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Did toxic algae kill hundreds of elephants in Botswana?

Published

1 year ago

December 9, 2024

Did toxic algae kill hundreds of elephants in Botswana?

An investigation into the sudden deaths of at least 350 elephants in Botswana in 2020 has revealed the cause was almost certainly a “toxic brew” of open water tainted by a species of cyanobacteria that released cyanotoxins, essentially contaminating the elephants’ watering holes.

According to researchers, approximately 20 watering holes in Botswana’s Okavango Delta had been contaminated across roughly 6,000sq km (2,316 square miles).

So what happened, and how?

What is cyanobacteria and how does it harm elephants?

Although not all cyanobacteria, commonly referred to as blue-green algae, is toxic, some cyanobacteria can produce a type of deadly algal blooms (HABs) in standing water. This is the type which was discovered in the investigation carried out by researchers at King’s College London.

The study showed that the African elephants (Loxodonta africana) died in May and June 2020 after drinking from water holes contaminated with these toxic algal blooms.

“Scientists believe that the production of cyanotoxins is related to certain environmental triggers, for example, sudden rise in water temperature, nutrient loading, salinity,” Davide Lomeo, Earth observation scientist at King’s College London, a collaborator with Plymouth Marine Laboratory and the Natural History Museum in London, and lead researcher in the recent study, told Al Jazeera.

How did the elephant deaths come to light?

In early to mid-2020, a series of routine aerial surveys conducted by helicopter by the conservation organisation, Elephants Without Borders, revealed multiple elephant carcasses scattered across the landscape of the Ngamiland district of northern Botswana.

The aerial survey showed 161 elephant carcasses and 222 sets of bones, while also counting 2,682 live elephants throughout the eastern region of the Okavango Panhandle. In addition, the distance between the dead elephants indicated the deaths had been sudden, rather than gradual.

“The strong clustering of carcasses also suggests that the event was sudden, with limited dispersal of elephants prior to death,” the authors of the study said.

A combination photo shows dead elephants in Okavango Delta, 2020 [Handout via Reuters]

How did researchers identify toxic algae as the cause of death?

Before researchers confirmed it was toxic algae which killed the elephants, they had to rule out several other probable causes.

“Although this area is a known poaching hotspot in Botswana, this was ruled out since elephant carcasses were found with tusks intact,” the authors of the study said.

Other initial theories included virulent and bacterial causes, such as encephalomyocarditis virus or anthrax, but the evidence taken from the field – such as the age of the dead elephants and the absence of any clinical signs of disease, meant the researchers ruled these out as the cause.

The distribution of carcasses and bones suggested a unique “spatial pattern”, which indicated that localised factors may have played a role in the mass die-off. This led to further exploration of specific environmental and ecological conditions in the affected areas.

There were several other factors that served as evidence that the elephant watering holes were to blame. Using satellite photos, researchers measured the distance the elephants walked after they drank from the watering holes – an average of 16.5km (10.2 miles). Many of the elephants died shortly thereafter, roughly 3.6 days (88 hours), after they drank from the nearby contaminated water holes.

The report states that 88 hours aligned with previously reported toxicological timelines for other large mammals which have died from blue algal poisoning.

In addition, Lomeo’s previous body of doctoral work investigating the history of mass-mortality events and water quality in waterbodies in Africa served as evidence to further look into the theory of water hole contamination.

“This event was what led to this idea, since it was a well-covered news at the time, but no one really knew why they died. I then applied my skills in geospatial and computational data science to investigate the event under a well-known set of methods typically applied in epidemiological investigations (eg COVID-19),” explained Lomeo.

Blooming blue-green algae caused by cyanobacteria in water bodies, rivers and lakes can be poisonous for animals [Shutterstock]

What is still unknown about the elephant deaths?

It is impossible to measure the level of toxicity for each waterhole from aerial photos. In addition, it is unclear whether elephants drank from one watering hole or several, according to researchers.

“It is highly likely that they drank from multiple pans before their death. It cannot be established if the fatal intoxication occurred in a single drinking event, but it seems more plausible that if cyanotoxins were present and were the cause of the die-off, this was through toxins bioaccumulation in elephants’ organs,” stated the study.

Although it is clear that the toxic waterholes were the likely source of the elephants’ mass mortality, there remains some uncertainty about the findings due to the timing of the mass die-off.

“The event occurred during the COVID-19 movement restrictions, and timely intervention was not possible. Therefore, tissue samples [which would have confirmed the presence/ absence of cyanotoxins] were not collected. Post-mortem investigations also need to be done within a certain timeframe, beyond which samples would be too degraded. Additionally, cyanotoxins cannot be detected from satellites, so the links can only be but indirect,” Lomeo explained.

As the aerial data was collected considerable time after the deaths in March and May 2020 – researchers could not definitively rule out the involvement of other animals in the elephant deaths.

Furthermore, smaller creatures may have been missed in the aerial survey, potentially limiting scientists’ understanding of the full scope of the incident.

“The area is well-known for very high predation rates, meaning that animal carcasses disappear quickly because of scavengers like hyenas and vultures. Hence, the involvement of other animals cannot be ruled out,” Lomeo said.

The specific conditions that would produce the level of toxicity in a watering hole that would be lethal to surrounding animal species are also still unknown.

“There is still uncertainty. We know that certain cyanobacteria species are more likely to produce cyanotoxins, and we know which toxins each species typically produces,” said Lomeo.

According to the research, cyanotoxins exhibit significant variations in their potency and effects. Certain types are extremely toxic, capable of causing death even in very small concentrations. Others, while less immediately dangerous, may still pose health risks at higher levels without necessarily being lethal. The field of cyanotoxin research remains active, with many aspects yet to be fully understood and explored.

Despite this, the overall findings of the study have been widely accepted. “The cause of the die-off has been officially attributed by the Government of Botswana to environmental intoxication by cyanobacterial toxins, also known as cyanotoxins,” the study’s authors said.

Could this happen again?

Although mass deaths of elephants are rare, researchers cannot be certain it will not happen again and that it will only affect elephants or land animals.

“[In] all arid systems where animals are dependent on stagnant water in lakes/ponds are susceptible to this [mass die-offs], the aquatic life in lakes also can be harmed in this same manner. We have even seen this in rivers and oceans where high nitrification from agricultural run-off combined with warming temperatures leads to disastrous bacterial blooms,” George Wittemyer, a behavioural ecologist at Colorado State University, one of the institutes involved in a study in Kenya that revealed that elephants use individual names, told Al Jazeera.

While it was relatively easy for researchers to identify the elephant carcasses from the air due to their size, the sudden deaths of smaller animals might not be so easy to identify.

Related Topics:africa Botswana Climate climate crisis environment europe explainer Featured health news science and technology United Kingdom wildlife

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Trump's national security team comes to convince Congress to back Iran war

Published

7 hours ago

March 4, 2026

Press Room

Trump's national security team comes to convince Congress to back Iran war

President Donald Trump’s top national security advisers were to spend much of the day on Tuesday making the case to members of Congress for the U.S.-Israel war on Iran, as Democrats and some of his fellow Republicans clamored for more information.

World

Iran’s senior clerics ‘exposed’ after building strike in Qom, succession choice looms

Published

8 hours ago

March 3, 2026

Press Room

Iran’s senior clerics ‘exposed’ after building strike in Qom, succession choice looms

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Senior Iranian clerics would have been left “exposed” after an Israeli airstrike hit a meeting place where they were supposed to be convening Tuesday — days after a strike leveled the Tehran compound of Supreme Leader Ayatollah Ali Khamenei, a defense analyst has claimed.

The clerics, members of the Assembly of Experts, had reportedly planned to meet at the location in Qom to deliberate succession plans for Khamenei, who was killed in the strikes, according to The Times of Israel.

“This second strike would be another embarrassment to what has been left of the regime,” Kobi Michael, a senior researcher at the Institute for National Security Studies and the Misgav Institute, told Fox News Digital.

“It indicates intelligence dominance and superiority because any movement is detected, meaning they would feel exposed,” Michael added.

Iranian Supreme Leader Ayatollah Ali Khamenei was killed in an Israeli airstrike Saturday. (Getty Images)

“As of now, the leadership would feel insecure and hunted, with all of their plans collapsing one after another.”

“They would feel totally isolated and understand that the biggest risk might come from home — from a potential uprising next,” he added.

Israel Defense Forces spokesman Brig. Gen. Effie Defrin confirmed that the Israeli Air Force struck the building where senior clerics had planned to assemble, The Times of Israel reported.

KHAMENEI’S DEATH OPENS UNCERTAIN CHAPTER FOR IRAN’S ENTRENCHED THEOCRACY

A general view of Tehran with smoke visible in the distance after explosions were reported in the city, Monday, in Iran. (Contributor/Getty Images)

It remains unclear how many of the 88 members were present at the time of the strike, according to an Israeli defense source cited by the outlet. The second strike on Iran’s leadership comes amid a broader military campaign.

As previously reported by Fox News Digital, U.S. forces have struck more than 1,700 targets across Iran in the first 72 hours of Operation Epic Fury, according to a U.S. Central Command fact sheet.

The campaign is aimed at dismantling Iran’s security apparatus and neutralizing what officials describe as imminent threats.

According to U.S. Central Command, targets have included command-and-control centers, the Islamic Revolutionary Guard Corps Joint Headquarters, the IRGC Aerospace Forces headquarters, integrated air defense systems and ballistic missile sites.

FIREBRAND ANTI-AMERICAN CLERIC ALIREZA ARAFI SEEN AS CONTENDER TO REPLACE IRAN’S KHAMENEI

The USS Thomas Hudner fires a Tomahawk land attack missile in support of Operation Epic Fury, Sunday, while at sea. (U.S. Navy/via Getty Images)

“We need strategic patience and determination, and in several weeks most of the job will be accomplished,” Michael added. “Even if the regime does not collapse, Iran will not be like we used to know.

CLICK HERE TO DOWNLOAD THE FOX NEWS APP

“I assume that the U.S. and Israel will establish a very robust monitoring mechanism that will enable them to react whenever the regime tries to reconstitute its military capacities again.”

Emma Bussey is a breaking news writer for Fox News Digital. Before joining Fox, she worked at The Telegraph with the U.S. overnight team, across desks including foreign, politics, news, sport and culture.

World

Hungarian veto proves EU needs less unanimity, says new Dutch PM

Published

10 hours ago

March 3, 2026

Press Room

Hungarian veto proves EU needs less unanimity, says new Dutch PM

Hungary’s last-minute veto on the €90 billion loan to Ukraine highlights the need for the European Union to move away from unanimity, Rob Jetten, the new prime minister of the Netherlands, said on his first trip to Brussels since taking office.

“The new Dutch goverment is in favour of less and less decision-making by unanimity on the European level,” Jetten told a group of media, including Euronews, on Tuesday.

“This is a clear example of why that is important because we cannot explain to our constituents that Europe is sometimes way too level in reacting to great issues that affect us all,” he added.

Jetten called on his Hungarian counterpart, Viktor Orbán, to abide by the delicate deal that the 27 EU leaders reached in December after fraught negotiations. The compromise saw Hungary, Slovakia and the Czech Republic promising the necessary unanimity to amend the EU budget rules in exchange for being exempted from the joint borrowing.

Officials and diplomats in Brussels believe that by vetoing a critical piece of the loan at the last stage of the legislative process, Orbán has breached the principle of sincere cooperation that binds the bloc’s decision-making.

“If you reach political agreement on the Council level, we expect every member state to uphold that agreement. And if not, it’s a big task for the European Commission take action,” Jetten said.

In the new coalition programme, the Netherlands calls for the “simplification” of the Article 7 procedure that can deprive member states of voting rights when they commit grave violations of the rule of law. Hungary has been under Article 7 for years, but there has never been sufficient political momentum to move to the harder enforcement phase.

“It is absolutely necessary that we support Ukraine in the months to come to make sure they can continue their fight against Russian aggression,” Jetten went on.

“With less and less American support for the Ukrainians in terms of money and weapons, it is up to the Europeans to deliver.”

Orbán’s veto centres on the interruption of Russian oil supplies through the Druzhba pipeline, which Kyiv says was attacked by Russian drones on 27 January and has remained non-operational since then.

But Orbán says Ukrainian President Volodymyr Zelenskyy has deliberately shut down the pipeline for “political reasons” to influence the results of the upcoming Hungarian elections. Orbán trails in opinion polls by double digits.

Caught between the two rival camps, the European Commission has asked Zelenskyy to repair Druzhba and Orbán to lift his veto. Meanwhile, Hungary and Slovakia have proposed a fact-finding mission to inspect the damaged section of the pipeline.

“We expect the European Commission to solve this issue,” Jetten said. “If it’s helpful to have any fact-finding missions on the pipeline to fix this issue, I’m open to it. But everything begins with: a political agreement at the Council level is a political agreement.”

‘Too early’ for a date on Ukraine’s accession

Among the first debates facing Jetten as premier is the future of enlargement, a topic on which the Netherlands has expressed well-known reservations in the past.

Zelenskyy is advocating for a specific date for Ukraine’s accession to be enshrined in a prospective peace deal, something that could offset the pain of territorial concessions. Last week, he openly suggested 2027 as an aspirational benchmark.

The Commission says it cannot commit to a clear-cut date but is working on legal avenues to revamp the notoriously complex process and ensure the Ukrainian people have greater certainty in their path to membership.

Asked about the potential reform, Jetten said enlargement should be reconsidered from a “geopolitical perspective” but urged the bloc to be “careful” with next steps, warning that the essence of the European project risks being undermined.

“We are very open-minded to look into broader support for these (candidate) countries, but moving too fast is not the way to move forward,” the premier said.

“I think, at the moment, it’s not possible to set a date for enlargement with Ukraine, but it is possible to talk with them, and I will do that with President Zelenskyy, (about) how Europeans can support Ukraine in the important reforms that they have undertaken. But at this moment, it is too early to set the date.”

Jetten also touched upon the US-Iranian strikes on Iran, which have pushed the Middle East into uncharted territory. Wholesale gas prices have soared in reaction to the war, prompting fears that Europe might soon face a prohibitive bill to refill its underground reserves, which are running low after the heating season.

“Obviously, the Iran war can have a big impact on strategic reserves, not only in Europe but also in Asia. So we have to prepare ourselves for any case that this war will continue for many more weeks and impact the strategic reserves in the Netherlands and abroad,” he said, noting extra measures would be taken “if necessary”.

“I think the broader concern is what this war and everything that’s going on in the Strait of Hormuz is going to affect in terms of pricing.”

‘The Netherlands is back’

Jetten’s D66 party has formed a minority goverment with the liberal VVD and the conservative CDA, all of which support European integration. His tenure puts an end to the fractious four-party coalition headed by the right-wing, Eurosceptic Party for Freedom (VVD) of Geert Wilders, which was marked by constant disagreements.

Among the priorities, his executive has pledged to ramp up defence spending, simplify regulation, promote new technologies and expand renewable energy.

“As a founding (member) and the fifth (largest) economy within the EU, the Netherlands is back at the table to work closely together with everyone here in Brussels and our allies within the EU,” Jetten said.

“We see a lot of opportunities to strengthen the European economy and competitiveness, and also to make sure that we do our job with a lot of tax-based money to invest in the European defence and the European defence industry.”

Jetten and the other 26 leaders are heading for a no-holds-barred fight on the next Multiannual Financial Framework (MFF), the bloc’s seven-year budget. Brussels has proposed a €2-trillion template that some capitals consider politically unpalatable.

Where to cut spending will be a major fracture line. Germany, the Nordics and the Baltics want a greater focus on strategic priorities, while Spain, Italy and Eastern Europe want to preserve the prominence of agriculture and cohesion funds.

The Dutch premier made it clear that the next budget should focus on the big transitions shaping the continent’s future: defence, technology and climate.

“A modern MFF doesn’t mean an exploded MFF in terms of numbers,” he said.

“The Netherlands will look into the numbers very closely, and we will have a lot of debate on this topic in the months to come.”