The Effects of Synthetic Shading on Thermal Bleaching of Aquacultured Orbicella faveolata Corals

Graduation Date


Document Type

Honors Thesis

Degree Name

Bachelor of Science


Natural Sciences and Mathematics

Director of the Honors Program

Lynn Sondag, MFA

First Reader

Vania Coellho, PhD

Second Reader

Tyler Johnson, PhD


Coral bleaching occurs when the organisms are faced with a high degree of thermal stress, causing them to expel their zooxanthellae (algal symbionts), resulting in a white appearance and a decrease in their nutritional intake. Due to rising ocean temperatures caused by climate change, this problem has become pervasive over the last 40 years (Hughes et al., 2017). This study will explore data collected from research conducted at Dominican University of California, coupled with literature on coral organisms and their ecosystems, to demonstrate measures that can be taken to reduce incidents of coral bleaching. In the experiment, the impact of synthetic shading on the thermal bleaching of aquacultured fragments of an endangered species of corals, Orbicella faveolata, were observed over the course of eight degree heating weeks (DHWs). A total of 342 corals, including three genotypes, A (F1A), B (F1255), and C (F3A), were equally divided into three treatments: normal water temperature, no shade (control); high water temperature, no shade (NS); and high temperature, 80% shade (80S). The control tanks were set at 26.5℃, while NS and 80S tanks were set at 31.5℃. Pictures were taken at each DHW and corals were scored on a standardized color scale. Analysis of the scores demonstrated that for all genotypes, shading was an effective measure to reduce bleaching. The results of this experiment are promising, as they allude to a possible method of lowering the incidence rate of coral bleaching.

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