<
https://www.sciencealert.com/oxygen-levels-in-earths-lakes-are-plummeting-study-reveals>
"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.
Chinese Academy of Sciences (CAS) geographer Yibo Zhang and colleagues used
satellite images, along with geographic and climate data, to reconstruct the
events that led to these oxygen losses. More than 80 percent of the 15,535
lakes they examined now have depleted oxygen levels.
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.
Zhang and team calculated 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."
Cheers,
*** Xanni ***
--
mailto:xanni@xanadu.net Andrew Pam
http://xanadu.com.au/ Chief Scientist, Xanadu
https://glasswings.com.au/ Partner, Glass Wings
https://sericyb.com.au/ Manager, Serious Cybernetics
