Table 2.
Nitrogen Isotope Results of Coral Skeleton-bound Organic Matrix δ15N.
| Samples | Age | Photosymbiotic Assignment | Mean δ15N Muscatine Method (‰) | Mean δ15N persulfate-denitrifier method (‰) |
|---|---|---|---|---|
| Diploria labyrinthoformis-TR1 | Modern | Z | 4.07 ± 0.15 | — |
| Diploria labyrinthoformis-TR2 | Modern | Z | 3.92 ± 0.10 | — |
| Favia fragum-TR1 | Modern | Z | 4.55 ± 0.09 | — |
| Favia fragum-TR2 | Modern | Z | 3.91 ± 0.21 | — |
| Desmophyllum dianthus | Modern | AZ | 9.49 | 10.30 |
| Diploria strigosa-TR1 | Holocene | Z-like | 5.75 ± 0.20 | — |
| Diploria strigosa-TR2 | Holocene | Z-like | 6.10 ± 0.10 | 4.42 |
| Oulophyllia sp. | Late Miocene | Z-like | — | 6.19 |
| Acropora papillare | Early Miocene | Z-like | 3.86 | 3.06 |
| Caryophyllia sp. (1) | Early Miocene | AZ-like | — | 11.30 |
| Caryophyllia sp. (2) | Early Miocene | AZ-like | — | 10.70 |
| Antiguastrea lucasiana-TR1 | Oligocene | Z-like | 3.99 ± 0.34 | — |
| Antiguastrea lucasiana-TR2 | Oligocene | Z-like | 4.14 ± 0.20 | — |
| Gablonzeria sp.-TR1 | Norian | Z-like | 2.83 ± 0.19 | 3.02 |
| Gablonzeria sp.-TR2 | Norian | Z-like | 4.05 ± 0.23 | — |
| Disticomeandra sp. (1)-TR1 | Norian | Z-like | 4.65 ± 0.60 | — |
| Disticomeandra sp. (1)-TR2 | Norian | Z-like | 4.03 ± 0.27 | 4.16 |
| Disticomeandra sp. (2)-TR1 | Norian | Z-like | 2.64 ± 0.84 | — |
| Disticomeandra sp. (2)-TR2 | Norian | Z-like | 3.55 ± 1.43 | — |
*Error is one standard deviation from the mean. Precision of the persulfate/denitrifier method results is 0.2‰. Samples of the same species analyzed separately are labeled “(1)” and “(2).” Replicates of the same sample are labeled “TR1” and “TR2” respectively; Desmophyllum dianthus and the Miocene samples did not yield enough mass for replicates. Zooxanthellate- (Z) and Azooxanthellate-like (AZ) morphologies are inferred based on morphological characters11. Z = zooxanthellate coral (modern), AZ = azooxanthellate coral (modern), Z-like = zooxanthellate-like coral (fossil), AZ-like = azooxanthellate-like coral (fossil).