Waving meadows of emerald grasses part as a portly shape drifts through the shallowwaters. Like a blimp led astray, the creature uses its front flippers to paddle gently as itnibbles on the seagrass that makes its home. Silt stirs from the shallow seafloor, coralreefs reveal themselves in a riot of colours, with shoals of fish scurrying out of the way,and an entire ecosystem comes into view.