After a three-year hiatus caused by the COVID-19 pandemic, Duke’s student chapter of the American Society of Civil Engineers (ASCE) returned to the Carolinas in-person gathering. And they were in it to win it, taking home awards in four out of the five events in which they competed.
Duke sent seven Duke undergraduates to the symposium, which was hosted by The Citadel in Charleston, South Carolina: Leo Lee, Harrison Kendall, Arthur Tsang, Hana Thibault, Anya Dias-Hawkins, Sarah Bailey and Grace Lee.
When not going for gold, the students also attended business meetings and professional workshops related to the civil engineering profession.
(Left to right) Leo Lee, Harrison Kendall, Arthur Tsang, Hana Thibault, Anya Dias-Hawkins, Sarah Bailey, Grace Lee at The Citadel after the Symposium awards banquet.
Duke ASCE students also enjoyed networking with peers for the first time in years, meeting chapter members from other schools such as North Carolina Agricultural and Technical State University, North Carolina State University, The Citadel, Horry Georgetown Technical College, and Clemson University.
Sarah Bailey, Harrison Kendall, Anya Dias-Hawkins, and Hana Thibault before competing in the Quiz Bowl competition.
But when the lights came up, the gloves came off, and Duke’s students faced off against their peers in five competitions. Sophomore Anya Dias-Hawkins and junior Sarah Bailey earned third place for their efforts in the Geotechnical competition, where students were tasked with a real-life geotechnical design problem.
Juniors Grace Lee and Leo Lee along with senior Arthur Tsang won first place for their design in the Lightest Bridge competition, where popsicle bridges had to withstand a weight of 200 lbs.
Sophomores Anya Dias-Hawkins, Harrison Kendall and Hana Thibault also took home first place honors in the Freshmore competition, where students were tasked with designing an imaginary city. Lastly, Harrison Kendall won an individual award for his paper and presentation in the Daniel W. Mead Paper competition.
Arthur Tsang, Leo Lee, and Grace Lee standing on their winning Lightest Bridge design.
Duke ASCE is extremely excited to continue their efforts at the Carolinas symposium next year and hopes to send many more competitors. The group plans to compete in larger competitions such as Concrete Canoe next year at UNC Charlotte. With enough preparation, the students hope to advance to the national conference in 2024.
If you are interested in getting involved with Duke ASCE and/or competing in next year’s symposium, please email co-Presidents Sarah Bailey and Harrison Kendall at sarah.a.bailey@duke.edu or harrison.kendall@duke.edu.
Post by Harrison Kendall, civil engineering class of ‘25
Chimpanzees are among the best studied primates for parasite interactions. Photo credit: Wikimedia Commons
Fleas, tapeworms, Giardia, pinworms: Parasites are all around us. But some animals are more susceptible than others. Take the well-studied chimpanzee, for example: it’s known to host over 100 parasites. In contrast, species like the indri, a lemur only found on Madagascar, are only known to host about 10 parasites. Many other primates are so poorly studied that only one parasite has ever been recorded.
Relative to the chimpanzee, the indri is poorly known for its parasites. Credit: James Herrera.
In a new study published in the Journal of Animal Ecology, we examined which traits of both primates and parasites predict the likelihood of their interactions. Using advanced techniques in social network analysis, called the exponential random graph, we were able to simultaneously test the traits of primates and parasites to determine what predisposes primates to infection and what gives some parasites a unique advantage.
For primates, larger species that are found in warmer, wetter climates are more likely to host diverse parasites, compared to smaller species living in drier, cooler climates. Further, species in the same branches of the evolutionary tree and those that live in the same geographic region are more likely to share parasites than more distantly related species found on different continents. Viruses, protozoa, and helminth worms are more likely to infect diverse primates than fungi, arthropods, and bacteria. Parasites that are known to infect non-primate mammals are also more likely to infect diverse primates.
A photo from a microscope slide showing the blood parasite Plasmodium falciparum. One of the pathogens that causes malaria, P. falciparum also infects 118 other primates. In contrast, there are at least 30 other kinds of Plasmodiumthat only infect one or a few primates and their disease effects are poorly understood. Photo credit: Wikimedia Commons.
These new results were made possible by the great advances being made in infectious disease ecology. Over the last two decades, Dr. Charles Nunn at Duke University’s Evolutionary Anthropology and Global Health departments has been working with teams of researchers to compile all published records of primate-parasite interactions. Combing through the literature, almost 600 published sources were obtained to glean which parasites are found in over 200 primates species, with over 2,300 interactions recorded. With the analytical tools in social network science mastered by Duke Sociology professor Dr. James Moody, we were able to systematically test how traits of both hosts and parasites affect the likelihood of their interaction for the first time. While many previous studies used subsets of this database and examined either hosts or parasites in isolation, we were able to make new inferences about the critical links in this unique ecological network.
This work builds on a recent study that showed how extinction of primate hosts could lead to the co-extinction of almost 200 parasite species. While at first this might seem like a good thing, in fact it could have negative impacts on biodiversity as a whole. Many parasites don’t actually cause disease or death in the hosts, and some may even have beneficial properties. We simply don’t know enough about these critical and co-evolved relationships to understand what effects host-parasite coextinctions could have in the long-term.
While it might seem strange to worry about parasite extinctions, they are actually an important part of biodiversity and ecosystem functions. Understanding how primates and parasites interact reveals new insights into coevolutionary theory, and could also contribute to the conservation of underappreciated species richness. While from a public health perspective, we’d like to see some parasites disappear, like corona and ebola viruses, from an evolutionary stance, the sheer diversity of parasites and their intimate relationships with their hosts make them fascinating and crucial components of biodiversity.
By James Herrera, Ph.D., Duke Lemur Center SAVA Conservation Initiative
The Duke Medical Ethics Journal (DMEJ) is a golden opportunity to listen to the ways the world around me hurts and heals. It means asking questions – who is being marginalized in my communities? Where is the injustice in my community? What can I do about it? And when these questions feel too big and too heavy, DMEJ means having a community of mentors, friends, and soul-strengtheners to ask the questions with me. Some of my most cherished experiences at Duke since freshman year have been those rooted in exploring the humanities.
Engaging with the field of ethics through the Kenan Institute of Ethics Living Learning Community as well leading the Duke Medical Ethics Journal (DMEJ) has given me a strong appreciation for the utilization of humanities in healthcare.
Before I saw the Spring 2021 DMEJ edition come together, I never realized how deeply identity could influence health. I had always thought of peoples’ identity in terms of cultural identity, not enough in terms of fertility or neurodiversity, until I read the pieces written by my fellow DMEJ writers. I realized more than ever that healthcare at its deepest level is not just about the biomedical model but it’s also about care, care for the values the lives of its practitioners and patients.
COVID-19 has also naturally brought up questions on the importance of mask-wearing, social distancing, and now, vaccinating. Though most students interested in entering the healthcare field typically fall on one side of the argument, it is safe to say that all of us had to take up more responsibility for ourselves and for others. What does it take to do what is right? The ethics (and effort!) surrounding this responsibility makes for deep conversations puts the “care” in healthcare. And these deep conversations are what DMEJ is all about.
Our upcoming issue, winter 2021, will be about the post-covid era. What does a return to normalcy even mean in an age where normal has been changed forever? And two of our bloggers have already written deeply affecting pieces on post pandemic mental health. To stay up to date on what DMEJ is up to, subscribe to our listserv. We’re always looking for more voices to join our conversation. 🙂
Collaborating with a colleague in Shanghai, we recently published an article that explains the mathematical concept of ‘in-betweening,’in images – calculating intermediate stages of changes in appearance from one image to the next.
Our equilibrium-driven deformation algorithm (EDDA) was used to demonstrate three difficult tasks of ‘in-betweening’ images: Facial aging, coronavirus spread in the lungs, and continental drift.
Part I. Understanding Pneumonia Invasion and Retreat in COVID-19
The pandemic has influenced the entire world and taken away nearly 3 million lives to date. If a person were unlucky enough to contract the virus and COVID-19, one way to diagnose them is to carry out CT scans of their lungs to visualize the damage caused by pneumonia.
However, it is impossible to monitor the patient all the time using CT scans. Thus, the invading process is usually invisible for doctors and researchers.
To solve this difficulty, we developed a mathematical algorithm which relies on only two CT scans to simulate the pneumonia invasion process caused by COVID-19.
We compared a series of CT scans of a Chinese patient taken at different times. This patient had severe pneumonia caused by COVID-19 but recovered after a successful treatment. Our simulation clearly revealed the pneumonia invasion process in the patient’s lungs and the fading away process after the treatment.
Our simulation results also identify several significant areas in which the patient’s lungs are more vulnerable to the virus and other areas in which the lungs have better response to the treatment. Those areas were perfectly consistent with the medical analysis based on this patient’s actual, real-time CT scan images. The consistency of our results indicates the value of the method.
The COVID-19 pneumonia invading (upper panel) and fading away (lower panel) process from the data-driven simulations. Red circles indicate four significant areas in which the patient’s lungs were more vulnerable to the pneumonia and blue circles indicate two significant areas in which the patient’s lungs had better response to the treatment. (Image credit: Gao et al., 2021)We also applied this algorithm to simulate human facial changes over time, in which the aging processes for different parts of a woman’s face were automatically created by the algorithm with high resolution. (Image credit: Gao et al., 2021. Video)
Part II. Solving the Puzzle of Continental Drift
It has always been mysterious how the continents we know evolved and formed from the ancient single supercontinent, Pangaea. But then German polar researcher Alfred Wegener proposed the continental drift hypothesis in the early 20th century. Although many geologists argued about his hypothesis initially, more sound evidence such as continental structures, fossils and the magnetic polarity of rocks has supported Wegener’s proposition.
Our data-driven algorithm has been applied to simulate the possible evolution process of continents from Pangaea period.
The underlying forces driving continental drift were determined by the equilibrium status of the continents on the current planet. In order to describe the edges that divide the land to create oceans, we proposed a delicate thresholding scheme.
The formation and deformation for different continents is clearly revealed in our simulation. For example, the ‘drift’ of the Antarctic continent from Africa can be seen happening. This exciting simulation presents a quick and obvious way for geologists to establish more possible lines of inquiry about how continents can drift from one status to another, just based on the initial and equilibrium continental status. Combined with other technological advances, this data-driven method may provide a path to solve Wegener’s puzzle of continental drift.
The theory of continental drift reconciled similar fossil plants and animals now found on widely separated continents. The southern part after Pangaea breaks (Gondwana) is shown here evidence of Wegener’s theory. (Image credit: United States Geological Survey)The continental drift process of the data-driven simulations. Black arrow indicates the formation of the Antarctic. (Image credit: Gao et al., 2021)
The study was supported by the Department of Mathematics and Physics, Duke University.
CITATION: “Inbetweening auto-animation via Fokker-Planck dynamics and thresholding,” Yuan Gao, Guangzhen Jin & Jian-Guo Liu. Inverse Problems and Imaging, February, 2021, DOI: 10.3934/ipi.2021016. Online: http://www.aimsciences.org/article/doi/10.3934/ipi.2021016
Yuan Gao
Yuan Gao is the William W. Elliot Assistant Research Professor in the department of mathematics, Trinity College of Arts & Sciences.
Jian-Guo Liu is a Professor in the departments of mathematics and physics, Trinity College of Arts & Sciences.
Dr. Bryan Batch, a Duke endocrinologist and researcher, studies treating metabolic disorders (like diabetes) with non-pharmacological approaches. But, she says, her parents’ medical professions, and the hard work that went into them, resulted in her not wanting to pursue science at all as a child.
Bryan Batch MD
When she took biology in middle school however, it clicked. It didn’t feel like “the slog of math,” she says, because she enjoyed studying life in its different forms. This infatuation with science combined with a love for other people pushed her to pursue medicine.
Now, Dr. Batch focuses on racial disparities. She says that a huge issue with disparities, whether they involve race, poverty, food insecurity, educational opportunity, or health insurance, is that they are often driven by policy. “We are not trained to know how to affect change in policy in medical school — it’s not something we are taught. But I do think if physicians got more involved in politics and policy we would be able to make significant positive impact.”
What she does try to do is adapt to individual patient needs in the moment. Her work at Duke signifies what she, as a healthcare provider, can do within the time spent with patients to interact in the best way possible. For example, she can understand if someone has a literacy issue and adapt her methods of explanation so that their literacy doesn’t hinder their understanding. While it can be challenging for one person to change systemic issues or share lived experiences with people of different backgrounds, Dr. Batch makes every effort to create a comfortable environment where she is able to leave a positive impact.
These impacts have no doubt been affected by COVID-19, which Dr. Batch describes as one of the most challenging experiences in her twenty years of practicing medicine. Although telephone and video conferencing have been available for years, Dr. Batch explains that only now is there a drive to put them to use. “It was like someone came up behind you and just whacked you on the head,” she says — no warning, no time to get organized.
Dr. Batch feels lucky to be in endocrinology, where there is flexibility for remote visits. Yet, even when patients do have the chance to have an in-person visit, some don’t want to. If they do, the physical separation, masks, and face shields create a feeling of distance. Dr. Batch spends much of her clinical time at the Durham Veteran Affairs Hospital, across the street from Duke Hospital, where many hearing-impaired patients have difficulty understanding her words because her mask takes away the ability to read lips.
Dr. Batch says that even after the pandemic has passed, more than 30% of visits may remain over the telephone, which can give patients increased access to their doctors.
The challenges have infiltrated her research too, where now the only people she can bring in are those who need to visit the VA Medical Center for another reason anyway, like going to the eye doctor. Overall, she says, she has been surrounded by phenomenal people who rolled up their sleeves and said “let’s get it done.” Still, it has been exhausting.
The Durham Veterans Administration Medical Center, where Dr. Batch conducts most of her practice.
To her, family is everything, and she tries her best to stay in touch with the people who matter most as a way to get through it all.
Even before COVID-19, Dr. Batch has been intentional about living her life to the fullest and staying true to her core values. If that means rescheduling things at work to be with her kids, she is unapologetic. She chose endocrinology as a specialty in part because it’s very family-oriented, and she feels lucky to have colleagues who understand the flexibility she values. Her ultimate goal is to leave a mark on the world but she also wants her happiness to come from what matters, so she stays close to her big family and lots of friends.
While sacrifices are inevitable in any career, Dr. Batch tries not to make large ones on the homefront. She takes it day by day, week by week, she says, to make it such that “work” and “life” are in harmony as much as possible. It is easy to get caught up and have the years go by, one day realizing that the important people have pulled away. Dr. Batch is deliberate about making the time for these people, including her two children and husband.
Dr. Batch is a role model for young people, particularly for women of color. She shared an anecdote about her inattentive high school counselor, to whom she went for a signature on her college application list. Seeing Yale, Harvard, and Brown, he told her that she was “reaching too high.” Batch responded, “I’m not here for your opinion on this list. I’m here for you to sign this form..
She ended up at Yale.
She says she had the courage to talk back to the counselor because her parents instilled the idea of working hard and pushing higher. What matters, she says, is believing in yourself and surrounding yourself with people who believe in you.
Unfortunately, Batch said, underestimation by others resonated throughout her college, medical school, residency, and fellowship, because she is a woman or because she is Black.
At the end of the day, Dr. Bryan Batch never let other people define her experience but instead allowed her hard work to prove her value and propel her to always reach higher.
Guest Post by Viha Patel, Class of 2021, NC School of Science and Math
Over the past decades, we have adopted computers into virtually every aspect of our lives, but in doing so, we’ve made ourselves vulnerable to malicious interference or hacking. I had the opportunity to talk about this with Miroslav Pajic, the Dickinson Family associate professor in Duke’s electrical and computer engineering department. He has worked on cybersecurity in self-driving cars, medical devices, and even US Air Force hardware.
Miroslav Pajic is an electrical engineer
Pajic primarily works in “assured autonomy,” computers that do most things by themselves with “high-level autonomy and low human control and oversight.” “You want to build systems with strong performance and safety guarantees every time, in all conditions,” Pajic said. Assured Autonomy ensures security in “contested environments” where malicious interference can be expected. The stakes of this work are incredibly high. The danger of attacks on military equipment goes without saying, but cybersecurity on a civilian level can be just as dangerous. “Imagine,” he told me, “that you have a smart city coordinating traffic and that… all of (the traffic controls), at the same time, start doing weird things. There can be a significant impact if all cars stop, but imagine if all of them start speeding up.”
Pajic and some of his students with an autonomous car.
Since Pajic works with Ph.D. students and postdocs, I wanted to ask him how COVID-19 has affected his work. As if on cue, his wifi cut out, and he dropped from our zoom call. “This is a perfect example of how fun it is to work remotely,” he said when he returned. “Imagine that you’re debugging a fleet of drones… and that happens.”
In all seriousness, though, there are simulators created for working on cybersecurity and assured autonomy. CARLA, for one, is an open-source simulator of self-driving vehicles made by Intel. Even outside of a pandemic, these simulators are used extensively in the field. They’ve become very useful in returning accurate and cheap results without any actual risk, before graduating to real tests.
“If you’re going to fail,” Pajic says, “you want to fail quickly.”
Guest Post by Riley Richardson, Class of 2021, NC School of Science and Math
The beauty of research is that it allows you to take control of your own path.
“We are very lucky to be in the position to decide what we love to do and do it,” says Tai-ping Sun, a Duke biology professor studying the plant hormone GA. Researchers get to take control of their own path, she said. Every day is an opportunity to learn something new, design and analyze experiments and decide what direction to take.
Tai-ping Sun is a professor of Biology at Duke
Sun studies the GA signaling pathway because it regulates plant growth and development. She got interested in GA when she was a post-doctoral fellow at Harvard University in 1988. At the time, a lot of tools needed to be developed. As she was developing new tools to clone plant genes, she came across a GA mutant that was different. Her research is very important to understanding how the mutations in the GA signaling pathways can control the height of a plant. In fact, she says, GA mutations were one of the reasons for the success of the “Green Revolution” in the 1960s.
Sun’s current research revolves around identifying the mechanisms of the cell that make GA hormones and identifying how GA mutations have affected this pathway. Her team has identified important facets of the pathway, such as the structure and function of the nuclear receptors that allow for transcription that drives the GA response. Her team has also identified transcription factors that control the rate of the signaling pathway such as the DELLA proteins that act as master growth repressors to inhibit GA response. In fact one of her favorite discoveries is that GA triggers destruction of the DELLA proteins to activate the GA signaling pathway.
A figure from a 2004 paper by Sun on plant growth. All three of the mutants grew less well than wild type plants.
“As a scientist, the most exciting thing is to discuss experimental data, and then trying to deduce hypothesis or modify models and then come up with new experiments for testing,” she said.
But research is not without its challenges, Sun says “not everything that you do works out the first time.” That’s why she says that as a researcher the most important thing is to have an interest in your field as well as perseverance.
Guest post by Anika Jain, Class of 2021, NC School of Science and Math
We are all born with defining physical characteristics. Whether it be piercing blue eyes or jet black hair, these traits distinguish us throughout our entire lives. However, there is something that all of our attributes have in common, a shared origin: genes.
Beyond dictating our individual features, genes instruct cells to create proteins that are essential for a variety of processes, from controlling muscle function to managing digestive systems. Despite their importance in the workings of our body, genes can also code for detrimental diseases, such as Huntington’s disease or Duchenne muscular dystrophy.
Raluca Gordân, Ph.D.
These types of diseases are exactly what Raluca Gordân, Ph.D. is battling through her research. She and her group are trying to figure out how to decode the non-coding genome, the DNA apart from protein-coding genes. They are deepening their understanding of the role non-coding areas of the genome play in the expression of the coding genes and the production of proteins.
Gordân, an associate professor in biostatistics and bioinformatics at Duke, said a majority of disease-causing genetic mutations derive from the genome outside of genes.
“That is a huge search space,” she says, chuckling. “Genes only make up about 2% of the genome. If we don’t understand what those non-coding regions are doing, it’s hard to make predictions about what the mutation in those regions would be doing and how to connect that to the development of a disease.”
Gordân recently published a paper, entitled “DNA mismatches reveal conformational penalties in protein–DNA recognition,” which focuses on transcription factors and their exceptional ability to bind to mispaired DNA, misspellings that occur as DNA is copied. During regular replication, nucleotide bases (the building blocks of our DNA) are paired correctly, where adenine pairs with thymine and cytosine goes with guanine. However, when an error occurs during replication, mispairs start to appear, as adenine may pair with guanine instead.
“Normally, those are mistakes that get repaired by specific mismatch repair pathways but that repair might not happen if one of these transcription factors sits on the replication error and doesn’t allow the repair mechanism to see it,” Gordân explains. “Normally, one would expect the transcription factors not to bind to those errors. But we found that they can bind way better than their actual genomic targets.”
Modeling of the binding between mismatched DNA and transcription factors.
To expand on her computational discovery, Gordân is now following up with a study of transcription factor binding to mismatches in living cells, observing whether they adopt their usual role of regulating gene expression or contribute to the development of mutations.
Gordân’s research is a product of her passion and desire to make change. It also can be attributed to a series of realizations she made during college and inspirational mentors who guided her along the way.
While pursuing her undergraduate degree, Gordân was a purely computer science major, concentrating on cryptography. However, as she was nearing the end of her four years of college, she soon found herself yearning for the opportunity to do more. She began looking into machine learning applications and enrolled in a course based around genetic algorithms which she credits for launching her career path.
At that point, she attained what she describes as her “first taste of genetics” and her interest in bioinformatics was irrevocably piqued. Thereafter, Gordân applied for a PhD at Duke, where she worked with advisor Alex Hartemink investigating transcription factor proteins in regulatory genomics. At Duke, her work was primarily computational. But with her postdoctoral advisor Martha Bulyk of Harvard Medical School, Gordan was exposed to the more experimental aspects of biology.
Today, she recognizes these experiences as integral to her ongoing research, which requires her to frequently iterate between observational approaches and computational work.
Gordân is acclimating to the newly quarantined world. While she strives to continue her research, in the pandemic, it has changed her routine.
“I think what was affected a lot since the pandemic started is the fact that we don’t meet in person,” she says. “A lot of the quick progress was being made when we were in the same physical space and were able to get feedback immediately, with students learning about each other’s results in the lab, in real time. That was replaced with Zoom meetings, where students get to see the other students’ results mainly at lab meetings, weeks or months later. Those continuous discussions that were going on in the lab all the time. We’re missing that.”
Gordân offered some thoughtful parting advice to aspiring computational biologists, like me.
“I was trained as a computer scientist, so I wasn’t really sure about experimental work. But after actually doing the experimental work, I realized how much value there is in doing both,” she said. “You have to pick what you’re strongest at, either the computational or experimental part, but you should not be afraid of the other side.”
Guest Post by Akshra Paimagam, Class of 2021, NC School of Science and Math
We offered fruit-eating ruffed lemurs at the Duke Lemur Center fresh lettuce each afternoon for 10 days. They happily ate it and their gut microbiomes shifted, suggesting that leafy greens could be incorporated into the lemurs’ standard dietary regimen to boost foraging opportunity and fiber intake.
Red-ruffed lemurs and black-and-white ruffed lemurs are some of Madagascar’s most iconic wildlife. Sporting a long snout and a neck ruff to rival those of the Elizabethan court, these primates naturally live in the rainforests, where they mostly eat fruits and flowers, and make their living as seed dispersers and pollinators.
Ruffed lemurs really like romaine lettuce and their gut bugs do too! (Lydia Greene)
Ruffed lemurs also live in zoos worldwide, where they are given fruit-rich diets to match those foraged by their wild peers. But scientists are starting to realize that the fruit eaten by wild lemurs is quite different from the domesticated fruit provided at zoos. Wild fruits are seedy, pulpy, and thick-skinned, whereas orchard fruits are fleshy, plump, and sweet. From a nutritional standpoint, wild fruits contain more fiber, whereas orchard fruits contain more sugar.
Our team wondered if a fiber boost might benefit Duke’s ruffed lemur colony. But would these fruit-loving lemurs eat their veggies?
Cue the salad bar.
To test this idea, we offered ruffed lemurs at the Duke Lemur Center a lot of lettuce. Lettuce seemed like a pretty palatable way to stimulate foraging behavior, while boosting fiber intake.
With help from the research department, we offered 19 ruffed lemurs 150-200 grams of romaine lettuce each day, which is about double the weight of their standard diet. We repeated this regimen every day for 10 days, while recording the lemurs’ feeding behavior and collecting fecal samples for gut microbiome analysis. Because gut microbes are chiefly responsible for converting plant fiber into energy for the lemurs, measuring changes to the lemurs’ microbiomes offered a way to ‘see’ the impact of lettuce consumption.
It turns out that ruffed lemurs really like lettuce. They consistently ate lettuce every day and showed no decline in consumption across the study. Younger animals ate more lettuce than did geriatric lemurs, but all lemurs spent more time crunching on lettuce stalks than the leaves.
And their gut microbiomes responded. We noted two microbes that were more abundant on the lettuce diet: a known fiber digester from the Ruminococcaceae family, and a microbe known for its positive association with host health in other animals called Akkermansia.
Despite their classification as fruit eaters, ruffed lemurs readily eat lettuce. We think lettuce can be used to extend the lemurs’ foraging time while boosting dietary fiber. And it might just help replicate the lifestyles experienced by wild ruffed lemurs in their native Malagasy rainforests. At the Duke Lemur Center, lettuce is now a routine item offered to ruffed lemurs (and other species too!). Next time you come out for a tour (once it’s safe to do so), you might get to see them crunching away on their new favorite snack!
Like wine, cheese, and savvy financial investments, many tropical trees become more valuable with age. This is particularly true when it comes to carbon storage, because old trees are often the biggest trees and the larger the tree, the more carbon it stores.
The value of big, old trees in combating climate change was underscored in a recent study of Gabon’s forests, led by the Nicholas School of the Environment’s John Poulsen. The team’s striking finding — that half of Gabon’s wealth of carbon is found in the largest 5% of trees — has implications that reach far beyond the sparsely populated Central African country’s borders.
Nicholas School Ph.D. student Graden Froese admires a forest giant in Ivindo National Park, Gabon.
Tropical forests play a key role in the global carbon cycle by keeping carbon out of the atmosphere. Trees take in CO2 — one of the infamous, heat-trapping greenhouse gases — during photosynthesis and use the carbon to grow, making new leaves, thicker and taller trunks, and more expansive root systems.
Scientists can estimate how much carbon a tree holds by measuring its trunk. So, like rainforest tailors, trained technicians traveled to all corners of the country to measure the girth and height of tens of thousands of trees.
This extraordinary two-year long effort was one of the first nationwide forest inventories in the tropics, making Gabon a leader in comprehensive forest monitoring.
John Poulsen is an associate professor of tropical ecology.
Poulsen and collaborators used the tree measurements to estimate the amount of carbon stored in Gabon’s forests and to determine why some forests hold more carbon than others.
“The field techs deserve all the credit”, Poulsen explained, “as they often walked for days through thick forest, traversing swamps and enduring humid, buggy conditions to measure trees. We turned their sweat and toil into information that could be used by Gabon’s government to prioritize areas for conservation.”
Who needs ladders, when you have colleagues? The field team collaborates to measure a forest giant.
The team analyzed a suite of environmental factors to see their effects on carbon storage. Of the natural factors, only soil fertility had a noticeable positive effect on tree biomass. Much more important was the impact of humans. As human activities such as agriculture and logging tend to target large trees, more heavily human-disturbed forests had a much different structure than pristine forests. The farther a study area was from human settlements, the more likely it was to host large trees and consequently, higher amounts of carbon.
The paper notes that Gabon stands out as a country with “one of the highest densities of aboveground forest carbon.” In fact, Gabon’s undisturbed forests store more carbon than those in the Amazon, which have been referred to as the lungs of the planet.
According to Poulsen, “Gabon is the second most forested country in the world with 87% forest cover, a deforestation rate near zero…” Because of its impressive forest cover and its location straddling the equator, Gabon’s forests host an incredibly diverse array of plants and animals, including many threatened and endangered species. Rural communities depend on these forests for their livelihoods.
Unfortunately, even Gabon’s ‘small’ trees make for spectacular felled logs.
However, Gabon’s impressive forests are valuable to more than just wildlife, climate researchers, and local communities. The logging industry also sees these forests as a chance for profit. More than half (about 67%) of Gabon’s forests are under contract with logging companies to harvest timber, putting them at risk of losing many of their carbon-storing giants.
Poulsen’s study highlights the importance of a more nuanced approach to forest conservation in Gabon. One that doesn’t simply focus on stopping deforestation or promoting restoration, as is prescribed in many international climate change plans, but an approach that recognizes the necessity of preserving high conservation value, old growth forests.
Guest Post by Anna Nordseth, a graduate student in the Nicholas School of the Environment.
