Microbes from Floor and Wall Layers at a Viking Age and Medieval Farm in Iceland Reveal Living Conditions, Human Respiratory Diseases and the Presence of Domestic Animals

DNA shed by living organisms can persist in the soil for thousands of years and provide valuable insights into past environments and human activities. The aim of this study is to add to our knowledge of people’s lives, health and living conditions and husbandry inside a turf house at the farm Skálanes, East Iceland, from the tenth to fifteenth centuries AD. The examination is performed through analysis of bacterial gene sequences of 16S ribosomal RNA in environmental DNA samples from soil, eDNA was extracted and sequenced to identify archaeologically relevant bacterial DNA sequences such as human- and livestock-related bacteria. Key results include the presence of Ruminiclostridium sufflavum and Aphodomorpha intestinavium, which reveal evidence of domestic animals. Two bacterial species found in the samples are related to humans: Romboutsia hominis, a potentially gut-protective bacterium, and the bacterium Simkania negevensis, that may indicate human respiratory infections. The outcomes of the study contribute to both Icelandic and international archaeology by revealing microbial traces and information that cannot be observed when applying traditional excavation techniques.