The sudden die-off of over a hundred Amazonian river dolphins in recent days has raised fears that rising global heat could be passing the tolerance threshold of species in vulnerable areas.
Floating corpses of the endangered mammals, along with thousands of dead fish, were seen at Lake Tefé where the temperature is now like a hot bath after a protracted drought has dried up most of the water.
Residents of the small community in Amazonas state described the scene in apocalyptic terms. “The past month in Tefé has seemed like a science-fiction climate-change scenario,” said Daniel Tregidgo, a British researcher living in the area. “Regular sightings of pink river dolphins are one of the great privileges of living in the heart of the Amazon. Pretty much every time I go to the market to have breakfast I see them come to the surface and it reminds me why I live here.
“To know that one has died is sad, but to see piles of carcasses, knowing that this drought has killed over 100, is a tragedy.”
Read also:AFDB launches reports on Africa’s climate change, green growth financing needs
Ayan Fleischmann, who is a geoscience researcher at the Mamirauá Institute, said that several possible causes were being investigated, including disease and sewage contamination. But he said the water depth and temperature were “certainly a main component” of the mass mortality. “At 6pm yesterday, in Lake Tefé we measured more than 39C (102.2F). This is very hot, horrible.” For context, 37C would be considered a hot bath for humans.
Brazil has suffered from unusually extreme weather in recent months as a consequence of human-caused climate breakdown and an El Niño as in other parts of the world. Swathes of land in the south of the country have been flooded by intense rainstorms, while the north is parched by an unusually fierce dry season.
The level of the Amazon, which is the world’s biggest river is reported to have fallen by 30cm each day over the past two weeks. At this time of year, the average depth in Manaus is 4.4 metres (14ft) lower from its rainy season peak. This year, it has already dried up by 7.4 metres, which local biologists have described as “absurd”.
Story was adapted from the Guardian.
