Diatom communities of travertine-precipitating springs on a gradient of anthropogenic disturbance in the Sandia Mountains, New Mexico

Carbonate-rich waters of travertine-precipitating springs facilitate unique physiochemical environments that support distinct diatom species assemblages adapted to the environmental stress of constant carbonate precipitation. Diatom communities in spring systems may be further limited by the impacts of historical and ongoing anthropogenic disturbance, which includes recreational activity and hydrologic modification of springs using spring boxes and wells. This study focused on impacts of water chemistry and anthropogenic disturbance on diatom assemblages found in travertine-precipitating springs. Data were collected in the fall of 2016 and spring of 2017 at eight spring sites, including six known to precipitate travertine, in the Sandia Mountains of central New Mexico. Water chemistry, benthic diatoms, sediment composition, percent organic matter, and categorical disturbance variables were analyzed. Hydrochemical analysis showed five of six springs known to precipitate travertine were actively forming travertine (saturation index of calcite near or greater than 1.00) during the fall sampling period. Diatom taxa observed in springs were indicative of active travertine precipitation (e.g., Diatoma mesodon, Halamphora montana), higher conductivities (e.g., Diploneis oblongella, Pinnularia spp.), and degree of hydrologic modifications to springs (e.g., Eucocconeis flexella, Gomphonema truncatum). Species richness was greater in non-travertine precipitating springs and diatom density varied among the springs, but was greater in springs during the spring sampling season. Diatom assemblage analysis, disturbance characterization, and other biological assessments can be used to prioritize restoration of springs with unique habitats, such as travertine-precipitating springs