New insights on the ecology of underground ecosystems toward a sustainable management strategy

Abstract

Underground cavities represent some of the less explored places on the planet. In fact, excluding the known carbonate dissolution/precipitation processes, leading to the formation of holes in the host rock, as well as speleothems, little is known about the ecology of these fascinating and enigmatic ecosystems. In spite of this, caves are generally object of tourist adaptations, which can activate an irreversible impairment of the biogeochemical equilibria, whose load, until now, is not estimated accurately, due to the scanty information in this regard. In this study, the most of research activities were carried out in the karst system of the Pertosa-Auletta Cave (Southern Italy), located in the Cilento, Vallo di Diano and Alburni National Park, chosen as study model for the different natural characteristics (the fossil trail without flowing waters and the active trail crossed by a perennial subterranean river) and diverse human fruition (tourist and closed to the public paths), hosting more than 60.000 visitors per year. The project aimed at shedding light on the abiotic (clastic sediments and vermiculations, water and atmosphere) and biotic (microbiota and lampenflora) compartments of this relatively unknown ecosystem and at the understanding of the effects of tourist adaptations in cave environment, with the definition of sustainable strategies for the mitigation of the related damages. Firstly, adopting an integrated approach, we characterized cave vermiculations, obtaining a comprehensive knowledge of their chemistry and microbiology: the abundance of calcite in their mineral composition and traces of microbial activity, with evidences of dissolution morphologies and organic matter, as well as biologically mediated secondary minerals precipitation. Microbial community, involved in vermiculation formation processes, is characterized by the dominance of Proteobacteria, Acidobacteria and, in higher humidity conditions, of Actinobateria, with several unknown groups. [...] [edited by Author]