Queensland floodwaters are causing concern as they approach the Great Barrier Reef.
Scientists from James Cook University, the Queensland Environmental Protection Agency and the Department of Natural Resources are meeting at the flooded Fitzroy River to assess the situation.
It is feared that sediment and chemical run-off from farmland and mining sites could threaten corals on the reef.
The main problem with sediment is one of the things it will do is settle on coral and physically smother them in high enough concentrations, said Dr David Haynes of the Coastal Developmental Unit of the Great Barrier Reef Marine Park Authority.
If the corals are in dirty water then the coral's food source is cut off for as long as the water is dirty.
Pesticides and heavy metals that would normally be contained on the farms and mining sites, and so not pose a threat to the environment, have been washed out with the floodwater. However, one of the greatest threats to the reef may actually be the water itself.
In the past what we have found with these sorts of floods is that it is actually the fresh water which can damage the corals more, said Dr Haynes.
The scientists are unable to stop the floodwater run-off, and so can only monitor the situation through water sampling and diving down onto the reef to assess damage.
Dr Haynes says that the level of damage depends on how the flood plume hangs around. Other animals can swim away, but corals are rooted to where they are and they have to take anything that comes past them.