Coral Bleaching Susceptibility Is Decreased following Short-Term (1–3 Year) Prior Temperature Exposure and Evolutionary History

Abstract

Coral exposed to short periods of temperature stress (≥1.0°C above mean monthly maximum) and/or increased frequencies of high temperatures may bolster resilience to global warming associated with climate change. We comparedMontastraea cavernosa(Linnaeus, 1767; Cnidaria, Scleractinia, Faviidae) from the Florida Keys National Marine Sanctuary (FKNMS) and the Flower Garden Banks National Marine Sanctuary (FGBNMS). Thermal stress has been reported frequently within the FKNMS; however, corals in the FGBNMS experience nominal exposures to similar stressors. Corals were exposed to three temperatures (27°C, 31°C, and 35°C) for 72 h. Colonies from the FKNMS lost significantly fewer viable and necrotic zooxanthellae under conditions of acute stress (35°C) than the FGBNMS colonies. This indicates that the FKNMS corals are less temperature-sensitive than those in the FGBNMS. The observed differences point to greater prior temperature exposure and adaptation in the former versus the latter site when correlated to previous years of thermal exposure.

Responses to High Seawater Temperatures in Zooxanthellate Octocorals

“…The question arose regarding whether this response was region-specific to the western Indo-Pacific, or the Great Barrier Reef. It is now known that the same cellular responses occur under the same conditions in the Caribbean species Montrastraea cavernosa and Millepora alcicornis [79]. These authors also found that bleaching susceptibility is decreased in coral and their symbionts when species have been exposed to prior bleaching events ( i.e.…”

“…Many earlier studies focus on heat stress occurring over a temporal scale of weeks, including degree heating weeks (DHW [79]). This study reveals that expelled Symbiodinium cells in some corals, such as Sarcohphyton ehrenbergi , begin exhibiting signs of potentially reversible PCD after 9 hrs, and signs of irreversible PCD after 12 hrs.…”

“…These apoptotic and necrotic responses in the zooxanthellae under high heat conditions, however, have now been observed in three families of the Scleractinia in two oceans, and two families of the Octocorallia in the western Indo-Pacific. Although there may be variation between these taxa regarding observed responses, there are clearly parallel responses as well [79], [81].…”

Symbiont communities and host genetic structure of the brain coral Platygyra verweyi, at the outlet of a nuclear power plant and adjacent areas

“…2003). In addition, Haslun et al. (2011) suggested that corals that are exposed to frequent and short‐term temperature stress tend to be less temperature sensitive than those that are not exposed to such stress.…”

“…A recent study has shown that coral hosts are affected less by seawater temperature stress over a short period of time through exaptation (Strychar & Sammarco 2008). Haslun et al. (2011) have also shown that corals that are exposed to frequent seawater temperature stress tend to be less temperature sensitive than those not exposed to such stress.…”