Carbon and hydrogen isotopic compositions of algae and bacteria from hydrothermal environments, Yellowstone National Park

摘要: Abstract Stromatolites forming today on a small scale in hydrothermal environments are chemical and biological analogues of much larger Precambrian formations. Carbon isotopic composition varied as function CO 2 concentration, pH, species composition. Stratiform, layered stromatolites grew silica-depositing springs at 55° to 70°C; they consisted mainly unicellular alga, Synechococcus, filamentous, photosynthetic bacterium, Chloroflexus. These thermophiles become enriched 12 C the concentration carbon dioxide effluent waters increases. At 40 ppm total inorganic C, δ 13 organic was ∼ −12%., whereas 900 similar −25%.. Conical or conophytons (principally blue-green alga Phormidium Chloroflexus ) 40°-55°C. In older, broader conophytons, dominant organism. Their values were −18%. variety hot springs. carbonate-depositing springs, i.e., saturated, consisting algae bacteria had most negative (to −30%.). isotope ratios directly comparable kerogen from stromatolites. The presence activity methanogenic heterotrophic, aerobic anaerobic did not alter significantly original matter. hydrogen fractionation between thermophilic organisms water is 0 −74 for temperatures 85° 46°C, respectively. Acidophilic fractionated isotopes lesser extent than inhabiting neutral pH Because matter retains some its signature, relationships levels, temperature, modern their environment those can be inferred.