Near the top
Nothing can live in sand that's being blown around by the wind. There's too little moisture, nothing to eat, and constantly varying temperatures and light levels as the grains get buried and then uncovered again. At least that's the consensus opinion of all the experts who were with us today.
These dunes are less hospitable to life than most areas of the Arctic and Antarctic.
Lifeless?
Of course if you collect a sample of sand you will find bacterial cells and spores in it, but those were blown in from somewhere else and are not residents. They aren't growing.
He has invented a device for measuring the strength of the soil surface
Our research station is in the far distance
I am sure that deep inside the dune, though, the conditions are more favorable. We found that the surface temperature of the sand was 31 Celsius (pretty warm) but just a few inches down it was only 12 degrees.
You can see fifty miles from here!