Microbial ecology of tourist Paleolithic caves

Into the Unknown: Microbial Communities in Caves, Their Role, and Potential Use

“…Mainly, but not exclusively for shelter and storage, but also as places for artistic expression, burial, or ceremonial sites [1,2]. Today, caves are mainly objects of tourist activity, with people visiting show caves to admire Paleolithic paintings or interesting rock formations [3,4]. Furthermore, some caves are explored by adventurers during caving [5].…”

Comparison of Actinobacteria communities from human‐impacted and pristine karst caves

“…In addition, caves are considered to be extreme environments, as they are oligotrophic, due to the complete darkness, low and constant temperatures, and high humidity (Barton & Jurado, 2007 ; De Mandal et al, 2017 ; Ortiz et al, 2014 ). Some of these caves contain Paleolithic artwork and, consequently, have been frequently visited by tourists for a long time (Alonso et al, 2019 ; Bontemps et al, 2021 ; Schabereiter‐Gurtner et al, 2002 ). Thus, human‐mediated dispersion of endogenous as well as exogenous nutrients and microorganisms inside the caves, together with human metabolism may induce changes in internal microclimatic and microbiological conditions (Hoyos et al, 1998 ; Mulec, 2014 ).…”

“…Microorganisms can be somewhat resilient to changes (Johnston et al, 2012 ; Tomczyk‐Żak & Zielenkiewicz, 2016 ). However, community shifts may also occur, which deserves attention if those shifts favor microorganisms with biodeterioration ability (F. Bastian et al, 2010 ; Bontemps et al, 2021 ; Fernandez‐Cortes et al, 2011 ; Sánchez‐Moral et al, 1999 ) or increase the proportion of species harboring strains with pathogenic potential (Bercea et al, 2019 ; Neral et al, 2015 ; Rajput et al, 2012 ). In such cases, these shifts could represent a threat to cave conservation and the health of visitors.…”

“…Since the 1960s, the Lascaux Cave has undergone several microbial outgrowth events until recently and has been subjected to (often unsuccessful) chemical treatments, which have resulted in the formation of various visual marks (including stains on walls) that have threatened the Paleolithic artwork (F. Bastian et al, 2010 ; Bontemps et al, 2021 ; Martin‐Sanchez et al, 2015 ). Lascaux was closed to the public in 1963 to ensure cave conservation; despite this, microbial imbalance persisted and surface alterations kept forming, leading to visual marks on wall surfaces (Bontemps et al, 2021 ).…”

“…Since the 1960s, the Lascaux Cave has undergone several microbial outgrowth events until recently and has been subjected to (often unsuccessful) chemical treatments, which have resulted in the formation of various visual marks (including stains on walls) that have threatened the Paleolithic artwork (F. Bastian et al, 2010 ; Bontemps et al, 2021 ; Martin‐Sanchez et al, 2015 ). Lascaux was closed to the public in 1963 to ensure cave conservation; despite this, microbial imbalance persisted and surface alterations kept forming, leading to visual marks on wall surfaces (Bontemps et al, 2021 ). Although the few microbiological studies conducted in this cave have suggested that Actinobacteria is a prevalent bacterial group (Alonso et al, 2018 , 2019 ; Martin‐Sanchez et al, 2012 ), a more complete investigation of the Actinobacteria community is lacking, especially at the species level.…”