The new study from University of California – San Diego demonstrates how virtual technology can capture and be used to assess how coral reefs are recovering after bleaching. This is through a combination of imaging and 3D structuring software. The technology was tested out in Palmyra Atoll, which is located in the tropical Pacific due south of the Hawaiian Islands.
According to the World Wildlife Fund for Nature coral reefs face a number of threats, including climate change (corals cannot survive if the water temperature is too high). It is noted that global warming has already led to increased levels of coral bleaching. When corals are stressed by changes in conditions such as temperature, light, or nutrients, they expel the symbiotic algae living in their tissues, causing them to turn completely white.
In 2015, the Palmyra regions saw a temperature-related widespread bleaching event, affecting over 90 percent of the corals surrounding the island. Overtime, 90 percent of the affected corals recovered.
To assess the recovery process, the research group used a big data set made up of thousands of pictures of the reef, amassed over eight years. These images were sequenced together using specially developed software to form 3D photographic mosaics of the ecosystem, which became a virtual representation of the corals.
According to lead researcher Professor Mike Fox: “This imaging provides a way of getting back into the environment in a virtual world. It allows us to bring the reef back into the lab.”
The custom visualization software is called VisCore, and it enables researchers to re-examine thousands of photographs that comprise a mosaic. For this process, 15,000 images for every 10 square-meter area of coral reef. Once created the repeaters were able to use virtual reality headsets to dive into the images can assess the changes taking place to the corals.
In terms of the ecological importance, the photomosaics showed the important role that a reef-building species – a crustose coralline algae – plays with recovering the corals. The alga could be used in other parts of the world to assist with the settlement of juvenile corals.
The research is published in the journal Coral Reefs, with the research paper titled “Limited coral mortality following acute thermal stress and widespread bleaching on Palmyra Atoll, central Pacific.”