South Florida Sun-Sentinel: As pyramids rose in the Nile valley and the monuments of Greece and Rome went up and fell into ruin, two species of coral patiently built reefs off the coasts of Florida and the Caribbean islands. These vast undersea structures, often compared to tropical rain forests, support a rainbow of fish, crabs and other creatures. But in the past few decades, elkhorn and staghorn coral have declined in many areas 90 percent because of global warming, ship groundings, storm damage, pollution …