Beijing: A new study published on Saturday reveals a significant decline in oxygen levels in lakes worldwide, driven by long-term climate warming and increasing heatwaves.

The research, featured in Science Advances, analyzed dissolved oxygen data—measuring the amount of oxygen available in water—from over 15,000 lakes around the globe over the past two decades. The findings show that 83 percent of lakes are experiencing a drop in oxygen levels in their surface waters. Alarmingly, the average rate of oxygen loss in lakes is higher than in both oceans and rivers, underscoring the severity of the issue.

According to the study's authors, climate warming is the primary driver, accounting for 55 percent of the oxygen decline by reducing the solubility of oxygen in water. Additionally, eutrophication—the increased concentration of nutrients in lakes, often from agricultural runoff—accounts for about 10 percent of the oxygen loss.

The research also highlights the growing impact of heatwaves, which accelerate oxygen depletion. The study found that during heatwaves, oxygen levels in lakes can decline by an additional 7.7 percent compared to conditions under average temperatures.

“These findings underscore the profound impact of climate change on freshwater ecosystems, which rely on adequate oxygen levels to sustain aerobic life and maintain healthy biological communities,” said co-author Zhang Yunlin, a researcher at the Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences.

The decline in dissolved oxygen threatens lake ecosystems, potentially leading to species extinction, mass die-offs of aquatic organisms, and even the collapse of commercial fishing industries.

While previous studies have reported oxygen losses in lakes—for instance, a 2021 study in Nature documented widespread declines in temperate regions—the new research provides a more comprehensive global view. It includes lakes larger than 10 square kilometers across tropical, temperate, and cold climate zones.

The authors stress the urgent need to address the escalating threat of oxygen depletion. Co-author Shi Kun, also from the Nanjing Institute, suggested focusing on reducing nutrient concentrations in lakes by limiting fertilizer usage, controlling livestock waste emissions, and improving the management of urban and industrial wastewater.

“Planting submerged vegetation and constructing wetlands can also help restore lake ecosystems,” Shi told Xinhua.

While the study provides practical suggestions to combat eutrophication, it does not offer specific solutions to address the broader causes of climate change and heatwaves.

Researchers from China’s Nanjing University and Britain’s Bangor University also contributed to the study.