The shallow coral reefs that we all know, are like the tip of an iceberg – they are the more visible part of an extensive coral ecosystem that reaches into depths far beyond where most people visit. The invisible reefs, known as mesophotic coral ecosystems (MCEs) are widespread and diverse, however they remain largely unexplored in most parts of the world. With the global climate heating up, the world’s shallow coral reefs are predicted to experience increasing levels of catastrophic bleaching. This report asks the question – can MCEs provide a “life boat” for shallow coral reefs that are suffering decimation from rising sea surface temperatures and other anthropogenic impacts?
Picture a coral reef — most people will probably imagine brightly coloured corals, fish and other animals swimming in well-lit shallow waters. In fact, the coral reefs that live close to the surface of the sea — the ones that we can swim, snorkel, or dive near and see from space — are only a small portion of the complete coral reef ecosystem. Light-dependent corals can live in much deeper water (up to a depth of 150 m in clear waters). The shallow coral reefs from the surface of the sea to 30–40 m below are more like the tip of an iceberg; they are the more visible part of an extensive coral ecosystem that reaches into depths far beyond where most people visit. These intermediate depth reefs, known as mesophotic coral ecosystems (MCEs), are the subject of this report.