Not for nothing, but when it comes to water masses and climate change, the ocean gets the (sea) lion’s share of attention. But on land, about 117 million albeit smaller bodies of water play the necessary ecological, social and economic role. Lakes are relatively small, but “relative” is a key term there – the Great Lakes of North America, for example, account for 20 percent of the freshwater on the Earth’s surface. We also rely on them for food, fresh water, transportation and more.
New research identifies the interconnected challenges facing the world’s lakes. According to Sapna Sharma, co-author of the study and an associate professor in York University’s biology department, many of the climate change-related effects that keep these watering holes relatively hidden, despite these waters potentially facing an extensive set of problems. “I hope people get a sense of how widespread the effects of climate change on lakes are,” she told Ars. “If you just go and look at a lake, you may not know all the changes it’s going through.”
To study this, Sharma and colleagues from several universities around the world studied hundreds of research papers on lakes. These papers came from all over the world and some date back to the 1930s, she said. Sharma and her fellow researchers all have different areas of expertise, allowing them to review and synthesize the existing literature.
Sharma noted that there are a host of other articles that all focus on different aspects of the impact of climate change on lakes, but they tend to focus on particular niches, rather than the phenomenon as a whole. “It was the novelty of putting it in a single document, in a single document,” she said.
Smoke on (or sometimes near) the water
The hundreds of papers painted a complex picture of the past, present and future of lakes under a rapidly changing climate. On a purely mechanical level, a warmer planet means less ice cover. In the fall and winter, ice takes longer to grow on lakes, and it disappears earlier in spring and summer.
The heat also causes the water to stratify earlier, meaning the colder, heavier water will sink below the warmer, lighter water. Furthermore, a changing climate may mean that lakes experience more drought or flooding due to a greater number of storms.
These mechanical phenomena can wreak havoc on life that depends on the lake for livelihood or their livelihood (in the case of humans). For example, an enhanced seasonal stratification process can increase the likelihood of harmful algal blooms that can use up the oxygen in a lake and kill its other inhabitants. Algae blooms can also affect water quality for humans. Some lake fish prefer to live in colder, deeper waters, so a warming lake can invade their habitat.
The human element
All of this, in turn, can affect people on a cultural and economic level, Sharma said. In some cases, a decrease in annual lake ice can lead to cancellations of ice fishing tournaments, ski races and similar events. These events can be a big attraction for small communities and generate a lot of tourist money.
Regular algal blooms on a lake can also lower the property values of nearby homes or cottages. Around the world, these issues are affecting more marginalized people, Sharma added. For example, algae blooms can make local water undrinkable for some indigenous communities in Canada. “There are also some economic, social and cultural consequences,” she said.
Sharma said new technologies such as remote sensing and testing for biodiversity and the presence of species of flora and fauna using environmental DNA, or eDNA, will help researchers understand and potentially address the challenges lakes face in the future. The research notes that to help lakes thrive during climate change, new and diverse perspectives need to be brought into the conversation, including those from researchers from myriad fields and those from people living in countries outside of North America and Europe.
BioScience, 2022. DOI: 10.1093/biosci/biac052 (About DOIs)