An Evaluation of the Effects of Geothermal Energy Development on Aquatic Biota in the Gysers Area of California
The Geysers of Sonoma County, California, currently the larges geothermal energy field in the world, is expected to expand its electrical generating capacity considerably in the coming years. However, these future developments may result in watershed modification and potentially deleterious effects on aquatic biota due to the topography of the area. Analysis of the response of benthic populations and communities to past and ongoing geothermal energy development and operational practices was undertaken by means of an extensive six site sampling program on Big Sulfur Creek and a concentrated colonization study above, in, and below a heavily impacted tributary (Little Geysers Creek).
Differences in species diversity were noted among the six Big Sulfur Creek sites that were selected relative to the presence or absence of natural fumaroles or hot springs and the absence or stage of geothermal energy development. Distribution and colonization patterns of a population of sericostomatid caddisfly, Gumaga nigricula, and especially its dominance in high silt areas, suggest that both siltation and fumarole activity may select for certain populations.