Changes to three lakes in the Andes mountains are warning signs of the impact of climate change on other parts of the world, researchers from Queen’s University said.
Biology professors Neal Michelutti and John Smol from the university’s Paleoecological Environmental Assessment and Research Lab (PEARL) travelled to Cajas National Park in Ecuador last August.
The researchers collected core samples from the bottom of the lake, which showed major changes to microscopic algae called diatoms in the past several centuries.
“We know there have been big changes in climate in recent years, but we can’t put that in perspective unless you go back hundreds or thousands of years,” Michelutti said.
The core samples showed that about 50 years ago, around the 1960s when temperatures began to rise, there was a significant increase in open-water diatoms in all three lakes.
These algae are particularly sensitive to changing conditions and are considered sentinels of environmental change, often signalling a change in the physical properties of the water column, which can affect how nutrients circulate through the lake.
“It sounds trivial, but it does actually change the whole physics of the lake. These algae are indicating that the whole physical structure of the lake is changing,” Smol said.
“Who cares about little algae? Well, they are the base of everything. Once the algae change, the whole ecosystem starts changing.”
Michelutti and Smol were part of a team of researchers from Canada and the United States that went to study the impact rising temperatures have had on mountain lakes.
The research team also included Alexander Wolfe from the University of Alberta, Colin Cooke from the government of Alberta, William Hobbs of the Washington State Department of Ecology and Mathias Vuille from the University at Albany, SUNY.
“The Andes are a region that has undergone some significant environmental changes in the recent century,” Michelutti said, noting that temperatures in the area have increased at twice the global average in the past 30 years.
The most obvious effect of increased temperatures are the melting glaciers, but Michelutti said that until now, the region’s lakes have not been studied much.
The three lakes in the Cajas National Park are considered pristine and can only be accessed by hiking trails. Boats are prohibited on the lakes.
“The big advantage of lakes is they have a history book at the bottom — the lake sediments. Anyone can measure the temperature now, but no one knows what the temperature was like in the 1850s,” Smol said.
“The fact that we can do the paleo record, we can show (that), no, this isn’t part of some long-term cycle. No, this doesn’t happen every 50 years.”
While the research involved three lakes high in the Andes mountains, both Queen’s professors said the results can be added to research on more accessible Canadian lakes.
“The diatom changes, the changes in the algae that we see in the Andes, are exactly the same as the changes that we see in Canadian lakes. This is true around Kingston, all the way up to the Arctic and the Prairies,” Michelutti said.
“We’re starting to put together now a global signal of how lakes respond to climate and they are responding in a similar way.”
View original article at: Changes to algae in remote lakes warning signs of climate change: Queen’s researchers