The Hawaiian Ko\u02bba Card: coral health and bleaching assessment color reference card for Hawaiian corals

Keisha D Bahr,Rebecca M Weible,Justin J Han,Sarah J L Severino,Angela Richards Dona,Anita O Tsang,Yuko O Stender,Andrew Graham,Ashley E Mcgowan,KuʻUlei S Rodgers

doi:10.1007/s42452-020-03487-3

Keisha D Bahr, Rebecca M Weible + Show 8 more

Open Access

https://doi.org/10.1007/s42452-020-03487-3

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Abstract

Coral reefs are the foundation to our social, cultural, and economic life; however, reefs around the world are currently being threatened by many local and global impacts. Ongoing increases in seawater temperature pose significant threats to the integrity of these valuable ecosystems through extensive coral bleaching events. Therefore, we developed a coral health reference card, the Hawaiian Koʻa (coral) Card, to assess and quantify coral bleaching and to educate the community about its impacts in Hawai‘i. To accurately quantify the change in coral color during bleaching, controlled laboratory studies followed by field validations and surveys were conducted. Colors presented on the Hawaiian Koʻa Card have been linked to physiological state and health (e.g., symbiont density, chlorophyll levels, photosynthetic performance) of common coral species in Hawaiʻi due to bleaching. The Hawaiian Koʻa Card provides a technical solution to inform and improve management of our nearshore resources through collaborative monitoring efforts by community members, educators, researchers, and managers on a state-wide scale, which will assist in determining management efficacy, identifying regions and species of resilience, establishing baselines and focus areas, and developing and executing rapid response plans.

Highlights

Rising global seawater temperatures are threatening the health of coral reef ecosystems worldwide through frequent and prolonged bleaching events [1,2,3,4,5]
To assure the widest spatial coverage of ecologically important coral species represented on the Hawaiian Koa Card, coral species selection criteria was based on the Hawai‘i Coral Reef Assessment and Monitoring Program’s (CRAMP) determination of the species with the highest total percent cover throughout the Main Hawaiian
Statistical analyses were performed in R using a non-parametric Spearman’s rank correlation

Summary

Introduction

Rising global seawater temperatures are threatening the health of coral reef ecosystems worldwide through frequent and prolonged bleaching events [1,2,3,4,5]. The synergistic effects of increased temperature, irradiance, and often, reduced water flow that can cause mass bleaching and coral mortality are pronounced during El Niño Southern Oscillation (ENSO) years [6, 7]. Coral bleaching occurs when elevated seawater temperatures cause the breakdown of the relationship between the coral-animal and their symbiotic intracellular algal partners [2, 8, 10]. As corals lose their algal symbionts, or “bleach”, the color of the colony begins to lighten until the tissues are transparent and the skeleton becomes visibly white [7, 10, 11].

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