The Aziza Cave, a major karstic cave in Morocco: biocorrosion and bat ethology

Abstract

The Aziza Cave is situated in the High Atlas Mountains, on the Tazougart Plateau, within the province of Errachidia in southeastern Morocco. The cave entrance is located approximately 30 m above the bed of the Oued Guir River. The system reaches a maximum surveyed depth of 90 m, with its lowest point at an elevation of 969 m above sea level, and extends over a total mapped length exceeding 4 km. The cave is segmented into several sections by a series of sumps. The passages situated beyond of the sumps extend for more than 1.3 km and exhibit morphological features distinct from those observed in the downstream sections. Located within the Saharan bioclimatic zone, the Aziza Cave hosts seven bat species that use the site at different times of the year, each occupying specific zones within the system. As a result, the composition and distribution of the cave’s chiropteran assemblage vary seasonally. Topographic and photogrammetric surveys conducted in conjunction with behavioral observations of bat activity within the cave provide evidence for the influence of bat ethology on biocorrosion processes. Several sections of the cave display characteristic morphologies and notable enlargements that appear to be associated with their biogenic activity. The observed morphologies are closely associated with bat species that occupy the cave during the spring and summer seasons, forming large, densely aggregated colonies. The cave further displays a complex and diverse mineral assemblage, largely influenced by the presence of phosphate- and sulfate-bearing minerals. The detection of hexahydrite, epsomite, and vivianite constitutes a rare mineralogical occurrence within cave systems.