Castaway Resolution
(Book)

The Kimei family and a second group of castaways, led by Sergeant Campbell, had finally joined forces after both had been forced to land on the bizarre planet Lincoln, whose continents were huge floating coral colonies, inhabited by even stranger lifeforms. They had survived crash-landings and venom-filled bites and disease, their own despair, and even the destruction—and consumption!—of one of their floating islands, and had learned to live, even prosper, in their strange new home.