# Geomicrobiology: Latest Advances and Prospects
## 2 An Overview of Published Articles  
This Special Issue compiles five cutting-edge research articles and reviews addressing diverse aspects of geomicrobiology, such as the application of DNA sequencing technologiesto caves [21], the search of microbial biosignatures in lava tubes [22], the distribution of the bacterial genus _Euzebya_ in terrestrial environments [23], the potential damage versus protection of lichens in a Cappadocian church [24], and the growth of bacteria in Saharan dust intrusions [25]. [PERSON], in a memoir about his activities [6], included the subsection \"Some broader implications of the foregoing geomicrobiological investigations\". There he refers to the microbial attack of ancient cave art and particularly cited a few papers on the damages to Altamira Cave rock art. Altamira in Spain and Lascaux in France, are perhaps two of the most investigated caves in the world due to the importance of their Paleolithic paintings and the geomicrobiological processes that have led to their deterioration. Some of these processes were originated by new species of bacteria and fungi isolated and described from such caves [26; 27; 28]. Lascaux Cave was discovered in 1940, and its notoriety lies in the set of 915 figures and numerous geometric symbols from the Solutrean period (17,000 years old). The cave was open to the public in 1948 and aroused great interest among the press and public, with 30,000 visitors per year recorded in 1955, and 100,000 in 1960. The high number of visitors, artificial lighting, and drastic changes in environmental conditions led the cave to suffer several microbial crises caused by the colonization of bacteria and algae and the appearance of green stains that reached a critical level in 1962, leading to its closure. In 2001, another microbial crisis occurred with the appearance of white mycelia caused by the fungus _Fusarium solanti_, and later, black stains on the painted walls due to the colonization by a new fungus, _Ochroconis lascauxensis_[28]. In 2015, a comprehensive history was published on the problems that occurred at Lascaux after its discovery, and the geomicrobiological research carried out from 2009 till 2015. These studies shed light on the microbial ecology of the cave and the origin of the microbial crises [29]. The other two papers were published in 2016 and 2017 [30; 31]. Since 2018 and up to the present, Prof. [PERSON]'s team has been publishing a series of articles on the geomicrobiology of Lascaux [32; 33; 34; 35; 36; 37; 38; 39; 40; 41]. [PERSON] et al. [21] reviewed the application of next-generation DNA sequencing in the study of cave microbiomes, and particularly in Lascaux Cave. The use of metabarcoding and metagenomics provided an exhaustive description of cave microbial diversity in different halls and galleries, or substrata (water, sediments, bedrock, etc.) within a cave, or the effect of cave disturbance in Lascaux and elsewhere. This knowledge is of great importance to understand the global functioning of caves and to provide fundamental information to design cave conservation strategies. Lava caves or lava tubes are distributed worldwide. These types of caves follow in number and importance to karstic caves and harbor an extremely high biodiversity and variety of secondary mineral and microbial deposits where microbial-mineral interactions can be studied [42; 43]. Many lava tubes have been detected on the surface of Mars which suggested that lava caves may be biotopes of potential interest for the search of extraterrestrial life [44; 45; 46]. [PERSON] et al. [22] studied the microbial communities present in a wide range of speleothems from two geographically distant lava caves from Hawai'i and New Mexico and found large differences in their microbial communities. _Actinobacteriota_ were abundant in New Mexico caves, while Hawaiian caves contained more unclassified bacteria at the genus and species level.