A fully grown Reef operates as a living city for its inhabitants, providing for all of their needs and desires as a side effect of its own life processes. Living space, food, water, transport, and data and communications support are all provided by various systems produced by the Reef or by organisms living symbiotically within it (in many cases, the inhabitants themselves may live in symbiotic union with the reef, their biological waste products feeding or otherwise helping to sustain it).
Reefs may be constructed using gengineered organisms, synsects, builder bots, or some combination of all three. In general they are constructed (grown) in the shallow coastal waters of terraformed planets or large habitats and are built up from materials extracted from the water and sea floor.
Smaller Reefs may be grown entirely from natural biological materials and are mostly submerged, providing homes for aquatic or amphibious humans of various sorts. Larger Reefs may extend hundreds of meters above (and below) the surface and usually employ a combination of natural materials and gengineered forms that have been modified to incorporate carbon nanofiber, diamondoid, and various metals for extra strength, durability, electrical conductance, or other desired properties. These larger habitation structures often support populations of millions, with each type of being occupying a portion of the reef that suits it best, with the reef itself modifying its local structure to better accommodate its inhabitants.
Tech Levels: Biotech 5
Cost: Public Domain for the designs, Moderate to Expensive to implment. Low ongoing.