The effects of artificial shading on coral bleaching due to thermal stress in the endangered coral species Orbicella faveolata
Location
Guzman 202, Dominican University of California
Start Date
4-20-2017 3:00 PM
End Date
4-20-2017 3:30 PM
Student Type
Undergraduate - Honors
Faculty Mentor(s)
Vania Coelho, Ph.D.
Presentation Format
Oral Presentation
Abstract/Description
Coral reefs are one of the most diverse ecosystems in the world, yet due to bleaching caused by the synergy between thermal stress and high light intensity, these ecosystems are being threatened. This study aimed to test the effects of different shade intensities paired with high temperature on the growth of the endangered Caribbean species, Orbicella faveolata. It was hypothesized that by decreasing light intensity, the corals would be better able to withstand thermal stress. Two hundred and fifty-nine coral fragments, from four coral colonies were used in the experiment. Ten to twelve fragments from each colony were placed per aquaria, for a total of 43 per tank. Six aquaria were placed under metal halide light fixtures, with two tanks per treatment: 26.5 degrees Celsius, no shade (control); 31.5 degrees Celsius, no shade (HTNS); and 31.5 degrees Celsius, 80 percent shade (HT80S). We determined cumulative thermal stress using degree heating week (DHW) measurements, following NOAA’s Coral Reef Watch methodology. Our results showed that over an approximate one-month period, up to DHW 8, the greatest growth was observed in the HTNS treatment (0.1 g buoyant weight), with no statistically significant difference between controls and HT80S. This suggests, at least in the short-term, that high temperature and high light intensity promote faster growth in this species. Further studies would be necessary in order to understand the long-term consequences of this rapid growth, particularly considering this is a type of boulder coral, which naturally exhibits slower growth.
The effects of artificial shading on coral bleaching due to thermal stress in the endangered coral species Orbicella faveolata
Guzman 202, Dominican University of California
Coral reefs are one of the most diverse ecosystems in the world, yet due to bleaching caused by the synergy between thermal stress and high light intensity, these ecosystems are being threatened. This study aimed to test the effects of different shade intensities paired with high temperature on the growth of the endangered Caribbean species, Orbicella faveolata. It was hypothesized that by decreasing light intensity, the corals would be better able to withstand thermal stress. Two hundred and fifty-nine coral fragments, from four coral colonies were used in the experiment. Ten to twelve fragments from each colony were placed per aquaria, for a total of 43 per tank. Six aquaria were placed under metal halide light fixtures, with two tanks per treatment: 26.5 degrees Celsius, no shade (control); 31.5 degrees Celsius, no shade (HTNS); and 31.5 degrees Celsius, 80 percent shade (HT80S). We determined cumulative thermal stress using degree heating week (DHW) measurements, following NOAA’s Coral Reef Watch methodology. Our results showed that over an approximate one-month period, up to DHW 8, the greatest growth was observed in the HTNS treatment (0.1 g buoyant weight), with no statistically significant difference between controls and HT80S. This suggests, at least in the short-term, that high temperature and high light intensity promote faster growth in this species. Further studies would be necessary in order to understand the long-term consequences of this rapid growth, particularly considering this is a type of boulder coral, which naturally exhibits slower growth.