The 'entrance' zone is climatically variable and is influenced by the environmental conditions prevailing in the immediate external environment of the cave while the 'dim light' zone (innermost part of the cave) it is characterized by little or no light; furthermore, the temperature is relatively stable throughout the year and the relative humidity level reaches the maximum values ​​recorded in the cave. Another zone located between the entrance and the dim zone (i.e. the “transition” zone) has the characteristics of the entrance or dim zone (Christodoulou et al. 2015). Photosynthetic microorganisms are capable of using light at various wavelengths between 400 and 700 nm for primary production; it can therefore be concluded that the progressive reduction of natural light controls the growth of photosynthetic microflora (Pantazidou 1996, Ascencio and Aboal 2000, Beltran and Ascencio 2009, Lamprinou et al. 2009, Roldan and Hernandez-Marine 2009, Christodoulou et al. 2011, Albertan