The South Pacific is a truly special place that I got a bit carried away exploring, to the point that I may need several posts to cover things I’ve come across. This February 21st Sentinel-2 image shows the inside of the Fakarava atoll, which itself is a part of the Tuamotu Archipelago (the largest atoll chain in the world) in French Polynesia. These peculiar star-like features are coral mounds that remain just below the water’s surface.

Zooming out, the stitched image below shows a slice of the archipelago, with Fakarava being the rectangular shaped atoll on the left, 55km in length. When Darwin came up with the idea that atolls formed from subsiding volcanoes, he did not provide an explanation for the irregular shapes of some atolls such as this one. One explanation is that as a conical volcano degrades into a seamount, some of its sides may erode irregularly through underwater landslides and tsunamis, providing a variety of shapes that coral will then colonize (read more here).

Satellite data from ESA’s Copernicus program. CC BY-SA 3.0 IGO.