Data from: Oxygen deprivation implicated in rapid coral mortality under acute heating events
Data files
Aug 03, 2026 version files 352.58 KB
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Figure_2a.csv
13.23 KB
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Figure_2b.csv
13.22 KB
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Figure_2c.csv
103.12 KB
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Figure_2d_e.csv
103.50 KB
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Figure_2f.csv
629 B
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Figure_3a_b_c_d.csv
622 B
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Figure_4a_b_c.csv
111.06 KB
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README.md
7.21 KB
Abstract
While coral bleaching is a well-known consequence of marine heatwaves, rapid coral mortality via tissue disintegration is an understudied threat; one that precludes any chance of recovery. We show that tissue disintegration can occur within hours to days of acute heat stress, marking a critical survival threshold. Microscale oxygen measurements indicate rapid deoxygenation of coral tissue immediately preceding tissue disintegration. We hypothesise that the simultaneous impairment of photosynthetic oxygen supply and increased holobiont oxygen demand overwhelm a coral’s ability to maintain basal metabolic functions. Theoretical oxygen flux calculations support this, suggesting that passive diffusion alone is insufficient to meet metabolic demand under these conditions. These findings highlight intrinsic oxygen deprivation as a potential mechanism for rapid coral mortality and suggest a new, more immediate thermal limit for corals, urging further investigation into the thermal conditions and mechanisms that trigger this response.
Dataset DOI: 10.5061/dryad.wwpzgmt1k
Description of the data and file structure
This dataset contains measurements from controlled acute heat-stress experiments conducted on reef-building corals collected from the Red Sea and the Great Barrier Reef. The primary objective was to evaluate micro-environmental oxygen dynamics and stress/mortality during acute heating.
Oxygen microsensors were used to record tissue-surface and overlying seawater oxygen concentrations, concentration boundary-layer profiles, and changes in oxygen dynamics under varying flow conditions as temperatures were elevated above local summer means. These micro-environmental profiles were combined with video observations of tissue disintegration to calculate oxygen flux relative to coral metabolic demand across multiple species and genotypes.
Abbreviations & Terms Glossary
- DBL: Diffusive Boundary Layer (the thin fluid boundary layer adjacent to the coral tissue surface where molecular diffusion dominates transport).
- OX: Oxygen concentration.
- J: Oxygen flux (calculated rate of oxygen transfer per unit surface area).
- SD: Standard Deviation.
- SE: Standard Error.
- NA: Not Available / Not Applicable (data not captured or unmeasurable at specific treatment steps).
Code/Software & Missing Data Notes
- Missing Data (NA): In Figure_2f.csv, missing values are denoted as NA (Not Available). These occur at specific temperatures and flow conditions where DBL thickness was lower than the step size used in the microsensor profile, meaning the thickness could not be accurately resolved.
- Time Skew Correction: In Figure_3a_b_c_d.csv, the sensor recording software occasionally skipped time intervals. The column Corrected time (s) accounts for true elapsed real time, whereas Original time (s) records raw software timestamps.
Files and variables
File: Figure_2a.csv
Description: CSV file containing data used to plot Figure 2a. Vertical oxygen concentration micro-profiles measured from the coral tissue surface into the overlying water column under control and elevated temperature treatments.
Variables
- Depth: refers to the depth (in micrometres) of the microsensor during the profile for the corresponding oxygen measurement.
- Temperature: refers to the temperature (degrees Celsius) of the treatment for the corresponding oxygen measurement.
- OX Mean: refers to the mean oxygen concentration (micromoles of oxygen per litre).
- OX SD: refers to plus or minus 1 standard deviation around the mean oxygen measurement (micromoles of oxygen per litre).
File: Figure_2b.csv
Description: CSV file containing data used to plot Figure 2b. Vertical oxygen concentration micro-profiles across microsensor depth steps, highlighting tissue-surface hypoxia under acute heat stress.
Variables
- Depth: refers to the depth (in micrometres) of the microsensor during the profile for the corresponding oxygen measurement.
- Temperature: refers to the temperature (degrees Celsius) of the treatment for the corresponding oxygen measurement.
- OX Mean: refers to the mean oxygen concentration (micromoles of oxygen per litre).
- OX SD: refers to plus or minus 1 standard deviation around the mean oxygen measurement (micromoles of oxygen per litre).
File: Figure_2c.csv
Description: CSV file containing data used to plot Figure 2c. Real-time continuous oxygen dynamics recorded at the coral tissue surface over time during incremental heating steps.
Variables
- Minutes: refers to time in minutes.
- OX Mean: refers to the running mean across 60 seconds for the oxygen measurements (micromoles of oxygen per litre).
- OX SD: refers to plus or minus 1 standard deviation around the running average across 60 seconds for the oxygen measurements (micromoles of oxygen per litre).
- Sensor: refers to the sensor location and replicate.
File: Figure_2d_e.csv
Description: CSV file containing data used to plot Figures 2d and 2e. Comparative real-time oxygen depletion curves across different sensor positions and flow regimes during acute heating.
Variables
- Minutes: refers to time in minutes.
- OX Mean: refers to the running mean across 60 seconds for the oxygen measurements (micromoles of oxygen per litre).
- OX SD: refers to plus or minus 1 standard deviation around the running average across 60 seconds for the oxygen measurements (micromoles of oxygen per litre).
- Sensor: refers to the sensor location and replicate.
File: Figure_2f.csv
Description: CSV file containing data used to plot Figure 2f. Diffusive Boundary Layer (DBL) thickness response across increasing temperature steps under low vs. high flow regimes.
Variables
- Temperature: refers to the temperature (degrees Celsius) of the treatment for the corresponding diffusive boundary layer (DBL) thickness measurement.
- DBL Thickness Mean: refers to the mean DBL thickness at each temperature.
- DBL Thickness SE: refers to plus or minus 1 standard error around the mean DBL thickness at each temperature.
- Flow: refers to the flow regime in the treatment.
File: Figure_3a_b_c_d.csv
Description: CSV file containing data used to plot Figures 3a, 3b, 3c, and 3d. Physical parameters, dynamic fluid properties, and thermodynamic calculations used to derive oxygen flux (J; nanomoles of oxygen per square centimetre per second) across temperatures and flow regimes.
Variables
- Temperature: refers to temperature in degrees Celsius.
- Temperature (K): refers to temperature in Kelvin.
- Viscosity (mpa-s): refers to the viscosity at each temperature in millipascals per second.
- DBL thickness low flow: refers to the DBL thickness in micrometres under low flow conditions at each temperature.
- DBL thickness high flow: refers to the DBL thickness in micrometres under high flow conditions at each temperature.
- J: refers to the temperature/timepoints to be plotted on the x-axis.
- Time (h): refers to the labels used for corresponding temperature/timepoints on the x-axis.
- Corrected time (s): the sampling time in seconds at which each individual oxygen measurement was completed. The software program occasionally skipped timepoints, leading to a skew in the number of data points vs. elapsed time. This was corrected in this column.
- Original time (s): the sampling time in seconds at which each individual oxygen measurement was completed.
File: Figure_4a_b_c.csv
Description: CSV file containing data used to plot Figures 4a, 4b, and 4c. Comparative oxygen decline curves over time across distinct coral species and genotypes under acute heat stress.
Variables
- Minutes: refers to time in minutes.
- Mean: refers to the mean oxygen concentration (micromoles of oxygen per litre).
- SD: refers to plus or minus 1 standard deviation around the mean oxygen concentration (micromoles of oxygen per litre).
- Sensor: refers to the species for which the oxygen microsensor was measuring.