About This Project

Corals are bleaching at unprecedented rates due to global warming. The Caribbean has lost 70% of hard coral cover since the 1970s. However, some corals are more resilient to bleaching than others because they are associated with heat-tolerant symbiont algae. We want to examine coral-symbiont associations in the Caribbean to determine which corals in the community are most likely to survive future bleaching events and if these corals are in need of restoration.

Ask the Scientists

What is the context of this research?

Corals host zooxanthellae that provide food to their coral hosts and are critical for their survival. Coral-zoox relationships can be disrupted during marine heating by a process called coral bleaching, which leads to increased morbidity and mortality of coral hosts. Because the unique traits of coral and zoox species combinations determine their vulnerability to thermal stress, the regional loss of coral species is potentially predictable. What is not yet predictable is how the loss of coral and their associated zoox species will affect the remaining coral-zoox symbiosis network. A complete network will provide a basis for predicting how the loss of vulnerable Caribbean coral-zoox association will affect the stability of the network.

What is the significance of this project?

Coral-zoox combinations have different thermal tolerances and bleach or perish at different thermal stress levels. Given that recent bleaching events in the Caribbean are more frequent and severe, it is important that we know which corals and which zoox are going to last and which combinations will perish in the coming years. We want to determine the zoox identities for all Caribbean coral species, and their average thermotolerance scores for both partners, in order to identify potential vulnerabilities in the Caribbean coral symbiosis network. Identifying vulnerabilities in the network will help to inform and inspire resilience-based management of coral reefs in the Caribbean. This type of management strategy is key to operating sustainable fisheries and reefs for tourism.

What are the goals of the project?

The aim of this study is to apply a systems approach to all 65 known reef-building corals and their associated symbionts in the Caribbean to identify, first, the network-critical Symbiodiniaceae and their coral host species for Caribbean reefs, and second, which of these critical species are best adapted for surviving inevitable marine heating events and increasing average temperatures. Combining these results with measures for phylogenetic distinctiveness will provide a short-list of Caribbean corals for restoration projects to focus on. We will incorporate metadata about conservation status using IUCN and EDGE scores to determine which corals are most vulnerable to extinction in the Caribbean.