The magnificent Great Barrier Reef in Australia has again been in news: it has been reduced to a mere shadow of its former self. A recent comparison of contemporary photographs with pictures taken in 1980 has laid bare this distressing fact to the Great Barrier Reef Marine Park Authority. The comparison confirms the worst fears of the Authority's scientists that the "reef flats" -- the coral plateaus on the landward side of the reefs -- are being smothered under sediment.
According to a research study carried out in 1992 for the Queensland Department of Environment and Heritage, the quantity of sediment that reaches the Great Barrier Reef is 4 times of what it was a century ago. The sedimentation has been accelerated by land clearing, sugarcane harvesting and cattle grazing. No small damage is done by fertilisers containing phosphates and nitrates that get mixed with the sediments. These nutrients hasten the formation of seaweed and algae that kill off or asphyxiate the corals.