Last month, a portion of the Negro River in the Amazon rainforest near Manaus, Brazil, shrank to a depth of just 12.7 metres — its lowest level in 120 years, when measurements began. In Lake Tefé, about 500 kilometres west, more than 150 river dolphins were found dead, not because of low water levels, but probably because the lake had reached temperatures close to 40 °C.

These are symptoms of the unprecedented drought gripping the Amazon rainforest this year. Climate change is involved. But researchers who study the rainforest say other factors have come together to exacerbate this crisis, which has cut river communities off from supplies including food, and has forced Indigenous residents to use dirty, contaminated water, resulting in gastrointestinal and other illnesses.

Read more: scientificamerican.com

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