Uncovering the origin of the black stains in Lascaux Cave in France

Abstract

Lascaux Cave in France was discovered in 1940. Since being opened to visitors the cave has suffered three major microbial outbreaks. The current problem is the fast dissemination of black stains which are threatening the Palaeolithic paintings. Previous data pointed to the involvement of new fungal species in the formation of black stains on the rock walls and ceiling. However, it appears that there could be other reasons for the formation of different and extensive black stains coating the surface of the clayey sediments. Our analyses reveal that black stains on clayey sediments are mainly produced by Acremonium nepalense, a manganese oxide-depositing fungus, widely distributed in the cave. Thus, in Lascaux Cave, the black stains have a dual origin: on limestone rocks they are mainly produced by the accumulation of fungal melanins, and on clayey sediments by the biogenic deposition of black manganese oxides.

Nutrient input influences fungal community composition and size and can stimulate manganese (II) oxidation in caves

“…The remaining four strains are approximately 98–99% identical to other cultured strains (across > 487 bp regions of the ITS). Two of these share high identity to cultured Mn(II)‐oxidizing strains from an acid mine drainage site (Santelli et al ., ), and two are nearly identical to Acremonium napalense strains from Lascaux Cave (Martin‐Sanchez et al ., ), the Mn(II)‐oxidizing fungus later found in black coatings on cave sediment surfaces (Saiz‐Jimenez et al ., ). Notably, more than half (five out of the nine) cultured strains are at least 97% identical to sequences retrieved from molecular analyses, indicating that these organisms are environmentally relevant; however, all of these organisms were found in low abundance, highlighting the limitations of current culturing techniques.…”

Complex bacterial diversity in the white biofilms of the Catacombs of St. Callixtus in Rome evidenced by different investigation strategies

“…Different kinds of biofilms from cave and catacombs surfaces have been studied by various authors (Sanchez-Moral et al, 2005;Portillo et al, 2008;Urzì et al, 2010;Cuezva et al, 2012;De Leo et al, 2012;Saiz-Jimenez et al, 2012). The approach used by different authors in these previous investigations to study the bacterial community of white biofilms was generally culture-independent, DNA-and RNA-based .…”

Anthropization level of Lascaux Cave microbiome shown by regional‐scale comparisons of pristine and anthropized caves

“…Against this background, it can be anticipated that the particular anthropization of Lascaux Cave should lead to even more drastic modifications in the ecology of cave organisms. Preliminary assessments of Lascaux microorganisms have been carried out using culture-based and cloning/sequencing approaches (Bastian, Alabouvette, Jurado, et al, 2009;Dupont et al, 2007;Martin-Sanchez, Nováková, Bastian, Alabouvette, & Saiz-Jimenez, 2012;Saiz-Jimenez, Miller, Martin-Sanchez, & Hernandez-Marine, 2012), but without targeting the entire microbial community (the scale of cloning/sequencing being a limit), the arthropod phylum, (Ager et al, 2010). This is compatible with fragmented data available from cave ecosystems, e.g., for culturable bacteria (Ikner et al, 2007) and fungi (Adetutu et al, 2011;Shapiro & Pringle, 2010), but not with DGGE findings on fungi (Adetutu et al, 2011) or the analysis of bleach treatment of cave walls (Pfendler et al, 2018).…”