A multi-trait systems approach reveals a response cascade to bleaching in corals

Area of Science:

• Marine Biology
• Coral Reef Ecology
• Climate Change Science

Background:

• Climate change disrupts coral-algal symbiosis, leading to mass bleaching events and coral mortality.
• Previous studies identified physiological complexities during thermal stress but lacked mechanistic understanding of coral bleaching.

Purpose of the Study:

• To compare thermal stress responses in two distinct coral species, Acropora millepora and Stylophora pistillata.
• To integrate multiple stress indicators to elucidate the mechanisms of coral bleaching.

Main Methods:

• Utilized a multi-trait-based approach comparing 14 stress indicators over time.
• Simulated a thermal anomaly to assess coral physiological responses.
• Focused on two phylogenetically distinct and widely distributed coral species.

Main Results:

• Identified conserved stress responses across both coral species, including symbiont loss and antioxidant activation preceding physiological collapse.
• Observed species-specific differences in antioxidant regulation timing and dimethylsulfoniopropionate (DMSP) production during bleaching.
• Noted a two-fold increase in DMSP in A. millepora versus a 70% decrease in S. pistillata.

Conclusions:

• Defined a cascading response to thermal stress conserved across coral species, crucial for understanding bleaching mechanisms.
• Highlighted that coral bleaching is a conserved process, with antioxidant capacity adaptations driving species-specific thermal tolerance.
• Emphasized the importance of antioxidant mechanisms in determining coral sensitivity to thermal stress.