TAMBO was founded by an eccentric scientist searching for a way to produce limitless quantities of food.  He found it in a self-replicating catalyst that converts seawater into an edible paste.  This paste is revolting to look at, horrifying to smell, and achingly bitter to taste, but it is edible.  The surface of Tambo used to be over 90% covered by ocean, so now it is over 90% covered by this stuff.  They say that if you strain out the liquid from the paste, you can more easily choke it down with a glass of pure rainwater.  "They" are of course the nonviolent criminals and other undesirables who have been exiled to Tambo from the rest of the Nag sector.  The remorseful scientist attempted to flee, but was located and humanely imprisoned elsewhere rather than subjected to his creation.  His researches are closely supervised lest he achieve similar success again.