environmental science
3D Coral Imaging: Using a
GoPro to Visualize Coral Reefs By Alex Reulbach Photo by Holobionics. [CC-BY-SA 4,0]
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abitats across the world are quickly disappearing due to damaging human activities, and coral reefs are no exception. With coral reef disappearance accelerating at an alarming rate, scientists are working rapidly to understand the reasons these habitats are dying before it is too late. One method for studying coral reefs, used by UNC-Chapel Hill marine ecologist Esteban Agudo and his team, has allowed scientists to quickly study coral reef ecosystems at a previously inconceivable level of detail. The method-structure from motion photogrammetryhas allowed Agudo and his team to further our understanding of coral reef habitats by making 3-dimensional (3D) Ph.D. student Esteban Agudo reconstructions of coral reefs and analyzing these structures for ecological trends. Esteban Agudo, a marine ecologist and PhD student in the Department of Biology, lived in Venezuela before joining the Bruno Lab at UNC in 2019. Agudo’s research with his team in Venezuela focused on exploring the fish communities found within coral reefs in Archipelago de Los Roques National Park. During Agudo’s time working with his research team and his colleague Dr. Jose Cappelletto in Venezuela that he stumbled upon the process of 3D reconstruction that his current research relies upon. Be-
ing avid divers, Agudo and Cappelletto would frequently record their dives with a GoPro camera. On one of these trips, Agudo realized the potential his GoPro videos could have in studying the structure of coral reefs. As Agudo recalls, “At first we just started playing, just using a GoPro to take videos and finding the right software to use for 3-dimensional reconstruction. In that way we came up with pretty decent reconstructions of coral reef structure.”¹ As soon as they realized that this method of coral reef restoration was successful, they believed it could be utilized to solve problems in marine ecology. To see if their method of 3D reconstruction could effectively be used to answer ecological questions, Aldo Croquer, Agudo’s former advisor and one of the team members, suggested that they start out on a small scale. They wanted to know “how much coral reef fish are related to the structural complexity of a coral colony.”¹ Agudo relates structural complexity in coral reefs to the 3D framework that plants and trees create in a forest. In more structurally complex forests, different plants and trees create many nooks and crannies have many nooks and crannies that give refuge to the animals that inhabit the forest. The idea is very similar in coral reef habitats. “Coral reef fish are totally dependent on the refuge that they can find between the corals, rocks, and sponges you can find in a coral reef,” says Agudo.¹ More structurally complex corals have a greater number of holes, overhangs, and nooks that many reef fish depend on for shelter from predation. Agudo and his team hypothesized that as the structural complexity of a coral colony increased, the reef fish abundance and biodiversity would increase as well.
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