Secrets of the Boiling River

An unusual waterway winds through part of the Amazon rainforest in Peru. This river’s water is hot—dangerously hot. In some spots, it reaches nearly 100°C (212°F). That’s water’s boiling point, the temperature at which it turns to gas.

The Boiling River is well-known to locals, who call it Shanay-Timpishka (shah-NIGH teem-PEESH-kah). But scientists are still learning about it. In 2019, a research team set out to explore the river. The team was led by Rosa Vásquez Espinoza, a scientist who studies tiny living things called microbes. Microbes can survive in all types of environments, some even in extreme conditions. The team wondered: What microbes could they find in the Boiling River? 

An odd river winds through part of the Amazon rainforest in Peru. This river’s water is dangerously hot! It reaches nearly 100°C (212°F) in some spots. That’s the boiling point of water. At this temperature the liquid turns to gas.

The Boiling River is well known to locals. They call it Shanay-Timpishka (shah-NIGH teem-PEESH-kah). But scientists are just beginning to study it. A team set out to explore the river in 2019. It was led by Rosa Vásquez Espinoza. She’s a scientist who studies microbes. They’re microscopic creatures. Microbes can survive in all types of environments. Some even live in extreme conditions. The team wondered what microbes they might find in the Boiling River.

The Boiling River flows for 6 kilometers (4 miles) before linking to waterways that feed into the Amazon River. At its start, the Boiling River is 21°C (70°F), room temperature. Downstream, the river flows over faults, deep cracks in Earth’s crust. Water seeps underground, where temperatures are hotter than at the surface. The water heats up. Pressure then forces the hot water up into the river.

There are other spots where hot water spews from Earth. But most are found near volcanoes, where magma, or molten rock, heats water underground. The Boiling River is 700 km (430 mi) from the nearest active volcano. “The fact that it is not volcanic— and so massive—is very unusual,” says Andrés Ruzo. He’s a geologist who is studying how Earth heats the river. 

The Boiling River flows for 6 kilometers (4 miles). Then it links to other waterways. They feed into the Amazon River. The Boiling River is 21°C (70°F) at its start. That’s room temperature. The river flows over faults downstream. Faults are deep cracks in Earth’s crust. Water seeps underground. There, temperatures are hotter than at the surface. The water heats up. Pressure forces the hot water up into the river.

There are other spots where hot water spews from Earth. Most are found near volcanoes. Water underground is heated by magma, or molten rock. The Boiling River is 700 km (430 mi) from the nearest active volcano. “The fact that it is not volcanic—and so massive—is very unusual,” says Andrés Ruzo. He’s a geologist. He’s studying how Earth heats the river. 

Vásquez’s team collected many samples along the river. They wore protective equipment to scoop water and sediment so they didn’t get burned. The team also gathered soil and scraped microbes off rocks.

Vásquez noted where each sample came from, the water temperature, and the plants and rocks nearby. The team took the samples to a lab to analyze.

The samples contained a trove of microscopic creatures! Vásquez is now studying the role they play in their environment. She and Ruzo hope their work encourages people to save the rainforest. “This research could help us come up with strategies to protect the jungle,” says Ruzo. 

Vásquez’s team collected many samples along the river. They wore protective gear so they didn’t get burned. They scooped up water and sediment. The team also gathered soil. They scraped microbes off rocks too. 

Vásquez noted where each sample came from. She noted the water temperature. And she noted the plants and rocks nearby. The team took the samples to a lab to study.

The samples had a lot of microbes! Vásquez is now studying the role they play in their environment. She and Ruzo hope their work encourages people to save the rainforest. “This research could help us come up with strategies to protect the jungle,” says Ruzo.