Tourists Can Save Mexico City’s Ancient Canals

Tourists are often cited as the cause of environmental degradation but rarely employed as the saviors of a threatened ecosystem, and yet that is exactly what a researcher hopes to do in Mexico City’s Xochimilco canals.

The precolonial system of canals and floating farms is a top tourist destination, and a flotilla of colorful wooden trajineras powered by gondoliers carry an estimated 2 million passengers through the wetlands every year.

The UNESCO World Heritage site is a 6,400-acre wetland crisscrossed by 105 miles of ancient canals that are home to 11 percent of the country’s biodiversity. One of the city’s few surviving links to its Aztec ancestors, the reserve protects 5,475 acres of floating farms known as chinampas built from the canals’ nutrient-rich soil, which makes them one of the most productive kinds of agriculture in the world. 

“Xochimilco has everything. It gives food and water, regulates the capital’s weather and mitigates flooding, provides work, and is rooted in tradition,” Claudia Alejandra Ponce de León, professor of environmental sciences at the National Autonomous University of Mexico, told National Geographic.

Trajinera could help restore the Xochimilco canals in Mexico City

But decades of pollution are taking their toll on the wetlands, which have been a dumping ground for human waste and a repository of agriculture runoff, and are choked by both algae blooms and water lilies (the latter, an invasive species, were intentionally introduced in the 1980s for decoration). When the blooms die and decompose, they also release greenhouse gases, contributing to global climate change.

Now Refugio Rodriguez Vázquez, a clean water activist and biotechnology professor at Mexico’s National Polytechnic Institute, believes she has a solution, and it depends on tourists.

Vázquez, who began studying the wetlands in 2016, is utilizing microscopic air pockets 2,500 times smaller than a grain of salt to breathe new life into the polluted waters, National Geographic reports. “Nanobubbles can penetrate this sludgy sediment,” Vázquez said. 

“Each tiny, negatively charged bubble is attracted to positively charged pollutants and harmful toxins. This union causes the nanobubbles to release hydroxyl radicals, which can extinguish pathogens and slowly break down the cell walls of algae,” National Geographicexplains.

To deliver the bubbles, Vázquez has created an ingenious system of pipes powered by solar panels she’s attached to the roofs of trajineras. And now she wants to employ all 1,100 of the tourist boats to extract water from the canal and release it back as thousands of nanobubbles that will fight the pollution and protect the wetlands — and ancient cultural traditions.

This piece originally ran in Out Traveler print magazine. The Spring 2022 issue is now available on newsstands.