Keeping Color in the Corals: Research Informs Decisions at War in the Pacific National Historical Park

By Summer Boulais, I&M Science Communicator

June 2024
Imagine snorkeling through a vibrant coral reef surrounded by a kaleidoscope of colors. Schools of fish are dancing in and out of the strong, healthy structures. Now, envision a desolate and faded coral reef with an eerie silence in place of where marine life once thrived. This is what happens when coral reefs succumb to the environmental stressors they’re currently up against.

Coral reefs provide habitats for marine creatures, but they face threats driven by climate change and pollution.

NPS

Ecosystems made up of reef-building corals play a crucial role in the lives of both sea creatures and people. Despite being living creatures themselves, corals are home to many marine species which allows biodiversity to thrive. Coral reefs buffer the shoreline from incoming storms and large waves, protecting people onshore from wave energy, storm surge, and coastal erosion. At places like War in the Pacific National Historical Park (NHP), in Guam, they also provide recreational swimmers and divers with incredible opportunities to see the wonders of marine ecosystems for themselves.

Spot the difference in coral tissue that is bleached (white) vs. healthy (brown).

NPS

An ongoing serious threat to corals around the world is bleaching. Increasing ocean temperatures cause stress to corals that can force them to eject the beneficial algae living within their tissues. This results in the corals completely losing their color and turning white, essentially bleached. Corals that survive a bleaching event become more susceptible to disease and mortality. Elevated ocean temperatures caused by climate change are the leading cause of coral bleaching.

One thing we can do to help coral reefs is to lessen our impacts as humans on the land. The coral reefs in Guam face threats derived from land-based pollution and erosion. Proper watershed management and waste disposal are critical for the future of Guam’s corals. Working hard to reduce waste and spread the word on the importance of protecting corals can have immediate positive impacts.

One management technique being explored to help coral reef health is planting heat-tolerant corals raised in nurseries. There are currently two coral nurseries in Guam. Researchers raise coral fragments until they can be replanted in areas where coral need to be reestablished. This can help coral reefs recover and become more resilient against warming temperatures. However, park managers need information on the status of the coral reefs before implementing strategies and taking action. For example, planting nurseries in areas where corals are already struggling to adapt to erosion may result in unsuccessful nurseries.

As part of the inventory, researchers observed Acropora globiceps, a threatened species.

NPS/Burdick

At War in the Pacific NHP, the National Park Service’s Inventory and Monitoring Division sent researchers out to gather data on the park’s coral species to help determine the best management strategy. Scuba divers photographed the reefs at various depths with underwater cameras to later identify and map coral throughout the park. A total of 245 hard coral species were recorded, including two species listed under the United States Endangered Species Act. Signs of coral stressors were noted, such as stress induced by erosion and areas of significant bleaching. Research has shown a significant correlation between coral mortality and bleaching. These results highlight the need for better land-based stewardship and fostering a connection of land and sea. Scientists and park managers will use this information to track trends in coral-reef health and decide best strategies to help protect the wide array of corals in the park.

At War in the Pacific NHP and other places around the globe, threats coral reef systems face can seem almost overwhelming. This research helps keep those vibrant hues alive to provide marine species a home to thrive in. With continued monitoring and proactive management efforts, we can help mitigate threats and strive to preserve these crucial ecosystems and their beauty.

This article was summarized from the source below:

O'Connell K, Burdick D, Vaccarino M, Lock C, Zimmerman G, Bhagat Y. 2024. Coral species inventory at War in the Pacific National Historical Park: Final report. Natural Resource Report. NPS/WAPA/NRR—2024/2619. National Park Service. Fort Collins, Colorado. https://doi.org/10.36967/2302040