About This Project

Understanding the dynamics of coral reef recovery is of great importance as reefs are experiencing severe decline. Density of juvenile corals is often correlated with reef recovery trajectory. Settlement, success, and growth of juvenile corals is especially influenced by habitat structural complexity. This study will combine fluorescence imaging methods with 3D underwater photography to assess the relationship between reef structural complexity and reef recovery potential.

Ask the Scientists

What is the context of this research?

Scleractinian corals are sessile, marine invertebrates that serve as the primary building blocks of modern tropical reefs. Coral reefs are experiencing unprecedented decline due to more severe and frequent heat related stress (i.e., bleaching and tropical storms) and human pressures. Reef recovery, that is, naturally restoring coral populations to pre-disturbance levels, is governed by both ecological and environmental factors. The interplay between these factors can give insight into recovery potential and trajectory. Thus, researchers must develop innovative approaches to effectively monitor populations and understand how the environment may mediate mortality and anticipated recovery.

What is the significance of this project?

Density of juvenile corals (corals smaller than 5 cm) is often used as a proxy for recruitment success, a metric correlated with recovery trajectory. High abundance of juvenile corals is often indicative of settlement success and post-settlement survivorship. Environmental factors, such as light, depth, and wave energy, influence early coral life stages, all of which are mediated by habitat complexity. Three-dimensional habitat structure can therefore distinguish between consolidated reef and unsuitable habitat, affect small-scale water motion, modify irradiance, and provide protection from grazing, predation, and competitive smothering. Though seemingly challenging, 3D underwater imaging methods have allowed researchers to easily study the 3D shapes of coral reefs.

What are the goals of the project?

Traditional methods of estimating coral juvenile density are all small in scale, and possess a series of biases, such as intense training, time-consuming hands-on manual analyses, and/or expensive image analysis programs. Both coral animals and their symbiotic algae contain fluorescent pigments that react under UV or blue light. However, no study to date has used fluorescence juvenile detection imaging methods to quickly and effectively assess patterns between habitat structural complexity and recruitment and survival. The objective of this project is to combine fluorescence imaging methods with 3D imaging techniques to assess the relationship between the environment, namely structural complexity, and coral settlement, survival, and growth.