Archaeal and Extremophilic Bacteria from Different Archaeological Excavation Sites

Abstract

Beside natural factors, human activities are important for the development of microbiomes. Thus, local soil bacterial communities are affected by recent activities such as agriculture, mining and industry. In addition, ancient human impacts dating back centuries or millennia have changed soils and can emboss the recent bacterial communities up to now, representing a certain long-term “memory of soil”. Soil samples from five different archaeological excavation places were investigated for the presence of Archaea with a Next Generation Sequencing (NGS) analysis of the DNA coding for 16S r-RNA sequences. It was found that the abundance of Archaea differs strongly between less than one and more than 40 percent of bacteria. A Principal Component Analysis (PCA) of all samples shows that the archaeological excavation places can be distinguished from each other by the archaeal component of soil bacterial communities, which presents a typical pattern for each place. Most samples are marked by the dominance of Crenarchaeota, which are presented mainly by ammonia-related types. High contents of Nanoarchaeaota have been observed in one ash deposit of a historical saline and all samples of a historical tannery area. These samples are also marked by a significant presence of Dadabacteria. The specific abundancies of special Archaea—among them ammonia-oxidizing and sulphur-related types—are due obviously to former human activities and support the concept of the “ecological memory of soil”.

Beta-Diversity Enhancement by Archaeological Structures: Bacterial Communities of an Historical Tannery Area of the City of Jena (Germany) Reflect the Ancient Human Impact

“…The observed differences in bacterial communities from the different sampling sites and, in particular, the differences between inside-vat and outside-vat samples, confirm the hypothesis that former human activities affect strongly the local bacterial composition in soils [4,6]. It supports the concept that the local bacteria communities represent a kind of local ecological memory which is related to the former use of place [5,63].…”

“…The outside-vat samples HB34, HB36 and HB40 show a considerable abundance of Archaea above 10% of OTUs, in total [63]. In general, the Archaea abundance of vat-internal samples is lower than that of the outside samples.…”