Q. Coral microatolls, recently used in a study to reconstruct 90 years of sea-level history in the Indian Ocean, are colonies of which genus of corals?
Answer: Porites
Notes: A recent study conducted at Mahutigalaa reef in the Maldives used Porites coral microatolls to reconstruct sea-level changes from 1930–2019. These disk-shaped corals grow sideways once constrained by the lowest tide, making their upper surface a natural marker of past sea levels. Researchers X-rayed growth bands in the corals, similar to tree rings, and combined them with uranium-thorium dating. This study provided the longest sea-level record for the central Indian Ocean, revealing early acceleration of sea-level rise since the late 1950s.