Study Finds Aldabra Atoll’s Shoreline Stable for Past 51 Years Despite Rising Seas
VICTORIA, Seychelles — A recent study, published on December 13, 2024 in Scientific Reports, has shed light on the remarkable resilience of Aldabra Atoll’s shoreline, which has shown minimal change over the past 51 years despite rising global sea levels. The research was conducted by the University of Zurich and the Seychelles Islands Foundation (SIF) using aerial and satellite imagery spanning from 1960 to 2011.
The results show that more than 60 per cent of the shoreline has remained unchanged over the period. On average, the shoreline changed at a rate of 0.25 plus-or-minus 0.36 metres per year, with significant localised erosion trends. The highest rate of shoreline growth, +3.13 metres per year, was observed on the lagoon side of Picard Island, while the most significant erosion, a total loss of 214 metres over the 50-year period, occurred along the lagoon shoreline of Grande Terre.
Anabelle Constance, a conservation and spatial ecologist at the SIF and first author of the study, stated: “Atolls are dynamic and have adapted to grow vertically with changing sea levels over hundreds and even thousands of years. However, this balance relies on the availability of loose sediments from nearby coral reefs.” The difference between Aldabra’s inner and outer shorelines is attributed to their composition — the outer shore is mostly solid limestone, which has undergone cementation, making it more durable.
