Following the people and events that make up the research community at Duke

Category: Environment/Sustainability Page 1 of 13

Do Snakes Have Tails? and Other Slithery Questions

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Dhruv Rungta, a member of the Wild Ones club, with a ring-necked snake during a herpetology walk with Dr. Nicki Cagle in the Duke Forest.
Upper left: Dr. Nicki Cagle holding a ring-necked snake. Photo by Montana Lee, another Wild Ones member.

On a sunny Friday in September, Dr. Nicki Cagle led a herpetology walk in the Duke Forest with the Wild Ones. The Wild Ones is an undergraduate club focused on increasing appreciation for the natural world through professor-led outings. Herpetology is the study of reptiles and amphibians.

Dr. Cagle is a senior lecturer in the Nicholas School of the Environment at Duke and the Associate Dean of Diversity, Equity, and Inclusion. Along with teaching courses on environmental education and natural history, she is also the science advisor for a citizen science project focused on reptiles and amphibians, or herpetofauna, in the Duke Forest. Volunteers monitor predetermined sites in the Duke Forest and collect data on the reptiles and amphibians they find.

“We get a sense of abundance, seasonality… and how the landscape is affecting what we’re seeing,” Dr. Cagle says. There is evidence that herp populations in the Duke Forest and elsewhere are decreasing.

Dr. Nicki Cagle flipping over a cover board with members of the Wild Ones. The cover boards are used to monitor reptiles and amphibians for a citizen science project in the Duke Forest.

The project relies on transects, “a sampling design… where you have a sampling spot at various intervals” along a line of a predetermined length. In this case, the sampling spots are “traps” meant to attract reptiles and amphibians without harming them. Each site has a large board lying on the ground. “Different herps are more likely to be found under different objects,” Dr. Cagle explains, so the project uses both wooden and metal cover boards.

But why would snakes and other herps want to hide under cover boards, anyway? Reptiles and amphibians are “cold-blooded” animals, or ectotherms. They can’t regulate their own body temperature, so they have to rely on their environment for thermoregulation. Snakes might sun themselves on a rock on cold days, for instance, or hide under a conveniently placed wooden board to escape the heat.

Salamanders that use the cover boards might be attracted to the moist environment, while “snakes will tend to go under cover boards either to hide — like if they’re about to molt and they’re more vulnerable — to look for prey, or just to maintain the proper temperature,” Dr. Cagle says.

Citizen scientists typically check the boards once a week and not more than twice a week. Volunteers have to avoid checking the traps too often because of a phenomenon called “trap shyness,” where animals might start avoiding the traps because they’ve learned to associate them with pesky humans flipping the boards over and exposing their otherwise cozy resting places. By checking the traps less frequently, scientists can reduce the likelihood of that and minimize disturbance to the animals they’re studying.

The first snake we saw was a worm snake, dark above with a pink stomach.

Dr. Cagle gave the Wild Ones a behind-the-scenes tour of some of the cover boards. Using a special, hooked tool conveniently stashed in a PVC pipe next to the first cover board, we flipped each board over and looked carefully underneath it for slithery movements. We didn’t find any under the first several cover boards.

But then, under a large sheet of metal, we saw a tiny snake squirming around in the leaf litter. There was a collective intake of breath and exclamations of “snake!”

Dr. Cagle captured it and held it carefully in her hands. Snakes, especially snakes as young as this one, can be all too easily crushed. We gathered around to look more closely at the baby snake, a species with the adorable name “worm snake.” It was dark above with a strikingly pink underside. The pink belly is a key field mark of worm snakes. Earth snakes are also found around here and look similar, but they tend to have tan bellies.

After a minute or two, the worm snake made a successful bid for freedom and wriggled back under the board, disappearing from sight almost immediately.

Crossing over a dry “intermittent stream,” which Dr. Cagle describes as “the running-water equivalent of a vernal pool.” A vernal pool is a temporary wetland that is dry for much of the year.

Some of the cover boards revealed other animals as well. We found a caterpillar chrysalis attached to one and several holes — probably made by small mammals — under another.

Whatever made the holes, we can safely assume it wasn’t a snake. According to Dr. Cagle, the term “snakehole” is misleading. Most snakes don’t make their own holes, though some of them do use existing holes made by other animals. One exception is the bull snake, which is known for digging.

We found a young five-lined skink sunning itself on top of one of the metal cover boards. (Thermoregulation!) Juvenile five-lined skinks are colloquially known as blue-tailed skinks, but the name is somewhat misleading — the adults don’t have blue tails at all.

The snakes we were looking for, meanwhile, were often elusive. Some vanished under the leaf litter before we could catch them. Sometimes it was hard to tell whether we were even looking at a snake at all.

“What are you?” Dr. Cagle muttered at one point, crouching down to get a better look at what was either a stick-esque snake or a snake-esque stick. “Are you an animal? Or are you just a wet something?” (Just a wet something, it turned out.)

The Duke Forest is a valuable community resource with a complicated history. “We know that slavery was practiced on at least four properties” in the Duke Forest, Dr. Cagle says, and the forest is located on the traditional hunting grounds of several indigenous peoples. The interpretive signs along the Shepherd Nature Trail, which we walked part of during our herpetology outing, were designed in collaboration with the Occaneechi Band of Saponi. Today, the Duke Forest is used for research, recreation, timber management, and wildlife management and conservation.

Later on, we found at least three young ring-necked snakes (Diadophis punctatus) under different cover boards. One of them was particularly cooperative, so we passed it around the group. (“All snakes can bite,” Dr. Cagle reminded us, but “some have the tendency to bite less,” and this species “has the tendency not to bite.”) Its small, lithe body was surprisingly strong. The little snake wrapped tightly around one of my fingers and seemed content to chill there. A living, breathing, reptilian ring. That was definitely a highlight of my day.

The faint, dark line on this ring-necked snake’s underside (on the bottom of the loop) is the anal vent. Everything below that point (farther from the head) is considered the official tail of a snake.

If you’ve ever wondered if snakes have tails, the answer is yes. The official cut-off point, Dr. Cagle says, is the anal vent. Everything below that is tail. In between flipping over cover boards and admiring young snakes, we learned about other herps. Near the beginning of our walk, someone asked what the difference is between a newt and a salamander.

“A newt is a type of salamander,” Dr. Cagle says, “but newts have an unusual life cycle where they spend part of their life cycle on land… and that is called their eft phase.” As adults, they return to the water to breed.

We learned that copperheads “tend to be fatter-bodied for their length” and that spotted salamanders cross forest roads in large numbers on warm, rainy nights in early spring when they return to wetlands to breed.

Students holding a ring-necked snake. Above: Kelsey Goldwein (left), Gurnoor Majhail (one of the co-presidents of the Wild Ones), and Simran Sokhi (background on right). Below: Emily Courson (left) and Barron Brothers.

Perhaps the most interesting herp fact of the day came near the end of our walk when one of the students asked how you can tell the sex of a snake. Apparently there are two ways. You can measure a snake’s tail (males usually have longer tails), or you can insert a metal probe, blunted at the end, into a snake’s anal vent. Scientists can determine the sex of the snake by how deep the probe goes. It goes farther into the anal vent if the snake is a male. Why is that? Because male snakes have hemipenes — not two penises, exactly, but “an analogous structure that allows the probe to slide between the two and go farther” than it would in a female snake. The more you know…

Looking for snakes on a herpetology outing with Dr. Cagle and the Wild Ones. Photograph by Gurnoor Majhail.

Disclaimer: Handling wild snakes may result in snake bites. It can also be stressful to the snakes. Furthermore, some snakes in this area are venomous, and it’s probably best to familiarize yourself with those before getting close to snakes rather than afterward. Snakes are amazing, but please observe wildlife safely and responsibly.

Bonus snake! I saw this adorable fellow on the Duke Campus and thought it was an earthworm at first. Dr. Cagle thinks it might be a rough earth snake. I did not check to see if it had a tan belly.
Post by Sophie Cox, Class of 2025

Meet New Blogger Kyla: Humans Grow up. Ideas Do, Too.

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If you asked my eight-year-old self what I wanted to be when I grew up, the answer would have been, resoundingly, “an inventor!” It was around this time that I also decided, with surprising assuredness for a shy second grader, that I would one day build a saltwater-powered car.

I must have heard the idea somewhere, although to this day I don’t quite recall where. Perhaps it was a story on the radio. NPR was a constant background noise in the basement where I spent countless hours playing and tinkering alongside my father in his hobby shop. Or maybe it was buried somewhere in a book or science magazine. They were often stacked in neat piles, filling bookcases in many corners of our house. It also could have floated across the dinner table in conversations between my parents and older siblings. Everyday talk of high school biology and current events seemed light years out of the grasp of my eight-year-old brain.

Kyla Hunter, Duke Engineering 2023.

Regardless of where it came from, the idea stuck. Before I knew what it meant to conduct research or study engineering, I found myself charmed by novel ideas and drawn to the possibility of discovery. For some reason, this “car that runs on salt water” took shelter in my mind and secured itself as the perfect idea: an ingenious invention that was good for the planet. At the time, of course, I never thought about how this whimsical, far-fetched idea was fundamentally tied to my core interests and values. Now, however, as a 21-year-old senior studying mechanical engineering, passionate about renewable energy technology and protecting the planet, it all makes perfect sense.

My interest in engineering is, at its core, a love for creativity, combined with a desire to solve problems. A fondness for physics certainly helps too, but that came much later. As a child, the desire to practice creativity manifested primarily as a love for art. Some of my earliest childhood memories are toiling away at my little table in the corner of the living room, carefully sorting the crayons in my tin Crayola box. Today, I practice creativity in my critical thinking, brainstorming, and implementation of the iterative design process.

At an elementary school science fair, I presented my model V8 engine and explained how it worked. I was drawn to many different interests before I settled on engineering, but it’s clear that the passion was always there.

The other facet that drew me towards engineering, the desire to solve problems, evolved from an early love for nature and a passion for environmentalism. I remember seeing my grandparents’ devastated home in the aftermath of Hurricane Sandy, and the noticeable decline in pollinators to my mother’s garden. In high school, when I heard the term “environmental engineering,” it was the first time I realized such a field existed. I immediately felt the various pieces of my interests and values click together. There are many ways to be creative and to solve problems, but for me, the combination led down a path towards pursuing engineering.

An entry from my second-grade journal, declaring my dearly held beliefs. In many ways, nothing has changed (including my ability to spell). 

Despite the way I’ve laid it out, this is not to say there was a linear path between latching onto an eccentric notion as an eight-year-old, and deciding to pursue my current career as a soon-to-be graduate. Looking back now, I can see the symbolism in this cornerstone of an idea. With hindsight, I recognize why it appealed to different facets of my just-blossoming identity, and the ways in which I returned to it over the next several years. However, this is what is bound to happen when you expose yourself to as many new ideas as possible: one (at least) will catch your attention. The point is not to latch onto the first idea you stumble upon and pursue it relentlessly. The point is to keep an open mind to all ideas – and pay careful attention to the ones that light up inside your brain. The ones that stick in the back of your mind, and continuously pop up at unsuspecting times. 

One of my favorite serendipitous moments in life is when, soon after learning something new, that newfound idea pops up somewhere else. It’s like receiving an unexpected gift in the form of previously inaccessible appreciation. Imagine turning over a stone and happening to uncover an insect that you just spent all night studying. It feels purely by chance, but it’s not quite.

The more you expose yourself to new ideas, the more they will appear. You never know when a story you stumble across by accident will move you to action, or lead to something bigger. A magazine I stumbled across by chance led to a research topic of an entire semester. A book I read in high school came up in an interview I had last week. An idea I heard at eight years old about an eco-friendly car perhaps started a life-long captivation with science that led me to become an engineer. Our life is made up of decisions that are based on millions of data points, determined by our history, background, and the types of ideas we surround ourselves with daily.

As a blogger for the Duke Research Blog, my goal is to make it easier for more people to have more exposure to more ideas. Each new idea has the potential to build bridges, whether expanding to new fields, or building upon an existing network of knowledge. Expanding our realm of understanding allows for challenging perspectives and broadening understandings. These are not ideas for the sake of ideas, but for the larger goal of enabling meaningful connections with others.

When more people have access to more ideas, everyone benefits. However, there’s no denying that much of the research going on at Duke is very high-level, usually going unread by much of the student body. Other fascinating content goes unnoticed simply due to the busy lives of Duke students, and the sheer volume of exciting events. (If only we could all be multiple places at once.)  My goal is to take ideas – whether overly intimidating or underappreciated—and present them in a way that is more accessible for anyone who is interested.

When I first heard of the idea of salt-water running cars, the idea was just that: an idea. The frenzy began in 2007 when John Kanzius, an American engineer, accidentally discovered how to “burn” salt water while attempting to research a cure for cancer. Today, the QUANT e-Sport Limousine is an all-electric sports car concept that uses an electrolyte flow cell, powered by salt water. It actually works, and was authorized for on-road testing in Germany a few years ago soon after its debut. It is many years from authorization, and it will likely be an even longer time before it is a viable option from an economic standpoint, but the progress is apparent.

Fifteen years since my infatuation with this idea, I can’t help but feel slightly emotionally connected to it. Humans grow up. Ideas do, too. I did not invent the first car that runs on salt water, but I am eternally grateful for every new idea that fuels my curiosity, shapes my values, and expands my current perspectives.

Post by Kyla Hunter, Class of 2023

What Are Lichens, and Why Does Duke Have 160,000 of Them?

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Saxicolous lichens (lichens that grow on stones) from the Namib Desert, and finger lichen, Dactylina arctica (bottom left insert), common in the Arctic, on display in Dr. Jolanta Miadlikowska’s office. The orange color on some of the lichen comes from metabolites, or secondary chemicals produced by different lichen species. The finger lichen is hollow.

Lichens are everywhere—grayish-green patches on tree bark on the Duke campus, rough orange crusts on desert rocks, even in the Antarctic tundra. They are “pioneer species,” often the first living things to return to barren, desolate places after an extreme disturbance like a lava flow. They can withstand extreme conditions and survive where nearly nothing else can. But what exactly are lichens, and why does Duke have 160,000 of them in little envelopes? I reached out to Dr. Jolanta Miadlikowska and Dr. Scott LaGreca, two lichen researchers at Duke, to learn more.

Dr. Jolanta Miadlikowska looking at lichen specimens under a dissecting microscope. The pale, stringy lichen on the brown bag is whiteworm lichen (Thamnolia vermicularis), used to make “snow tea” in parts of China.

According to Miadlikowska, a senior researcher, lab manager, and lichenologist in the Lutzoni Lab (and one of the Instructors B for the Bio201 Gateway course) at Duke, lichens are “obligate symbiotic associations,” meaning they are composed of two or more organisms that need each other. All lichens represent a symbiotic relationship between a fungus (the “mycobiont”) and either an alga or a cyanobacterium or both (the “photobiont”). They aren’t just cohabiting; they rely on each other for survival. The mycobiont builds the thallus, which gives lichen its structure. The photobiont, on the other hand, isn’t visible—but it is important: it provides “food” for the lichen and can sometimes affect the lichen’s color. The name of a lichen species refers to its fungal partner, whereas the photobiont has its own name.

Lichen viewed through a dissecting microscope. The black speckles visible on some of the orange lichen lobes are a “lichenicolous” fungus that can grow on top of lichen. There are also “endolichenic fungi… very complex fungal communities that live inside lichen,” Miadlikowska says. “We don’t see them, but they are there. And they are very interesting.”

Unlike plants, fungi can’t perform photosynthesis, so they have to find other ways to feed themselves. Many fungi, like mushrooms and bread mold, are saprotrophs, meaning they get nutrients from organic matter in their environment. (The word “saprotroph” comes from Greek and literally means “rotten nourishment.”) But the fungi in lichens, Miadlikowska says, “found another way of getting the sugar—because it’s all about the sugar—by associating with an organism that can do photosynthesis.” More often than not, that organism is a type of green algae, but it can also be a photosynthetic bacterium (cyanobacteria, also called blue-green algae). It is still unclear how the mycobiont finds the matching photobiont if both partners are not dispersed together. Maybe the fungal spores (very small fungal reproductive unit) “will just sit and wait” until the right photobiont partner comes along. (How romantic.) Some mycobionts are specialists that “can only associate with a few or a single partner—a ‘species’ of Nostoc [a cyanobacterium; we still don’t know how many species of symbiotic and free-living Nostoc are out there and how to recognize them], for example,” but many are generalists with more flexible preferences. 

Two species of foliose (leaf-like) lichens from the genus Peltigera. In the species on the left (P. canina), the only photobiont is a cyanobacterium from the genus Nostoc, making it an example of bi-membered symbiosis. In the species on the right (P. aphthosa), on the other hand, the primary photobiont is a green alga (which is why the thallus is so green when wet). In this case, Nostoc is a secondary photobiont contained only in the cephalodia—the dark, wart-like structures on the surface. With two photobionts plus the mycobiont, this is an example of tri-membered symbiosis.

Lichens are classified based on their overall thallus shape. They can be foliose (leaf-like), fruticose (shrubby), or crustose (forming a crust on rocks or other surfaces). Lichens that grow on trees are epiphytic, while those that live on rocks are saxicolous; lichens that live on top of mosses are muscicolous, and ground-dwelling lichens are terricolous. Much of Miadlikowska’s research is on a group of cyanolichens (lichens with cyanobacteria partners) from the genus Peltigera. She works on the systematics and evolution of this group using morphology-, anatomy-, and chemistry-based methods and molecular phylogenetic tools. She is also part of a team exploring biodiversity, ecological rules, and biogeographical patterns in cryptic fungal communities associated with lichens and plants (endolichenic and endophytic fungi). She has been involved in multiple ongoing NSF-funded projects and also helping graduate students Ian, Carlos, Shannon, and Diego in their dissertation research. She spent last summer collecting lichens with Carlos and Shannon and collaborators in Alberta, Canada and Alaska. If you walk in the sub basement of the Bio Sciences building where Bio201 and Bio202 labs are located, check out the amazing photos of lichens (taken by Thomas Barlow, former Duke undergraduate) displayed along the walls! Notice Peltigera species, including some new to science, described by the Duke lichen team.

Lichens have value beyond the realm of research, too. “In traditional medicine, lichens have a lot of use,” Miadlikowska says. Aside from medicinal uses, they have also been used to dye fabric and kill wolves. Some are edible. Miadlikowska herself has eaten them several times. She had salad in China that was made with leafy lichens (the taste, she says, came mostly from soy sauce and rice vinegar, but “the texture was coming from the lichen.”). In Quebec, she drank tea made with native plants and lichens, and in Scandinavia, she tried candied Cetraria islandica lichen (she mostly tasted the sugar and a bit of bitterness, but once again, the lichen’s texture was apparent).

In today’s changing world, lichens have another use as well, as “bioindicators to monitor the quality of the air.” Most lichens can’t tolerate air pollution, which is why “in big cities… when you look at the trees, there are almost no lichens. The bark is just naked.” Lichen-covered trees, then, can be a very good sign, though the type of lichen matters, too. “The most sensitive lichens are the shrubby ones… like Usnea,” Miadlikowska says. Some lichens, on the other hand, “are able to survive in anthropogenic places, and they just take over.” Even on “artificial substrates like concrete, you often see lichens.” Along with being very sensitive to poor air quality, lichens also accumulate pollutants, which makes them useful for monitoring deposition of metals and radioactive materials in the environment.

Dr. Scott LaGreca with some of the 160,000 lichen specimens in Duke’s herbarium.

LaGreca, like Miadlikoska, is a lichenologist. His research primarily concerns systematics, evolution and chemistry of the genus Ramalina. He’s particularly interested in “species-level relationships.” While he specializes in lichens now, LaGreca was a botany major in college. He’d always been interested in plants, in part because they’re so different from animals—a whole different “way of being,” as he puts it. He used to take himself on botany walks in high school, and he never lost his passion for learning the names of different species. “Everything has a name,” he says. “Everything out there has a name.” Those names aren’t always well-known. “Some people are plant-blind, as they call it…. They don’t know maples from oaks.” In college he also became interested in other organisms traditionally studied by botanists—like fungi. When he took a class on fungi, he became intrigued by lichens he saw on field trips. His professor was more interested in mushrooms, but LaGreca wanted to learn more, so he specialized in lichens during grad school at Duke, and now lichens are central to his job. He researches them, offers help with identification to other scientists, and is the collections manager for the lichens in the W.L. and C.F. Culberson Lichen Herbarium—all 160,000 of them.

The Duke Herbarium was founded in 1921 by Dr. Hugo Blomquist. It contains more than 825,000 specimens of vascular and nonvascular plants, algae, fungi, and, of course, lichens. Some of those specimens are “type” specimens, meaning they represent species new to science. A type specimen essentially becomes the prototype for its species and “the ultimate arbiter of whether something is species X or not.” But how are lichens identified, anyway?

Lichenologists can consider morphology, habitat, and other traits, but thanks to Dr. Chicita Culberson, who was a chemist and adjunct professor at Duke before her retirement, they have another crucial tool available as well. Culbertson created a game-changing technique to identify lichens using their chemicals, or metabolites, which are often species-specific and thus diagnostic for identification purposes. That technique, still used over fifty years later, is a form of thin-layer chromatography. The process, as LaGreca explains, involves putting extracts from lichen specimens—both the specimens you’re trying to identify and “controls,” or known samples of probable species matches—on silica-backed glass plates. The plates are then immersed in solvents, and the chemicals in the lichens travel up the paper. After the plates have dried, you can look at them under UV light to see if any spots are fluorescing. Then you spray the plates with acid and “bake it for a couple hours.” By the end of the process, the spots of lichen chemicals should be visible even without UV light. If a lichen sample has traveled the same distance up the paper as the control specimen, and if it has a similar color, it’s a match. If not, you can repeat the process with other possible matches until you establish your specimen’s chemistry and, from there, its identity. Culberson’s method helped standardize lichen identification. Her husband also worked with lichens and was a director of the Duke Gardens.

Thin-layer chromatography plates in Dr. LaGreca’s office. The technique, created by Dr. Chicita Culberson, helps scientists identify lichens by comparing their chemical composition to samples of known identity. Each plate was spotted with extracts from different lichen specimens, and then each was immersed in a different solvent, after which the chemicals in the extracts travel up the plate . Each lichen chemical travels a characteristic distance (called the “Rf value”) in each solvent. Here, the sample in column 1 on the rightmost panel matches the control sample in column 2 in terms of distance traveled up the page, indicating that they’re the same species. The sample in column 4, on the other hand, didn’t travel as far as the one in column 5 and has a different color. Therefore, those chemicals (and species) do not match.

LaGreca shows me a workroom devoted to organisms that are cryptogamic, a word meaning “hidden gametes, or hidden sex.” It’s a catch-all term for non-flowering organisms that “zoologists didn’t want to study,” like non-flowering plants, algae, and fungi. It’s here that new lichen samples are processed. The walls of the workroom are adorned with brightly colored lichen posters, plus an ominous sign warning that “Unattended children will be given an espresso and a free puppy.” Tucked away on a shelf, hiding between binders of official-looking documents, is a thin science fiction novel called “Trouble with Lichen” by John Wyndham.

The Culberson Lichen Herbarium itself is a large room lined with rows of cabinets filled with stacks upon stacks of folders and boxes of meticulously organized lichen samples. A few shelves are devoted to lichen-themed books with titles like Lichens De France and Natural History of the Danish Lichens.

Each lichen specimen is stored in an archival (acid-free) paper packet, with a label that says who collected it, where, and on what date. (“They’re very forgiving,” says LaGreca. “You can put them in a paper bag in the field, and then prepare the specimen and its label years later.”) Each voucher is “a record of a particular species growing in a particular place at a particular time.” Information about each specimen is also uploaded to an online database, which makes Duke’s collection widely accessible. Sometimes, scientists from other institutions find themselves in need of physical specimens. They’re in luck, because Duke’s lichen collection is “like a library.” The herbarium fields loan requests and trades samples with herbaria at museums and universities across the globe. (“It’s kind of like exchanging Christmas presents,” says LaGreca. “The herbarium community is a very generous community.”)

Duke’s lichen collection functions like a library in some ways, loaning specimens to other scientists and trading specimens with institutions around the world.

Meticulous records of species, whether in databases of lichens or birds or “pickled fish,” are invaluable. They’re useful for investigating trends over time, like tracking the spread of invasive species or changes in species’ geographic distributions due to climate change. For example, some lichen species that were historically recorded on high peaks in North Carolina and elsewhere are “no longer there” thanks to global warming—mountain summits aren’t as cold as they used to be. Similarly, Henry David Thoreau collected flowering plants at Walden Pond more than 150 years ago, and his samples are still providing valuable information. By comparing them to present-day plants in the same location, scientists can see that flowering times have shifted earlier due to global warming. So why does Duke have tens of thousands of dried lichen samples? “It comes down to the reproducibility of science,” LaGreca says. “A big part of the scientific method is being able to reproduce another researcher’s results by following their methodology. By depositing voucher specimens generated from research projects in herbaria like ours, future workers can verify the results” of such research projects. For example, scientists at other institutions will sometimes borrow Duke’s herbarium specimens to verify that “the species identification is what the label says it is.” Online databases and physical species collections like the herbarium at Duke aren’t just useful for scientists today. They’re preserving data that will still be valuable hundreds of years from now.

Symposium Explores How People and Nature are Inextricably Entwined

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The massive Keeler Oak, a white oak (Quercus alba) in New Jersey.

An April symposium at Grainger Hall, People and Nature, brought a diverse set of speakers, both from Duke and other U.S. institutions, to examine the relationship between human culture and land and to discuss pressing issues such as environmental justice. The session was organized by PhD students Nicholas School of the Environment and the biology department.

Paul Manos of Duke Biology

Professor Paul Manos of Duke Biology told us  how oaks, ubiquitous tree species in temperate regions, can make people think about nature. A walk in the woods looking at the different oaks can result in a fascinating journey of natural history. For those who are curious enough, an inquiry into the lives of oaks will take them deep into topics such as evolutionary history, leaky species boundaries, plant-animal interactions, among others, Manos said. Keeping true to the theme of the symposium, Manos explored some hypotheses about the first time that humans had contact with oaks, and how this relationship unfolded ever since.

Orue Gaoue of Tennessee-Knoxville

Associate Professor Orou G. Gaoue of the University of Tennessee, Knoxville,  took us through a detailed case study of human and plant interactions with long-term data from the country of Benin, in Africa. He showed how the harvest of the African mahogany (Khaya senegalensis) affects human demography and even the marriage dynamics of the Fulani people, with many other insights into the intertwined relationship of the locals and their harvest.

Andrew Curley of Arizona

Central to the morning sessions were the rights of nature and the granting of personhood to non-humans, which is common in the cosmology of many indigenous cultures. For instance, Andrew Curley, assistant professor at the University of Arizona, mentioned in his talk that the O’odham people in the Sonoran Desert confer the Saguaro cactus personhood status. His talk exposed how colonial dynamics have created climate catastrophes and drought around the Colorado River, how indigenous peoples have to navigate these foreign systems, and how they understand their relationship with the land and water.

Michelle Carter, a first-year Masters of Environmental Management (MEM) student at Duke, examined the feasibility of the rights of nature in the US legal system. These rights allow certain natural features (e.g. rivers) to stand as a sole party in litigation and recover damages on their behalf. However, effective application and the enforcement of policy have been lacking.

The second part of the symposium focused on environmental justice. Duke Ph.D. student Maggie Swift presented a land acknowledgement which was divided into three parts: recognition of the violent history of the past; an understanding of the present with a celebration of the lives and achievements of current indigenous peoples; and a call to action so that participants were encouraged to financially support native-led organizations.  Links for donations and more information can be found on the symposium website. The land acknowledgement was followed by a brief presentation on the project Unearthing Duke Forest  that explores the human history surrounding Duke Forest.

Why is it important to jointly consider people and nature in your work? What insights do you gain in your work by taking this approach?

People & NAture
Christine Folch of Duke Cultural Anthropology

Assistant professor Christine Folch, from Duke’s Department of Cultural Anthropology provided an analysis of the discourse around climate change. At the center was the question “do you believe in climate change?” which has ingrained the element of doubt and the ability of the speaker to say “no, I don’t.”  

Associate professor Louie Rivers III, from NC State University,  gave a talk on perceived environmental risks and their influence on social justice. He pointed out that these questions  could be dismissed by certain groups such as black farmers, who are concerned and disproportionally affected by environmental issues but might not relate to how the question is addressed.

Sherri White-Williamson, Environmental Justice Policy director at NC Conservation Network, explained the concept of environmental justice and provided concrete examples of how certain policies (e.g. federal housing/lending policies or interstate highway systems) can create inequalities that leave communities of color to bear the exposure of environmental degradation. She also made us aware that this year is the 40th anniversary of the birth of the US environmental justice movement that started when an African-American community  in Warren County, North Carolina organized to fight a hazardous waste landfill.

No exploration of people and nature would be complete without including the seas. A team of three students at the Duke University Marine Lab, undergrad Maddie Paris, second-year MEM Claire Huang, and Ph.D. student Rebecca Horan, presented two case studies of social and ecological outcomes linked to education and outreach interventions conducted in tropical marine environments.

Their first case study was on turtle education in Grenada, West Indies. Here a 10-week summer program for local children ages 9-12 created an improved understanding of marine turtle biology and its connection to the health of the ocean and their communities. The second case study was a 4-week training course for fisher people and fisheries officers in Mtwara, Tanzania. These participants increased their skills in monitoring the local reefs and were better equipped to educate their communities on marine environmental issues.

The symposium ended with two open questions for the audience, which should be considerations for anyone doing environmental research:  Why is it important to jointly consider people and nature in your work? What insights do you gain in your work by taking this approach?

Guest post by Rubén Darío Palacio, Ph.D. 2022 in Conservation Biology from the Nicholas School of the Environment, and science director of conservation non-profit Fundacion Ecotonos in Colombia.

Vernal, Ephemeral, Spring Beauty by Any Other Name

Nicki Cagle, Ph.D., with perfoliate bellwort, an ephemeral forest plant also known as wild oats (Uvularia perfoliata).

“Ephemeral” is one of my favorite words. It conjures up images of vernal pools and fireflies and flowers in spring. It comes from ephēmeros, a Greek word meaning “lasting a day.” English initially used it in a scientific sense, to refer to fevers and then in reference to short-lived organisms like flowers or insects. Today “ephemeral” is most often used to describe anything fleeting or short-lived.

The term “spring ephemeral,” for instance, refers to flowers that are visible for only a short time each spring before they disappear.

Nicki Cagle, Ph.D, a senior lecturer in the Nicholas School of the Environment, led a spring ephemeral workshop in the Korstian Division of Duke Forest on a Friday afternoon in late March. The workshop was hosted by DSER, the Duke student chapter of the Society for Ecological Restoration. We focused on identifying herbaceous plant species and families, particularly spring ephemerals.

“Spring ephemerals are perennials that emerge early in the spring and then grow, reproduce, and disappear from the surface of the forest floor in just a few short weeks,” Cagle explains. We also found several species that aren’t technically ephemerals but still bloom in early spring — before the tree canopy emerges and plunges the floor into shade.

Oxalis violacea, a species of wood sorrel.

The first plant Cagle points out is Oxalis violacea, a type of wood sorrel. “This particular species will have purple flowers,” she says. The genus name, Oxalis, refers to the plant’s oxalic acid content. “You can nibble on it,” but “you don’t want to nibble on it too much.” Oxalic acid, which is also found in common foods like spinach, gives the leaves a pleasant, lemony taste, but it can cause problems if eaten in excess.

Common bluet (Houstonia caerulea).

When we come across a patch of lovely, pale violet flowers with yellow centers, Cagle challenges the workshop participants to determine which family it belongs to. She offers two options: Rubiaceae, a large family that often has either opposite or whorled leaves and four to five petals and which includes familiar plants like coffee, or Violaceae, a very small plant family whose members “tend to have everything in fives” (like petals, stamens, and sepals) and often have basal leaves. Answer: Rubiaceae. This particular species is Houstonia caerulea, the common bluet. Its yellow centers help distinguish it from related species like the summer bluet, tiny bluet, and purple bluet. If anything, Cagle says, the plant’s presence is “an indicator of disturbance,” but it’s still good to have around.

Here’s the little brown jug (Hexastylis arifolia).

Next we come across two species in the Hexastylis genus. They are sometimes called wild ginger, but the name is misleading. Hexastylis species are not related to the ginger you buy in the store, which is in a completely different family. Hexastylis is, however, in the same family as the Asarum genus, which Cagle thinks of as “proper” wild ginger. Asarum and Hexastylis have traditionally been used as food and medicine, but they also contain toxins. According to Cagle, they belong to “one of the few plant families that have fossilized remains in the United States,” even dating back to the late Cretaceous Period.

The two species we see are Hexastylis arifolia, the little brown jug, and Hexastylis minor which looks similar but “tends to have a much more rounded form.” Like many spring ephemerals, Hexastylis is often dispersed by ants. The seeds have elaiosomes, fatty deposits that ants find attractive.

“We have a lot of different violets of varying origins” in this area. According to Cagle, this one is likely to be a common blue violet, Viola sororia.

There’s a patch of violets near the Hexastylis plants. “We have a lot of different violets… of varying origins” around here, Cagle says. Many of the native species have both a purple form and a variety that’s white with purple striping. Other species in the violet family come in different colors altogether, and Cagle says many of those are of European origin.

The Johnny-jump-up pansy, for instance, can have “funkier colors,” like yellow or pinkish purple and is native to Europe and Asia. Violets can be hard to identify. Some species are distinguished mainly by characteristics like the lobes (projections in leaves with gaps between them) or the hairiness of the leaves. The bird’s foot violet and wood violet, for example, “tend to have really deep lobes.”

Cagle says the violet we’re looking at is likely the common blue violet, characterized by smooth leaves and petals, purple or purple-and-white flowers, and rounded or slightly arrow-shaped leaves.

The Cranefly orchid (Tipularia discolor) reproduces later in the year. The purple on the bottom of the leaves, and sometimes on the top as well (see right), helps protect the plant from sunlight and herbivores.

The orchid family, Orchidaceae, is one of the largest families of flowering plants in the world. Many of its members are tropical, including the Vanilla genus, but “we do have a number of native orchids” here as well, including yellow and pink lady’s slipper orchids, putty-root, and the cranefly orchid.

The cranefly orchid, Tipularia discolor, isn’t yet in bloom, but we come across the leaves several times on our walk. According to Cagle, Tipularia discolor “isn’t actually a spring ephemeral” because it reproduces later in the year. However, “it’s ephemeral in its own way,” the leaves disappear by the time it flowers. Cagle says the plant’s scientific name can remind you what to look for: “‘Tip-’ because you’re going to tip this leaf over” to look at the underside and “discolor” because the leaves are a striking purple underneath. Some of the ones we see are purple on top as well. Cagle explains that the purple coloration serves as sunscreen and protection from critters that eat plants.

The plant gets its common name (and its scientific genus name, interestingly) from its delicate flowers, which are supposed to resemble craneflies. When the plant blooms, “the flowers are so delicate and so subtle that most of the time you miss them.” Pollinators like Noctuid moths, on the other hand, find the flowers easily and often. Cranefly orchids even have “specialized seed structures” that “get fused onto insects [such as the moths]… and carried off.”

Rue anemone (Thalictrum thalictroides or Anemonella thalictroides).
Cagle with giant chickweed (Stellaria pubera).

The rue anemone, unlike the cranefly orchid, is a true spring ephemeral. It belongs to a more “primitive” family and has lots of petals in a spiral arrangement. The species is also known as windflower “because they flutter and dance as the breeze comes through.” Cagle mentions that the plant is “usually pollinated by flies and little bees” and serves as an important food source for insects in early spring. But “how do these even exist” in a forest with so many plant-eating deer? Many spring ephemerals, Cagle explains, have “some really potent toxins” that protect them from large herbivores.

We stop briefly to examine perfoliate bellwort, also known as wild oats (Uvularia perfoliata), and giant (or star) chickweed. Chickweed is in the pink family, named not for the color but because “the petals… [look] as if they’re cut by ‘pinking shears,’” which have saw-toothed blades that leave notches in fabric.

Trout lily (Erythronium umbilicatum). According to Cagle, “No spring ephemeral walk is actually complete without finding some trout lilies.”

Near the end of our walk, we find several trout lilies. That’s fortunate. “No spring ephemeral walk is actually complete without finding some trout lilies,” Cagle says.

Unsurprisingly, trout lilies belong to the lily family. “Their flower structure,” Cagle says, “is very symmetrical” with three petals and three sepals. In trout lilies, the sepals resemble petals, too. This particular species is Erythronium umbilicatum. The species name, umbilicatum, refers to its “really long peduncle,” or flower stalk, which “allows the seed to actually touch the ground.” The seed is dimpled, Cagle says, “like a little belly button.” The name “trout lily,” meanwhile, refers to the mottled pattern on the leaves.

Spring beauty (Claytonia virginica), “a quintessential spring ephemeral.”

At the base of a tree near a small river, Cagle points out a flower called spring beauty (Claytonia virginica), “a quintessential spring ephemeral.” Some flowers, like the common bluet we saw earlier, thrive in disturbed areas, but plants like the spring beauty need rich, undisturbed habitat. That makes them good indicator species, species that can help scientists gauge environmental conditions and habitat quality. When a natural area is being restored, for example, scientists can measure restoration progress by comparing the “restoration site” to an undisturbed “reference site.”

According to Cagle, the spring beauty is pollinated by “bee flies… flies that kind of look like bees.” After pollination, the flowers turn pink. Cagle says this is common among ephemerals. One theory is that the color change signifies which flowers have already been pollinated, but others think it’s just a result of senescence, or aging.

Spring beauties are also “photonastic,” meaning they open and close in response to changing light conditions. “There is some evidence that the Iroquois would eat this plant in order to prevent conception,” Cagle says, but today the plant—like many spring ephemerals—is under protection in some areas. Human activities, sadly, have contributed to the decline of too many spring ephemerals.

Alum root (Heuchera americana) near the end of the walk. According to Cagle, its roots can be used “to form mordant for dyes.” Members of the Saxifrage family, which includes alum root, often have five petals, five sepals, and five stamens.

Not all of the plants we saw are spring ephemerals. Some, although they bloom in early spring, “wouldn’t technically be considered ephemeral because their leaves stick around even if their blooms don’t last long.” True ephemerals, on the other hand, “are plants that just seem to disappear off the face of the planet (or the forest floor) after a few weeks,” Cagle says. Only three of the species we found during the workshop are true ephemerals: the windflower, trout lily, and spring beauty. However, these aren’t the only spring ephemerals found in the area. Cagle’s personal favorite is bloodroot, with its “bright white petals” and pollen “that looks like it’s glowing.”

Next time you’re in the woods, keep your eyes out for ephemerals and other early spring flowers, but look quickly. They won’t be here for long.

By Sophie Cox

Post and Photos by Sophie Cox, Class of 2025

What’s Up In Space? 3 Experts Weigh In

On Friday, February 25th, 2022 the brand-new Duke Space Diplomacy Lab (SDL) had an exciting launch with its first panel event: hosting journalists Ramin Skibba, Loren Grush, and Jeff Foust for a conversation on challenges in space within the next year. Moderated by Benjamin L. Schmitt of Harvard University, the conversation was in line with the SDL’s goals to convene a multidisciplinary group of individuals for the development of research, policy proposals, and solutions to mitigate risks in space.

In conversation, three key themes arose:

  1. U.S Russia Relations

With the current Russian invasion in Ukraine and the subsequent strain on U.S-Russia relations, the geopolitics of space has been in the limelight. Control of outer space has been a contentious issue for the two countries since the Cold War, out of which an uneasy yet necessary alliance was forged. Faust remarked that he doesn’t see U.S-Russia space relations lasting beyond the end of the International Space Station (ISS) in 2030. Grush added that before then, it will be interesting to see whether U.S-Russia relations will sour in the realm of space, simply because it’s questionable whether the ISS could continue without Russian support. However, Russia and NASA have historically acted symbiotically when it comes to space, and it’s unlikely that either party can afford to break ties.

2. Space debris

Major global players, from the U.S to China to India to Russia, are all guilty of generating space debris. Tons of dead satellites and bits of spacecraft equipment litter the areas around Earth – including an estimated 34,000 pieces of space junk bigger than 10 centimeters – and if this debris hit something, it could be disastrous. Grush paints the picture well by comparing spacecrafts to a car on a road – except we just trust that the satellite will maneuver out of the way in the event of a collision, autonomously, and there are absolutely no rules of the road to regulate movement for any other vehicles.

A computer-generated graphic from NASA showing objects in Earth orbit that are currently being tracked. 95% of the objects in this illustration are orbital debris, i.e., not functional satellites.

Skibba suggests that the best thing to do might be to make sure that more stuff doesn’t enter space, since the invention of technologies to clean up existing space debris will take a while. He also points to efforts to program new spacecrafts with graveyard orbit and deorbit capabilities as a necessary step.

3. Who is in charge of space?

Faust explained that commercial space exploration is moving incredibly fast, and legal regulations are struggling to keep up. Tons of companies are planning to launch mega-constellations in the next few years, for reasons that include things like providing higher-speed Internet access – something that we can all benefit from. Yet with new players in space comes the question of: who is in charge of space? The Artemis Accords are the existing rules that govern space at an international level, but they function as an agreement, not law, and with more players in space comes a need for legally binding terms of conduct. But as Grush puts it, “there’s a tension between the nimble, rapid commercial environment and a regulatory environment that wasn’t quite prepared to respond.”

The eight signees of the Artemis Accords

Beyond who rules over space, there’s also the question of decolonizing space. Skibba brings up that amidst a growing number of mega-constellations of satellites being launched, there are key questions being asked about who has access to space, and how we can level the playing field for more countries and companies to enter space exploration.

Space is uncharted territory, and to understand it is no small feat. While science has come incredibly far in terms of technological capabilities in space, it’s clear that we don’t know what we don’t know. But with a more multilateral, global approach to exploring space, we may just be able to go even farther.

Post by Meghna Datta, Class of 2023

Measuring What Climate Change Does, Not Just Whether It’s Happening

Duke has a goal of being a “climate university,” Nicholas School of Environment Dean Toddi Steelman said in introducing a panel discussion on Climate Change Science during Research Week. She said it’s a vision in which the university’s focus on climate informs every aspect of its mission, from education and operations to community partnerships – and, of course, research.

Five Duke climate scientists spoke on the Feb. 1 panel, all remotely. (View the Discussion.)

Jim Clark, professor of statistical science at the Nicholas School, described our planet’s climate as a “moving target” when it comes to understanding its impact on biodiversity. Complex connections exist between species, like a “system of interactions” between each other, that responds to climate change.

Our understanding of this system is limited by population data collection like the Breeding Bird Survey and the USDA Forest Inventory & Analysis — projects that lack “co-located monitoring of multiple species groups,” Clark said. Such measures fail to capture the relationships between species.

Professor James Clark

Instead, Clark advocates moving away from static models like these population measurements and towards the question of “How does change in the whole community respond to the environment and other species?” In order to understand our dynamic climate, we need an equally dynamic conception of biodiversity, he argued.

Marc Jeuland, associate professor of public policy and global health, and leader of the Sustainable Energy Researchers Initiative (SETI), talked about the “deep inequities” in energy access across rural parts of developing regions and the prospect of accomplishing “a just and sustainable energy transition” of their energy sources.

He thinks the transition can be accomplished with existing sustainable energy technologies like wind and solar.

The problem has two main parts, he said. First is the lack of clean cooking energy, with 2.6 billion humans dependent on solid fuels (wood and charcoal) and polluting stoves. The second is the lack of electricity and electrical services, with 760 million people going without and millions more lacking reliable service, he said.

Professor Marc Jeuland

Jeuland said there is an urgent need to reallocate resources to spread climate solution technologies in these parts of the world.

Jeuland and his SETI team tirelessly investigate how to overcome energy poverty and the populations they affect most – primarily in Africa and Southern Asia – to understand the feasibility and tradeoffs with the adoption of increased access to alternative fuels.

Emily Bernhardt, the James B. Duke distinguished professor of biogeochemistry in the Nicholas School and chair of Duke Biology, addressed the question of how climate change and sea level rise will impact coastal communities and ecosystems.

She said we don’t really have to wait to see what will happen: predominantly low-income communities along the coast are already suffering the consequences of sea water and extreme weather events. But she said the regions’ struggles remain unsolved and underrepresented because they lack the economic and political power to affect change.

Professor Emily Bernhardt

Whenever an event like a hurricane occurs, coastal plain communities are susceptible to storm surges that introduce salt into freshwater environment – leading to sometimes catastrophic, often long-lasting impacts on existing ecosystems, Bernhardt said.

Bernhardt and hundreds of other scientists along the United States coast are working together on something she called “convergence research” that seeks solutions for coastal and other vulnerable communities. It’s called the Saltwater Intrusion and Sea Level Rise (SWISLR) Research Coordinating Network. 

Betsy Albright, associate professor of environmental science and policy, and Brian McAdoo, associate professor of earth and climate science, shared their zoom-hosting duties.

They talked about social justice and social science in mitigating the impact of climate change. Their work examines the role of local communities and governments in disaster recovery and how they can work to create systems to manage aid and other resources as extreme weather events become more common.

As with most climate issues, marginalized communities are disproportionately impacted by these events, they said. Albright and McAdoo are searching for ways to help these regions create the capacity to respond and become more resilient to future events.

Professor Elizabeth Albright
Professor Brian McAdoo

The climate crisis is arguably the greatest challenge of this generation, but this esteemed panel brought much-needed attention to the obstacles facing every aspect of the world of climate science research and how their research is working to overcome them.

Post by Nhu Bui, Class of 2024

The Climate Crisis is Imminent. These Experts Offer Solutions.

In April of 2019, the first government declared climate change to be a national emergency. Since then, over 1,900 local governments and more than 23 national governments have expressed the same sentiment.

A 2021 report released by the IPCC labeled climate change a ‘code red’ for humanity, and every day more than 2 million people search the term ‘climate crisis’ on Google. So it’s apparent, the climate crisis is imminent. What’s the solution? Experts at Duke’s annual Research Week posed their research-based solutions during a virtual panel hosted on February 1st. (View the Session)

The panel, mediated by Biology professor Mohamed Noor, began with a solution posed by professors Mark Borsuk and Jonathan Wiener. Known as solar radiation modification, SRM is “an attempt to moderate global warming by intentionally increasing the amount of incoming sunlight that is reflected by the atmosphere back to space,” according to Borsuk. Its primary technique is stratospheric aerosol injection. Wiener explained that their research is “trying to understand the risk… And we’re working to study these multiple impacts because all too often, as we’re all familiar with human decision making at the individual level or the governmental public policy level tends to focus on one thing at a time.” However, even with possible governance challenges at play, their research poses an extremely cheap yet effective solution for avoiding some of the worst impacts of climate change.

Dalia Patino Echeverri’s presentation on GRACE, an energy solution.

Next up on the panel was Dalia Patino Echeverri, an associate professor at Duke’s Nicholas School of the Environment. She began by ruminating on the challenges faced in Texas after the snowstorm last year, and how climate change intensified those challenges. Her research focuses on how to address the electricity issues that climate change is producing in our nation, through a system called ‘GRACE’. ‘GRACE’ is a power grid that is risk-aware for clean, smart energy usage.

“It considers the forecast of electricity, the amount of load on the forecast of electricity generation from wind and sun of resources, and looks at the availability of conventional resources to schedule this commercial resources.” said Echeverri. Its operating system is extremely intelligent minimizing expected value and total cost of energy during times of climate crisis.

Brian Silliman’s presentation on Duke Restore.

Finally, a solution was presented from Brian Silliman, the Rachel Carson Distinguished Professor for marine biology. He introduced a more grassroots approach to climate restoration, called Duke Restore.

“A lot of our research and those of others have shown that the presence of restored marine environments greatly protects human societies on the coastline from increasing threat storm surge, and flooding generated in large part by climate change impacts, etc.” Silliman began.

Duke Restore aims to go out into ecosystems and restore the shorelines that have been lost, indirectly aiding in climate crisis alleviation. Silliman is currently collaborating with governments and other conservation organizations to help change the way they plan to restore these ecosystems from the bottom up. ““We’re doing this here in North Carolina with the US Marine Corps, changing the planting designs to switch the restoration trajectory from failure to success.”

Kay Jowers explaining her ideas for a more equitable approach to policy solutions.

Kay Jowers, a Senior Policy Associate at the Duke Nicholas Institute for Environmental Policy Solutions, closed out the panel event with some final thoughts.

“My charge is to give you some food for thought about creating a more supportive environment for environmental and climate justice at Duke,” she began. She explained the need for action as compared to documentation and explained that equitable approaches are needed to avoid a climate disaster.

“In the world of Environmental Justice Studies, the communities, and the scholars have been calling for less problematization and documenting of problems, and more orientation towards solutions.” Her sentiments resonated deeply with the theme of the panel, as solution-based research is of paramount importance in the 21st century.

The Duke Research Week panel on climate change solutions posed tangible explications for the ever imminent climate crisis happening around the world. Though climate change is apparent now more than ever, researchers like these hold the solutions for the future.

Post by Skylar Hughes, Class of 2025

Finding the Tipping Point for Coastal Wetlands

Cypress swamp, eastern North Carolina. Photo by Steve Anderson, Duke

DURHAM, N.C. — The Albemarle-Pamlico Peninsula covers more than 2,000 square miles on the North Carolina coastal plain, a vast expanse of forested swamps and tea-colored creeks. Many people would probably avoid this place, whose dense thickets of cane and shrubs and waterlogged soils can slow a hike to a crawl.

“It’s hard fieldwork,” says Duke researcher Steve Anderson. “It gets really dense and scratchy. That, plus the heat and humidity mixed with the smell of sulfur and the ticks and the poison ivy; it just kind of adds up.”

But to Anderson and colleagues from Duke and North Carolina State University, these bottomlands are more than impenetrable marsh and muck and mosquitoes. They’re also a barometer of change.

Researchers surveying plants in Alligator River National Wildlife Refuge in 2016. Photo by Mathew Stillwagon, North Carolina State University

Most of the area they study lies a mere two to three feet above sea level, which exposes it to surges of ocean water — 400 times saltier than freshwater — driven inland by storms and rising seas. The salt deposits left behind when these waters recede build up year after year, until eventually they become too much for some plants to cope with.

Trudging in hip waders through stunted shrubs and rotting tree stumps, Anderson snaps a picture with his phone of a carpet of partridge berry trailing along the forest floor. In some parts of the peninsula, he says, the soils are becoming so salty that plants like these can no longer reproduce or are dying off entirely.

Along the North Carolina coast, understory plants such as this partridge berry (left) are quickly ceding ground to species such as this bigleaf marsh-elder (right) as the soils become too salty for them to thrive. Credit: Steve Anderson

In a recent study the team, led by professors Justin Wright and Emily Bernhardt of Duke, and Marcelo Ardón of NC State, surveyed some 112 understory plants in the region, making note of where they were found and how abundant they were in relation to salt levels in the soil.

The researchers identified a ‘tipping point,’ around 265 parts per million sodium, where even tiny changes in salinity can set off disproportionately large changes in the plants that live there.

Above this critical threshold, the makeup of the marsh floor suddenly shifts, as plants such as wax myrtle, swamp bay and pennywort are taken over by rushes, reeds and other plants that can better tolerate salty soils.

Certain dwindling plants could be an early warning sign that salt is poisoning inland waters, researchers say. Credit: Steve Anderson

The hope is that monitoring indicator species like these could help researchers spot the early warning signs of salt stress, Anderson says.

This research was supported by grants from the National Science Foundation (DEB1713435, DEB 1713502, and Coastal SEES Collaborative Research Award Grant No. 1426802).

CITATION: “Salinity Thresholds for Understory Plants in Coastal Wetlands,” Anderson, S. M., E. A. Ury, P. J. Taillie, E. A. Ungberg, C. E. Moorman, B. Poulter, M. Ardón, E. S. Bernhardt, and J. P. Wright. Plant Ecology, Nov. 24, 2021. DOI: 10.1007/s11258-021-01209-2.

Salt is poisoning the soils past a point of no return for some marsh plants; one team is trying to pinpoint the early warning signs. By Steve Anderson.

LowCostomy: the Low-Cost Colostomy Bag for Africa

It’s common for a Pratt engineering student like me to be surrounded by incredible individuals who work hard on their revolutionary projects. I am always in awe when I speak to my peers about their designs and processes.

So, I couldn’t help but talk to sophomore Joanna Peng about her project: LowCostomy.

Rising from the EGR101 class during her freshman year, the project is about building  a low-cost colostomy bag — a device that collects excrement outside the patient after they’ve had their colon removed in surgery. Her device is intended for use in under-resourced Sub-Saharan Africa.

“The rates in colorectal cancer are rising in Africa, making this a global health issue,” Peng says. “This is a project to promote health care equality.”

The solution? Multiple plastic bags with recycled cloth and water bottles attached, and a beeswax buffer.

“We had to meet two criteria: it had to be low cost; our max being five cents. And the second criteria was that it had to be environmentally friendly. We decided to make this bag out of recycled materials,” Peng says. 

Prototype of the LowCostomy bag

For now, the team’s device has succeeded in all of their testing phases. From using their professor’s dog feces for odor testing, to running around Duke with the device wrapped around them for stability testing, the team now look forward to improving their device and testing procedures.

“We are now looking into clinical testing with the beeswax buffer to see whether or not it truly is comfortable and doesn’t cause other health problems,” Peng explains.

Poster with details of the team’s testing and procedures

Peng’s group have worked long hours on their design, which didn’t go unnoticed by the National Institutes of Health (NIH). Out of the five prizes they give to university students to continue their research, the NIH awarded Peng and her peers a $15,000 prize for cancer device building. She is planning to use the money on clinical testing to take a step closer to their goal of bringing their device to Africa.

Peng shows an example of the beeswax port buffer (above). The design team of Amy Guan, Alanna Manfredini, Joanna Peng, and Darienne Rogers (L-R).

“All of us are still fiercely passionate about this project, so I’m excited,” Peng says. “There have been very few teams that have gotten this far, so we are in this no-man’s land where we are on our own.”

She and her team continue with their research in their EGR102 class, working diligently so that their ideas can become a reality and help those in need.

Post by Camila Cordero, Class of 2025

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