Microbial and geo-archaeological records reveal the growth rate, origin and composition of desert rock surface communities

0543793 - BC 2022 RIV DE eng J - Journal Article
Wieler, N. - Erickson Gini, T. - Gillor, O. - Angel, Roey
Microbial and geo-archaeological records reveal the growth rate, origin and composition of desert rock surface communities.
Biogeosciences. Roč. 18, č. 11 (2021), s. 3331-3342. ISSN 1726-4170. E-ISSN 1726-4189
R&D Projects: GA MŠMT(CZ) LM2015075; GA MŠMT(CZ) EF16_013/0001782
Institutional support: RVO:60077344
Keywords : biological soil crusts * Negev desert * hot * cyanobacterial * colonization * carbonates * signature * sequences * search * Israel
OECD category: Microbiology
Impact factor: 5.092, year: 2021
Method of publishing: Open access
https://bg.copernicus.org/articles/18/3331/2021/bg-18-3331-2021.pdf

Biological rock crusts (BRCs) are ubiquitous features of rock surfaces in drylands composed of slow-growing microbial assemblages. BRC presence is often correlated with rock weathering, soiling effect or mitigating geomorphic processes. However, their development rate is still unknown. In this work, we characterised and dated BRCs in an arid environment, under natural conditions, by integrating archaeological, microbiological and geological methods. To this end, we sampled rocks from a well-documented Byzantine archaeological site and the surrounding area located in the central Negev, Israel. The archaeological site, which is dated to the fourth to seventh centuries CE, was constructed from two lithologies, limestone and chalk. BRC started developing on the rocks after being carved, and its age should match that of the site. Using stable carbon and oxygen isotope ratios, we confirmed the biogenic nature of the crusts. The BRC samples showed mild differences in the microbial community assemblages between the site and its surroundings, irrespective of lithology, confirming the dominance of aeolian inoculation sources. All BRCs were dominated by Actinobacteria, Cyanobacteria and Proteobacteria. We further measured the BRC thickness on 1700-year-old building stone blocks and determined it to be 0.1-0.6 mm thick. Therefore, a BRC growth rate was estimated, for the first time, to be 0.06-0.35 mm kyr(-1). Our dating method was then validated on a similar archaeological site located ca. 20 km away, giving comparable values. We propose that BRC growth rates could be used as an affordable yet robust dating tool in archaeological sites in arid environments.
Permanent Link: http://hdl.handle.net/11104/0324743