Oceanographic Study Calculates Climatological Ranges and Anomalies for Pacific Coral Reef Ecosystems

In collaboration with several research partners, scientists in the PIFSC Coral Reef Ecosystem Division (CRED) have developed a methodology to generate consistent and comparable climatological data for the U.S. Pacific coral reef ecosystems, enabling them to ascertain climatological ranges and anomalies for the ecosystems. Data for the study were collected in surveys conducted by CRED as part of the Pacific Reef Assessment and Monitoring Program. Joining CRED staff in the research were colleagues from the Scripps Institution of Oceanography of the University of California San Diego, NOAA's Coral Reef Watch, and the University of Hawaii at Manoa (UH).

Coral reefs are exposed to a range of environmental forcings that vary on daily to decadal time scales and across spatial scales from reefs to archipelagos. Such environmental variability is a major determinant of the structure and function of reef ecosystems, including coral reef extent and growth rates and the abundance, diversity, and morphology of reef organisms. Proper characterization of environmental forcings, therefore, is a critical step toward understanding the dynamics and implications of abiotic-biotic interactions on reef ecosystems.

Long-term means in (A) sea-surface temperature, (B) wave energy, (C) chlorophyll-a concentration, and (D) irradiance in 
        coral reef ecosystems across the U.S. Pacific.
Long-term means in (A) sea-surface temperature, (B) wave energy, (C) chlorophyll-a concentration, and (D) irradiance in coral reef ecosystems across the U.S. Pacific.

To quantify environmental forcings on coral reefs, the recently completed study combined high-resolution bathymetric information with modeled wave data and remotely sensed data of sea-surface temperature, chlorophyll-a concentration, and irradiance. Study results indicate considerable spatial heterogeneity in climatological ranges and anomalies across the 41 islands and atolls for which data were examined, with emergent spatial patterns specific to each environmental forcing. For example, wave energy was greatest at northern latitudes and generally decreased with latitude. In contrast, chlorophyll-a concentration was greatest at reef ecosystems proximate to the equator and at northernmost locations, showing little synchrony with latitude. In addition, the U.S. Pacific coral reef ecosystems with the highest chlorophyll-a concentrations—Jarvis Island, Howland Island, Baker Island, Palmyra Atoll and Kingman Reef—are all uninhabited and characterized by high cover of hard corals and large numbers of predatory fishes. Metrics developed for this study will help to identify reef ecosystems most exposed to environmental stress and systems that may be more resistant or resilient to future climate change.

The team of scientists published their findings in the open-source online journal PLoS ONE. Jamison Gove of CRED and UH was senior author of the paper, titled "Quantifying Climatological Ranges and Anomalies for Pacific Coral Reef Ecosystems".