Since May, hundreds of elephants near the Okavango Delta in Botswana have died suddenly and inexplicably.
Mark Hiley, the co-founder of the conservation organization National Park Rescue, told Business Insider in July: “Conservationists on the ground report that dead elephants are walking in groups. Others are dying in their faces. This is a terrible scene.”
The researchers considered many possible explanations for mass deaths-is it poaching? poison? Coronavirus disease? But until now, they have been able to pinpoint the cause of death of epithelial cells.
Mmadi Reuben, chief veterinarian of the Botswana Wildlife and National Park Service, said on Monday that Botswana officials announced the killer. Press conference.
Cyanobacteria (also called cyanobacteria) bloom in local puddles.
Algae toxins affect humans and animals-they can be inhaled, swallowed or seeped into the skin, causing gastrointestinal problems, paralysis, and even death of dogs, fish and cattle.
Hundreds of dead elephants
Since spring, at least 330 elephants have died in Botswana.
To figure out what killed them, researchers studied samples collected from elephant carcasses in laboratories in South Africa, Zimbabwe, Canada, and the United States for months.
At first, officials did not think that algae blooms would exacerbate the extinction of elephants, because in the Okavango Delta, no other animals-not even hyenas that eat the elephant-have died in large numbers. Elephants in other parts of the country also remain healthy.
However, according to the Guardian, approximately 70% of deaths occurred near puddles containing algae blooms-convincing evidence that cyanobacteria are indeed the culprit. After the poisoned puddles in the area dried up during the dry season, death seems to be over in June.
The physiological effects of cyanobacteria are consistent with those observed by researchers in Okavango’s elephants. Healy said that some animals have lost control of their motor functions, which suggests that toxins are affecting the animal’s nervous system.
Climate change promotes algae blooms
When algae multiplies rapidly, it will form a layer of scum on the surface of ponds, lakes and even the ocean, which is called flowers.
The incentives behind these specific poisonous flowers and the reason why the elephants were hit the most are still unsolved mysteries.
Ruben said: “We still have many questions to answer, such as why there are only elephants and why only this area.” He added that the researchers had several hypotheses, but did not elaborate.
According to the Guardian, one speculation is that elephants are more susceptible to algae than other animals because they spend more time bathing in water holes and drinking a lot of water.
Researchers also know that, in general, when the water in which toxic algae live is warm and rich in nutrients such as phosphorus and nitrogen, the algae reproduce faster. These chemicals may come from fertilizer runoff.
Patricia Glibert, an environmental scientist who studies cyanobacteria, told Reuters: “This is equivalent to having the right conditions in the right place at the right time, and these species will reproduce.”
As the earth warms, scientists expect this bloom to occur more frequently.
Temperatures in southern Africa are rising twice as fast as the global average, so the blooming numbers of cyanobacteria in Botswana may continue to increase.
Gribert added: “These conditions are appearing more and more frequently in more places, so we see more of these poisonous flowers all over the world.”
This means that toxic algae can easily trouble elephants again in the future.
Ruben said: “It is important to monitor now to effectively detect the growth of these algal blooms in the water.”
Hiley previously told Business Insider that eco-tourism is the second largest sector of Botswana’s economy, after diamonds. Therefore, officials must pay close attention to potential cyanobacteria outbreaks to prevent another massive death.
He said: “This is one of the greatest disasters affecting elephants in this century, right in the middle of one of Africa’s most important tourist destinations.”
There are approximately 130,000 elephants in Botswana, which is the largest part of the African elephant population. However, this number is falling sharply. These animals were classified as vulnerable groups in 2016.
Mia Jankowicz provided coverage for this story.