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    New tool overcomes major hurdle in clinical AI design

    Harvard Medical School scientists and colleagues at Stanford University have developed an artificial intelligence diagnostic tool that can detect diseases on chest X-rays directly from natural-language descriptions contained in accompanying clinical reports.
    The step is deemed a major advance in clinical AI design because most current AI models require laborious human annotation of vast reams of data before the labeled data are fed into the model to train it.
    A report on the work, published Sept. 15 in Nature Biomedical Engineering, shows that the model, called CheXzero, performed on par with human radiologists in its ability to detect pathologies on chest X-rays.
    The team has made the code for the model publicly available for other researchers.
    Most AI models require labeled datasets during their “training” so they can learn to correctly identify pathologies. This process is especially burdensome for medical image-interpretation tasks since it involves large-scale annotation by human clinicians, which is often expensive and time-consuming. For instance, to label a chest X-ray dataset, expert radiologists would have to look at hundreds of thousands of X-ray images one by one and explicitly annotate each one with the conditions detected. While more recent AI models have tried to address this labeling bottlenck by learning from unlabeled data in a “pre-training” stage, they eventually require fine-tuning on labeled data to achieve high performance.
    By contrast, the new model is self-supervised, in the sense that it learns more independently, without the need for hand-labeled data before or after training. The model relies solely on chest X-rays and the English-language notes found in accompanying X-ray reports. More

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    Talk with your hands? You might think with them too!

    How do we understand words? Scientists don’t fully understand what happens when a word pops into your brain. A research group led by Professor Shogo Makioka at the Graduate School of Sustainable System Sciences, Osaka Metropolitan University, wanted to test the idea of embodied cognition. Embodied cognition proposes that people understand the words for objects through how they interact with them, so the researchers devised a test to observe semantic processing of words when the ways that the participants could interact with objects were limited.
    Words are expressed in relation to other words; a “cup,” for example, can be a “container, made of glass, used for drinking.” However, you can only use a cup if you understand that to drink from a cup of water, you hold it in your hand and bring it to your mouth, or that if you drop the cup, it will smash on the floor. Without understanding this, it would be difficult to create a robot that can handle a real cup. In artificial intelligence research, these issues are known as symbol grounding problems, which map symbols onto the real world.
    How do humans achieve symbol grounding? Cognitive psychology and cognitive science propose the concept of embodied cognition, where objects are given meaning through interactions with the body and the environment.
    To test embodied cognition, the researchers conducted experiments to see how the participants’ brains responded to words that describe objects that can be manipulated by hand, when the participants’ hands could move freely compared to when they were restrained.
    “It was very difficult to establish a method for measuring and analyzing brain activity. The first author, Ms. Sae Onishi, worked persistently to come up with a task, in a way that we were able to measure brain activity with sufficient accuracy,” Professor Makioka explained.
    In the experiment, two words such as “cup” and “broom” were presented to participants on a screen. They were asked to compare the relative sizes of the objects those words represented and to verbally answer which object was larger — in this case, “broom.” Comparisons were made between the words, describing two types of objects, hand-manipulable objects, such as “cup” or “broom” and nonmanipulable objects, such as “building” or “lamppost,” to observe how each type was processed.
    During the tests, the participants placed their hands on a desk, where they were either free or restrained by a transparent acrylic plate. When the two words were presented on the screen, to answer which one represented a larger object, the participants needed to think of both objects and compare their sizes, forcing them to process each word’s meaning.
    Brain activity was measured with functional near-infrared spectroscopy (fNIRS), which has the advantage of taking measurements without imposing further physical constraints. The measurements focused on the interparietal sulcus and the inferior parietal lobule (supramarginal gyrus and angular gyrus) of the left brain, which are responsible for semantic processing related to tools. The speed of the verbal response was measured to determine how quickly the participant answered after the words appeared on the screen.
    The results showed that the activity of the left brain in response to hand-manipulable objects was significantly reduced by hand restraints. Verbal responses were also affected by hand constraints. These results indicate that constraining hand movement affects the processing of object-meaning, which supports the idea of embodied cognition. These results suggest that the idea of embodied cognition could also be effective for artificial intelligence to learn the meaning of objects. The paper was published in Scientific Reports.
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    Using artificial intelligence to improve tuberculosis treatments

    Imagine you have 20 new compounds that have shown some effectiveness in treating a disease like tuberculosis (TB), which affects 10 million people worldwide and kills 1.5 million each year. For effective treatment, patients will need to take a combination of three or four drugs for months or even years because the TB bacteria behave differently in different environments in cells — and in some cases evolve to become drug-resistant. Twenty compounds in three- and four-drug combinations offer nearly 6,000 possible combinations. How do you decide which drugs to test together?
    In a recent study, published in the September issue of Cell Reports Medicine, researchers from Tufts University used data from large studies that contained laboratory measurements of two-drug combinations of 12 anti-tuberculosis drugs. Using mathematical models, the team discovered a set of rules that drug pairs need to satisfy to be potentially good treatments as part of three- and four-drug cocktails.
    The use of drug pairs rather than three- and four- drug combination measurement cuts down significantly on the amount of testing that needs to be done before moving a drug combination into further study.
    “Using the design rules we’ve established and tested, we can substitute one drug pair for another drug pair and know with a high degree of confidence that the drug pair should work in concert with the other drug pair to kill the TB bacteria in the rodent model,” says Bree Aldridge, associate professor of molecular biology and microbiology at Tufts University School of Medicine and of biomedical engineering at the School of Engineering, and an immunology and molecular microbiology program faculty member at the Graduate School of Biomedical Sciences. “The selection process we developed is both more streamlined and more accurate in predicting success than prior processes, which necessarily considered fewer combinations.”
    The lab of Aldridge, who is corresponding author on the paper and also associate director of Tufts Stuart B. Levy Center for Integrated Management of Antimicrobial Resistance, previously developed and uses DiaMOND, or diagonal measurement of n-way drug interactions, a method to systemically study pairwise and high-order drug combination interactions to identify shorter, more efficient treatment regimens for TB and potentially other bacterial infections. With the design rules established in this new study, researchers believe they can increase the speed at which scientists determine which drug combinations will most effectively treat tuberculosis, the second leading infectious killer in the world.
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    Dense liquid droplets act as cellular computers

    An emerging field explores how groups of molecules condense together inside cells, the way oil droplets assemble and separate from water in a vinaigrette.
    In human cells, “liquid-liquid phase separation” occurs because similar, large molecules glom together into dense droplets separated from the more diluted parts of the fluid cell interior. Past work had suggested that evolution harnessed the natural formation of these “condensates” to organize cells, providing, for instance, isolated spaces for the building of cellular machines.
    Furthermore, abnormal, condensed — also called “tangled” — groups of molecules in droplets are nearly always present in the cells of patients with neurodegenerative conditions, including Alzheimer’s disease. While no one knows why such condensates form, one new theory argues that the biophysical properties of cell interiors change as people age — driven in part by “molecular crowding” that packs more molecules into the same spaces to affect phase separation.
    Researchers compare condensates to microprocessors, computers built into circuits, because both recognize and calculate responses based on incoming information. Despite the suspected impact of physical changes on liquid processors, the field has struggled to clarify the mechanisms connecting phase separation, condensate formation, and computation based on chemical signals, which occur at much smaller scale, researchers say. This is because natural condensates have so many functions that experiments struggle to delineate them.
    To address this challenge, researchers at NYU Grossman School of Medicine and the German Center for Neurodegenerative Diseases built an artificial system that revealed how the formation of condensates changes the action at the molecular level of enzymes called kinases, an example of chemical computation. Kinases are protein switches that influence cellular processes by phosphorylating — attaching a molecule called a phosphate group — to target molecules.
    The new analysis, published online September 14 in Molecular Cell, found that the formation of engineered condensates during phase separation offered more “sticky” regions where medically important kinases and their targets could interact and trigger phosphorylation signals. More

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    New method for comparing neural networks exposes how artificial intelligence works

    A team at Los Alamos National Laboratory has developed a novel approach for comparing neural networks that looks within the “black box” of artificial intelligence to help researchers understand neural network behavior. Neural networks recognize patterns in datasets; they are used everywhere in society, in applications such as virtual assistants, facial recognition systems and self-driving cars.
    “The artificial intelligence research community doesn’t necessarily have a complete understanding of what neural networks are doing; they give us good results, but we don’t know how or why,” said Haydn Jones, a researcher in the Advanced Research in Cyber Systems group at Los Alamos. “Our new method does a better job of comparing neural networks, which is a crucial step toward better understanding the mathematics behind AI.”
    Jones is the lead author of the paper “If You’ve Trained One You’ve Trained Them All: Inter-Architecture Similarity Increases With Robustness,” which was presented recently at the Conference on Uncertainty in Artificial Intelligence. In addition to studying network similarity, the paper is a crucial step toward characterizing the behavior of robust neural networks.
    Neural networks are high performance, but fragile. For example, self-driving cars use neural networks to detect signs. When conditions are ideal, they do this quite well. However, the smallest aberration — such as a sticker on a stop sign — can cause the neural network to misidentify the sign and never stop.
    To improve neural networks, researchers are looking at ways to improve network robustness. One state-of-the-art approach involves “attacking” networks during their training process. Researchers intentionally introduce aberrations and train the AI to ignore them. This process is called adversarial training and essentially makes it harder to fool the networks.
    Jones, Los Alamos collaborators Jacob Springer and Garrett Kenyon, and Jones’ mentor Juston Moore, applied their new metric of network similarity to adversarially trained neural networks, and found, surprisingly, that adversarial training causes neural networks in the computer vision domain to converge to very similar data representations, regardless of network architecture, as the magnitude of the attack increases.
    “We found that when we train neural networks to be robust against adversarial attacks, they begin to do the same things,” Jones said.
    There has been extensive effort in industry and in the academic community searching for the “right architecture” for neural networks, but the Los Alamos team’s findings indicate that the introduction of adversarial training narrows this search space substantially. As a result, the AI research community may not need to spend as much time exploring new architectures, knowing that adversarial training causes diverse architectures to converge to similar solutions.
    “By finding that robust neural networks are similar to each other, we’re making it easier to understand how robust AI might really work. We might even be uncovering hints as to how perception occurs in humans and other animals,” Jones said.
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    Intelligent cooperation to provide surveillance and epidemic services in smart cities

    The potential of unmanned aerial vehicles (UAVs) to provide a safe environment and epidemic prevention services to people is huge. This potential has been harnessed by the scientists at Incheon National University to design a cooperative infrastructure for artificial intelligence-assisted aerial and ground operations using UAVs and mobile robots. This infrastructure can provide surveillance and epidemic prevention activities to smart cities.
    There has been a lot of interest in mobile robots and unmanned aerial vehicles (UAVs) in recent times, primarily because these technologies have the potential to provide us with immense benefits. With the rise of 5G technology, it is expected that UAVs or drones and mobile robots will efficiently and safely provide a wide range of services in smart cities, including surveillance and epidemic prevention. It is now well established that robots can be deployed in various environments to perform activities like surveillance and rescue operations. But till date, all these operations have been independent of each other, often working in parallel. To realize the full potential of UAVs and mobile robots, we need to use these technologies together so that they can support each other and augment mutual functions.
    To this end, a team of researchers led by Associate Professor Hyunbum Kim from Incheon National University, South Korea, have designed an Artificial Intelligence (AI)-assisted cooperative infrastructure for UAVs and mobile robots. In a paper published in volume 36 issue 3 of IEEE Network on 13 July 2022, the researchers outline the entire structure that can use UAVs and mobile robots in public and private areas for multiple operations like patrolling, accident detection and rescue, and epidemic prevention. According to Dr Kim, “It is critical to look at surveillance and unprecedented epidemic spread such as COVID-19 together. This is why we designed the next generation system to focus on aerial-ground surveillance and epidemic prevention supported by intelligent mobile robots and smart UAVs.”
    The system designed by the team is composed of two subsystems, one for public areas and one for private areas. Both systems comprise of a Centralized Administrator Center (CAC). The CAC is connected to various Unified Rendezvous Stations (URSs) that are situated in public areas. These URSs are where the UAVs and mobile robots receive replenishment and share data. Mobile robots are also equipped with charging facilities to recharge airborne docking UAVs. The public system aims at patrolling public areas, detecting accidents and calamities, providing aid, and performing epidemic prevention activities like transporting medical equipment. The private system can provide rapid medical deliveries and screening tests to homes.
    But what about privacy under such surveillance? Dr Kim allays concerns, saying, “Privacy is indeed a major concern for any surveillance mechanism. Therefore, we have created different privacy settings for different systems. For the public system, there are restricted districts where only authorized public UAVs can enter. For the private system, there are permanent private zones where no UAVs can enter except in emergencies and temporal access zones where permitted UAVs can enter with legal permission from the owners.”
    The authors are optimistic about the potential of this infrastructure to improve people’s lives. The system can provide a vast array of services, from detecting and preventing potential terror in public spaces to detecting and extinguishing fires in private homes. Indeed, two is better than one and we look forward to living in this cooperative and optimistic future!
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    Tiny, caterpillar-like soft robot folds, rolls, grabs and degrades

    When you hear the term “robot,” you might think of complicated machinery working in factories or roving on other planets. But “millirobots” might change that. They’re robots about as wide as a finger that someday could deliver drugs or perform minimally invasive surgery. Now, researchers reporting in ACS Applied Polymer Materials have developed a soft, biodegradable, magnetic millirobot inspired by the walking and grabbing capabilities of insects.
    Some soft millirobots are already being developed for a variety of biomedical applications, thanks to their small size and ability to be powered externally, often by a magnetic field. Their unique structures allow them to inch or roll themselves through the bumpy tissues of our gastrointestinal tract, for example. They could someday even be coated in a drug solution and deliver the medicine exactly where it’s needed in the body. However, most millirobots are made of non-degradable materials, such as silicone, which means they’d have to be surgically removed if used in clinical applications. In addition, these materials aren’t that flexible and don’t allow for much fine-tuning of the robot’s properties, limiting their adaptability. So, Wanfeng Shang, Yajing Shen and colleagues wanted to create a millirobot out of soft, biodegradable materials that can grab, roll and climb, but then easily dissolve away after its job is done.
    As a proof of concept, the researchers created a millirobot using a gelatin solution mixed with iron oxide microparticles. Placing the material above a permanent magnet caused the microparticles in the solution to push the gel outward, forming insect-like “legs” along the lines of the magnetic field. Then, the hydrogel was placed in the cold to make it more solid. The final step was to soak the material in ammonium sulfate to cause cross-linking in the hydrogel, making it even stronger. Changing various factors, such as the composition of the ammonium sulfate solution, the thickness of the gel or the strength of the magnetic field allowed the researchers to tune the properties. For example, placing the hydrogel farther away from the magnet resulted in fewer, but longer, legs.
    Because the iron oxide microparticles form magnetic chains within the gel, moving a magnet near the hydrogel caused the legs to bend and produce a claw-like grasping motion. In experiments, the material gripped a 3D-printed cylinder and a rubber band and carried each one to new locations. In addition, the researchers tested the millirobot’s ability to deliver a drug by coating it in a dye solution, then rolling it through a stomach model. Once at its destination, the robot unfurled and released the dye with the strategic use of magnets. Since it’s made using water-soluble gelatin, the millirobot easily degraded in water in two days, leaving behind only the tiny magnetic particles. The researchers say that the new millirobot could open up new possibilities for drug delivery and other biomedical applications.
    The authors acknowledge funding from the National Natural Science Foundation of China, Hong Kong RGC General Research Fund and Shenzhen Key Basic Research Project.
    Video: https://youtu.be/1va-OQvfJDg
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    How Kenyans help themselves and the planet by saving mangrove trees

    On the fringe of Kenya’s Gazi village, 50 kilometers south of Mombasa, Mwatime Hamadi walks barefoot on a path of scorching-hot sand toward a thicket of trees that seem to float where the land meets the Indian Ocean. Behind her moves village life: Mothers carry babies on their backs while they hang laundry between palm trees, women sweep the floors of huts thatched with palm fronds and old men chat idly about bygone days under the shade of mango trees.

    Hamadi is on her way to Gazi Forest, a dense patch of mangroves along Gazi Bay that coastal residents see as vital to their future. Mangroves “play a crucial role in safeguarding the marine ecosystem, which in turn is important for fisheries we depend on for our livelihood,” she says as she reaches a boardwalk that snakes through the coastal wetland.

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    Hamadi is a tour guide with Gazi Ecotourism Ventures, a group dedicated to empowering women and their community through mangrove conservation. This group is part of a larger carbon offset project called Mikoko Pamoja that has taken root and is now being copied farther south on Kenya’s coastline and in Mozambique and Madagascar.

    Through Mikoko Pamoja, residents of Gazi and nearby Makongeni are cultivating an economic ecosystem that relies on efforts to preserve and restore the mangrove forests. Revenue from carbon credits sold plus the money Hamadi and others earn from ecotourism are split between salaries, project costs and village improvements to health care, sanitation, schools and more.

    Mikoko Pamoja, launched in 2013, is the world’s first mangrove­-driven carbon credit initiative. It earned the United Nations’ Equator Prize in 2017, awarded for innovative solutions to poverty that involve conservation and sustainable use of biodiversity.

    “The mangrove vegetation was a thriving, healthy ecosystem in precolonial times,” says Ismail Barua, Mikoko Pamoja’s chairperson. During British rule, which stretched from the 1890s to 1963, the colonial government issued licenses to private companies to export mangrove wood. They did this without community involvement, which led to poaching of trees. Even after Kenya gained independence, mangroves were an important source of timber and fuel for industrial processes, main drivers of extensive destruction of the forests.

    Today, mangrove restoration is helping the region enter a new chapter, one where labor and resources are well-managed by local communities instead of being exploited. “The community is now able to run its own affairs,” Barua notes. Through innovative solutions and hard work, he says, “we’re trying to bring back a semblance of that ecosystem.”

    DOLIMAC/ISTOCK/GETTY IMAGES PLUS

    “The mangrove vegetation was a thriving, healthy ecosystem in precolonial times.…We’re trying to bring back a semblance of that ecosystem.”Ismail Barua

    A fragile carbon sponge

    The dominant mangrove species in Gazi Forest is Rhizophora murcronata. With oval, leathery leaves about the size of a child’s palm and spindly branches that reach to the sun, the trees can grow up to 27 meters tall. Their interlaced roots, which grow from the base of the trunk into the salt­water, make these evergreen trees unique.

    Salt kills most plants, but mangrove roots separate freshwater from salt for the tree to use. At low tide, the looping roots act like stilts and buttresses, keeping trunks and branches above the waterline and dry. Speckling these roots are thousands of specialized pores, or lenticels. The lenticels open to absorb gases from the atmosphere when exposed, but seal tight at high tide, keeping the mangrove from drowning.

    The thickets of roots also prevent soil erosion and buffer coastlines against tropical storms. Within these roots and branches, shorebirds and fish — and in some places, manatees and dolphins — thrive.

    Mangrove roots support an ecosystem that stores four times as much carbon as inland forests. That’s because the saltwater slows decomposition of organic matter, says Kipkorir Lang’at, a principal scientist at the Kenya Marine and Fisheries Research Institute, or KMFRI. So when mangrove plants and animals die, their carbon gets trapped in thick soils. As long as mangroves stay standing, the carbon stays in the soil.

    Robust estimates of mangrove forest area in Kenya before 1980 are not available, Lang’at says. However, with the clear-cutting of mangrove forests in Gazi Bay in the 1970s, he says, the area was left with vast expanses of bare, sandy coast.

    Other parts of the country experienced similar losses: Kenya lost up to 20 percent of its mangrove forests between 1985 and 2009 because no mechanism existed for their protection. The losses had a steep price: Just as mangroves absorb more carbon than inland forests, when destroyed, they release more carbon than other forests. And since the mangroves provided habitat and shelter for fish, their destruction meant that fishers were catching less.

    Recognizing this high cost, as well as the eco­system’s other benefits, Kenya’s government ratified the Forest Conservation and Management Act of 2016, a law protecting mangroves and inland forests. Cutting down mangroves is now banned throughout the country, except in very specific areas under very specific circumstances.

    Available data suggest that Kenya’s rate of mangrove loss has declined in the last two decades. The country is now losing about 0.65 percent of its mangrove forest annually, according to unpublished evaluations conducted in 2020 by KMFRI. Since the turn of the millennium, global mangrove deforestation has slowed as well, hovering between a loss of 0.2 and 0.7 percent per year, says a 2020 study in Scientific Reports.

    Mikoko Pamoja offers hope for turning around those declines. The project, whose Swahili name means “mangroves together,” has its roots in a small mangrove restoration effort that started in 1991 in Gazi Bay, spearheaded by KMFRI. The effort evolved into a scientific experiment to see what it would take to restore a degraded ecosystem. It attracted collaborators from Edinburgh Napier University, Europe’s Earthwatch Institute and other organizations across Europe.

    Now, Gazi Forest boasts 615 hectares of mangrove forest, including 56,000 individual seedlings planted by the community. Plans to plant more mangrove trees — at least 2,000 per year — are in the works.

    Creating carbon credits

    Gazi Forest siphons carbon from the atmosphere at a rate of 3,000 metric tons per year, says Rahma Kivugo, the outgoing project coordinator for Mikoko Pamoja. These aren’t merely ballpark numbers: To sell the carbon offsets collected by Mikoko Pamoja, forest managers must calculate the amount of carbon stored by mangroves.

    Volunteers venture into the forest twice a year, checking on 10 selected 10-square-meter plots in the wild forest and five plots in planted forest. Workers measure the diameter of mature trees at an adult’s chest height. They then estimate the trees’ height. Finally, they classify young trees as knee-height, waist-height, chest-height and higher.

    From these observations, researchers estimate the volume of mangrove material above ground in each plot and extrapolate for the whole forest area.

    Once they have an idea of the volume of plant material above ground, team members can estimate root volume below ground using a standardized factor specific to mangrove forests, says Mbatha Anthony, a research assistant at KMFRI in charge of carbon accounting. Even though mangrove forests store a lot of soil carbon, the project calculates carbon stored only by the tree itself because “calculating soil carbon is a resource-intensive undertaking for a small project like Mikoko Pamoja,” Anthony says.

    With an estimate of the total volume of biomass in the forest in hand, “we can then translate that into tons of carbon,” says environmental biologist Mark Huxham of Edinburgh Napier University, who helps Mikoko Pamoja with its calculations. In general, 50 percent of aboveground biomass is carbon. Below ground, 39 percent of biomass is carbon.

    The amount of carbon stored by Gazi Forest is then relayed to the Plan Vivo Foundation, a group based in Scotland that certifies carbon calculations. Once its calculations are certified, Mikoko Pamoja receives Plan Vivo Certificates, or PVCs.

    One PVC is equivalent to one metric ton of carbon dioxide emission reductions. These PVCs are submitted to the Association for Coastal Ecosystem Services — an organization that markets carbon credits for Mikoko Pamoja and similar projects. Through ACES, Mikoko Pamoja’s PVCs can then be purchased by anyone who wishes to offset their carbon emissions.

    Roughly 117 hectares of Gazi Forest have been demarcated for the sale of carbon credits. “Mikoko Pamoja generates approximately $15,000 annually from the sale of carbon credits,” Anthony says. From 2014 to 2018, the project generated 9,880 credits — 9,880 tons of avoided carbon dioxide emissions.

    Ismail Barua, chairperson of Mikoko Pamoja, stands at a water distribution kiosk funded by the organization’s conservation work.G. Kamadi

    A community at work

    Mikoko Pamoja sells carbon credits at more than $7 per ton. Revenues get split in a clearly defined manner, according to what residents decide are pressing needs of Makongeni and Gazi villages. Around 21 percent pays wages of residents involved with Mikoko Pamoja. And “more than half of what is earned goes toward community projects,” Kivugo says.

    In total, about $117,000 has gone to community projects since Mikoko Pamoja was founded. These projects include donating medicine to health clinics and textbooks to schools and digging clean water wells. Plans are under way to revive a windmill in Gazi for pumping water and renovate Makongeni’s primary school.

    “The need in the community is great. So carbon trading is unlikely to meet all the needs,” Huxham says. But the funds make a significant contribution to local livelihoods, which primes the community to support conservation, he says.

    The approach seems to be working. On a winding path into the forest, visitors encounter a signboard, with large letters in Swahili declaring, “Take note! This is a Mikoko Pamoja area protected by the community. Littering is prohibited! Trimming trees is prohibited!”

    This sign, written in Swahili, warns visitors to the Gazi Bay mangrove forest against littering and cutting down the trees.G. Kamadi

    Active community participation is central to Mikoko Pamoja’s success. Not only do community members plant mangrove seedlings and survey trees to gauge carbon storage, community scouts monitor the health of this ecosystem.

    Scouts clean up litter within the forests and survey the forest’s biodiversity. From a wooden watchtower above the forest, scouts also track and report illegal logging.

    “Should we spot suspicious activities in the forest, we will call the Kenya Forest Service rangers, who have the authority to detain and arrest any trespasser,” says local scout Shaban Jambia.

    Back at the boardwalk, Hamadi leads a small knot of visitors through the mangroves, pausing occasionally to touch a tree’s waxy leaves. She plucks a propagule — a dark-brown pod longer than her hand — from a tree belonging to the mangrove species Bruguiera gymnorhiza.

    She drops the propagule over the boardwalk’s handrail, into the soft marsh soil about 1.5 meters below. It lands, sticking almost perfectly perpendicular in the ground. “This will soon take root and germinate into a new plant,” she explains to the visitors. “That’s how this species propagates.”

    Hamadi, the tour guide, is one of 27 members of the Gazi Women Mangrove Boardwalk group. Members offer interpretive services to visitors for a fee. The women also prepare Swahili cuisine for sale to groups visiting the area.

    “A dish of coconut rice served with snapper fish is particularly popular, washed down with flavored black tea or tamarind juice,” says Mwanahamisi Bakari, the group’s treasurer.

    These ecotourism efforts have attracted international support. The World Wide Fund for Nature Kenya, for instance, constructed a conference facility, which the women’s group rents to those who want to use the location as a backdrop to discuss sustainability efforts.

    A template for others

    Mikoko Pamoja’s success is spurring conservation efforts throughout Kenya and beyond. For instance, on southern Kenya’s coast is the Vanga Blue Forest, a swath of mangroves five times as large as Gazi Forest. Of Vanga Blue’s more than 3,000 hectares of mangrove forest, a little more than 15 percent — 460 hectares — has been set aside for the sale of carbon credits following Mikoko Pamoja’s example.

    In 2020, with help from KFMRI, a network of scientists from countries along the western Indian Ocean published a blueprint for mangrove restoration. These guidelines are now being customized to suit the restoration plans of individual countries, says Lang’at. The group is also using Mikoko Pamoja’s carbon credit example to set up projects of its own.

    Madagascar’s first community-led mangrove carbon project, known as Tahiry Honko (which means “preserving mangroves” in the local Vezo dialect), was introduced in 2013 and then certified for carbon sale by Plan Vivo in 2019. With Mikoko Pamoja as a guide, Tahiry Honko “is helping tackle climate breakdown and build community resilience by preserving and restoring mangrove forests,” says Lalao Aigrette, an adviser at Blue Ventures, the conservation group coordinating the preservation effort.

    Tahiry Honko is generating carbon credits through the conservation and restoration of over 1,200 hectares of mangroves surrounding the Bay of Assassins on Madagascar’s southwest coast.

    In Mozambique, studies are under way to gauge how much mangrove preservation can protect communities against cyclones, says Célia Macamo, a marine biologist at Eduardo Mondlane University in Maputo, Mozambique.

    In the meantime, the Limpopo estuary and other locations along the Mozambican coast are sites of mangrove restoration efforts. KMFRI is helping local organizers structure their efforts. “We also hope they will assist us when we start working with carbon credits,” Macamo adds.

    Mangrove restoration projects have spread outside of Kenya’s Gazi Bay to places such as Limpopo estuary in Mozambique (shown), where residents collect and transport young seedlings.HENRIQUES BALIDY

    Blue economies

    Less than 1 percent of Earth’s surface is covered by mangroves, equivalent to 14.8 million hectares. “Because this area is minuscule compared to terrestrial forests, mangroves have been neglected throughout the world,” says James Kairo, chief scientist at KMFRI.

    At Gazi Bay, a 2011 assessment by the United Nations Environment Programme estimated that the mangrove forests are worth about $1,092 per hectare per year, thanks in part to the potential of fisheries, aquaculture, carbon sequestration and damages averted by the coastal protection that mangroves provide. Assuming that numbers in Gazi Bay hold for the rest of the world, mangroves could provide more than $16 billion in economic benefits planetwide.

    Toward the end of 2020, Kenya’s government included mangroves and seagrasses for the first time in its Nationally Determined Contributions, or NDCs — the greenhouse gas emission reduction commitments for countries that ratified the Paris Agreement. The agreement seeks to limit global warming to below 2 degrees Celsius above preindustrial levels.

    This inclusion commits Kenya to conserving mangroves to balance its emissions. Kenya’s government now “recognizes the potential and importance of the mangrove and seagrass resources that Kenya has,” Huxham says.

    “This is a great commitment on the part of the government. The next challenge is the implementation of these commitments,” says Kairo, who sits on the advisory board of the U.N. Decade of Ocean Science for Sustainable Development (2021–2030), which aims to support efforts to reverse the cycle of decline in ocean health.

    Now, scientists and community managers for that effort need to determine how mangroves can adapt to rising sea levels. “How can communities next to the sea live in harmony with this system, without impacting on their resiliency and productivity?” Kairo asks.

    Mikoko Pamoja is helping provide answers, Kairo adds. Thanks in large part to that small project that began in a secluded corner on the Kenya coast, those answers are now spreading to the rest of the world. More