Cross-sectional tomography slices providing an overview of the internal skeleton architecture, which was characterized in terms of (c, d) single-polyp volumetric thickness, (e) hardness (shore hardness value, higher values indicate a harder material), density, and porosity (ratio of the pore volume connected to the external skeleton surface to bulk volume of the skeleton). Boxplots in e show first and third quartiles, median line, and whiskers at +/-1.5 interquartile range. Asterisks represent significant differences computed with two-sided unpaired t test (polyp volume thickness, n = 9, F = 1.542, p < 0.05) or two-sided Mann-Whitney test (density, n = 15-21, p < 0.01; porosity, n = 15-21, p < 0.01). No significant difference in hardness was found between mangroves and reef corals (two-sided Mann-Whitney test, n = 120, p > 0.05). Source data are provided as a Source Data file.
