Corallimorph mouths

The arrows in this image point to mouths of individual corallimorphs, which are a type of invasive anemone that typically thrives in coral reefs that have been degraded by environmental or man-made disturbances. Each corallimorph mouth is surrounded by a corona of tentacles.

Coral reefs are prone to phase shifts where they quickly transition from coral-dominated to a uniformity of other organisms, typically algae. The Palmyra Atoll National Wildlife Refuge in the Central Pacific is a unique case where a transition from corals to corallimorphs occurred. USGS scientists discovered the Palmyra corallimorph infestation at a shipwreck site in 2008.