During 27–28 April 2013, twenty Porites colonies living at 1–5 m depths in the Republic of Palau were stained with alizarin red-S dye. We stained 20 colonies, 10 each in Nikko Bay (7.323N, 134.494E) and on Uchelbeluu reef (7.267N, 134.521E). Ten of the 20 colonies initially stained were located during subsequent sampling expeditions but we were unable to locate the ten remaining colonies, likely because either the tags or the colonies themselves were dislodged during storms. The skeletons of nine of the 20 stained colonies were located and sampled twice, on 4 November 2013 and 9–10 January 2015, to measure the number of dissepiments formed over time.

Dissepiments were counted in stained Porites corals to determine the frequency of dissepiment formation. Skeletal cores were extracted from living colonies previously stained with alizarin dye. The cores were sectioned and polished, and dissepiments were counted from microscope images.


See related dataset for coral dissepiment spacing (https://www.bco-dmo.org/dataset/688052).