"So, if the corals are exposed to it for significant periods, they will really suffer badly."
The research, published in the BMC Genomics magazine on Friday, used the common coral reef genome, Acropora millepora, to detect changes in coral biology.
During the recent floods in northern Queensland, a massive flood plume is detected leaving the Townsville region, with estimates close to ground reefs exposed to almost half of the normal salinity of the ocean.
The co-author of the report, Dr. Jean-Baptiste Raina of the University of Technology of Sidney said that part of the reef was very much affected in the 2017 bleaching event and it was only in the early stages of recovery.
"The fact that it follows several years of very high temperatures means that the corals are not resting," said Dr. Raina.
"So when it's not a high temperature it's rain, and it seems tensions never end at the moment and they do not let the reef recover."
In a sad irony scientists hoped that part of the reef could begin to recover more fully this year because the frequent rainfall in northern Queensland maintained the global low ocean temperature.
The researchers said that with the most extreme weather events planned in the coming years, it was necessary to do more to protect the slip.
They admit Acropora millepora Coral is particularly sensitive to changes in salinity, but adds that most other corals are also susceptible to varying degrees of rapid desalinization.
"This is a type of undervalued phenomenon," said Professor Miller.
"There is a greater appreciation of the fact that extreme temperature events cause damage to reefs, it is less known that the low salt conditions caused by extreme precipitation also damage coral reefs."
It is estimated that the Great Barrier Reef contributes $ 6.4 trillion a year to the Australian economy, mainly through tourism and the state of reefs as an international icon.
Stuart Layt covers health, science and technology for the times of Brisbane. He was the political reporter of Queensland for AAP.