Cast from the Past? Microbial Diversity of a Neolithic Stone Circle

Area of Science:

• Environmental Microbiology
• Archaeological Science
• Geomicrobiology

Background:

• Limestone rock pools host unique microbial ecosystems.
• Neolithic monuments like Arbor Low offer novel environments for studying microbial colonization.
• Understanding microbial impacts on stone heritage is crucial for conservation.

Purpose of the Study:

• To characterize the microbial diversity in rock pools at Arbor Low, a Neolithic monument.
• To investigate differences in microbial communities between rock pool walls and sediments.
• To assess the influence of spatial location on microbiome composition.

Main Methods:

• Molecular metabarcoding was employed to analyze bacterial, archaeal, and eukaryotic diversity.
• Samples were collected from rock pool walls and sediments across five distinct pools.
• Community structure was analyzed in relation to habitat characteristics and spatial separation.

Main Results:

• The microbiome comprised bacteria (23 phyla), archaea (4 phyla), and microbial eukarya (27 phyla).
• Significant differences were observed in bacterial populations between walls and sediments, and in archaea and eukarya between pools.
• A distant pool exhibited a markedly different community structure, indicating habitat discrimination and dispersal limitations.

Conclusions:

• Microbial assemblages in Arbor Low rock pools are structured by species sorting and dispersal limitation.
• The presence of Cyanobacteriota and Chlorophyta raises concerns regarding potential limestone degradation.
• Further research into microbial metabolic traits is needed to understand bioweathering and biomineralization processes.