1. Atacama Life Vida en Atacama Chris McKay & Maite Trujillo NASA Ames cmckay@mail.arc.nasa.gov mtrujillo@mail.arc.nasa.gov

2. A transect from arid to extreme arid Yungay station, extreme arid 50 times drier than Death Valley 500 km south of Yungay, arid about as dry as Death Valley

3. Colonized Stones in the Atacama Desert Warren-Rhodes et al. Micro. Ecol. 2005

4. Crestline for the coastal range in the Atacama Desert

5. Rock garden Altamira Vineyard

6. Moisture mm/yr Life Mars-like soils Soil Bacteria Hypolithic algae Shrubs and insects 1 525 125 Desert ecosystems Gobi Desert Mojave Desert Biology wins reducing Photochemistry wins, oxidizing Nitrate deposits 0.2

8. Moisture Bacterial Counts Biology>Oxidant Biology~Oxidant Biology<Oxidant

9. Implications Length scale of patchiness should vary with moisture. Soil organics will be patchy and correlate with soil organisms. Soil oxidant will be patchy and anti- correlated with organisms.