Mesophotic corals in Hawaii maintain autotrophy to survive low-light conditions: Stable isotope dataset

In mesophotic coral ecosystems, reef-building corals and their photosynthetic symbionts can survive with less than 1% of surface irradiance. How depth-specialist corals rely upon autotrophically and heterotrophically-derived energy sources across the mesophotic zone remains unclear. We analyzed the stable carbon (δ13C) and nitrogen (δ15N) isotope values of a Leptoseris community from the ʻAuʻau Channel, Maui, Hawaiʻi (65-125 m) including four coral host species living symbiotically with three algal haplotypes. We characterized the isotope values of hosts and symbionts across species and depth to compare trophic strategies. Symbiont δ13C was consistently 0.5‰ higher than host δ13C at all depths. Mean colony host and symbiont δ15N differed by up to 3.7‰ at shallow depths and converged at deeper depths. These results suggest that both heterotrophy and autotrophy remained integral to colony survival across depth. The increasing similarity between host and symbiont δ15N at deeper depths sugg..., , , # Mesophotic corals in Hawaiʻi maintain autotrophy to survive low-light conditions: Stable Isotope Dataset

The complete collection of files used by Backstrom *et al.* (2024) to organize and analyze all stable isotope data presented in this research article.

## Description of the data and file structure

The data are organized into three separate files, accompanied by an R script for processing/analyzing all biplot data:

1. A Microsoft Excel document (titled \"ProcB Manuscript Data CHB 1.15.24\") provides a metadata sheet outlining the organized data on all subsequent sheets. These sheets were used to process/analyze all regression data via JMP Pro 14. Outliers as defined and listed in the sheet (and tabulated in Supplementary Table 1) were excluded for analyses pertaining to those data.

2. A .csv file titled \"leptoseris.all.csv,\" reorganizing the stable isotope data for the whole sample set only by colony fraction (i.e., host vs. symbiont) to plot and run SIBER analyses.

3. Anot...