COS 106-1 - The impact of rising temperature on the prevalence of coral diseases and its predictability: A global meta-analysis

Tuesday, August 16, 2022

3:30 PM – 3:45 PM EDT

Location: 513D

Presenting Author(s)

SB

Samantha Burke

University of New South Wales Sydney, Australia

Slides (PDF)

Coauthor(s)

PP

Patrice Pottier

University of New South Wales Sydney, Australia
EM

Erin Macartney

University of New South Wales Sydney, Australia
TR

Tracey Rogers

University of New South Wales Sydney, Australia
ML

Malgorzata Lagisz

University of New South Wales Sydney, Australia
SD

Szymon M. Drobniak

University of New South Wales Sydney, Australia
TA

Tracy Ainsworth

University of New South Wales Sydney, Australia
SN

Shinichi Nakagawa

University of New South Wales Sydney, Australia

Background/Question/Methods

Coral reefs are one of the most diverse ecosystems, yet they are under severe threat from disease. Surveys of coral disease prevalence have become more abundant as outbreaks continue to disturb reefs. Temperature correlates highly with disease prevalence, so increasing temperatures with climate change may make corals more vulnerable to disease. However, this relationship is likely to be more complicated than it appears. Extreme temperatures may also reduce pathogens’ ability to infect hosts, and corals previously exposed to high temperatures may be more resistant to infection. In addition, factors specific to a coral species or reef environment may greatly alter disease susceptibility. As many have sought to uncover what drives outbreaks, there exists an opportunity for global analysis to compile the ample published data on coral disease prevalence. We conducted a global meta-analysis to test whether coral disease prevalence is related to global sea surface temperature. We compared changes in disease prevalence in relation to sea surface temperature data and along the time axis. We also compared disease prevalence between three ocean basins (Atlantic, Pacific, and Indian Oceans) to examine whether regional differences independent of temperature explain trends in disease prevalence.

Results/Conclusions

Our analysis included 113 studies which yielded 930 effect sizes spanning 30 years. Through time, coral disease prevalence increased significantly, with the rate of this increase itself rising as well. Disease prevalence was also positively related to average summer sea surface temperatures. At the same time, disease prevalence was becoming less predictable as more extreme summer temperatures were recorded. Rather surprisingly, coral disease prevalence decreased as degree heating weeks (a measure of cumulative anomalous sea surface temperatures) increased. Additionally, three major oceans differed when examining degree heating week interactions, but only Atlantic-Indian and Indian-Pacific Ocean interactions differed with average summer sea surface temperature. Our results suggest that an increase in sea surface temperature could be expected to promote infections, but anomalous thermal spikes (quantified by degree heating weeks) may have promoted thermal acclimation of corals, protecting them from disease. Our findings also illustrate the complexity of temperature’s influence on coral disease prevalence. Regardless, coral disease is increasing on a global scale, and a united effort is required to mitigate the impacts of anticipated future disease outbreaks.