Editor’s note: This article is part of the Pacific Islands Climate Adaptation Science Center’s ongoing series to bring awareness to the impacts, damages, and responses to coral bleaching and rising sea temperatures around Pacific Islands.
Emerging technologies used to monitor coral bleaching in Guam, CNMI
August 7, 2024
With the threat of coral bleaching taunting the region, Pacific Islands are looking to emerging technologies for a quicker, more accurate assessment of the harmful impacts.
“The most traditional method of observing coral bleaching events has been manual, in-water surveying. It is strenuous and takes a lot of time, effort, and resources to conduct,” said Dr. Romina King, associate professor of geography at the University of Guam (UOG) and PI-CASC’s Guam lead.
King co-leads a project funded by the U.S. Geological Survey and PI-CASC that will evaluate whether recent NASA remote sensing technologies are capable of more rapid assessments of coral bleaching over wide areas in the region. The project arose following the devasting effects of bleaching between 2013 and 2017, where Guam and the Commonwealth of the Northern Mariana Islands (CNMI) experienced the loss of more than a third of their shallow-living coral cover. Over the years, natural resource managers had noted that it was a challenge to build local capacity for coral surveying and monitoring.
“With this project, we are looking at using remote sensing technologies to observe a vast area of coral cover to assess bleaching events, all while maintaining accuracy. If successful, these will be invaluable tools for monitoring these precious marine ecosystems,” King said.
The tools she is referring to are a Multispectral Imaging, Detection, and Active Reflectance (MIDAR) instrument, which uses an array of LED emitters for high-frame-rate multispectral underwater imaging, and fluid lensing, a process in which wave distortions from aerial imagery can be removed for a clearer look underwater. The tools are deployed using unmanned aerial vehicles, or drones. Both tools were developed by Dr. Ved Chirayath, a former NASA scientist who now leads the Aircraft Center for Earth Sciences at the University of Miami’s Rosenstiel School, and a co-lead on the USGS PI-CASC project with King.
Following the Coral Bleaching Watch notice from the National Oceanic and Atmospheric Administration (NOAA), King wants to take the project a step further and conduct pre- and post-surveys of the anticipated coral bleaching event with the NASA technologies. PI-CASC is currently working with local scientists, natural resource managers, and the UOG Drone Corps to carry out these field missions in hopes of creating high-quality maps and datasets to show the extent of the projected bleaching event.
Monitoring in CNMI
As part of this project, PI-CASC supported the UOG Drone Corps’ travel to Saipan, CNMI, for similar missions with their coral reefs. The remote pilot team, consisting of UOG personnel from PI-CASC, NASA Guam Space Grant, and NASA Guam EPSCoR, aimed to extend their ongoing coral mapping missions on Guam to support natural resource groups from the CNMI’s conservation goals.
“With these highly detailed maps and comparing them with our imagery collected during a bleaching event, we can map out areas and hopefully identify the corals that become bleached,” said Rodney Camacho, lead biologist at the Division of Coastal Resource Management in Saipan. Camacho said that CNMI managers also use drones to monitor the range of bleaching, in addition to in-water photogrammetry and surveying.
A big part of detection, however, involves the community. Agencies rely on local dive shops, fishermen, and other community members to report sightings. Camacho said that a bleaching response plan was created to help educate the community on the signs of coral bleaching, with 17 indicator sites highlighted throughout the CNMI, in the islands of Saipan, Tinian, and Rota.
“Data from our long-term monitoring sites shows recovery from two lagoon sites and three forereef sites since the 2017 bleaching event,” Camacho said. “Should bleaching occur in the CNMI, we will see further decline in staghorn Acropora spp. habitat on the back reefs, within the Saipan Lagoon.”
Looking ahead, PI-CASC will continue supporting UOG Drone Corps and their mapping efforts. The Guam team is currently preparing a coral reef mapping campaign in Rota, and plans to return to Saipan for post-surveying — if a bleaching event occurs. Once the aerial imagery datasets from the drone missions are processed, they will be made available and accessible upon request for research purposes. To request permission or for more information about the datasets, email dronecorps@triton.uog.edu.
Check back with PI-CASC for more stories on coral bleaching! Our upcoming pieces will include coral species’ resilience to thermal stress and more.