Figure 4
From: Deoxygenation lowers the thermal threshold of coral bleaching
Incorporating hypoxia stress into the coral bleaching response. ROS accumulation is commonly observed in heat stressed corals, although it is unclear whether it is the actual trigger or a ‘smoking gun’, i.e. downstream of further upstream events that initiate the symbiotic breakdown22,97. Despite such uncertainties, hypoxia stress during heating may play a pivotal role in determining coral bleaching susceptibility. Specifically, hypoxia- and heat-driven excessive oxidative stress could hamper signalling of the Hypoxia-inducible Factor (HIF) hypoxia response system (HRS), enhance photodamage, and leave the coral immune-compromised. Increasing deoxygenation may thus increase coral bleaching susceptibility.
