BIOGEOCHEMISTRY OF ACID ROCK DRAINAGE IN PEEKABOO GULCH DRAINAGE, COLORADO

This project examines factors that influence non-anthropogenic acid rock drainage in the Peekaboo Gulch drainage basin, Sawatch Range, Colorado. The goal of this study was to conduct microbial, chemical and geological surveys in an attempt to identify and document those factors that influence the pH changes from the source of Peekaboo Creek to the confluence of Peekaboo Creek with the South Fork Lake Creek. Temperature, pH, dissolved oxygen and conductivity measurements were made in several locations in and around Peekaboo Gulch throughout the 2005 field season. Biotraps were set in June and recovered at periods of 30 days and approximately 60 days after deployment. Biotraps were shipped to Microbial Insights for analysis using DGGE technique. In addition, water samples were collected and preserved throughout the field season and will be analyzed for dissolved metal content. Precipitate samples were collected and are being analyzed using x-ray and SEM-EDX. Preliminary results indicate that dilution of stream water by seasonal snowmelt is a major factor affecting stream water pH whereas heavy rainfall does not appear to have a measurable effect. Initial results of microbial surveys point toward a relationship between peat moss, the acidic water and the microbes in the region. Further tests are currently being conducted to determine the extent of peat moss and other plant life involvement in the capture of the dissolved heavy metals in the water system. DNA samples are identified to species level where possible and give insights into the microbial ecosystems in the Peekaboo Gulch Drainage basin. The data collected provide a time series view of the changes of pH, chemistry and microbial populations in an alpine system affected by natural acid rock drainage.