Global change differentially modulates Caribbean coral physiology

Abstract

Global change driven by anthropogenic carbon emissions is altering ecosystems at unprecedented rates, especially coral reefs, whose symbiosis with algal symbionts is particularly vulnerable to increasing ocean temperatures and altered carbonate chemistry. Here, we assess the physiological responses of three Caribbean coral (animal host + algal symbiont) species from an inshore and offshore reef environment after exposure to simulated ocean warming (28, 31°C), acidification (300–3290 μatm), and the combination of stressors for 93 days. We used multidimensional analyses to assess how a variety of coral physiological parameters respond to ocean acidification and warming. Our results demonstrate reductions in coral health in Siderastrea siderea and Porites astreoides in response to projected ocean acidification, while future warming elicited severe declines in Pseudodiploria strigosa. Offshore S. siderea fragments exhibited higher physiological plasticity than inshore counterparts, suggesting that this offshore population was more susceptible to changing conditions. There were no plasticity differences in P. strigosa and P. astreoides between natal reef environments, however, temperature evoked stronger responses in both species. Interestingly, while each species exhibited unique physiological responses to ocean acidification and warming, when data from all three species are modelled together, convergent stress responses to these conditions are observed, highlighting the overall sensitivities of tropical corals to these stressors. Our results demonstrate that while ocean warming is a severe acute stressor that will have dire consequences for coral reefs globally, chronic exposure to acidification may also impact coral physiology to a greater extent in some species than previously assumed. Further, our study identifies S. siderea and P. astreoides as potential ‘winners’ on future Caribbean coral reefs due to their resilience under projected global change stressors, while P. strigosa will likely be a ‘loser’ due to their sensitivity to thermal stress events. Together, these species-specific responses to global change we observe will likely manifest in altered Caribbean reef assemblages in the future.

Starvation differentially affects gene expression, immunity and pathogen susceptibility across symbiotic states in a model cnidarian

“…Gene expression similarity was tested using PERMANOVA implemented with the pairwiseAdonis package v.0.4 [33]. Gene expression plasticity of symbiotic and aposymbiotic Aiptasia under starvation was estimated as a function of the distance of each point in the treatment group (starved) relative to the location of its clonal counterpart in the control group (fed) in PC space using the first two principal components [34,35]. Gene expression plasticity for symbiotic and aposymbiotic Aiptasia was then compared using an analysis of variance.…”

Gene expression plasticity facilitates acclimatization of a long-lived Caribbean coral across divergent reef environments

“…S1 ). While these in situ measurements only span one year of the reciprocal transplant experiment, previous work monitoring SST in this region over the last several decades via satellite products demonstrates that these temperature patterns are consistent across time for these reefs 62 , 63 . Additionally, these satellite SST data suggest that these reef locations did not experience thermal anomalies during the experimental period.…”

Exposure to global change and microplastics elicits an immune response in an endangered coral

“…This pattern was accompanied by enrichment of terms associated with amino acid catabolism, suggesting A. cervicornis may have mediated physiological stress through protein catabolism (Davies et al, 2016; Aguilar et al, 2019; Rädecker et al, 2021). While we did not assess host or symbiont physiological traits along with these gene expression profiles, it is likely that the growth and/or energy reserves may have been impacted as a result of treatment conditions (Aichelman et al, 2021; Scucchia et al, 2021; Bove et al, 2022a).…”