Planet's atmosphere, though a gasping death to humans and most animals, is paradise for Earth plants. The high nitrate content of the soil and the rich yellow sunlight bring an abundant harvest wherever adjustments can be made for the unusual soil conditions.
A Comparative Biology of Planet
Centauri Ecology
The Isle of the Deep is really not a single creature but a colony of thousands of individual tubules, an aquatic vector of the Mind Worm which terrorizes Planet's continents. Over its lifetime certain tubules secrete a tough, gluelike substance which hardens to form the characteristic shell that floats the colony and creates the appearance of a rogue island.
A Comparative Biology of Planet
Centauri Meditation
Although Planet's native life is based, like Earth's, on right-handed DNA, and codes for all the same amino acids, the inevitable chemical and structural differences from a billion years of evolution in an alien environment render the native plant life highly poisonous to humans. Juicy, ripe grenade fruits may look appealing, but a mouthful of organonitrates will certainly change your mind in a hurry.
A Comparative Biology of Planet
Biology Lab