SKETCH MAP OF ALDABRA
Wolfgang E. Grulke wrote : The Aldabra atoll is the world's largest raised coral atoll and is made up of a chain of more than a dozen islands. Together they are about 35 km wide and enclose a huge tidal lagoon so large that Manhattan could fit comfortably into it. The land itself is so low that King Kong could easily step over it. Aldabra is larger in land area than Mahe and makes up a third of the Seychelles total land area. Its shoreline is mainly fossilised coral limestone undercut by the relentless wave action. When you look around from the centre of the lagoon at high tide you get the impression of being out in the middle of a very calm ocean. At low tide more than 80% of the area of this lagoon is completely dry. Water covering almost 100 square kilometres has to drain totally every low tide and reenter with every high tide.
The islands are separated by deep narrow channels which form the only way that water can enter or exit the lagoon with the tides. Within these channels lie many mushroom-shaped coral outcrops undercut and shaped by the constant erosion of the tides rushing in and out twice a day. The uplifted reefs that make up terrestrial Aldabra consist of solid and partially fossilised corals which have been raised several metres above sea level. Primarily, the ground is hard coralline limestone eroded by the sea and rain to form sharp-edged potholes. There is little or no soil. What soil there is is derived from guano, coral and other marine detrius. Vegetation on the eroded and severely pock-marked surface of Aldabra is alternately sparse and so thick with scrub (primarily Pemphis acidula) that a man can be lost in it within a few steps. It supports a unique flora and fauna that includes more than a hundred thousand giant tortoises (Geochelone gigantea). The abundance of these herbivorous reptiles, reputed to be the largest terrestrial variety, is one aspect that makes Aldabra unique.
Extracted from "More About Aldabra" by Wolfgang E. Grulke - Copyright FutureWorld - All Rights Reserved.