Predicting 3D and 2D surface area of corals from simple field measurements

Area of Science:

• Marine Biology
• Ecology
• Geomorphology

Background:

• Coral reef structural complexity influences species richness, fish biomass, and ecosystem resilience.
• The three-dimensional (3D) surface area of individual coral colonies is crucial for various ecological and geological processes.
• Accurate quantification of coral surface area is vital for estimating carbonate production, studying coral predation, and assessing reef growth.

Purpose of the Study:

• To develop morphotaxon-specific conversion metrics for estimating coral colony surface area.
• To establish a method for calculating both total 3D and projected 2D surface area from simple field measurements.
• To provide a practical tool for assessing critical coral surface area parameters.

Main Methods:

• Underwater photogrammetry was employed to accurately measure the surface area of coral colonies.
• Bayesian models were utilized to analyze the relationship between colony maximum diameter and surface area.
• Conversion metrics were derived for 15 distinct coral morphotaxa.

Main Results:

• Strong non-linear (power) relationships were identified between colony maximum diameter and both total 3D and projected 2D surface area for 13 out of 15 morphotaxa.
• The developed conversion metrics provide a highly resolved and efficient estimation of coral surface area.
• The study demonstrates the feasibility of using simple field measurements for complex surface area assessments.

Conclusions:

• This research offers an efficient method for estimating coral surface area, crucial for ecological and geological applications.
• The findings support improved assessments of biotic surface area, tissue biomass, calcification rates, and coral demographic rates.
• The developed technique is valuable for monitoring reef restoration efforts and understanding coral reef ecosystem dynamics.