These habitats interconnect,and all are vital to the well being of the Great Barrier Reef. This is the little known story of one of the most complex and spectacular ecosystems on Earth. The Great Barrier Reef is over two thousand kilometres long,which means the lagoon that lies between the outer reef and the Australian mainland is vast. An area one and a half times the size of the British Isles. Pick a spot anywhere in the lagoon and you'll likely find sand,for about two-thirds of the seafloor here
is a shifting underwater desert. It looks barren, but there is life here. It's just that you don't often see it.