By Dhani Irwanto, 3 February 2016
Coral reefs are diverse underwater ecosystems held together by calcium carbonate structures secreted by corals. Coral reefs are built by colonies of tiny animals found in marine waters that contain few nutrients. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups. The polyps belong to a group of animals known as Cnidaria, which also includes sea anemones and jellyfish. Unlike sea anemones, corals secrete hard carbonate exoskeletons which support and protect the coral polyps. Reefs grow best in warm, shallow, clear, sunny and agitated waters.
Coral reefs begin to form when free-swimming coral larvae attach to submerged hard surfaces. As the corals grow and expand, reefs take on one of three major characteristic structures – fringing, barrier or atoll. Fringing reefs, which are the most common, project directly from the hard surfaces, forming reefs and expand in horizontal and vertical directions. Barrier reefs also project, but at a greater distance. If a fringing reef forms around a rocky island that subsides completely below sea level while the coral continues to grow upward, an atoll forms.
The Sunda shelf was exposed during the Ice Age, the most recent glacial period occurring during the last years of the Pleistocene, from approximately 110,000 to 12,000 years ago. It was in the Sundaland that man first found the ideal climatic conditions for development, and it was there that he invented farming, structure building, seafaring and civilization from 70,000 years ago. People of these civilizations were dependent on water for their mobilizations, so coastal areas were the most suitable places to live and then communities were formed there. They used stones and woods to build houses and other buildings since these materials were abundant in the region.
The Ice Age waned during the period 14,000 – 7,000 years ago that accompanied by sea level rise – as much as 130 m. The costal communities then moved to adjust the changing coastlines and remnants of their buildings were left sank under the sea. Finding the most suitable places to grow, coral reefs were formed on these buildings.
Based on the data of coral reefs and bathymetric maps, the author identifies the probable sites and ages of the ancient civilizations, as shown on the attached map. Note that not all of the coral reef sites were ancient civilizations because coral reefs could form on natural hard surfaces as well.
According to Plato’s narrative, Atlantis ended at around 11,600 years ago. Based on the above study, the location of the capital city of Atlantis is expected at one of the very ancient civilization sites shown on the map. Plato also wrote that the capital city of Atlantis at Solon’s time had been covered by a coral reef so it was not navigable.
Copyright © Dhani Irwanto, 2016. All rights reserved.