Bacterial community structure at different depths in soil sampled from sulfidic rich coastal areas of northern Finland, Sweden and Norway. Bacterial communities associated with acid sulfate soils in northern Fennoscandia

Acid sulfate soils occur naturally in coastal and inland areas where sufficient organic matter, iron and sulfate is, or has previously been, present. In these conditions reduced iron sulfides such as pyrite (FeS2) and iron monosulfide (FeS) are formed. Oxidation of the sulfides by sulfur and iron oxidating bacteria results in sharp acidification and release of metals to the environment. Acid sulfate soils for instance in Finland and Sweden are leaching huge amounts of acidity and metals into watercourses, often resulting in massive fish kills and deterioration of concrete and steel constructions. In this project the microbial communities and mechanisms leading to sulfide oxidation were studied. Soil was sampled from different depths of the reduced and oxidized layers of sulfide rich soils from Finland, Sweden and Norway and bacterial 16S rRNA gene amplicons sequenced. Drivers of bacterial community structure were analysed by comparing the bacterial and soil geochemical data and linkages between taxonomy and geobiochemical activities were identified.