Water Geochemistry and Mineralization within a Microbial Filamentous Community of a 50-52°C Hot Springs, Thermopolis, Wyoming

The 5 meter diameter Big Spring in Hot Springs State Park, Thermopolis, Wyoming, has a 1-1.5-meterr outflow channel, 150 meters long to the first cooling pond. The average rate of flow is 14 million L/day at a temperature of 51-53°C, and is geologically controlled by an east-west trending fault. Fourteen sites are placed at 10 meter intervals from the source spring, except were the channel is dissected by the park road. The pH, temperature, and specific conductivity were measured, with an electronic probe, at each site. Water samples were collected and analyzed for H2S on location. Depending upon time and weather, phosphate, nitrate and silica were also measured on location or in the laboratory soon afterward. Total dissolved solids, chloride, and CaMg-hardness were analyzed in the lab. Our results indicate a remarkable stability in the chemistry of the hot spring and its outflow over a two year period. Electron microscopy of biological samples taken from the hot spring and its outflow revealed the presence of calcium carbonate crystals along with "cauliflower"-like structures of putative mineral origin, embedded in the filamentous growth. Future research will focus on the interplay of mineral chemistry and organisms composing the microbial filamentous community.