Abstract:

Microorganisms have shaped the world around us, yet their role in karst processes and speleogenesis remains poorly understood. Biospeleogenesis is the formation of subsurface cavities and caves through the activities of microorganisms, by either respiratory (redox) or metabolic chemistries. In carrying out energy acquisition and the metabolic processes of growth, microorganisms change the local geochemistry of the environment. Such activities can dramatically accelerate speleogenesis and even lead to cave formation in geochemical environments that would otherwise not be conducive to dissolution. The aim of this chapter is to help the reader understand the importance of microbial activity in geochemistry and how such activity can lead to the formation and morphology of caves. The chapter then describes the role that microorganisms are known to have in speleogenesis (carbonic and sulfuric acid biospeleogenesis), hints that such activity may be occurring in newly described cave systems (iron biospeleogenesis), and a potential role in other cave systems (quartzite biospeleogenesis). It is hoped that the reader will gain an understanding of what motivates microorganisms to dramatically change their environment, understand the potential geochemical conditions where such activity could occur, and allow the informed geologist to make predictive statements as to the potential of, and for, biospeleogenesis