Have you ever heard the saying, “an elephant never forgets?” Unfortunately, 2020 will be a year that African elephants will remember with sorrow.
The story is one of environmental reckoning – the result of a devastating interaction between elephants and toxic algal blooms.
In 2020, a shocking event unfolded in Botswana, a country that is home to one-third of all African elephants. Approximately 350 of these majestic creatures met a tragically premature end, with their carcasses scattered across the Okavango Delta.
The deaths were no ordinary occurrence. They ignited global concern and sparked an intense investigation.
A new study, led by King’s College London, offers an alarming explanation. The deaths of 350 elephants in 2020 were caused by lethal blankets of toxic algae in watering holes – a deadly byproduct of climate change.
The initial discovery of elephant carcasses scattered in the northeastern sector of Botswana’s Okavango Delta triggered global concern.
With no evidence of poaching, the mystery of sudden mass elephant deaths deepened. As the death toll rose to an alarming 350, a theory started to surface. Could toxic algae blooming in the elephants’ watering holes be responsible?
The study was led by Ph.D. student Davide Lomeo at King’s College London. He was co-supervised by Plymouth Marine Laboratory (PML) and the Natural History Museum.
“Botswana is home to a third of all African elephants, and this unprecedented die-off within their largest remaining population underlines the escalating concerns surrounding the impact of drought and climate change on the Okavango Delta, one of the most important ecosystems in the world,” explained Lomeo.
The investigators turned to a combination of sophisticated satellite data and spatial analysis. They scrutinized the relationships between approximately 3,000 watering holes and the locations where the deceased elephants had been found.
The analysis revealed that waterholes near the carcasses showed a dramatic increase in algal levels and frequent bloom events in 2020, when compared with previous years.
“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,” noted Lomeo.
The researchers pointed out the events that led to this catastrophe. A grueling dry year in 2019, the driest in decades, was abruptly followed by an extraordinarily wet year in 2020.
The sudden shift stirred up substantial amounts of sediments and nutrients from the ground, providing ideal conditions for the growth of toxic algae.
“Southern Africa is projected to become drier and hotter under climate changes and, as a result, waterholes across this region will likely be drier for more months of the year,” said Lomeo.
“Our findings point to the potential negative effects on water quantity and quality, and catastrophic repercussions this could have on animals.”
To combat the threat posed by toxic algal growth, innovative technological solutions are emerging to aid in comprehensive water quality monitoring.
Earth observation applications, such as satellite imagery and remote sensing techniques, offer the potential to detect and monitor diverse sources of contamination swiftly.
By leveraging these advanced tools, scientists and authorities can gain valuable insights into water quality, enabling timely interventions and preventive measures.
Tackling the environmental impact of toxic algal blooms requires collaboration among researchers, local authorities, and communities.
By sharing knowledge and using sustainable methods, we can protect our valuable water resources. With scientific expertise, technology, and public awareness, we can ensure clean water for future generations.
The case of Botswana’s elephants sheds light on the severe ecological consequences of toxic algal proliferation.
The findings highlight the urgent need for comprehensive water quality surveillance across all water bodies.
This issue is a wake-up call for Botswana and the world, and points to the urgent need to tackle climate change and its effects on ecosystems.
The study is published in the journal Science of The Total Environment.
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