Ediacara biota
From 1985 to 1989, he worked in Papua New Guinea on coral reef ecology, supplementing many years of previous work on reefs elsewhere in the world. Since then his reef work involves localities in Australia, the Society Islands, the Egyptian Red Sea, Fiji, and other Pacific islands. His paleontological research involves fossil reefs, the Ediacara biota in Russia, Australia, Newfoundland, and California, extinction dynamics in open-ocean ecosystems, and the paleontology of the Galápagos Islands and sites in California.