Pardot Kynes, the Imperial Planetologist noticed that too.
“Water overshadows the other problems,” Kynes said. “This planet has
much oxygen without its usual concomitants—widespread plant life and
large sources of free carbon dioxide from such phenomena as volcanoes.
There are unusual chemical interchanges over large surface areas
And many visitors wondered where all the free oxygen comes from.
“The Arrakeen environment built itself into the evolutionary pattern
of native life forms,” his father said. “How strange that so few
people ever looked up from the spice long enough to wonder at the
near-ideal nitrogen-oxygen-CO2 balance being maintained here in the
absence of large areas of plant cover. The energy sphere of the planet
is there to see and understand—a relentless process, but a process
nonetheless. There is a gap in it? Then something occupies that gap.
Science is made up of so many things that appear obvious after they
are explained. I knew the little maker was there, deep in the sand,
long before I ever saw it.”
Without realising that it was coming from the same place as the spice, from the giant sandworms of Arrakis.
But his inner digestive “factory,” with its enormous concentrations of
aldehydes and acids, was a giant source of oxygen. A medium worm
(about 200 meters long) discharged into the atmosphere as much oxygen
as ten square kilometers of green-growing photosynthesis surface.
Additionally, there are some plants in the lower latitudes, where the air is (relatively) moistest.
“Are there any plants down there?” Paul asked.
“Some,” Kynes said. “This latitude’s life-zone has mostly what we call minor water stealers—adapted to raiding each other for moisture, gobbling up the trace-dew. Some parts of the desert teem with life. But all of it has learned how to survive under these rigors. If you get caught down there, you imitate that life or you die.”