In the middle of a big valley there were salty pools of standing water, surrounded by polygons of sun-baked mud. No camels had disturbed the soil crust. In places the pools were green with cyanobacteria.
Jon collected three samples of methane gas from the mud, and one sample of bacterial mat. The methane will be analyzed back at the NASA Ames Research Center to find out whether or not these bacteria prefer to use carbon-12 over carbon-13. There is methane on Mars, too, and nobody knows where it comes from. Maybe bacteria like these are making it.