About This Project

Coral reefs are in serious danger. The southern Great Barrier Reef (GBR) is currently experiencing one of the most extreme marine heatwaves in recorded history. The goal of this project is to uncover how life-long exposure to variable thermal regimes influence coral community resilience during the 2024 marine heatwave. I will visit the GBR to download currently deployed temperature loggers and collect data on benthic cover and coral health across 6 sites, extending monitoring to its 10th year.

Ask the Scientists

What is the context of this research?

Coral reefs are among the most threatened ecosystems on Earth, with over half of the world's reef-building corals lost since 1950. Reef-building corals live at the upper edge of their thermal limits, and persistent temperatures just one degree above a coral's typical summer maximum can cause coral bleaching. Marine heatwaves resulting in mass coral bleaching are now occurring frequently, having gone from one mild event last century to as many as five per decade in modern times. Remarkably, thermally extreme or variable habitats provide a glimmer of hope that heatwave-resilient corals may exist on reefs worldwide. Corals within these habitats can tolerate temperature fluctuations of up to seven degrees per day - conditions which are not predicted to occur on ordinary reefs until 2100.

What is the significance of this project?

To significantly advance our understanding of coral heat tolerance in the Anthropocene, this project will combine nearly a decade of coral reef benthic cover data with high-resolution seawater temperature records. This dataset provides an invaluable baseline record and perfect opportunity to investigate: (i) how life-long exposure to diverse thermal regimes influence coral heat tolerance, and (ii) how these thresholds relate to coral community resilience during the unfolding 2024 marine heatwave. For the 500 million people who rely on coral reefs for food, tourism and coastal protection, a better understanding of how diverse coral communities develop thermal tolerance will allow us to effectively conserve and manage coral reef ecosystems in the Anthropocene.

What are the goals of the project?

Whether coral populations and communities acclimated and/or adapted to variable thermal conditions can resist bleaching during increasingly frequent and severe marine heatwaves remains a critical outstanding question. The goal of this project is to investigate how life-long exposure to variable thermal regimes influence coral heat tolerance and if elevated thermal thresholds equate to coral community resilience during the unfolding 2024 marine heatwave. Specifically, we will (i) collect and redeploy temperature sensors and (ii) perform benthic surveys through both traditional percent cover surveys and digital photogrammetry across 6 sites at Heron Island. Data will be compared to historical records to track changes in seawater temperatures, demographics, composition and cover.