Document Type

Article

Publication Date

12-2018

DOI

10.1242/jeb.188581

Publication Title

Journal of Experimental Biology

Volume

221

Issue

24

Pages

jeb188581 (11 pp.)

Abstract

Spatial heterogeneity in environmental characteristics can drive adaptive differentiation when contrasting environments exert divergent selection pressures. This environmental and genetic heterogeneity can substantially influence population and community resilience to disturbance events. Here, we investigated corals from the highly variable back-reef habitats of Ofu Island in American Samoa that thrive in thermal conditions known to elicit widespread bleaching and mortality elsewhere. To investigate the relative importance of acclimation versus site of origin in shaping previously observed differences in coral tolerance limits at Ofu Island, specimens of the common Indo-Pacific coral Porites lobata from locations with differing levels of thermal variability were acclimated to low and high thermal variation in controlled common garden aquaria. Overall, there were minimal effects of the acclimation exposure. Corals native to the site with the highest level of daily variability grew fastest, regardless of acclimation treatment. When exposed to lethal thermal stress, corals native to both variable sites contained elevated levels of heat shock proteins and maintained photosynthetic performance for 1–2 days longer than corals from the stable environment. Despite being separated by <5 >km, there was significant genetic differentiation among coral colonies (FST=0.206, PCladocopium sp. (ITS type C15). Our study demonstrates consistent signatures of adaptation in growth and stress resistance in corals from naturally thermally variable habitats, suggesting that differences in the amount of thermal variability may be an important contributor to adaptive differentiation in reef-building corals.

Comments

Green Open Access

Funding Agency: United States Geological Survey -- Grant number 1434-00HQRU1585

National Science Foundation -- Grant number OCE06-23678

© 2018. Published by The Company of Biologists Ltd.

Original Publication Citation

Barshis, D. J., Birkeland, C., Toonen, R. J., Gates, R. D., & Stillman, J. H. (2018). High-frequency temperature variability mirrors fixed differences in thermal limits of the massive coral Porites lobata. Journal of Experimental Biology, 221(24), jeb188581. doi:10.1242/jeb.188581

ORCID

0000-0003-1510-8375 (Barshis)

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