| This study evaluates the effectiveness of a microbiological technique for paleoclimatic reconstruction, and also evaluates the use of microorganisms for developing a relative dating method. Different microbial trophic group ratios have previously been represented as indicators of paleoclimate, but this technique has not been adequately tested. Soils from a sample column representing the complete chronosequence from Hell Gap, Locality I, Wyoming, were plated on several solid media of different composition (rich, solid, and nitrite media). To test the viability of this method, the microbial data collected from Hell Gap were compared to prior paleoclimatic reconstructions completed at the site, and several statistical measures were applied to the data in order to better infer if they represent a climatic signature. Microbial data correlate to pH, but not to previous precipitation reconstructions. Because of trophic group ratios' correlation to pH, the use of this method as a paleoenvironmental reconstruction technique requires further testing before it can be implemented with confidence. Furthermore, moisture recharge seems to have an effect on rich, soil, and nitrite plate counts of microbial density. Despite this, density decreases with age, indicating that there is a temporal signature within this sample column. Microbial density could thus potentially be used as a relative dating technique. |
