Earth’s northernmost lakes have been considered the “canary in a coal mine” of environmental change, but a recent study from York University indicates that climate change will affect more than 100 million lakes worldwide.
The researchers set out to gain a better idea of how lakes are affected by climate change, so they analyzed freshwater lakes throughout the world. The results of the study imply that climate change has cumulative effects on lakes.
As water temperatures warm, stratification regimes change, dissolved oxygen levels drop, cyanobacterial blooms increase, and native cold-water fish habitats disappear. The researchers highlighted the dangers of deoxygenation and disruptions in the food chain.
“Algal blooms can block sunlight from reaching the deeper waters, and bacterial decomposition of sedimented algae can lead to a decrease in oxygen for deep-water fish and other aquatic life,” study co-author Dr. Iestyn Woolway. “In addition, episodic storms can cause nutrients to suddenly wash into lakes and foster the development of cyanobacterial blooms.”
“Events like an earlier summer season can also cause mismatches in fish spawning and foraging, often with widespread ramifications across the food web. Although a ‘longer summer’ may be welcome to many cottagers and campers, such weather conditions increase the risk of algal blooms, and especially cyanobacterial blooms, which can have far-reaching ecological consequences and even make drinking water toxic,” explained Professor John Smol.
According to Dr. Woolway, the ecological consequences of climate change coupled with the impacts of extreme climate events are already occurring in lakes globally. He said these impacts will continue to occur in the future – often without warning or time to adapt. “The results of these kinds of changes have been felt in lakes from Algonquin Park in Ontario to Lake Chad in Africa, the English Lake District in the U.K. to Lake Mead in the United States.”
The researchers emphasize that these changes in the water cycle will have far-reaching effects,
“The effects of climate change also interact synergistically with multiple environmental stressors exacerbating problems with water quantity and quality, including salinization, contamination, and the spread of invasive species,” said Professor Smol.
“As humans can’t survive without water, a better understanding of how climate change affects lake function is needed along with recognition of early warning signals.”
The experts hope technological advancements and diverse collaboration will lead to a better future understanding of climate change and lakes.
The study is published in the journal BioScience.