Prokaryotic and Eukaryotic Airborne Microorganisms as Tracers of Microclimatic Changes in the Underground (Postojna Cave, Slovenia)

Abstract

Bioaerosols in cave air can serve as natural tracers and, together with physical parameters, give a detailed view of conditions in the cave atmosphere and responses to climatic changes. Airborne microbes in the Postojna Cave system indicated very dynamic atmospheric conditions, especially in the transitory seasonal periods between winter and summer. Physical parameters of cave atmosphere explained the highest variance in structure of microbial community in the winter and in the summer. The airborne microbial community is composed of different microbial groups with generally low abundances. At sites with elevated organic input, occasional high concentrations of bacteria and fungi can be expected of up to 1,000 colony-forming units/m(3) per individual group. The most abundant group of airborne amoebozoans were the mycetozoans. Along with movements of air masses, airborne algae also travel deep underground. In a cave passage with elevated radon concentration (up to 60 kBq/m(3)) airborne biota were less abundant; however, the concentration of DNA in the air was comparable to that in other parts of the cave. Due to seasonal natural air inflow, high concentrations of biological and inanimate particles are introduced underground. Sedimentation of airborne allochthonous material might represent an important and continuous source of organic material for cave fauna.

Lack of cave-associated mammals influences the fungal assemblages of insular solution caves in eastern Canada

“…Sampling was conducted deeper within the cave at Grotteà la Patate than at the other two sites, and this may explain the comparatively low fungal diversity. Other studies have found that fungal diversity decreases with increasing distance from cave entrances (Kuzmina et al, 2012;Mulec et al, 2012). Most of the fungal taxa documented during this study have previously been found in caves in other regions (Vanderwolf et al, 2013a).…”

Aerosolized Microbes from Organic Rich Materials: Case Study of Bat Guano from Caves in Romania

“…There are different types of bioaerosol formation caused by wind, animals and humans, or splashing water (Mulec et al, 2012c). It occurs in natural and manmade environments.…”

Reasons for large fluctuation of radon and CO<sub>2</sub> levels in a dead-end passage of a karst cave (Postojna Cave, Slovenia)

“…The complexity and size of Postojna Cave, with its numerous known and unknown entrances at different levels and a long and highly ramified cave system, makes this cave a fascinating study site for a variety of physical and environmental studies (Bezek et al, 2012;Gosar et al, 2009;Kobal et al, 1988;Mulec et al, 2012;Šebela et al, 2010;Šebela and Turk, 2011;Vaupotič, 2008). In general the ventilation of Postojna Cave is characterised by convective airflow, controlled mainly by the temperature difference between the cave and the outside atmosphere, as discussed by for one measurement location in the Velika Gora (Great Mountain) chamber of Postojna Cave.…”