The proliferation of algae is accelerating in Canada lakes, including those far from urbanized areas. A new study shows that climate change would be the main cause.
A research team led by scientists from McGill University and Laval University has analyzed sediment carrots from 80 lakes in Canada to determine changes in algae levels over a long time. The study, published in the journal Communications Earth & Environmentreveals a spectacular increase in the production of lake algae since the 1960s.
“We have found that algae levels have increased in most Canadian lakes in the past 150 years, but that in the 1960s, this increase has accelerated spectacularly, at a pace seven times faster than before,” explains Irene Gregory-Eaves, co-author and biology professor at McGill University. The most surprising thing is that this phenomenon even occurred in isolated lakes, far from any immediate source of pollution or human activity. »»
By combining the study of natural archives, ie carrots of lake sediment dating from the 1800s, and automatic learning techniques, the team was able to determine the cause of these changes and identify trends over a long period. The researchers then compared these statements with historical data on air temperature, solar radiation and nearby human activity.
“Our research clearly indicates that climate change play a leading role in algae dynamics,” says Dermot Antoniades, co -author and limnology teacher at Laval University. Global warming leads to warming lakes, which promotes the proliferation of algae. »»
If other factors, such as solar influence and regional planning, have also played a role, warming nevertheless remains the main cause.
Previous studies focused on a small number of lakes or on shorter periods and often established a link between the growth of algae and local pollution, especially caused by the streaming of fertilizers.
“Our work reveals that climate change, in particular the increase in temperatures, constitute the main cause of the proliferation of algae, including in isolated lakes far from all human activity,” said Hamid Ghanbari, the main study of the study and postdoctoral researcher at Laval University, which was cosupervised by Dermot Antoniades and Irene Gregory-Eaves.
An issue that requires everyone’s mobilization
According to scientists, everyone should be aware of the situation.
“The lakes are bathing places, fishing, supply of drinking water and commercial activities,” recalls Dermot Antoniades. When algae proliferate uncontrolled, they can harm our health, cause the death of the fish, generate bad odors on the beaches and generate significant costs. »»
The results underline the need for coordinated action worldwide.
“Our study shows that local measures, such as reducing fertilizer runoff, are no longer enough. It is absolutely necessary to fight against climate change to protect the long -term lakes, ”says Hamid Ghanbari.
“A healthy lake is synonymous with a healthy population,” he continues. By ignoring these problems, we leave our water, our fauna and our economy deteriorate. Everyone, both citizens and governments and NGOs and businesses, must put their own so that we reduce our carbon footprint. »»
The study signatories are Hamid Ghanbari and Dermot Antoniades, of Laval University, Irene Gregory-Eaves, McGill University, and scientists from other Canadian universities.