By Tessa Koumoundouros, Yahoo News
The first dead elephants were discovered in May 2020. By July of that year, over 350 of the endangered animals had been found strewn lifeless across a remote region of Botswana.
Global concern rose rapidly as veterinarians at the scenes eliminated the usual suspects. There were no signs of starvation, infections, or naturally occurring anthrax, and the giant mammals’ tusks were still intact, ruling out poaching. Some of the elephants were found face down, suggesting a sudden collapse.
That left one prime suspect, toxic cyanobacteria – also known as blue-green algae – which now, four years later, a new study led by King’s College London supports.
Geographer Davide Lomeo and colleagues’ analysis of satellite data reveals toxic algal blooms had exploded in water sources near the Okavango Delta during the same time period, all but certainly poisoning the African bush elephants (Loxodonta africana).
“We identified 20 waterholes near fresh carcasses that experienced increased algal bloom events in 2020 compared to the previous three years combined. These waterholes also exhibited the highest average algal biomass of the period 2015 – 2023,” explains Lomeo.
The researchers examined the spatial relationship between 3,389 waterholes in the Okavango Delta, and the locations of the dead elephants.
“Algal blooms are routinely monitored by satellite, but this data isn’t often used to investigate mass mortality events,” says Lomeo.
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