Design an experiment to solve the following problem. Determine the rate of methanogenesis (CO2 + 4 H2 S CH4 + 2H2O) in anoxic lake sediments and whether or not it is H2-limited. Also, determine the morphology of the dominant methanogen (recall that these are Archaea, Section 16.2). Finally, calculate what percentage the dominant methanogen is of the total archaeal and total prokaryotic populations in the sediments. Remember to specify necessary controls.