Why we care
Coral reefs are valuable because they support a huge amount of marine life and provide essential cultural and environmental services. The infrastructure, or “bones,” of the reef are calcium carbonate and built by corals and coralline algae. For a reef to stay healthy and grow, it must create this mineral building block faster than it is lost through natural processes like storms or being consumed by fish, urchins and other coral predators. Scientists use a “carbonate budget”—comparing how much material is being made versus how much is being lost—to measure a reef’s overall health and its ability to provide habitat. Stressors such as ocean acidification and warming are making it harder for corals to grow and easier for the reef structure to break down. To protect these habitats, local managers need specific information on current reef conditions, future trends, and tools to help them choose the best conservation strategies. This project will develop decision-support tools to improve understanding of ocean acidification impacts and evaluate the efficacy of potential management responses in the U.S. Pacific Islands.
What we will do
In collaboration with the NOAA Coral Reef Conservation Program, the team will synthesize long-term coral reef environmental and ecological monitoring data into census-based carbonate budget assessments. Researchers will then describe spatial patterns, temporal trends, and drivers of coral reef carbonate production and erosion rates. Linking carbonate budgets with environmental data collected at the same sites over time allows the team to determine how the production and erosion of coral reef carbonate are correlated with ocean acidification parameters and vary across sites due to climate, oceanographic, human-induced, and/or ecological factors.
The team will use carbonate production rates, estimated using a state-of-the-art method called Structure-from-Motion. This method takes imagery of coral reefs at a site and recreates a 3-D representation of the reef. It is like taking pictures of a sand castle on a beach and then matching images based on common features like the drawbridge or tower to recreate the 3-D structure of the sand castle. Comparing the amount of carbonate at a site over time will provide the rate of growth or erosion.
From this work, the team will also develop a prototype version of a management strategy evaluation tool to forecast Pacific coral reef persistence under potential environmental and management scenarios.
Benefits of our work
This project fills critical knowledge gaps in understanding the key risks associated with ocean change and ocean acidification on U.S. Pacific Islands coral reef ecosystems. It also translates this information into accessible and actionable approaches for resilience-based ecosystem management. The major outcomes of this work are:
- Construct carbonate budget time series at priority long-term monitoring sites across the U.S. Pacific Islands.
- Attribute spatial and temporal patterns in carbonate production and erosion rates across the U.S. Pacific Islands to carbonate chemistry, temperature, and other environmental or ecological drivers.
- Develop a prototype decision-support tool for Oʻahu, Hawaiʻi that forecasts reef persistence under climate and management scenarios.
Investigators
Hannah Barkley, NOAA Pacific Islands Fisheries Science Center (PIFSC)
Ian Enochs, NOAA Atlantic Oceanographic and Meteorological Laboratory (AOML)
John Morris, AOML/Cooperative Institute For Marine And Atmospheric Studies (CIMAS)
Jessica Perelman, AOML/Cooperative Institute for Marine and Atmospheric Research (CIMAR)
Brian Powell, University of Hawai’i SOEST
Joy Smith, PISFSC/Cooperative Institute for Marine and Atmospheric Research (CIMAR)
