Thermophilic microorganisms in arable land around medieval archaeological sites in Northern Caucasus, Russia: Novel evidence of past manuring practices

Abstract

Thermophilic microorganisms in the soils of medieval cultivated fields located within the Kislovodsk Basin (Northern Caucasus, Russia) were selected as a means for the reconstruction of manuring practices. Thermophilic bacteria are specific groups of microorganisms that develop in manure during the composting process when temperatures reach 60-70°C. The abundance of this type of bacteria in soils depends greatly on the intensity of farming practices. In medieval cultivated soils (Alanic Culture, A.D. 500-800), high numbers of thermophilic bacteria were observed, indicating the long-term use of manure. In arable lands near Alanic settlements, the abundance of thermophilic bacteria decreased significantly with distance from the sites. The highest abundance of thermophilic bacteria was observed in the 500 m zone adjacent to the sites. Moreover, the highest concentration of thermophilic microorganisms was found in the soil within an Alanic corral. We suggest that dung accumulated in the paddock for a long time. Abundance of thermophilic microorganisms at archaeological sites could be used as a new indicator of the application of decomposed manure to ancient and medieval arable soils. K E Y W O R D Sancient manuring, anthropogenic soils, Northern Caucasus, thermophilic microorganisms Geoarchaeology. 2017;32:494-501.

Microbial community types and signature-like soil bacterial patterns from fortified prehistoric hills of Thuringia (Germany)

“…The investigation of archaeological material by r-RNA profiling showed significant differences between the bacterial communities of excavated objects and the surrounding soil on lower taxonomical levels, but larger similarities on the phylum level (Kazarina et al 2019). The determination of abundances of extremophiles could support specific insights into the interpretation of archaeological findings, for example by the enhanced presence of thermophilic bacteria (Chernysheva et al 2017).…”

Extremophiles in Soil Communities of Former Copper Mining Sites of the East Harz Region (Germany) Reflected by Re-Analyzed 16S rRNA Data

“…The sample material (No. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] is not any kind of typical natural soil, but surface material from the mine dumps, was brought from the ground to the surface during the site-related mining phases. The soil material was taken during dry weather periods.…”

“…19 has a special position between the soil samples of the ancient mining areas (No. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] and the comparative samples (20)(21)(22)(23)(24)(25). In contrast to the ancient shaft hole places and small mine dumps, the base area of the industrial mine dump has no vegetation and nearly no humus formation.…”

“…Traces of early human activities, which changed the structure and character of soils, can be stored over a long time and are reflected in the local compositions of the soil bacterial communities. This "ecological memory of soil" was observed, for example, on prehistorical settlements, working and burial places [10][11][12][13]. The understanding of "man-made environments", mining-related acidic soils among them, for example, remains an urgent challenge for investigations of soil microbial communities up to now [14].…”

Magnetic surveys locate Late Bronze Age corrals

“…However, the com posting o f animal dung o r plant residues causes heating; as a result, therm ophilic microorganisms develop and these can remain in the soil fo r an indefinitely long time. A large number o f therm ophilic microorganisms can be an indicator o f the accumulation and composting o f animal dung a t archaeological sites(Chernysheva, Korobov, & Borisov, 2017).…”