## 3 Results and Discussion
### Microalgae Identification
As for the mineral crusts, we found variability; they are usually made up of complex communities of various species of green algae and cyanobacteria (which sometimes form separate strata), but sometimes they are monospecific, made up of _Chlorosarcina_ sp. and other indeterminate coccoid green algae. Most of the samples belong to amphibious or submerged environments. Only a few were taken in aerial zones far from water, although sometimes with high levels of relative humidity. In such zones, genera such as _Leptolyngbya_, _Klebsormidium_, _Stichococcus_, _Chlorococcus_, _Brateococcus_, _Cosmarium_, _Phormidium_, _Navicula_ and _Chroococcus_ were observed, forming coloured sheens and sometimes crusts. These same genera appear in other submerged and amphibious zones, so they are not exclusive to aerial environments. In the sampling points where samples were taken in different seasons, it was observed that there may be small variations between the observed species of algae, however the general composition is largely maintained and the predominant algae are usually the same. The small variations may be due to seasonal environmental factors or cleaning and maintenance work on the fountains. If we compare the results with previous studies carried out on the fountains of the Alhambra [14; 15; 17; 18], only the genera _Brateococcus_, _Klebsormidium_, _Choricstis_, _Stichococcus_, _Cluococcus_, _Cynococcus_ and _Dichothrix_ had never been recorded before. The rest of the observed microalgae had already been recorded in the past. It could be considered that new genera have appeared, but it has to be remembered that the same fountains have not always been sampled. In the  
Figure 9: Photographs of the algal cultures _Brateococcus_ sp. (**a**) and _Klebsormidium_ sp. (**b**) and two different species of _Leptolyngbya_ (**c,d**). thesis by [PERSON] [15] only seven fountains in the Nasrid Palaces were sampled, while in the study by [PERSON] et al. [18] only samples from the Lindaraja fountain and the central fountain of the _Patio de la Sultana_ were studied. In addition to some of the genera currently identified, in the previous works there are also some different ones. Specifically, we can observe a much greater number of species in the thesis by [PERSON] in 1994 [15], even though only the Nasrid Palaces' fountains were considered. One of the explanations for this phenomenon is that the presence of microalgae in these fountains was much greater 26 years ago, because today much more attention is paid to these microorganisms and the fountains undergo much stricter maintenance (Figure 10). The genera we have identified are also common in other monumental fountains in Spain and Italy, where the following genera have been found: _Phormidium, Calothrix, Leptolynghya, Lynghya, Symploca, Schizothrix, Myxoscarina, Chamaesiphon, Chroococcidiopsis, Pleurocapsa, Chlorogloea, Pseudopleurococcus, Pleurastrum, Apatococcus, Chlorella, Chlorosarcina, Chlorosarcinopsis, Cosmarium, Chlorococcum, Scenedesmus, Stichococcus, Navicula, Nitzschia, Achnanthes_ and _Cymbella_[18; 24; 25]. In addition to fountains, microalgae are also pioneers in colonising other stone monuments and are significant agents in their biodeterioration. In fact, algae and cyanobacteria are the majority components in the biofilms found in stone buildings in Europe, while cyanobacteria are the majority components in those found in Latin America [26]. In a study carried out on the most common green algae and cyanobacteria in monuments of different types of stone in the entire Mediterranean basin [27], all of the genera we found in the Alhambra were present. In fact, _Klebsormidium_ sp., which did not appear in the fountains of the Alhambra in the past, is among the most common species in stone monuments. All of this information makes it clear that the microalgae growing in the Alhambra and Generalife are species that are very widespread and which are commonly found in stone monuments.