THE EFFECT OF HUMAN INTERFERENCE ON THE GROWTH OF MICROBIAL COMMUNITIES AT THE BIG SPRING, HOT SPRINGS STATE PARK, THERMOPOLIS, WY

Characterization of the microbial communities, in relationship to the water geochemistry, at Hot Springs State Park, has been an undergraduate research project at Central Wyoming College (CWC), since 2006. The park is located 40 miles north of CWC in Thermopolis, WY. The Big Spring is 5 meters in diameter, ~52°C, with an average flow of 60 L/s, and is geologically controlled by an east-west trending fault. The spring flows down a 150-meter long channel to the first cooling pond (47°C). Sites along this outflow channel have been routinely collected for water and microbes and analyzed over the past 4 years, showing a consistent pattern from spring to cooling pond.

Recent procedures by the park staff have resulted in the disturbance of the microbial mats and other growth in the spring and its outflow channel. Removal of the microbes (using a large push broom) by the park employees happens approximately every two weeks. The presence of the bacterial mats, filaments, algae and other growth has drastically been reduced, if not destroyed, over the past year. Before the removal began the filamentous bacteria were long and “flowy”, with many trapped gas bubbles and thick mats. The time between the channel “cleanings” appears to be too short for the filaments to grow long, and the overall character of the growth is significantly different when compared to the observations taken before this new procedure began.

Current research includes a temporal study of the re-growth after such a disturbance using close observation of the growth patterns within a selected site, and correlation of the water geochemistry with the microbial phenotype. Our site is approximately 3 meters down channel from the Big Spring. The site was prepared by vigorously scrubbing the substrate until it was visibly absent of microbes. Six sets of sterilized microscope slides were secured to this substrate using cleaned rocks from the same area. At two-week intervals, one set of slides are collected and observed. Photographs are taken to document the morphologic changes to the growth over time. Photomicroscopy and 16rRNA assays are used to characterize the microbes at this site. Observing and characterizing the temporal changes in this community of organisms may contribute to the limited knowledge of this hot spring and the impact of human disruption on their existence.