth and adaptability characteristics, and that the genetic variation of the algae may possibly be affected by eutrophication: the researchers found different types of populations during periods of heavy eutrophication in Mariager Fjord.
“We know surprisingly little about the ecology of diatoms, about where the cells that give rise to blooms come from and whether it is the same populations that recurrently bloom in a particular location or whether it differs between seasons. My research may contribute to answering these questions, and perhaps increase knowledge of how algal blooms are affected by environmental changes and how the population dynamics of these algae appears in a microevolutionary perspective,” says Härnström.
The thesis Bloom dynamics and population genetics of marine phytoplankton – Community, species and population aspects was publicly defended on 25 September.