No abstract

Abstract:The present paper deals with biocommunities of cave Leontari, Attica (Greece) focusing on its lithophytic cyanobacteria, and the associated microfauna. The cave is of archaeological importance, not touristically exploited, naturally lighted through the entrance; it consists of one chamber with poor stalactite and stalagmite limestone decoration. During a survey in three campaigns, samples of cyanobacteria and soil invertebrates were collected from four sites (I-IV) along a light(PAR)-temperature-humidity gradient. Light microscopic observations of natural and cultured material have shown that epilithic and endolithic cyanobacteria were almost the exclusive component of cave photosynthetic microflora. Twenty two taxa were identified including the taxonomically interesting morphotypes Chroococcus spelaeus, Asterocapsa sp. and Chlorogloea sp. Arthropods were found as dominant soil invertebrates represented by nine taxa.

Caves and hypogean environments host various phototrophic microorganisms, with Cyanobacteria constituting the major group. The spatial and temporal distribution of Cyanobacteria (156 taxa in total) from three Greek caves, located in the limestone arc of Peloponnese and differing in morphology, was studied. The community patterns in different ecological niches were analyzed in relation to environmental parameters (Photosynthetically Active Radiation, Temperature, and Relative Humidity). Cyanobacterial communities were found to thrive in patchy biofilms and showed known protective strategies against desiccation and irradiation. The nMDS analysis of the cumulative seasonal samples per sampling site showed no general pattern of distribution, with a clear differentiation of cyanobacterial communities among the three caves. Only in the typical cave 'Kastria', cyanobacterial taxa showed growth habits in accordance with the gradient of light from entrance inwards.

Caves have generally been found to host phototrophic micro-organisms from various taxonomic groups, with cyanobacteria comprising an important group that have adapted to these stable and highly specific environments. A polyphasic study based on aspects of classical morphology and molecular data revealed two new monospecific genera from fresh material of Greek and Spanish caves. Both taxa are characterized by obligatory true branching (T-type, V-type and false branching), the presence of heterocysts, and reproduction by hormocysts and akinetes. They shared some similarities in their morphological characteristics as revealed by light, scanning electron and transmission electron microscopy, but phylogenetic analysis based on 16S rRNA gene sequences showed that the two phylotypes were different (89.8 % similarity); this represents an example of shared morphology in genetically different strains of cave-adapted species. Phenotypic and genetic traits strongly support classification of the phylotypes as independent taxa in the order Stigonematales (the most differentiated and complicated group of cyanobacteria), family Loriellaceae Geitl 1925. Hence, the names Iphinoe spelaeobios Lamprinou and Pantazidou gen. nov., sp. nov. and Loriellopsis cavernicola Herná ndez-Mariné and Canals gen. nov., sp. nov. are proposed.Caves represent a stable ecosystem where light controlling the growth of photosynthetic organisms is the limiting factor (Hernández-Mariné & Canals, 1994;Asencio & Aboal, 1996). However, a variety of microhabitats for autotrophic growth is created when adequate natural light reaches the inner part of the caves or when artificial lights are installed.There have been many studies concerning the photosynthetic microflora of these unique environments worldwide (Borzi, 1917;Chu, 1952;Chu et al., 1991;Friedmann, 1955Friedmann, , 1964 Şerbãnescu & Decu, 1962;Claus, 1962Claus, , 1964Hajdu, 1966;Golubić, 1967;Skuja, 1970;Bourrelly & Dupuy, 1973;Dobat, 1977;Leclerc et al., 1983;Abdelahad, 1989;Sant'Anna et al., 1991;Aboal et al., 1994;Asencio & Aboal, 1996, 2000 Ariño et al., 1997;Vinogradova et al., 1998;Dor & Dor, 1999; Hernández-Mariné et al., 2001; Roldán et al., 2004;Pantazidou & Roussomoustakaki, 2005;Lamprinou et al., 2009; Roldán & Hernández-Mariné, 2009). Despite the fact that Greece has more than 8000 karstic caves, since limestone is the dominant rock over the land area, studies on cave microflora are scarce (Anagnostidis et al., 1982; IliopoulouGeorgoudaki et al., 1993;Pantazidou, 1996Pantazidou, , 1997Pantazidou & Roussomoustakaki, 2005;Lamprinou et al., 2009). A similar situation is observed in Spain, even though several caves are known, mainly in the Mediterranean area (GraciaAlonso, 1974;Asencio & Aboal, 1996, 2000 Beltrán & Asencio, 2009; Hernández-Mariné et al., 2001; Roldán et al., 2004; Roldán & Hernández-Mariné, 2009).Abbreviations: LM, light microscopy; PAR, photosynthetically active radiation; RH, relative humidity; SEM, scanning electron microscopy; TEM, transmission electron microscopy.The ...

Abstract:al., Engene et al., 2013). These interesting and biochemically active compounds possess biological activity covering a wide range of antibacterial (Mundt et al