Algae promote growth of stalagmites and stalactites in karst caves (Škocjanske Jame, Slovenia)

Abstract

Growth of stalagmites and stalactites is in karst caves controlled by different parameters. In illuminated cave entrances growth of such carbonate structure is not controlled just by abiotic factors, but also by cyanobacteria. At present just a few examples are known where growth of speleothems is linked with biolithogenic activity of certain organisms. This work presents species composition of stromatolitic stalagmites and of stalactites the growth of which is enhanced by carbonate deposition promoted by cyanobacteria towards sun light. From the cave entrance in Skocjanske jame (Slovenia) in the algal community of stromatolitic stalagmites 35 taxa were identified with a low portion of coccoid cyanobacteria and taxa such as Calothrix sp., Homoeothrix sp. and Schizothrix sp. In carbonate depositions on the illuminated side of stalactites 14, mainly coccoid, cyanobacteria were identified. It seems that such biogenic carbonate formations could be far more widespread in subaerial habitats when algal propagulas meet adequate ecological factors for growth.

Microclimate and microbial characterization in the Zinzulusa show cave (South Italy) after switching to LED lighting

“…Due to their biotic component, they represent a food source for microorganisms. Furthermore, the production of metabolic acids, especially lactic and succinic, is involved in the surface bioerosion of speleothems (Northup and Lavoie, 2001;Camassa, 2003) or litholitic processes (Mulec et al, 2007) Lampenflora growth has been visible for a long time near the lights in Zinzulusa (Fig. 1c).…”

Ionic gold in calcrete revealed by LA-ICP-MS, SXRF and XANES

“…1). Biogenic calcite production has been suggested for trees and the surrounding soils in Australia (Verboom and Pate, 2006) and elsewhere (Braissant et al, 2004;Cailleau et al, 2005); and there is mounting evidence for carbonate precipitation by micro-organisms and fungi (Burford et al, 2006;Dick et al, 2006;Lian et al, 2006;Ercole et al, 2007;Mulec et al, 2007;Schmidt Mumm and Reith, 2007;Singh et al, 2007). Separating out the specific roles played by plant roots and their associated micro-organisms in the process of natural carbonate formation is difficult, e.g.…”

A survey of the algal flora of anthropogenic caves of Campi Flegrei (Naples, Italy) archeological district

“…Reduced light intensity, low nutrient input, and absence of seasonality (Dayner and Johansen, 1991;Pedersen, 2000) are the predominant features that influence distribution and composition of algal assemblages in natural and artificial caves, but temperature, humidity, and occurrence of flowing water also play a role in the establishment of algal settlements (Mulec et al, 2007). Many cave habitats currently suffer the impact of increasing tourist fluxes; artificial lights and human traffic are strong factors that can deeply modify equilibria within algal populations (Chelius et al, 2009).…”