Corals escape bleaching in regions that recently and historically experienced frequent thermal stress

Abstract

The response of coral-reef ecosystems to contemporary thermal stress may be in part a consequence of recent or historical sea-surface temperature (SST) variability. To test this hypothesis, we examined whether: (i) there was a relationship between the historical frequency of SST variability and stress experienced during the most recent thermal-stress events (in 1998 and 2005 -2006) and (ii) coral reefs that historically experienced frequent thermal anomalies were less likely to experience coral bleaching during these recent thermal-stress events. Examination of nine detrended coral d 18O and Sr/Ca anomaly records revealed a high-(5.7-year) and low-frequency (.54-year) mode of SST variability. There was a positive relationship between the historical frequency of SST anomalies and recent thermal stress; sites historically dominated by the high-frequency mode experienced greater thermal stress than other sites during both events, and showed extensive coral bleaching in 1998. Nonetheless, in 2005Nonetheless, in -2006, corals at sites dominated by high-frequency variability showed reduced bleaching, despite experiencing high thermal stress. This bleaching resistance was most likely a consequence of rapid directional selection that followed the extreme thermal event of 1998. However, the benefits of regional resistance could come at the considerable cost of shifts in coral species composition.

Effects of thermal stress on key processes driving coral-population dynamics

“…Our sensitivity analyses agreed, in part, with studies on the Great Barrier Reef (Tanner et al 1996) that showed differential mortality was a major driver of coralpopulation dynamics, but differential recruitment and postsettlement mortality processes were also important in the present study. Therefore, we have moved away from simply adopting 'supply-side ecology' to reef corals (as systems driven solely by differential recruitment events) because environmental drivers also matter (Anthony & Connolly 2004, Hoogenboom & Connolly 2009), especially in a warming ocean where thermal stress has recently become more intense and frequent (Thompson & van Woesik 2009).…”

Mechanisms of Thermal Tolerance in Reef-Building Corals across a Fine-Grained Environmental Mosaic: Lessons from Ofu, American Samoa

“…More recently, focus has shifted toward understanding the plasticity of thermal tolerance in corals, and numerous studies have identified a direct link between thermal preconditioning and bleaching susceptibility from both field observations (Castillo and Helmuth, 2005;Maynard et al, 2008;Thompson and van Woesik, 2009;Castillo et al, 2012;Shuail et al, 2016) and experimental manipulation (Brown et al, 2000(Brown et al, , 2002Dove et al, 2006;Middlebrook et al, 2008;Bellantuono et al, 2012b;Bay and Palumbi, 2015). For example, Acropora, Pocillopora, and Porites from the Great Barrier Reef showed lower rates of bleaching during the 2002 bleaching event than the 1998 event, despite more intense conditions during the 2002 event (Maynard et al, 2008).…”

Species composition, habitat, and water quality influence coral bleaching in southern Florida

“…Resale or republication not permitted without written consent of the publisher Helmuth 2005, Finelli et al 2006, and (5) the potential adjustments of gene pools to thermal stresses through time (Stat et al 2008, Thompson & van Woesik 2009.…”