3D imaging: Raising Awareness About Endangered CoralsCatch of the Week
Jay Maclean talks to Yasmeen Smalley-Norman on how 3D photography can help conservationist and researchers visualize these rare ocean resources.
Today, with the oceans in danger from the impacts of climate change, coral reefs are particularly at risk because of their unique structure and location in shallow tropical waters. The most immediate threat is higher summer sea temperatures causing corals to lose the vital zooxanthellae that feed them and endow them with their color, resulting in bleaching—and death if the water does not cool again soon enough.
Other threats are more chronic: muddying of waters from land runoff that denies the corals the light needed by the zooxanthellae, and chemicals from factory and mining runoff that are toxic to the sensitive polyps. In the longer-term future, rising sea levels can leave the immobile corals in depths where there is no longer sufficient light for the zooxanthellae, while ocean acidification threatens to take away the conditions needed to form the coral skeletons (and shells and skeletons of many other marine organisms).
Corals that are vulnerable or endangered are listed by the International Union for the Conservation for Nature (IUCN) on the advice of coral scientists. One way to help preserve such corals is to create broader, keener awareness of them—beyond the scientific community to conservationists, to communities, and to decision makers. For a long time scientists have been sounding warnings but even the Great Barrier Reef remains inadequately protected and is in more danger than ever.
3D imaging is a new, captivating, interactive way to raise awareness of the plight of these corals, bringing them to life on screen as no ordinary photo or video can. In a 3D image, the viewer can change the perspective of the scene using a mouse or scrolling, moving seamlessly around the coral from one angle to another.
For conservationists on the ground, it is important to know if endangered corals are in the neighborhood of a proposed coastal development and are likely to be affected. 3D imaging is a great help for them, as well as, for example, tour guides, students, and marine-oriented nongovernment organizations (NGOs) in identifying endangered corals. The viewer can enlarge the image greatly, peer into the polyps, and gauge the coral’s relative dimensions, all in full color. And there are other uses of these images. For instance, 3D imaging done at regular periods can show how a fast a coral is growing or is recovering from bleaching—or not—and the imaging software can provide accurate details of the coral’s growth in area and volume.
The images can be made into 3D models, using a 3D printer. The technology is available to produce them in color, though expensive at the moment, and for some endangered corals, if conservationists do not succeed in preserving them, the models will be all we will have.
One photographer utilizing this 3D technology on corals is Yasmeen Smalley-Norman, an underwater photographer and 2016-2017 Fulbright Scholar in the Philippines. Yasmeen is based at De La Salle University, where she works with Dr. Wilfredo Licuanan and his team of researchers.
Yasmeen takes up the story: “I graduated from Rochester Institute of Technology in 2013 with a BFA in Photojournalism and a BS in Biomedical Photographic Communications. My interest in 3D modeling corals came about from my first dive trips to the Caribbean while an undergraduate at RIT, and I wanted to learn more and better visualize these rare ocean resources. Photographing while diving is a task in itself, and I’m looking for specific coral species that are endangered or vulnerable. Fortunately, I work with a great team of researchers at De La Salle University, and I have a great diving partner: Dea Licuanan, a marine science research assistant who divides her time between the University of the Philippines Marine Science Institute and De La Salle University in Manila. While we’re diving, Dea carries a folder of waterproof images of coral species: some of the 166 vulnerable or 10 endangered coral species among the more than 500 coral species in Philippine waters.”
Yasmeen’s equipment is a heavy, bulky camera housing with twin strobes and looks like an alien Cyclops-like robot. Underwater, fortunately, it is weightless. The camera is a Canon 7D and the Aquatica housing with its large acrylic dome ‘eye’ is designed for the camera and its very wide angle lens.
Scuba dives can be up to two and a half hours long, generally in water 10 meters or less deep. The pair of divers cruise slowly over the coral heads until Dea finds a suspected vulnerable coral. Corals are notoriously difficult to identify; identification often relies on seeing the pattern of septa or partitions within the polyps, in other words their individual skeletons.
“They generally contract, withdraw their tentacles, when you wave the water around over them, and then you can see the growth form of the skeleton” Dea says.
When a coral has been identified as being on the IUCN list, Yasmeen swings into action. Keeping her camera close to the reef, she photographs the target coral from side to side, then up and down, taking on average about 100 photos from what looks to the observer to be much the same place. She then follows a sequential pattern of vertical and horizontal movement at slightly different angles. “It’s like painting with numbers. You have to remember where you are in the sequence. If you are distracted and forget, you have to start again. It usually takes 20 minutes to capture all the images needed just for one coral.”
Back on land, the images are downloaded onto a computer. Each is a big file, 27 megabytes. After an expedition, Yasmeen processes them into 3D models using a software called Autodesk Remake, which is accessed by cloud computing. For this the files are reduced to 3 megabytes each; otherwise processing time would take too long. The 3D models are amazingly clear even at that size.
The process is not straightforward; the software first finds a size marker that is placed near the coral to be imaged and the software uses that as a guide to shaping the 3D pattern. Clever software! It also decides what it can exclude, like a fish that passes by in one or two shots. However, it can be fooled by a nearby soft coral or seaweed that will appear in the final image and is waving to and fro in the current, resulting in a blurry image. But with careful planning and proper photographic technique, scuba divers and photographers can use this technology to bring coral reef images to life.
Thanks to Dr Wilfredo Licuanan for reviewing the text.
View the 3D model of P. lichtensteini
Jay Maclean is an ADB consultant.