( CNN ) -- Floods have devastated the landscape of the state of Queensland , Australia , but they also present a high risk to the Great Barrier Reef . Stretching over 2,300 kilometers ( 1,430 miles ) along the northeast coast of Australia , large parts of the southern Great Barrier Reef are `` flooded '' with fresh water . Currently the biggest plumes of fresh water reach about 200 kilometers ( 124 miles ) north from the mouths of the Fitzroy and Burnett Rivers , and stretch around 70 kilometers ( 43 miles ) off the coast . `` These are extraordinary events . The whole of the inner-shore reef lagoon filled with river water , '' says Jon Brodie , Principle Researcher for the James Cook University 's Australian Center for Tropical Freshwater Research . Brodie and his team regularly monitor the reefs and are immersed in studying the impact of the flood waters . Brodie describes the threat to many coral reefs closest to the flooding rivers as `` quite high '' but expects the flood waters to affect in some way the reefs stretching from Frazer Island , 200 kilometers ( 124 miles ) north of Brisbane , all the way to Cairns , 1,500 kilometers ( 930 miles ) away . The prevailing tides and south easterly winds mean the flood waters will probably continue to head north . `` It 's quite remarkable to see . If you were to snorkel where the flood water meets the seawater and look to one side , the sea water will be clear with visibility to 50 meters while the other side is fresh , dirty brown water where visibility is down to one meter , '' says Brodie . The mix of nutrients , sediment and pesticides from agricultural run-off , plus currently unknown amounts of trace metals from flooded mines , will likely have an immediately devastating impact on corals and sea grasses , says Brodie . Salinity could go down to ten parts per thousand or less and remain like that for weeks ; `` nothing can live in those conditions , '' says Brodie . The immediate death of corals and sea grass is expected , which could then have a devastating affect on other marine creatures like dugongs that feed on sea grass . When the Fitzroy River ( that flooded Rockhampton before Christmas ) suffered severe flooding in 1991 , the corals and sea grasses around the Keppel Islands suffered 100 percent coral mortality . Bigger fishes can swim away from the deluge of fresh water , but smaller coral reef fish may suffer the same fate as the corals they live around , says Brodie . While corals can recover from `` bleaching '' ( when coral organisms die leaving what looks like a white skeletal structure ) , it 's a slow process . Some recovery around the Keppel Islands was seen after 10 years , while other coral species and marine organisms were still recovering until the latest floods . Other marine species can actually benefit from floods . `` Some fish species thrive in the current flood plume conditions which can enhance productivity for some popular inshore species , '' Andrew Skeat , General Manager of the Great Barrier Reef Marine Park Authority said in a press statement . Other unwanted long term effects can be algae blooms which can upset the reef ecosystems . `` It will take some time before the impacts of these flood plumes on the marine ecosystem and on the industries that use these areas are known , '' said Skeat . Climate scientists have blamed the excessive rainfall the region has seen in the last month on the latest La Niña weather event . La Niña refers to the cooling of the central and eastern Pacific that drives wetter conditions in eastern Australia . Brodie agrees with the cause of the heavy rain : `` It was predicted . It certainly fits the pattern of severe weather events from climate change modeling . '' Queensland suffered its wettest ever December , according to the Australian Bureau of Meteorology , during what it describes as a `` very strong '' La Niña event in the Pacific Ocean . In June 2010 the bureau stated that La Niña was likely to have an affect on Australia by the end of that year . A previous La Niña event happened in 1974 when a record flood of the Brisbane River killed 14 people .
Flood water will have devastating effects on corals and sea ##grass in parts of Great Barrier Reef . Flood water is full of chemicals , pesticides and nutrients that kill coral . Inshore coral reef lagoon region likely to be full of fresh water for weeks . Coral reefs can take over a year to recover from ' bleaching '