The Snotty and the Stringy: Energy for Subsurface Life in Caves

Abstract

Caves are subterranean environments that support life largely in the absence of light. Because caves are completely or almost completely removed from the photosynthetic productivity of the sunlit realm, most cave ecosystems are supported either by inputs of organic matter from the surface or by in situ sources of inorganic chemical energy. The majority of caves have very low energy and nutrient availability and thus, generally low biological activity and productivity. However, those caves that have abundant inorganic chemical energy or high organic carbon influx represent subterranean oases that support robust microbial communities and diverse animal life. In this chapter, we review the energy resources available to cave microbiota and describe several examples that illustrate the vast diversity of subsurface habits contained within caves.