This study investigated whether differences in bleaching susceptibility in the coral Montipora capitata are heritable by examining the survival of larvae and juveniles from parents that had and had not bleached in 2015. Larvae and juveniles from bleached parents had lower survival than those from non-bleached parents when exposed to high temperatures, suggesting bleaching susceptibility may be heritable. The results indicate corals are not adapting fast enough to rising temperatures and highlight the need to understand coral adaptation to better predict reef persistence under climate change.

1. Similar responses to high temperature stress among
coral parents, larvae, and juveniles
Nina Bean1, Dr. Crawford Drury2, Casey Harris3
Reef-building corals are threatened by rising seawater
temperatures which induces coral bleaching.
Bleaching is the loss of symbiotic algae (Family:
Symbiodiniaceae) and can lead to coral mortality1.
In 2015, there was a bleaching event in Kāne‘ohe Bay,
Hawai‘i where some Montipora capitata colonies
bleached, while those directly adjacent did not.
Coral bleaching can be influenced by:
• Genotype2
• Acclimatization ability4
• Associated microbial5 and algal6 communities.
Determine if differences in M. capitata bleaching susceptibility are heritable by
measuring the survivorship of larvae and juveniles from parents that had and had
not bleached in 2015.
Collecting Larvae
Montipora capitata gametes were collected from colonies in Patch
Reef 13, Kāne‘ohe Bay, O‘ahu during the new moon spawning in July
2018 using a net funneling system.
Experimental Set up
Pools of nonbleached, bleached and crossed larvae were made and split up in to
two temperature treatments, 30.1℃ and 27.5℃ (control). Larvae in each
treatment were placed in falcon tubes to analyze survivorship. The remaining
larvae were allowed to settle into the juvenile stage for 13 days and then were
exposed to temperature treatments.
n=50, 15 replicates n= ~73, 2 replicates
Gates Coral Laboratory:
• Dr. Crawford Drury
• Casey Harris
• Josh Hancock
• Kira Hughes
• Jen Davidson
Hawaiʻi Institute of Marine Biology
University of Hawaiʻi at Mānoa
Key:
• Bleached (BL) = Colonies that
bleached in 2015 and recovered.
“Bleached larvae” are from these
colonies.
• Nonbleached (NBL) = Colonies that
did not bleach in 2015.
“Nonbleached larvae” are from
these colonies.
• Crossed (NBLxBL) or (X) = Larvae
with NBL and BL parents.
• Montipora capitata larvae and juveniles are just as sensitive to high
temperature stress as their parents.
• These results suggest an underlying heritability of genes and/or epigenetic
modifications relating to bleaching susceptibility that are passed down
from parent to offspring.
• Corals do not appear to be adapting or acclimating fast enough to keep up
with the current warming trends.
Larval SurvivorshipSize of larvae on Day 3
Treatment
Ambient Bleached (BL)
Ambient Nonbleached (NBL)
Ambient Crossed (X)
High Bleached (BL)
High Nonbleached (NBL)
High Cross (X)
Statistics
• Multi-factor ANOVA
• Tukey’s HSD post-hoc test
• Cox Proportional Hazards model
• Bars represent standard error
Introduction Methods
Results
Project Objective
Significance
It is imperative to understand whether corals can adapt or acclimate to our rapidly
changing climate in order to forecast coral reef persistence, estimate their
resulting goods and services, and identify critical conservation and restoration
activities.
Main Takeaways
Juvenile Survivorship
p<0.001
Acknowledgements
1. University of Hawaiʻi at Mānoa
2. Hawaiʻi Institute of Marine Biology
3. Rosenstiel School of Marine and
Atmospheric Science
Larvae Juveniles
References
1) T.M. DeCarlo et al., (2017) DOI: 10.1038/srep44586 2) L. D’Croz et al., (2004) DOI: 10.1007/s00338-004-
0397-7 3) R. Berkelmans et al., (2006) DOI: 10.1098/rspb.2006.3567 4) M. Ziegler et al., (2017) DOI:
10.1038/ncomms14213 5) R. Cunning et al., (2016) DOI: 10.3354/meps1173
Bleached individuals had lower survivorship than nonbleached individuals
in the high temperature treatment in both larval and juvenile stages.
Bleached larvae in the high temperature
treatment were the smallest.
p<0.001 p<0.002