Mar 31, 2025 08:53 PM
https://www.sciencealert.com/oxygen-leve...dy-reveals
EXCERPTS: Earth's lakes are experiencing an alarming drop in oxygen levels, new research shows. Similar trends have also been observed across rivers and seas. But some lakes are losing oxygen up to nine times faster than oceans.
A new study has now identified how much the different mechanisms responsible are contributing to this loss of lake oxygen globally, which between 1980 and 2017 was 5.5 percent in surface waters and 18.6 percent in deep waters.
[...] From 2003 to 2023, 85 percent of these lakes experienced a steady increase in the number of heatwave days per year. Higher temperatures reduce oxygen's ability to dissolve in water. ... heatwaves have contributed to 7.7 percent of the oxygen loss witnessed, through rapid and substantial fluctuations in oxygen's water solubility.
The researchers attributed another 10 percent to increasingly severe algal blooms. These are also being exacerbated by warming conditions, as well as increasing nutrients, including fertilizer runoff and livestock manure, entering our waterways.
However, long-term temperature increases account for the bulk of the lake deoxygenation, according to the research.
Current warming accounts for up to 55 percent of the decrease in lake oxygen levels, the researchers estimate. If this trend continues, Earth's lakes could have up to 9 percent less oxygen by the end of the century under worst-case climate scenarios, the team warns... (MORE - missing details)
EXCERPTS: Earth's lakes are experiencing an alarming drop in oxygen levels, new research shows. Similar trends have also been observed across rivers and seas. But some lakes are losing oxygen up to nine times faster than oceans.
A new study has now identified how much the different mechanisms responsible are contributing to this loss of lake oxygen globally, which between 1980 and 2017 was 5.5 percent in surface waters and 18.6 percent in deep waters.
[...] From 2003 to 2023, 85 percent of these lakes experienced a steady increase in the number of heatwave days per year. Higher temperatures reduce oxygen's ability to dissolve in water. ... heatwaves have contributed to 7.7 percent of the oxygen loss witnessed, through rapid and substantial fluctuations in oxygen's water solubility.
The researchers attributed another 10 percent to increasingly severe algal blooms. These are also being exacerbated by warming conditions, as well as increasing nutrients, including fertilizer runoff and livestock manure, entering our waterways.
However, long-term temperature increases account for the bulk of the lake deoxygenation, according to the research.
Current warming accounts for up to 55 percent of the decrease in lake oxygen levels, the researchers estimate. If this trend continues, Earth's lakes could have up to 9 percent less oxygen by the end of the century under worst-case climate scenarios, the team warns... (MORE - missing details)