Authors Name: 
Matti Ruuskanen
University of Helsinki
Life Sciences
Highly commended

The genus Beggiatoa and its effects on the nutrient cycles of the Baltic Sea

Beggiatoa is a bacterial genus with worldwide distribution in both marine and fresh water sediments. It has various ecologically important metabolic pathways that have a profound impact on its environment. Because new bacterial species were originally included in the genus Beggiatoa based on their morphology, the existing taxonomical classification does not support the currently known phylogeny of the genus. Beggiatoa is also widespread in the Baltic Sea, which suffers from eutrophication and which incidentally offers ideal habitats for Beggiatoa on vast areas of sea bottom. Beggiatoa seems to have a wide occurrence in the Baltic Sea and its metabolic pathways are known to have an effect on the cycling of carbon, nitrogen, phosphorus and sulfur. However, according to our best knowledge its potential distribution and impact on the nutrient cycles in the Baltic Sea has been previously overlooked. The subject of the Bachelor's thesis arose from these issues. On the basis of this literary review, it can be concluded that Beggiatoa probably has a widespread occurrence in the Baltic Sea on both the Baltic Proper and many coastal areas with low oxygen content. Because of its metabolic capabilities Beggiatoa has an impact on the environment at least on a local scale and prehaps for the whole Baltic Sea. In its environment, Beggiatoa channels the energy of detritus on the sea bottom to higher trophic levels, increases the cycling of nitrogen back to primary producers and detoxifies the sulfide originating from the sediment. Beggiatoa's effects on phosphorus cycling are more unclear. Beggiatoa would need more study both in the laboratory and in the field to elucidate its impact on the Baltic Sea and in other environments. The genus is also clearly in need of a taxonomical revision on the basis of 16S rRNA sequences.