US EditionAmazon Lakes Hit Record Temps, Killing 200 Dolphins
A 2023 drought and heat wave raised Lake Tefe's temperature to 41°C, killing over 200 endangered pink and tucuxi dolphins, with five lakes exceeding 37°C, researchers said.
- On November 7, 2025, hydrologist Ayan Fleischmann was sent to Lake Tefé in Amazonas state after dolphins began washing up dead, and the investigators published findings in the journal Science as COP30 summit opened.
- Satellite analysis shows the drought and heat began in September–October 2023, with four drivers—strong solar heating, shallow waters, low wind speeds and high turbidity—that reinforced one another.
- Researchers measured exceptionally high surface and subsurface temperatures, with 41 degrees Celsius in October 2023 and over 37 degrees Celsius in half the central Amazonian lakes, heat penetrating more than 6 feet.
- At Lake Tefé, more than 200 Amazon river dolphins and tucuxi dolphins were found dead between late September and October 2023, while 3,000 fish died at one aquaculture pond and river communities faced isolation and shortages.
- Satellite data indicate a long‑term warming trend of about 0.6 degrees Celsius per decade since 1990, and with the 2024 record drought, researchers urge long‑term monitoring and inclusion of Indigenous, riverine and Afro‑descendant communities at COP30.
26 Articles
26 Articles
Dolphins boiled alive as Amazon lake temperatures exceed 40°C, researchers highlight new climate threat
WASHINGTON, Nov 7 — When dolphins began washing up dead by the dozens on Lake Tefe in Brazil’s Amazonas state, hydrologist Ayan Fleischmann was sent to find out why.What he...
Hundreds of dolphins have died in the Amazon region of Brazil. This tragic mass death caused horror two years ago. Now it is clear why the marine mammals died. In September and October 2023 more than 330 dolphins died, as the American Marine Mammal Foundation writes. Many fish also died. The animals died during a heat and drought wave – but only now researchers have found out what the reason for this mass death was. Several factors played a role…
In the great winter of 2023, temperatures exceeded the limit of Jacuzzis in the Amazon Lakes. More than 200 dolphins died and local communities were isolated.
Hundreds of dolphins died two years ago in lakes of the Amazon. Now researchers explain: An unfortunate combination of several factors was responsible.
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