The world's biggest island cluster by count sits off Finland, not the tropics
Indonesia spans more than 17,500 islands and about 284 million people, yet the top spot for sheer number goes to Finland's Archipelago Sea, with roughly 40,000 mostly empty islets. Even the word archipelago began as a name for a single sea, the island-studded Aegean.
Italian sailors called the Aegean Sea arcipelago, a word that may be a garbled form of its Greek name. Because that sea is crowded with islands, the meaning slid from the water to the land scattered across it, and eventually to any chain or cluster of islands. A tidier-sounding origin, from Greek words for chief and sea, was proposed by the scholar Buondelmonti and still turns up, though it is a learned folk etymology.
Geologists sort these clusters by how they formed. Oceanic islands are volcanic peaks that rise straight from the seabed with no continental rock underneath: Hawaii, the Galapagos and the Mascarenes in the Indian Ocean, as well as Portugal's Azores with their hot springs. Continental fragments broke away from a mainland, sometimes carved off by glaciers, as with the Farallon Islands near California. Continental islands, by contrast, still rest on the shelf of their parent landmass, like those of British Columbia's Inside Passage and Canada's Arctic archipelago. Coral cays, such as the Florida Keys, build up as currents pile sediment onto reefs.
Humans now make archipelagos too, using reclaimed land, floating platforms or submerged structures. Dubai built the Palm Islands and The World for tourists, while the Netherlands is creating Marker Wadden as a refuge for birds and other wildlife.
Isolation on scattered islands can produce creatures found nowhere else. The Camiguin bulbul, a songbird, lives only on the Philippine island of Camiguin. In Indonesia, the Sangihe tarsier inhabits an island about 200 kilometres north-east of Sulawesi, and in 2008 a population on neighbouring Siau was recognised as a separate species. Closer to Europe, Scotland counts more than 700 islands around its coast.
Source: Archipelago
