Hundreds of dolphins have been found dead in the Amazon Lake in hotter water than jacuzzis, a study has found

When The dolphins started to wash up dead With the brochures of Lake Tefe in Strazil’s Amazonas State, Hydrologist ayan fleschmanmann was sent to find out why.
What he and his colleagues found was startling: A brutal drought and extreme heat wave that began in September 2023 had turned the lake into a stinking cauldron. The pool’s water reaches 41 degrees, or 105.8 degrees which is hotter than most spa baths.
Their findings, published Thursday in Jelly Science, spotlight the effects of global warming on tropical regions and aquatic ecosystems, and come as speeches at the United Nations’ COP30 TOPS TO KILD in Brazil.
“You can’t put your finger in the water,” Lead author Fleischmann, from West Brazil’s Mamiraua Institute for Sustainable Development, told AFP.
He recalled the “psychological impact” of seeing the carcasses of Amazon River Dolphins and Tucuxis, another type of freshwater dolphin.
Bruno Kelly / Reuters
It’s a “neglected problem,” he said, adding that tropical lakes, important to food security and livelihoods of local communities, have been studied more than those in Europe and North America, and thought to be more sustainable.
While this study focuses on 2023, another Record – Amazon Record Drought was made the following year. Such events are becoming more frequent, severe, and long-lasting due to human-induced climate change.
In all, the team visited 10 lakes in the middle of Amazonia, to find that the maximum daytime temperatures exceed 37 degrees, which is much higher than the 29-3 degrees Celsius considered normal.
The most extreme reading came from Lake Tefe, which saw its surface area drop by 75%.
According to the Consumer Product Safety Commission, a hot tub is usually set between 100 and 102 degrees Fahrenheit, or less than 40 degrees Celsius.
Authorities from the World Wildlife Fund Brazil said it was found that 153 dolphins were found dead in the week of September 23, 2023, including 130 pink dolphins and 23 bottlenose dolphins. Both are listed as endangered on the IUCN Red List and maintain the watchdogs of “Riverdolphins.org’s lucky charm”.
“Weather is here”
What made it even more remarkable, said Fleischmanman, was that the same temperature was found nowhere but throughout the deep water column.
Using a computer model, the team identified four key drivers: Strong solar heat, shallow water, low wind speed, and high turbidity – a measure of water damage.
These things reinforce each other. Shallywss increases the disturbance, which affects more heat, while the lower air carries less heat, leaving the water more exposed to be removed by the sky and more sunlight.
Another stressor for aquatic life was heavy sweating between highs and lows, with a high of 41c at Tefe followed by a nighttime low of 27c.
Bruno Kelly / Reuters
Although most of the National and Global attention is focused on the more than 200 dead dolphins recorded in less than two months, they represent only an episode of a wider social – environmental problem, with fish also dying in the gills.
There was even a phytoplankton bloom that turned into a red lake as the algae were suppressed – the subject of a forthcoming paper supporting those who escaped.
To understand the long-term trends, the researchers went back to Nasa satellite data starting in 1990, and found that the Amazonian lakes have been warming at about 0.6c per hour for ten years, higher than the global average.
“Weather weather is here, there’s no denying it,” Fleischmanman said.
He also added that he will be present at the Cop30 conference aimed at the long-term view of the Amazon basin and the greater inclusion of local people – including the indigenous inhabitants of the kings, and Afro-Desterine communities – in building solutions.
A study published in the hydrological gene Processes found that the drought has “significant effects on the temperature of the water in the river” since the radiation in these periods is very strong while the water levels are low and the foot traffic is low.
“Rising temperatures in rivers can have significant and often damaging effects on aquatic life, affecting species and entire ecosystems,” study co-author and University of Birmingham Professor David Hannah. Professor David Hannah. “Drought conditions are often associated with high atmospheric temperatures and such patterns will be more intense and more likely to change the climate.”


