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A scientist in his laboratory is not only a technician: he is also a child placed before natural phenomena which impress him like a fairy tale.
- Marie Curie

For those of us in the temperate world, coral reefs are a colourful underwater world seen only on the occasional vacation or in a Disney film. But coral reefs are more than just a pretty face.  They are the most biologically diverse marine ecosystems on the planet. Millions of people in the developing countries depend on coral reefs every day, for shoreline protection, for food, and for income.

The amazing diversity and wealth of resources on coral reefs is made possible by a symbiosis between the corals (reef-building animals) and the microscopic algae (known as zooxanthallae) which live in the coral tissue. Corals themselves are mostly white - the colour of their skeleton. In some species, there is pink or purplish hue due to some pigmentation in the animal. Most of the colour you actually see in corals when diving or snorkelling comes from the zooxanthallae living in the transparent coral tissue. It is those tiny little plants, discernible only under a microscopic, that provide corals, the framework of the entire ecosystem, with a source of food.

When subject to environmental stress like abnormally hot water, corals can “bleach” due to a breakdown of the symbiosis with the colourful zooxanthallae. If the condition persists, the coral will die due to a lack of food. Understanding the sensitivity of corals to increasing ocean temperatures is crucial to the conservation of coral reef ecosystems and the many services those ecosystems provide.

Research

I lead research at the intersection of climate, marine and ecological science to evaluate the impact of climate variability and climate change on coral cover and diversity. My past research has attributed episodes of mass “coral bleaching” and associated coral mortality around the world over the past three decades to human-caused climate change. Recent modeling predicts that ocean warming over the next three to four decades may make mass coral bleaching a frequent occurrence on most reefs worldwide, depending on assumptions about acclimation and adaptation.

Our ongoing research combines climate modeling, satellite observations and field data collection to evaluate how past climate experience affect coral reef resilience to heat stress and identify ecosystems and habitats which may be more naturally resilient to climate change. The primary focus of this research is the Central Equatorial Pacific, which, thanks to the El Nino / Southern Oscillation, is a natural laboratory for testing hypotheses about the effect of past climate experience on coral reefs. I lead field annual field expeditions to the Gilbert Islands of Kiribati to document the geological history of the coral reefs and the response of the coral community to recent warm water events.

Want to learn more?

For some general information on the coral reef health and some interesting photos of bleached corals, check Coral Watch or Reefbase. If you're wondering when and where coral bleaching may happen, my colleagues at NOAA's Coral Reef Watch track the occurrence of the thermal stress that can lead to bleaching in real-time using satellite observations of ocean temperatures.