Dissepiment mapping was conducted on two Porites corals from the southern fore reef of Palmyra Atoll (5.866N, 162.109W) in the central Pacific Ocean. These two corals were selected for dissepiment analysis because even though they were collected within 5 m of each other and at the same depth (13 m), one coral has exceptionally clear density banding while the other coral has almost no visible banding pattern. An additional coral from Palau was also used for dissepiment spacing measurements. This core was collected from a colony in Airai Bay (7.329N, 134.557E) and drilled to a depth of 30 cm into the skeleton.

Dissepiment spacing was measured in cores from Palau and Palmyra Atoll. Skeletal cores collected from live colonies were sectioned and polished, and dissepiments were visualized under a microscope with an automated stage.

See related dataset for coral dissepiment counts (https://www.bco-dmo.org/dataset/688125).