The tide of brown water that is now polluting the sea off eastern Australia is bound to damage already damaged marine ecosystems. The world needs Australia to restore its mangroves, which is where the nutrients carried in the brown water would have been recycled. As well as sediment, the brown water carries nutrients and pesticides from agricultural run-off, together with whatever nasties have been washed out of flooded coalmines. Salinity of the sea-water could drop to 10 parts per 1,000 or even less and remain like that for weeks. After the Fitzroy river flooded Rockhampton in 1991, all the corals and sea grasses round the Keppel Islands died. The area had not yet recovered when the brown tide returned at the beginning of January, and keeps coming. The fresh water now entering the seas off Australia is expected to drift northwards to where the Great Barrier Reef is already struggling with rising sea temperatures. In ecological terms, worse, perhaps very much worse, is on the way. Australia owes it to the rest of the world to get a handle on its regular floods. Or she won’t be right, mate.
Australian floods: Why were we so surprised? | Environment | The Guardian