Tidal zone Adele Island sits in the Indian Ocean 104km off the north coast of Western Australia on t

Tidal zoneAdele Island sits in the Indian Ocean 104km off the north coast of Western Australia on the shallow continental shelf. While the permanently exposed part (the dark green grass covered bit) is a mere 2.9km long, the concentric rings of different tidal regimes and their varied sandbanks extend a full 24.5km, bounded by the surrounding dark blue of deeper waters. The radial lines coming out from the land are produced by the 6 metre high tides that affect the area as the water ebbs and surges on its twice daily round.The island itself is a ridge of stabilised storm tossed sand with a maximum altitude of 4 metres sitting atop an underlying limestone platform, but despite this the place is a key breeding ground (and protected sanctuary) for lesser frigate birds, pelicans and cormorants, among others. Efforts are underway to clear the place of Polynesian rats, which are a threat to young seabirds, and have killed off many species on other islands. Back in the ice age when sea levels were some 120 metres lower, the isle was much larger, and would have more than filled the scope of this image.LozImage credit: NASAhttp://go.nasa.gov/1OYqb08http://bit.ly/1OGVqkAhttp://bit.ly/1OGVwIM -- source link
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