Seaweed smothering Great Barrier Reef?
This is an old, old claim about the destructive effects of nutrient runoff from those evil Queensland farms -- but the reef is still there
SEAWEED is choking the Great Barrier Reef and killing coral, new research has found. Scientists in one of the largest studies of water quality pollution on the reef yesterday revealed the shock impact on the $1 billion-a-year tourism drawcard.
Poor water quality on the reef due to run-off, nutrients and high turbidity was increasing the amount of seaweed and reducing biodiversity of corals, the study found.
Hot spots include the inshore reef north of the Burdekin River and the entire Wet Tropics zone from Townsville to Port Douglas.
"Seaweeds are a natural part of the reef," said Australian Institute of Marine Science coral reef ecologist Dr Katharina Fabricius. "But what we don't want is billions of algae smothering coral. "Choking is a loaded term but when seaweed abundance becomes too high there is no space left for coral to grow."
The study has just been published in the authoritative scientific journal Ecological Applications. It used data collated from 150 reefs and at more than 2000 water quality stations across the Great Barrier Reef Marine Park since 1992.
Principal investigator Dr Glenn Death said seaweed cover increased fivefold under poor water quality. "The diversity of corals was also affected, decreasing in poor water quality," he said. "Currently, the water on 22 per cent of reefs - about 647 reefs - on the Great Barrier Reef does not meet water quality guidelines."
The study predicts that if water quality was improved in these areas, seaweed would be reduced by more than one-third and the number of coral species would bounce back by 13 per cent.
The Great Barrier Reef Marine Park extends 2000km along the northeast Australian coast and covers 345,000sq km.