Resistance to Thermal Stress in Two Different Farmed Genotypes of Pseudodiploria clivosa Corals Under Low Light Conditions

Olivia A. Lang-Brown, Tesia J. De Leon, Kayla J. Kukaua, Romeo Mays, Stephen M. Raymundo, and Vania R. Coelho, Department of Natural Sciences and Mathematics, Dominican University of California, 50 Acacia Avenue, San Rafael, CA 94901

Climate change continues to increase ocean temperatures causing corals to become thermally stressed, eventually leading to bleaching, which is when corals expel their symbiotic algae, become paler in color and potentially die. For this reason it is important to find thermally resistant corals for restoration purposes. This experiment analyzed the effect of high temperature on two aquacultured genotypes, D12 and D17, of Pseudodiploria clivosa under low light, testing 25-27 fragments per genotype per treatment for a total of 102 corals. Specimens were placed in two sets of temperature-controlled aquaria: three tanks at low temperature, 26.5 degrees Celsius, and three at high temperature, 31.5 degrees Celsius. All aquaria received five moles of quanta per square meter per day as their total photosynthetic active radiation input. Water quality was monitored and adjusted daily, including salinity and nutrients. Cumulative thermal stress over time was measured in Degree Heating Weeks (DHWs) as described by the National Oceanic and Atmospheric Administration. We measured the extent that the corals bleached over 10 DHWs using a standardized reference card to measure color changes. Analyzing all corals combined, we observed that those in high temperature tanks showed statistically significant color change starting at DHW 2 when compared to controls. The same was observed for genotype D12, but there was no difference for genotype D17 until DHW 3. By DHW 10 about 80 percent of all corals were bleached, including one hundred percent of D12 corals, but only half of D17 corals. Considering the future increase in ocean temperatures due to global warming, we recommend the propagation of genotype D17 over D12 in coral restoration projects.

Additional Abstract Information

Presenters: Olivia Lang-Brown, Tesia De Leon, Kayla Kukaua, Romeo Mays, Stephen Raymundo, Vania Coelho

Institution: Dominican University of California

Type: Poster

Subject: Ecology

Status: Approved

Time and Location

Session: Poster 6
Date/Time: Fri 12:30pm-1:50pm
Location: Poster Location TBA