The 2020 deaths of over 350 elephants in Botswana’s Okavango Delta were caused by cyanotoxins from harmful algal blooms (HABs) contaminating watering holes, researchers have found. The toxic blooms, triggered by environmental factors like rising water temperatures and nutrient buildup, resulted in a sudden and localized die-off. Initial theories, including poaching and disease, were dismissed due to intact tusks and the absence of clinical signs. Furthermore, aerial surveys revealed scattered carcasses, ruling out gradual mortality. Satellite data indicated elephants walked 16.5 km after drinking the contaminated water, dying within an average of 88 hours. Although the study attributes the deaths to cyanobacteria, uncertainties remain due to the lack of timely tissue sampling as the deaths occurred during the COVID-19 pandemic, thereby hindering the collection of tissue samples. Meanwhile, scientists warn that similar events could occur in arid regions, posing risks to both terrestrial and aquatic species dependent on stagnant water sources.
SOURCE: AL JAZEERA
