The Diatom Flora of Hall’s Cave, Kerr County, Texas

This paper presents the results of a study to identify the species and distribution of diatoms growing in various habitats and on different substrates in Hall’s Cave, a limestone cave located on the Edward’s Plateau in western Kerr County, central Texas, USA. A diverse diatom assemblage that includes at least seventeen taxa was found growing in low to very low light conditions in different parts of the cave interior and on the walls of the cave entrance. Many other species were found in low numbers and may have been transported into the cave. One diatom species, Nitzschia palmida Carter is dominant in many samples, and overall, is the most abundant diatom observed in this investigation. This is the f irst published occurrence of N. palmida in the Western Hemisphere. These diatoms, all found typically in wet or damp settings, have adapted to growing in the cave environment. Nine species were common in only one sample, a scraping of wet guano-rich sediment on the floor at the back of the cave. These diatoms either survived passage through the digestive system of bats or were transported to the back of the cave by other means. The abundance and diversity of diatoms in Hall’s Cave suggests that diatoms may have been living in the cave for as long as there has been adequate moisture, nutrients and light, making them potential proxies for paleoenvironmental studies.