Hinsby Cadillo-Quiroz on microbes' life-sustaining properties

National Geographic Explorer Hinsby Cadillo-Quiroz was teaching microbial ecology when his scientific career path took on a more personal meaning. It was 2017, and he received word that his mother’s house in Huarmey, a small Peruvian coastal town north of Lima, was obliterated by extreme weather following one of the strongest El Niño phenomena the country had seen in decades.

As one of tens of thousands who were displaced, Cadillo-Quiroz’s mother lived on her roof for months. “She couldn’t rescue anything. All the childhood pictures, videos, stuff that is not replaceable, all of that disappeared,” Cadillo-Quiroz recalls. For this microbial ecologist, the event gave new meaning to his work: identifying solutions to disasters wrought by climate change, at the microbial level to benefit the large-scale (macrobial) level.

“Well,” he starts about how experiencing this tragedy shaped his unique motivation, “I have a stake in this, which is, I already lost the memories of my childhood, and my family and friends  suffered. I don’t want this for other people, I don’t want this for you. So I’m strongly motivated to take work on this very seriously,” Cadillo-Quiroz says. Some of his work involved identifying solutions for the long term, but with climate change-related threats growing in frequency, Cadillo-Quiroz’s research team has pivoted to exploring more immediate ways of mitigating destruction by a problem that's already here. 

“There is a rush, and we therefore are always trying to have nearly immediate deployment and testing to make a difference in a shorter time frame.”

Cadillo-Quiroz takes this interview from Arizona State University, where he is a professor of microbiology and investigates the role of microbes in ecosystems and the earth’s processes. Microorganisms are both producers and consumers of major greenhouse gasses responsible for the earth’s warming: carbon dioxide, methane, and nitrous oxide. Microbes account for exponentially greater biomass than all animals on Earth combined, so, though invisible to the naked eye, Cadillo-Quiroz emphasizes the importance of understanding the magnitude of their presence and actions. “The Amazon Forest is teeming with microbes on almost every surface. In fact, the Amazon is one of the ultimate frontiers for an ecologist seeking to decipher how microbes and plants and animals sustain what I call a garden of Eden,” says Cadillo-Quiroz. Scientifically, there is so much to learn hence Cadillo-Quiroz’s love for and focus on the region.

Environmental conditions, often influenced by humans, determine whether microbes carrying  out production or consumption of greenhouse gasses are highly active or not. Cadillo-Quiroz’s research examines how these tiny creatures are affected by and influence the global thermostat—the work could help make predictions about gas level changes. 

One question scientists like Cadillo-Quiroz seek to answer is how to make climate change matter to people who aren’t burdened directly by its effects.

“What I always say to this is ‘that’s exactly what you want, is for the effects to be afar because the day that it affects you directly it’s too late. It’s going to wipe away your door with little to do at that point. We’re not going to wait for the whole Amazon to disappear to worry about the effects climate change could have in latitudes where other people are not affected in that immediate moment.’”

Cadillo-Quiroz’s fascination with microbes began at an early age. He grew interested in the microworld after he got his first look at dirty water under a microscope when he was 11 and in middle school. “The things that are there. The shapes, the speed they move. It’s another universe completely,” Cadillo-Quiroz recalls.

This first view of the micro universe “beneath our noses” moved him. “It’s amazing to learn about planets and galaxies, but they are far away. Under the microscope, it looks like other galaxies, except they’re right there. You can do things with it.”

Edward O. Wilson, one of the biggest names in evolutionary biology in recent decades, retired with his own revelation about microbes after dedicating his life mainly to insects and humans. “He said ‘look, if I were to do this again I would become a microbial ecologist.’ Ten billion bacteria live in a gram of ordinary soil, a mere pinch held between the thumb and your forefinger. In that pinch of soil, you have the secret to life, the secret to keeping life on Earth." Cadillo-Quiroz adds.

Cadillo-Quiroz is as intrigued by what microbes reveal about themselves as he is about their mysteries, and he acknowledges the challenges of working with a subject that is invisible to the naked eye. “In the absence of being able to see them, weigh them, touch them, you need to rely on many other ways to reveal their process, show their complexities.”

Everything must be done through triangulation.

“I can wow you and create fire from the respiration of microbes. I can take you to a pond and squeeze the ground and you’ll see bubbles, and if I put a lighter to it I can light it up. I can show you that it is the breathing, respiration of the microbes that holds fire within.”

Cutting edge technology also helps. A mass spectrophotometer is a device Cadillo-Quiroz uses to separate molecules. It is so precise, it can offer a peek into how microbes sequester carbon. Microbes ingest a piece of dead plant matter (which contains carbon) and transform the carbon into a metabolite, a product of the microbe’s metabolism. The metabolite could potentially remain in that state for thousands of years in the environment, thus preventing the carbon in the dead plant matter from being released into the atmosphere.

The microbial world is hard to see, but reveals itself vast. “Microbes, only the ones on Earth, are many more in number than the stars we can see [in the universe],” Cadillo-Quiroz illustrates. 

Searching for solutions

Right now, Cadillo-Quiroz is focusing on a worrying trend in the Amazon. It’s one place where microbial presence is declining, and the Amazon, which has historically served as one of the world’s most efficient carbon sinks, is transforming into a carbon source. The most noticeable evidence of this is in post-mining soils. 

Since 2022, Cadillo-Quiroz has worked alongside fellow Explorers Josh West and Jennifer Angel-Amaya as part of one of the teams on the National Geographic and Rolex Perpetual Planet Amazon Expedition, a multi-year science and storytelling journey that will span the entire Amazon River Basin from the Andes to the Atlantic. Cadillo-Quiroz and team are exploring two rivers in the Peruvian Amazon to better understand the impact of deforestation and mining on the rivers and on general water quality. Even the commonly-known problem of mercury pollution has wider effects that require more research, and the larger threats of unregulated mining operations remains little studied. 

The team measures the drainage of rainfall through streams, and the paths it takes to get there to understand how mining affects rapid runoff. Cadillo-Quiroz also gathers data around greenhouse gas emissions directly from mining ponds to understand the changing water dynamics The data will help inform the way forward for restoration strategies in mining-impacted areas; it is a unique evaluation of carbon and mercury production in mining ponds, and their subsequent impact on water flow paths.

Of the threats to the planet’s terra firma, mining is the most devastating for this reason: no one knows how long it will take for that soil to sprout vegetation again. Earth’s biological capacity to sustain life dwindles with the loss of microbes, which have taken lifetimes to accumulate and adapt.

“Even if you take that soil, put it in a nice and protected greenhouse, add seeds, they’re not going to grow as they normally do because the soil has lost most of its biological properties—its microbes. There are no nutrients and there are no microbes to extract nutrients either. The old sands surfaced by mining have different and sparse microbes that have been buried for centuries or thousands of years, meters down, living in a very different chemical environment with no plants.”

With such tremendous microbial loss, Cadillo-Quiroz says restoring the post-mining soils to their former state is unlikely. “From my experience, it’s been decades of nothing happening, or very little.” It’s why stronger, innovative, interventions are needed. “So the Amazon is not going to come back to what it was, but it can take a new direction.”

As a problem solver, Cadillo-Quiroz is experimenting with rebuilding an adapted Amazon, where tolerant plants and animal species can thrive in soil-impoverished, heat-retaining environments. The possibilities are promising. “What we may have is a new type of forest than before.”

The Amazon’s megadiversity could supply its own solutions. There are cluster environments within the region where plants, microbes, and animals have already learned to thrive in sandy, dry patches, having adapted to natural environmental changes over the years. Understanding water, carbon, and gas behavior where these tolerant species exist naturally can help efforts to restore vegetation in bare areas, neutralize the problem of carbon pollution, and regenerate the Amazon in a new way.

“That’s been very encouraging. If anything, the Amazon is the perfect seeding material,” Cadillo-Quiroz says. And it’s the perfect testing site, though working near the crosshairs of illegal mining activity poses challenges. Peru’s unregulated mining history, particularly in the La Pampa gold rush town where the team bases its operations, is pervasive, and ever evolving.

“It’s a dynamic zone and we knew that when we started the project. Some of our study ponds were not active for years, and now we start seeing miners,” he explains.

Recalling the last expedition, during which Cadillo-Quiroz and his team took 2000 drone images of mining ponds, he says “you can hear explosions. Military interventions happen near where the scientists are doing their work.”

One non-negotiable part of pursuing the research and restoration efforts is partnering with local communities—sometimes former miners themselves. In part, it’s about safety. Local communities can provide insights about potential danger. It’s also about the long-term goal of developing a sustainable balance between protecting the environment and protecting human livelihoods.

“Now we can think of how to assist recovery, and we can do one important thing,” Cadillo-Quiroz says. His work encourages local communities to seize opportunities to help rebuild the Amazon, alleviating pressures to earn a living through mining. “Local communities can choose to either be extractors, or helpers of this new thinking around the Amazon,” Cadillo-Quiroz encourages. The goal is to make recovery participation an attractive and useful alternative by creating jobs in related work, like fruit harvesting or sustainable management. 

“Almost any work done in the Amazon is not possible without working with the communities. When this project finishes, I want what is left behind to help communities generate new ideas, new processes of their own.” 

Cadillo-Quiroz says he sees hope in the next generation of scientists. “University students are right on the edge where they want to earnestly change the world. And we want to change the world too. It’s the perfect match,” he laughs. To their local partners, the message is always “we want to empower you to be part of the solution.”

Nelida Rojas, who goes by Señora Nellie, is an example of a local partner. During the latest expedition in July, the team was in need of a place to store equipment. They rented a small storage space in Señora Nellie’s home. The team learned that she was a forestry engineer.  “As soon as she finished studying she dedicated herself to doing the hard work of raising her family, and postponing on some level all the training she received as a student,” Cadillo-Quiroz recalls.

After some time of keeping equipment in her home, Cadillo-Quiroz noticed that new vegetation began sprouting all over the property. “Señora Nellie was actually trying to genetically mix plants. Even though she made a decision to stay home at one point, I believe she never abandoned her heart for forestry.”

Señora Nellie has joined Cadillo-Quiroz’s team as the breeding expert for palm plant replanting, and has set a goal of breeding 500 trees for this leg of the project. 

“That’s the type of partnering and working with the locals I would like to do for our projects.”

Cadillo-Quiroz’s work is still in progress. The plan is to continue collecting data that will inform how water movement has changed on the surface channels or deep underground , how various post mining ponds change over time and emissions, and how water movement is dispersing mercury and other compounds from this area. 

What’s certain is that the problem needs immediate attention, and Cadillo-Quiroz is operating with urgency and optimism about the future. 

“Mega events caused by the intensity of climate variation unfortunately may repeat again,” He says. “It will be challenging, yet worthy of preventing and very worthy of stopping.”

ABOUT THE WRITER
For the National Geographic Society: Natalie Hutchison is a Digital Content Producer for the Society. She believes authentic storytelling wields power to connect people over the shared human experience. In her free time she turns to her paintbrush to create visual snapshots she hopes will inspire hope and empathy.