Bat Biostalactites Originating from Outside the Cave in Upper Silesia, Poland

Biostalactite produced as a result of the activities of the insectivorous bat species Eptesicus serotinus is described. A guano (bat faeces) deposit was found in Poland, which suggests the possibility of creating such structures not only in warm and arid climatic zones but also outside caves in temperate climate countries. The research revealed that the temperate climate bat stalactite is made of urea, accompanied by a small and variable amount of non-crystalline organic substance that comes from bat guano. Lack of contact with cave minerals is a way to save the original composition without intrusions of calcite or other minerals which come from the bottom or vault of the cave. An X-ray diffractometric analysis shows a number of dominant minerals in crystalline form present in the examined material. Detected minerals are mainly taranakite H₆K₃Al₅(PO₄)₈·18H₂O, urea crystals and ammonium aluminium hydrogen phosphate Al₂(NH₄)OH(PO₄)₂·H₂O. Formation of bat biostalactites is often observed in hot and dry caves, but the temperate climate in Poland eliminates this phenomenon due to high air moisture and quick microbiological digestion processes.