A worker tends to a rural farm in Hanoi, Vietnam, where technology is making it easier to harvest an ancient fern called Azolla. Some scientists and farmers view Azolla as a solution to our modern-day agricultural and environmental challenges.
This “Arctic Azolla event” had devastating impacts on marine life. To date, scientists are trying to figure out how it ended. But they documented that the extraordinary event cooled down the Arctic by at least 40 degrees Fahrenheit — effectively freezing the poles and triggering several cycles of ice ages. “This carbon dioxide sequestration changed the climate from greenhouse to white house,” says Jonathan Bujak, a paleontologist who has researched the Arctic through expeditions since 1973.
Some farmers and scientists, such as Bujak, are looking to this ancient fern, which manipulated the Earth’s climate around 49 million years ago with its insatiable appetite for carbon dioxide, as a potential solution to our modern-day agricultural and environmental challenges. “There is no other plant like Azolla in the world,” says Bujak.
Decoding the Azolla plant
Azolla lives in symbiosis with a cyanobacterium called Anabaena that made the plant’s leaf cavities its permanent home at an early stage in Earth's history. This close relationship with Anabaena enables Azolla to accomplish a feat that is impossible for most plants: directly splitting dinitrogen molecules that make up 78 percent of the Earth’s atmosphere.
A dinitrogen molecule consists of two nitrogen atoms tightly locked together in one of the strongest bonds in nature. The semi-aquatic fern’s ability to split nitrogen, called nitrogen-fixing, made it a highly revered plant in East Asia. Rice farmers used Azolla as a biofertilizer since the 11th century in Vietnam and China.
For decades, scientists have attempted to decode Azolla’s evolution. Cell biologist Francisco Carrapico, who worked at the University of Lisbon, has analyzed this distinctive symbiosis since the 1980s. To his amazement, in 1991, he found that bacteria are the third partner of the Azolla-Anabaena symbiosis.
“Azolla and Anabaena cannot survive without each other. They have co-evolved for 80 million years, continuously exchanging their genetic material with each other,” says Bujak, co-author of The Azolla Story, which he published with his daughter, Alexandra Bujak, an environmental scientist. Three different levels of nitrogen fixation take place within the plant, as Anabaena draws down as much as 2,200 pounds of atmospheric nitrogen per acre annually.
“Using Azolla to mitigate climate change might sound a bit too simple. But that is not the case,” Bujak says. “At a microscopic level, extremely complicated biochemical reactions are constantly occurring inside the plant’s cells that machines or technology cannot replicate yet.”
In 2018, researchers based in the U.S. managed to sequence Azolla’s complete genome — which is four times larger than the human genome — through a crowdfunded study, further increasing our understanding of this plant. “Azolla is a superorganism that works efficiently as a natural biotechnology system that makes it capable of doubling in size within three to five days,” says Carrapico.
Making Azolla mainstream again in agriculture
While scientific groups in the Global North have been working towards unraveling the tiny fern’s inner workings, communities in the Global South are busy devising creative ways to return to their traditional agricultural roots by tapping into Azolla’s full potential.
Pham Gia Minh, an entrepreneur living in Hanoi, Vietnam, is one such citizen scientist who believes that Azolla could be a climate savior. More than two decades after working in finance and business development, Minh is now focusing on continuing his grandfather’s legacy, an agricultural scientist who conducted Azolla research until the 1950s. “Azolla is our family’s heritage,” says Minh.
Pham Gia Minh, an entrepreneur and citizen scientist in Hanoi, Vietnam, believes that Azolla could be a climate savior
Pham Gia Minh
Since the advent of chemical fertilizers in the early 1900s, farmers in Asia abandoned Azolla to save on time and labor costs. But rice farmers in the country went back to cultivating Azolla during the Vietnam War after chemical trade embargoes made chemical fertilizers far too expensive and inaccessible.
By 1973, Azolla cultivation in rice paddy fields was established on half a million hectares in Vietnam. By injecting nitrogen into the soil, Azolla improves soil fertility and also increases rice yields by at least 27 percent compared to urea. The plants can also reduce a farm’s methane emissions by 40 percent.
“Unfortunately, after 1985, chemical fertilizers became cheap and widely available in Vietnam again. So, farmers stopped growing Azolla because of the time-consuming and labor-intensive cultivation process,” says Minh.
Minh has invested in a rural farm where he is proving that modern technology can make the process less burdensome. He uses a pump and drying equipment for harvesting Azolla in a small pond, and he deploys a drone for spraying insecticides and fertilizers on the pond at regular intervals.
As Azolla lacks phosphorus, farmers in developing countries still find it challenging to let go of chemical fertilizers completely. Still, Minh and Bujak say that farmers can use Azolla instead of chemical fertilizers after mixing it with dung.
In the last few years, the fern’s popularity has been growing in other developing countries like India, Palestine, Indonesia, the Philippines, and Bangladesh, where local governments and citizens are trying to re-introduce Azolla integrated farming by growing the ferns in small ponds.
Replacing soybeans with Azolla
In Ecuador, Mariano Montano Armijos, a former chemical engineer, has worked with Azolla for more than 20 years. Since 2008, he has shared resources and information for growing Azolla with 3,000 farmers in Ecuador. The farmers use the harvested plants as a bio-fertilizer and feed for livestock.
“The farmers do not use urea anymore,” says Armijos. “This goes against the conventional agricultural practices of using huge amounts of synthetic nitrogen on a hectare of rice or corn fields.”
He insists that Azolla’s greatest strength is that it is a rich source of proteins, making it highly nutritious for human beings as well. After growing Azolla on a small scale in ponds, Armijos and his business partner, Ivan Noboa, are now building a facility for cultivating the ferns as a superfood on an industrial scale.
According to Armijos, one hectare of Azolla in Ecuador can produce seven tons of proteins. Whereas soybeans produce only one ton of protein per hectare. “If we switch to Azolla, it could help in reducing deforestation in the Amazon. But taming Azolla and turning it into a crop is not easy,” he adds.
Henriette Schluepmann, a molecular plant biologist at Utrecht University in the Netherlands, believes that Azolla could replace soybeans and chemical fertilizers someday — only if researchers can achieve yield stability in controlled environments over long durations.
“In a country like the Netherlands that is surrounded by water with high levels of phosphates, it makes sense to grow Azolla as a substitute for soybeans,” says Schluepmann. “For that to happen, we need massive investments to understand these ferns’ reproductive system and how to replicate that within aquaculture systems on a large scale.”
Pollution control and carbon sequestration
Currently, Schluepmann and her team are growing Azolla in a plant nursery or closed system before transferring the ferns to flooded fields. So far, they have been able to continuously grow Azolla without any major setbacks for a total of 155 days. Taking care of these plants’ well-being is an uphill struggle.
Unlike most plants, Azolla does not grow from seeds because it contains female and male spores that tend to split instead of reproducing. To add to that, growing Azolla on a large scale in controlled environments makes the floating plants extremely vulnerable to insect infestations and fungi attacks.
“Even though it is easier to grow Azolla on a non-industrial scale, the long and tedious cultivation process is often in conflict with human rights,” she says. Farms in developing countries such as Indonesia sometimes use child labor for cultivating Azolla.”
History has taught us that the uncontrolled growth of Azolla plants deprives marine ecosystems of sunlight and chokes life underneath them. But researchers like Schluepmann and Bujak are optimistic that even on a much smaller scale, Azolla can put up a fight against human-driven climate change.
Schluepmann discovered an insecticide that can control Azolla blooms. But in the wild, this aquatic fern grows relentlessly in polluted rivers and lakes and has gained a notorious reputation as an invasive weed. Countries like Portugal and the UK banned Azolla after experiencing severe blooms in rivers that snuffed out local marine life.
“Azolla has been misunderstood as a nuisance. But in reality, it is highly beneficial for purifying water,” says Bujak. Through a process called phytoremediation, Azolla locks up pollutants like excess nitrogen and phosphorus and stops toxic algal blooms from occurring in rivers and lakes.
A 2018 study found that Azolla can decrease nitrogen and phosphorus levels in wastewater by 33 percent and 40.5 percent, respectively. While harmful algae like phytoplankton produce toxins and release noxious gases, Azolla automatically blocks any toxins that its cyanobacteria, Anabaena, might produce.
“In our labs, we observed that Azolla works effectively in treating wastewater,” explains Schluepmann. “Once we gain a better understanding of Azolla aquaculture, we can also use it for carbon capture and storage. But in Europe, we would have to use the entire Baltic Sea to make a difference.”
Planting massive amounts of these prehistoric ferns in any of the Northern great water bodies is out of the question. After all, history has taught us that the uncontrolled growth of Azolla plants deprives marine ecosystems of sunlight and chokes life underneath them. But researchers like Schluepmann and Bujak are optimistic that even on a much smaller scale, Azolla can put up a fight against human-driven climate change.
Traditional carbon capture and storage methods are not only expensive but also inefficient and could increase air pollution. According to Bujak’s estimates, Azolla can sequester 10 metric tonnes of carbon dioxide per hectare annually, which is 10 times the average capacity of grasslands.
“Anyone can set up their own DIY carbon capture and storage system by growing Azolla in shallow water. After harvesting and compressing the plants, carbon dioxide gets stored permanently,” says Bujak.
He envisions scaling up this process by setting up “Azolla hubs” in mega-cities where the plants are grown in shallow trays stacked on top of each other with vertical farming systems built within multi-story buildings. The compressed Azolla plants can then be converted into a biofuel, fertilizer, livestock feed, or biochar for sequestering carbon dioxide.
“Using Azolla to mitigate climate change might sound a bit too simple. But that is not the case,” Bujak adds. “At a microscopic level, extremely complicated biochemical reactions are constantly occurring inside the plant’s cells that machines or technology cannot replicate yet.”
Through Azolla, scientists hope to work with nature by tapping into four billion years of evolution.
Katalin Karikó, pictured, and Drew Weissman won the Nobel Prize for advances in mRNA research that led to the first Covid vaccines.
The work for which they garnered the illustrious award and its accompanying $1,000,000 cash windfall was completed about two decades ago, wrought through long hours in the lab over many arduous years. But humanity collectively benefited from its life-saving outcome three years ago, when both Moderna and Pfizer/BioNTech’s mRNA vaccines against COVID were found to be safe and highly effective at preventing severe disease. Billions of doses have since been given out to protect humans from the upstart viral scourge.
“I thought of going somewhere else, or doing something else,” said Katalin Karikó. “I also thought maybe I’m not good enough, not smart enough. I tried to imagine: Everything is here, and I just have to do better experiments.”
Unlocking the power of mRNA
Weissman and Karikó unlocked mRNA vaccines for the world back in the early 2000s when they made a key breakthrough. Messenger RNA molecules are essentially instructions for cells’ ribosomes to make specific proteins, so in the 1980s and 1990s, researchers started wondering if sneaking mRNA into the body could trigger cells to manufacture antibodies, enzymes, or growth agents for protecting against infection, treating disease, or repairing tissues. But there was a big problem: injecting this synthetic mRNA triggered a dangerous, inflammatory immune response resulting in the mRNA’s destruction.
While most other researchers chose not to tackle this perplexing problem to instead pursue more lucrative and publishable exploits, Karikó stuck with it. The choice sent her academic career into depressing doldrums. Nobody would fund her work, publications dried up, and after six years as an assistant professor at the University of Pennsylvania, Karikó got demoted. She was going backward.
“I thought of going somewhere else, or doing something else,” Karikó told Stat in 2020. “I also thought maybe I’m not good enough, not smart enough. I tried to imagine: Everything is here, and I just have to do better experiments.”
A tale of tenacity
Collaborating with Drew Weissman, a new professor at the University of Pennsylvania, in the late 1990s helped provide Karikó with the tenacity to continue. Weissman nurtured a goal of developing a vaccine against HIV-1, and saw mRNA as a potential way to do it.
“For the 20 years that we’ve worked together before anybody knew what RNA is, or cared, it was the two of us literally side by side at a bench working together,” Weissman said in an interview with Adam Smith of the Nobel Foundation.
In 2005, the duo made their 2023 Nobel Prize-winning breakthrough, detailing it in a relatively small journal, Immunity. (Their paper was rejected by larger journals, including Science and Nature.) They figured out that chemically modifying the nucleoside bases that make up mRNA allowed the molecule to slip past the body’s immune defenses. Karikó and Weissman followed up that finding by creating mRNA that’s more efficiently translated within cells, greatly boosting protein production. In 2020, scientists at Moderna and BioNTech (where Karikó worked from 2013 to 2022) rushed to craft vaccines against COVID, putting their methods to life-saving use.
The future of vaccines
Buoyed by the resounding success of mRNA vaccines, scientists are now hurriedly researching ways to use mRNA medicine against other infectious diseases, cancer, and genetic disorders. The now ubiquitous efforts stand in stark contrast to Karikó and Weissman’s previously unheralded struggles years ago as they doggedly worked to realize a shared dream that so many others shied away from. Katalin Karikó and Drew Weissman were brave enough to walk a scientific path that very well could have ended in a dead end, and for that, they absolutely deserve their 2023 Nobel Prize.
This article originally appeared on Big Think, home of the brightest minds and biggest ideas of all time.
With conventional fuel cells as their model, researchers learned to use similar chemical reactions to make a fuel from microbes in pee.
Plus, urine contains water, phosphorus, potassium and nitrogen, the key ingredients plants need to grow and survive. Human urine could replace about 25 percent of current nitrogen and phosphorous fertilizers worldwide and could save water for gardens and crops. The average U.S. resident flushes a toilet bowl containing only pee and paper about six to seven times a day, which adds up to about 3,500 gallons of water down per year. Plus cows in the U.S. produce 231 gallons of the stuff each year.
Pee power
A conventional fuel cell uses chemical reactions to produce energy, as electrons move from one electrode to another to power a lightbulb or phone. Ioannis Ieropoulos, a professor and chair of Environmental Engineering at the University of Southampton in England, realized the same type of reaction could be used to make a fuel from microbes in pee.
Bacterial species like Shewanella oneidensis and Pseudomonas aeruginosa can consume carbon and other nutrients in urine and pop out electrons as a result of their digestion. In a microbial fuel cell, one electrode is covered in microbes, immersed in urine and kept away from oxygen. Another electrode is in contact with oxygen. When the microbes feed on nutrients, they produce the electrons that flow through the circuit from one electrod to another to combine with oxygen on the other side. As long as the microbes have fresh pee to chomp on, electrons keep flowing. And after the microbes are done with the pee, it can be used as fertilizer.
These microbes are easily found in wastewater treatment plants, ponds, lakes, rivers or soil. Keeping them alive is the easy part, says Ieropoulos. Once the cells start producing stable power, his group sequences the microbes and keeps using them.
Like many promising technologies, scaling these devices for mass consumption won’t be easy, says Kevin Orner, a civil engineering professor at West Virginia University. But it’s moving in the right direction. Ieropoulos’s device has shrunk from the size of about three packs of cards to a large glue stick. It looks and works much like a AAA battery and produce about the same power. By itself, the device can barely power a light bulb, but when stacked together, they can do much more—just like photovoltaic cells in solar panels. His lab has produced 1760 fuel cells stacked together, and with manufacturing support, there’s no theoretical ceiling, he says.
Although pure urine produces the most power, Ieropoulos’s devices also work with the mixed liquids of the wastewater treatment plants, so they can be retrofit into urban wastewater utilities.
This image shows how the pee-powered system works. Pee feeds bacteria in the stack of fuel cells (1), which give off electrons (2) stored in parallel cylindrical cells (3). These cells are connected to a voltage regulator (4), which smooths out the electrical signal to ensure consistent power to the LED strips lighting the toilet.
Courtesy Ioannis Ieropoulos
Key to the long-term success of any urine reclamation effort, says Orner, is avoiding what he calls “parachute engineering”—when well-meaning scientists solve a problem with novel tech and then abandon it. “The way around that is to have either the need come from the community or to have an organization in a community that is committed to seeing a project operate and maintained,” he says.
Success with urine reclamation also depends on the economy. “If energy prices are low, it may not make sense to recover energy,” says Orner. “But right now, fertilizer prices worldwide are generally pretty high, so it may make sense to recover fertilizer and nutrients.” There are obstacles, too, such as few incentives for builders to incorporate urine recycling into new construction. And any hiccups like leaks or waste seepage will cost builders money and reputation. Right now, Orner says, the risks are just too high.
Despite the challenges, Ieropoulos envisions a future in which urine is passed through microbial fuel cells at wastewater treatment plants, retrofitted septic tanks, and building basements, and is then delivered to businesses to use as agricultural fertilizers. Although pure urine produces the most power, Ieropoulos’s devices also work with the mixed liquids of the wastewater treatment plants, so they can be retrofitted into urban wastewater utilities where they can make electricity from the effluent. And unlike solar cells, which are a common target of theft in some areas, nobody wants to steal a bunch of pee.
When Ieropoulos’s team returned to wrap up their pilot project 18 months later, the school’s director begged them to leave the fuel cells in place—because they made a major difference in students’ lives. “We replaced it with a substantial photovoltaic panel,” says Ieropoulos, They couldn’t leave the units forever, he explained, because of intellectual property reasons—their funders worried about theft of both the technology and the idea. But the photovoltaic replacement could be stolen, too, leaving the girls in the dark.
The story repeated itself at another school, in Nairobi, Kenya, as well as in an informal settlement in Durban, South Africa. Each time, Ieropoulos vowed to return. Though the pandemic has delayed his promise, he is resolute about continuing his work—it is a moral and legal obligation. “We've made a commitment to ourselves and to the pupils,” he says. “That's why we need to go back.”
Urine as fertilizer
Modern day industrial systems perpetuate the broken cycle of nutrients. When plants grow, they use up nutrients the soil. We eat the plans and excrete some of the nutrients we pass them into rivers and oceans. As a result, farmers must keep fertilizing the fields while our waste keeps fertilizing the waterways, where the algae, overfertilized with nitrogen, phosphorous and other nutrients grows out of control, sucking up oxygen that other marine species need to live. Few global communities remain untouched by the related challenges this broken chain create: insufficient clean water, food, and energy, and too much human and animal waste.
The Rich Earth Institute in Vermont runs a community-wide urine nutrient recovery program, which collects urine from homes and businesses, transports it for processing, and then supplies it as fertilizer to local farms.
One solution to this broken cycle is reclaiming urine and returning it back to the land. The Rich Earth Institute in Vermont is one of several organizations around the world working to divert and save urine for agricultural use. “The urine produced by an adult in one day contains enough fertilizer to grow all the wheat in one loaf of bread,” states their website.
Notably, while urine is not entirely sterile, it tends to harbor fewer pathogens than feces. That’s largely because urine has less organic matter and therefore less food for pathogens to feed on, but also because the urinary tract and the bladder have built-in antimicrobial defenses that kill many germs. In fact, the Rich Earth Institute says it’s safe to put your own urine onto crops grown for home consumption. Nonetheless, you’ll want to dilute it first because pee usually has too much nitrogen and can cause “fertilizer burn” if applied straight without dilution. Other projects to turn urine into fertilizer are in progress in Niger, South Africa, Kenya, Ethiopia, Sweden, Switzerland, The Netherlands, Australia, and France.
Eleven years ago, the Institute started a program that collects urine from homes and businesses, transports it for processing, and then supplies it as fertilizer to local farms. By 2021, the program included 180 donors producing over 12,000 gallons of urine each year. This urine is helping to fertilize hay fields at four partnering farms. Orner, the West Virginia professor, sees it as a success story. “They've shown how you can do this right--implementing it at a community level scale."