Global warming may benefit salmon in Norwegian rivers by causing more rainfall that dilutes industrial acids blown from other parts of Europe, scientists said on Friday.
OSLO Global warming may benefit salmon in Norwegian rivers by causing more rainfall that dilutes industrial acids blown from other parts of Europe, scientists said on Friday.
In the past, a spring thaw used to wash out large amounts of poisonous nitrates accumulated in winter snows, according to a long-term study of rain, snow and river acidification by the Norwegian Institute for Water Research (NIVA).
But climate change in the past 20-30 years means that more precipitation falls as rain, washing nitrates more evenly around the year into rivers and curbing a spring surge when salmon smolt are most vulnerable to poisoning.
A smolt is a young salmon at the stage when it migrates from fresh water to the sea.
"For salmon this is a good situation because nitrate is acidifying the rivers. Salmon go through a physiological change in the spring to adapt to the marine environment," said Atle Hindar, a researcher at NIVA who led the study.
"The smolt are extremely sensitive during the spring. If the acidification is reduced it will benefit the smolt," he said of the study that covered the chemistry of five rivers in Norway.
"Norway is a very important country for the reproduction of salmon, together with Scotland and Canada," he said. Among the most prized fish, salmon are born in rivers, swim out to the ocean and return to spawn.
Nitrate comes largely from burning oil, mainly in cars and ships in European nations including Britain to Germany and is blown north by prevailing winds.
Many scientists say that a build-up of heat-trapping gases from burning fossil fuels in vehicles, power plants and factories is pushing up world temperatures.
They say that the overall effects could be disastrous, including more storms, droughts, floods and rising sea levels that could swamp low-lying Pacific islands.