Coral reefs are among the planet’s most biologically diverse habitats, supporting between 25% and 40% of all known marine species. In addition, they provide protection against coastal erosion and underpin the subsistence of millions of people around the world.
Now, a new study reveals that, in fact, coral reefs cover a much larger area of Earth than previously thought. In an article published in the journal ‘Cell Reports Sustainability’, scientists reveal that about 348,000 square kilometers of the planet’s surface are covered by coral reefs—almost four times the area of Portugal.
This area includes a further 64,000 square kilometers beyond previous estimates, something made possible through the collection and analysis of more than 1.5 million satellite images. This allowed creating what the scientists involved in this project say is the first global map of the planet’s coral reefs.
“It’s more than just a map—it’s a tool for positive change for the reefs and for coastal and marine environments more broadly,” says Mitchell Lyons, from the University of Queensland and the study’s first author, in a statement. He adds that “these data will enable scientists, conservationists and policymakers to better understand and manage reef systems.”
The researchers also found that nearly 80,000 square kilometers of reef area sit on hard ground, rather than, for example, on sand or seagrass meadows.
However, from the total area, only about 80,000 square kilometers are actually considered coral habitats, i.e., “only about a quarter of the global area” will be able to support “significant amounts of corals,” reads the article. The remaining area continues to be classified as part of coral reefs or is conducive to these symbiotic organisms, but will currently have little coral abundance, being instead largely occupied by seagrass beds or algae.
According to the estimates, Indonesia is the country with the largest coral reef area, followed by Australia and the Philippines.
