Phylogenetic diversity of fungal communities in areas accessible and not accessible to tourists in Naracoorte Caves

Abstract

The fungal diversity in areas accessible and not accessible to tourists at UNESCO World Heritage-listed Naracoorte Caves was investigated with culture-dependent and culture-independent techniques for assistance in cave management protocol development. The caves were selected based on tourist numbers and configurations: Stick Tomato (open, high numbers), Alexandra (lockable openings, high numbers) and Strawhaven (control; no access). Culture-based survey revealed Ascomycota dominance irrespective of sampling area with Microascales (Trichurus sp.) being most frequently isolated. Some Hypocreales-like sequences belonging to Fusarium sp., Trichoderma sp. and Neonectria sp. (Stick Tomato) were cultured only from areas not accessible to tourists. These orders also were detected by DGGE assay irrespective of sampling area. The predominance of Ascomycota (especially Microascales) suggested their important ecological roles in these caves. Culture-independent analysis showed higher Shannon fungal diversity values (from ITS-based DGGE profiles) in tourist-accessible areas of these caves than in inaccessible areas with the fungal community banding patterns being substantially different in Stick Tomato Cave. Further investigations are needed to determine the cause of the differences in the fungal communities of Stick Tomato Cave, although cave-related factors such as use, configuration and sediment heterogeneity might have contributed to these differences.

Effect of organic matter enrichment on the fungal community in limestone cave sediments

“…Human visitation in caves has affected their intrinsic microbial communities (Chelius and Moore, 2004;Ikner et al, 2007;Adetutu et al, 2011;Saiz-Jimenez, 2012). Although the changes in the OTUs were detected along the course of the experiment (Figures 1-3), only one of many contaminant factors was analyzed.…”

“…Controlling these factors allows for evaluation of the effect of organic matter on the fungal communities in cave sediments. Beef and yeast extracts were chosen for their chemical similarity to components carried by visitors into caves, dead skin cells and other microorganisms; however, other nutrients, such as the ones present in lint, hair, and oils, could not be included (Adetutu et al, 2011) because of the difficulty in simulating and controlling the amount of contamination in the lab.…”

“…Studies that are dependent on, and independent of, fungal cultures, show that these variations could be expected in the controls (Adetutu et al, 2011;Taylor et al, 2013). Cave fungi are commonly described as opportunistic organisms that increase their population based solely on the inflow of organic matter (Nieves-Rivera et al, 2009;Jurado et al, 2010b;Saiz-Jimenez, 2012).…”

“…Uncontrolled and widespread fungal growth is responsible for the temporary closure of several tourist caves, necessitating biocide treatment to eliminate the targeted fungi as well as several native microorganisms of these caves (Bastian et al, 2009(Bastian et al, , 2010Jurado et al, 2010b;Martin-Sanchez et al, 2012b). These measures are taken to avoid risk to human health; however, not enough information is available regarding the effect of tourism on cave microorganisms, as a majority of the studies compare the microbial bloom in the tourist and non-tourist parts of the cave or among caves in the same area (Chelius and Moore, 2004;Adetutu et al, 2011). Therefore, the data could be misinterpreted because of the natural variations in the cave or among different caves.…”

Polyphasic insights into the microbiomes of the Takamatsuzuka Tumulus and Kitora Tumulus

“…In addition to the Lascaux and the Altamira Caves, recent reports describe microbiological problems and conservation efforts in the Mogao Grottoes with ancient wall paintings in Dunhuang, China (Ma et al, 2015), a Pleistocene cave with rock art (at least 39,900 years old) in Sulawesi, Indonesia (Aubert et al, 2014;Roebroeks, 2014), Naracoorte Caves in southeastern South Australia (Adetutu et al, 2011), and the Cave of Bats with rock art in Zuheros, Spain (Urzi et al, 2010). Microbial diversity and biodeterioration problems in mural (wall) painting environments have also been mentioned and discussed (e.g., Caneva et al, 2008;Saiz-Jiménez, 2003;Vanderwolf et al, 2013).…”