Juergen Freund / Various corals grow on mooring ball, Great Barrier Reef, Queensland, Australia

Juergen Freund / Artificial reef balls that have been in place for about 10 years with some encrusting corals, North Sulawesi, Indonesia, October 2009.

Juergen Freund / Liberty Wreck fully encrusted with corals, sponges and other marine life, Tulamben, Bali, Indonesia.

Juergen Freund / Old bottle underwater encrusted with coral & algae, Papua New Guinea