Sulfide-oxidizing bacteria of the genus Beggiatoa form colorful mats on the seafloor above active hydrothermal seeps at Guaymas Basin. 113 temperature profiles were taken around 15 Beggiatoa mats to investigate spatial relationships between mat color and hydrothermal seeps. Average in situ temperatures of phylogenetically diverse orange and white filaments are 8-12 degree C, indicating that Guaymas Beggiatoa live in relatively cool conditions. Average temperatures 40 centimeters beneath all Beggiatoa mats are approximately 90C. Orange filaments are usually concentrated over hotter subsurface temperatures in the center of a mat than the major concentration of white filaments at the periphery; however, the range of subsurface temperatures changes from one mat to another. Elevated temperature profiles beneath orange Beggiatoa correlate with the shallowest sulfide accumulation maxima. We propose that spatial heterogeneity of orange and white filaments in a Guaymas Beggiatoa mat is controlled by delivery of, and proximity to, energy sources in the shallow subsurface
