# Diversity and Seasonal Dynamics of Airborne Fungi in Nerja Cave, Spain
## 4 Discussion  
The microclimatological study in Nerja Cave shows two well defined ventilation patterns corresponding to summer (low ventilation) and winter (high ventilation). The type of ventilation regime is closely related with the concentration of airborne fungi in the cave. In fact, the higher number of spores was observed in summer due to air stagnation or low ventilation, whereas in winter, ventilation helped to remove and/or dilute spore concentrations. Similar phenomena were described in other caves [7; 19]. Figure 3 shows the distribution of the most abundant fungi across the different galleries and seasons. Several patterns can be observed, namely the practical absence of _Basidiomycota_. This pattern is opposite to that found in caves from Northern Spain, where the input of wood-rotting _Basionomycota_ spores related to _Quercus_ forests predominates in the \begin{table}
\begin{tabular}{c c c c} \hline
**Sampling** & **CFU m\({}^{-3}\) (SD) \({}^{*}\)** & **Identification (\% Similarity)** & **Abundance (\%)** \\ \hline \multirow{4}{*}{\begin{tabular}{c} [PERSON] \\ (LH) \\ \end{tabular} } & \multirow{4}{*}{30 (10)} & _Aspergillus spleaeus_ (99\%) & 50.00 \\  & & _Aureobasidium pullulans_ (100\%) & 16.67 \\  & & _Cutaneousproson mucoides_ (100\%) & 16.67 \\  & & _Scopularis bereicualis_ (100\%) & 16.67 \\ \hline \multirow{4}{*}{\
\begin{tabular}{c} Mountain Hall \\ (MH) \\ \end{tabular} } & \multirow{4}{*}{280 (0)} & _Aspergillus usatus_ (100\%) & 25.00 \\  & & _Aspergillus spleaeus_ (99\%) & 32.69 \\  & & _Aspergillus versicolor_ (100\%) & 5.77 \\  & & _Cladosporium phareospermum_ (100\%) & 1.92 \\  & & _Penicillium flavigenum_ (100\%) & 32.69 \\  & & _Scopularis bereicualis_ (100\%) & 1.92 \\ \hline \multirow{4}{*}{
\begin{tabular}{c} Exterior air \\ (EA) \\ \end{tabular} } & \multirow{4}{*}{230 (20)} & _Alternaria tenuissima_ (100\%) & 2.33 \\  & & _Aspergillus spleaeus_ (99\%) & 13.95 \\  & & _Aspergillus versicolor_ (100\%) & 20.93 \\  & & _Botrytis cinerea_ (100\%) & 2.33 \\  & & _Cladosporium cladosporoides_ (100\%) & 30.23 \\  & & _Cutaneousproson mucoides_ (100\%) & 4.65 \\  & & _Monocillium indicium_ (99\%) & 11.63 \\  & _Penicillium flavigenum_ (100\%) & 13.95 \\ \hline \end{tabular} \({}^{*}\)CPU: colony forming units; SD: standard deviation.  
\end{table} 
Table 3: \(Cont.\)ventilation period (winter) [18]. In Nerja Cave's surroundings, forests and dead trees are not prevalent. Another well-defined pattern is the higher diversity of _Ascomycota_ in the air in winter with relatively medium spore abundances, whereas in the summer period, the abundances of a few _Ascomycota_ (_Aspergillus versicolor, Parengyodontium album, Penicillin flavigenum_) were remarkable, but they were not retrieved outside the cave. The presence of _Ascomycota_ in the two seasons, irrespective of the high or low ventilation period, could be associated with the phototrophic biofilms. [PERSON] et al. [30] related the abundance of _Parengyodontium, Aspergillus_, and _Penicillin_ in the air of Tesoro Cave (Rincon de la Victoria, Malaga) at some 40 km from Nerja, with the abundant biofilms of cyanobacteria and algae originated by the artificial lighting used for allowing the visits. Nerja Cave houses also abundant phototrophic biofilms near the entrance, just in the Touristic Galleries. A similar association between phototrophs and _Ascomycota_ was reported by other authors [31; 32]. The senescence and lysis of old phototrophic biofilms can provide nutrients for the fungi and lead to the abundance of airborne spores in the halls close to the cave entrance. [PERSON] et al. [24] reported complex trophic interactions in Nerja Cave between the components of the biofilms, including processes of predation of bacteria and amoebas, and the occurrence of nematodes, fungi, and other _Eukaryota_. The higher diversity and relative abundance of _Ascomycota_ spores in winter are consistent with the entry of air according to the ventilation mode of Nerja Cave during this period of the annual cycle.