At Least 350 Elephants Died In Okavango Delta In 2020, Possibly From Cyanobacteria; Yes, It's Climate-Related
More than 350 elephants that died in mysterious circumstances probably drank toxic water, according to a new paper that warns of an “alarming trend” in climate-induced poisoning.
The deaths in Botswana’s Okavango delta were described by scientists as a “conservation disaster”. Elephants of all ages were seen walking in circles before collapsing and dying. Carcasses were first spotted in north-eastern Botswana in May and June 2020, with many theories circulating about the cause of death, including cyanide poisoning or an unknown disease. The incident was the largest documented elephant die-off where the cause was unknown, according to the lead researcher Davide Lomeo, a geography PhD student at King’s College London. “This is why it sparked so much concern,” he said.
Now, a new paper published in the journal Science of the Total Environment suggests the elephants were poisoned by water that contained toxic blooms of blue-green algae, or cyanobacteria. The climate crisis is increasing the intensity and severity of harmful algal blooms.
Researchers used satellite data to analyse the distribution of the carcasses relative to watering holes (there was no direct testing of samples because none were available). The team believes that the elephants generally walked just over 100km (62 miles) from the waterholes and died within 88 hours of drinking. In total they examined 3,000 waterholes, and found those that experienced increased cyanobacteria blooms in 2020 had high concentrations of carcasses. “They have no choice but to drink from them,” said Lomeo. It is possible other animals died from drinking from the waterholes, but bodies may not have been spotted from aerial surveys, and smaller carcasses could have already been taken by predators.
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https://www.theguardian.com/environment/2024/nov/29/mystery-mass-die-off-deaths-elephants-toxic-water-botswana