Flood runoff being released into the Gulf of Thailand from Bangkok could dilute the salt water and threaten marine life in the coastal areas, media reports said Tuesday.

Marine scientists have warned that some 10 billion cubic metres of floodwaters that will pour into the gulf in the coming weeks could cause salinity in the coastal areas to drop from the normal 32 parts per thousand (ppt) to just 2 ppt, The Nation newspaper reported.

Thailand’s coastal mangrove bio-systems can withstand short periods of low salinity.

“Normally, if freshwater pours into the sea and remains for only a week, it won’t substantially affect the area and creatures,” said Pramot Sojisuporn, associate professor at Chulalongkorn University.

But if the floodwater stays for months, as it is threatening to do, it could cause widespread problems, Mr. Pramot told a seminar on Tuesday.

The country’s central plains have been hit by the worst floods in decades, causing an inland sea of runoff that is now creeping through Bangkok en route to the gulf.

The capital’s centre, which is only 30 kilometres from the sea, has stayed dry, largely because authorities have diverted the waters into the western and eastern suburbs of the capital.