Microbial Influences on Local Carbon Isotopic Ratios and Their Preservation in Carbonate

摘要: Analysis of the carbon isotopic composition carbonates is a valuable tool for studying microbial processes and looking evidence life. Microbial fixation CO2 conversion organic to can produce measurable δ13C shifts in mat environment. Diffusion modeling demonstrates that substantial develop within diffusion boundary layer fluid when rapid prolonged several hours. Carbonates precipitate during preserve these microbially produced shifts. However, continued precipitation intervals respiration dominates or after cessation active growth commonly dilutes autotrophic signatures. Thus, preserved signatures rarely reflect magnitude mat. Interpretation observed carbonate depends on fully characterizing ambient eliminating other origins isoto...