Argentina's giant rodents dyed Hulk green by algae February 14, 2025

Capybaras in Argentina(Photo Juan MABROMATA/AFP/AFP)

Capybaras (Hydrochoerus hydrochaeris) are covered in bright green slime due to cyanobacteria in the waters of Lake Salto Grande, an artificial body of water created by the hydroelectric dam on the Uruguay River near Concordia, Entre Rios, Argentina, on February 13, 2025. (JUAN MABROMATA) (JUAN MABROMATA/AFP/AFP)

By AFP - Agence France Presse

Argentina's giant rodents dyed Hulk green by algae

First, a river turned blood red. Now Argentina's most beloved giant rodent, the capybara, has been covered in Hulk-green slime as pollution turns the country's waterways into traffic light colors.

The capybara, also known as the carpincho or chiguire, is the largest rodent in the world, measuring up to 1.35 meters in length and weighing up to 80 kilos.

An AFP photographer snapped several of the pea-green spotted tufted creatures along the Uruguay River north of Buenos Aires on Thursday, where a rotten smell hangs in the air and dead fish are scattered on the banks.

Every year, bacteria cause a thick greenish layer to cover the banks around the Salto Grande hydroelectric dam on the border between Argentina and Uruguay. The phenomenon has increased in intensity in recent years.

These cyanobacteria “are photosynthetic organisms that play an important role in the ecosystem,” Diego Frau, a biologist at the National Institute of Limnology, told AFP.

But in high concentrations, they can be destructive and toxic, he said.

High temperatures and high levels of nutrients in the water, partly driven by livestock farming, cause the algae to spread.

Climate change is causing the green tide, which can last several weeks, to become “more and more recurrent”, damaging ecosystems, he said.

In people, mild exposure to the bacteria can cause skin problems or “flu-like symptoms” such as diarrhea, vomiting, and headaches, Martin Novoa, a biologist at the Faculty of Food Sciences at the National University of Entre Ríos, told AFP.

Prolonged exposure can lead to liver and nervous system complications, he added.

At least 15 municipalities in the province of Buenos Aires have issued health alerts about the bacteria.

The outbreak comes a week after a stream running through a town near Buenos Aires turned blood red and gave off an unpleasant odor.

The stream runs through an area of textile and leather processing factories.

Residents accused the factories of dumping waste into the river.

The environmental authorities are studying the cause of the discoloration, which lasted a few hours.

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