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      Podcast: Curiosity Unbounded, Episode 1 — How a free-range kid from Maine is helping green-up industrial practices

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      The Curiosity Unbounded podcast is a conversation between MIT President Sally Kornbluth and newly-tenured faculty members. President Kornbluth invites us to listen in as she dives into the research happening in MIT’s labs and in the field. Along the way, she and her guests discuss pressing issues, as well as what inspires the people running at the world’s toughest challenges at one of the most innovative institutions on the planet.

      In this episode, President Kornbluth sits down with Desirée Plata, a newly tenured associate professor of civil and environmental engineering. Her work focuses on making industrial processes more environmentally friendly, and removing methane — a key factor in global warming — from the air.

      FULL TRANSCRIPT:

      Sally Kornbluth: Hello, I’m Sally Kornbluth, president of MIT, and I’m thrilled to welcome you to this MIT community podcast, Curiosity Unbounded. In my first few months at MIT, I’ve been particularly inspired by talking with members of our faculty who recently earned tenure. Like their colleagues, they are pushing the boundaries of knowledge. Their passion and brilliance, their boundless curiosity, offer a wonderful glimpse of the future of MIT.

      Today, I’m talking with Desirée Plata, associate professor of civil and environmental engineering. Desirée’s work is focused on predicting the environmental impact of  industrial processes and translating that research to real-world technologies. She describes herself as an environmental chemist. Tell me a little more about that. What led you to this work either personally or professionally?

      Desirée Plata: I guess I always loved chemistry, but before that, I was just a kid growing up in the state of Maine. I like to describe myself as a free-range kid. I ran around and talked to the neighbors and popped into the local businesses. One thing I observed in my grandparents’ town was that there were a whole lot of sick people. Not everybody, but maybe every other house. I remember being about seven or eight years old and driving home with my mom to our apartment one day and saying, “It’s got to be something everybody shares. The water, maybe something in the food or the air.” That was really my first environmental hypothesis.

      Sally: You had curiosity unbounded even when you were a child. 

      Desirée: That’s right. I spent the next several decades trying to figure it out and ultimately discovered that there was something in the water where my grandmother lived. In that time, I had earned a chemistry degree and came to MIT to do my grad work at MIT in the Woods Hole Oceanographic in environmental chemistry and chemical oceanography.

      Sally: You saw a pattern, you thought about it, and it took some time to get the tools to actually address the questions, but eventually you were there. That is great. As I understand it, you have two distinct areas of interest. One is getting methane out of the atmosphere to mitigate climate warming, and the other is making industrial processes more environmentally sound. Do you see these two as naturally connected?

      Desirée: I’ll start by saying that when I was young and thinking about this chemical contamination that I hypothesized was there in my grandmother’s neighborhood, one of the things—when I finally found out there was a Superfund site there—one of the things I discovered was that it was owned by close family friends. They were our neighbors. The decisions that they made as part of their industrial practice were just part of standard operating procedure. That’s when it clicked for me that industry is just going along, hoping to innovate to make the world a better place. When these environmental impacts occur, it’s often because they didn’t have enough information or know the right questions to ask. I was in graduate school at the time and said, “I’m at one of the most innovative places on planet Earth. I want to go knock on the doors of other labs and say, ‘What are you making and how can I help you make it better?'”

      If we all flash back to around 2008 or so, hydraulic fracturing was really taking off in this country and there was a lot of hypotheses about the number of chemicals being used in that process. It turns out that there are many hundreds of chemicals being used in the hydraulic fracturing process. My group has done an immense amount of work to study every groundwater we could get our hands on across the Appalachian region of the eastern United States, which is where a lot of this development took place and is still taking place. One of the things we discovered was that some of the biggest environmental impacts are actually not from the injected chemicals but from the released methane that’s coming into the atmosphere. Methane is growing at an exorbitant rate and is responsible for about as much warming as CO2 over the next 10 years. I started realizing that we, as engineers and scientists, would need a way to get these emissions back. To take them back from the atmosphere, if you will. To abate methane at very dilute concentrations. That’s what led to my work in methane abatement and methane mitigation.

      Sally: Interesting. Am I wrong about when we think about the impact of agriculture on the environment, that methane is a big piece of that as well?

      Desirée: You are certainly not wrong there. If you look at anthropogenic emissions or human-derived emissions, more than half are associated with agricultural practices. The cultivation of meat and dairy in particular. Cows and sheep are what are known as enteric methane formers. Part of their digestion process actually leads to the formation of methane. It’s estimated that about 28% of the global methane cycle is associated with enteric methane formers in our agricultural practices as humans. There’s another 18% that’s associated with fossil energy extraction.

      Sally: That’s really interesting. Thinking about your work then, particularly in agriculture, part of the equation has got to be how people live, what they eat, and production of methane as part of the sustainability of agriculture. The other part then seems to be how you actually, if you will, mitigate what we’ve already bought in terms of methane in the environment.

      Desirée: Yes, this is a really important topic right now.

      Sally: Tell me a little bit about, maybe in semi-lay terms, about how you think about removal of methane from the environment.

      Desirée: Recently, over 120 countries signed something called the Global Methane Pledge, which is essentially a pledge to reduce 45% of methane emissions by 2030. If you can do that, you can save about 0.5 degree centigrade warming by 2100. That’s a full third of the 1.5 degrees that politicians speak about. We can argue about whether or not that’s really the full extent of the warming we’ll see, but the point is that methane impacts near-term warming in our lifetimes. It’s one of the unique greenhouse gases that can do that.

      It’s called a short-lived climate pollutant. What that means is that it lives in the atmosphere for about 12 years before it’s removed. That means if you take it out of the atmosphere, you’re going to have a rapid reduction in the total warming of planet Earth, the total radiative forcing. Your question more specifically was about, how do we grapple with this? We’ve already omitted so much methane. How do we think about, as technologists, getting it back? It’s a really hard problem, actually. In the air in the room in front of us that we’re breathing, only two of the million molecules in front of us are methane. 417 or so are CO2. If you think direct air capture of CO2 is hard, direct air capture of methane is that much harder.

      The other thing that makes methane a challenge to abate is that activating the bonds in methane to promote its destruction or its removal is really, really tricky. It’s one of the smallest carbon-based molecules. It doesn’t have what we call “Van der Waals interactions”—there are no handles to grab onto. It’s not polar. That first destruction and that first C-H bond is what we as chemists would call “spin forbidden”. It’s hard to do and it takes a lot of energy to do that. One of the things we’ve developed in my lab is a catalyst that’s based on earth-abundant materials. There are some other groups at MIT that also work on these same types of materials. It’s able to convert methane at very low levels, down to the levels that we’re breathing in this room right now.

      Sally: That’s fascinating. do you see that as being something that will move to practical application?

      Desirée: One of the things that we’re doing to try to translate this to meaningful applications for the world is to scale the technology. We’re fortunate to have funding from several different sources, some private philanthropy groups and the United States Department of Energy. They’re helping us over the next three years try to scale this in places where it might matter most. Perhaps counterintuitive places, coal mines. Coal mines emit a lot of methane and it happens to be enriched in such a way that it releases energy. It might release enough energy to actually pay for the technology itself. Another place we’re really focused on is dairy.

      Sally: Really interesting. You mentioned at the beginning that you were at MIT, you left, you came back. I’m just wondering — I’m new to MIT and, obviously, I’m just learning it — but how do you think about the MIT community or culture in a way that is particularly helpful in advancing your work?

      Desirée: For me, I was really excited to come back to MIT because it is such an innovative place. If you’re someone who says, “I want to change the way we invent materials and processes,” it’s one of the best places you could possibly be. Because you can walk down the hall and bump into people who are making new things, new molecules, new materials, and say, “How can we incorporate the environment into our decision-making process?”

      As engineering professors, we’re guilty of teaching our students to optimize for performance and cost. They go out into their jobs, and guess what? That’s what they optimize for. We want to transition, and we’re at a point in our understanding of the earth system, that we could actually start to incorporate environmental objectives into that design process.

      Engineering professors of tomorrow should, say, optimize for performance and cost and the environment. That’s really what made me very excited to come back to MIT. Not just the great research that’s going on in every nook and corner of the Institute, but also thinking about how we might influence engineering education so that this becomes part of the fabric of how humans invent new practices and processes.

      Sally: If you look back in your past, you talked about your childhood in Maine and observing these patterns. You talked about your training and how you came to MIT and have really been, I think, thriving here. Was there a path not taken, a road not taken if you hadn’t become an environmental chemist? Was there something else you really wanted to do?

      Desirée: That’s such a great question. I have a lot of loves. I love the ocean. I love writing. I love teaching and I’m doing that, so I’m lucky there. I also love the beer business. My family’s in the beer business in Maine. I thought, as a biochemist, I would always be able to fall back on that if I needed to. My family’s not in the beer business because we’re particularly good at making beer, but because they’re interested in making businesses and creating opportunities for people. That’s been an important part of our role in the state of Maine.

      MIT really supports that side of my mind, as well. I love the entrepreneurial ecosystem that exists here. I love that when you bump into people and you have a crazy idea, instead of giving you all the reasons it won’t work, an MIT person gives you all the reasons it won’t work and then they say, “This is how we’re going to make it happen.” That’s really fun and exciting. The entrepreneurship environment that exists here is really very supportive of the translation process that has to happen to get something from the lab to the global impact that we’re looking for. That supports my mission just so much. It’s been a joy.

      Sally: That’s excellent. You weren’t actually tempted to become a yeast cell biologist in the service of beer production?

      Desirée: No, no, but I joke, “They only call me when something goes really bad.”

      Sally: That’s really funny. You experienced MIT as a student, now you’re experiencing it as a faculty member. What do you wish there was one thing about each group that the other knew?

      Desirée: I wish that, speaking with my faculty hat on, that the students knew just how much we care about them. I know that some of them do and really appreciate that. When I send an email at 3:00 in the morning, I get emails back from my colleagues at 3:00 in the morning. We work around the clock and we don’t do that for ourselves. We do that to make great sustainable systems for them and to create opportunity for them to propel themselves forward. To me, that’s one of the common unifying features of an MIT faculty member. We care really deeply about the student experience.

      As a student, I think that we’re hungry to learn. We wanted to really see the ins and outs of operation, how to run a research lab. I think sometimes faculty try to spare their students from that and maybe it’s okay to let them know just what’s going on in all those meetings that we sit through.

      Sally: That’s interesting. I think there are definitely things you find out when you become a faculty member and you’re like, “Oh, so this is what they were thinking.” With regard to the passion of the faculty about teaching, it really is remarkable here. I really think some of the strongest researchers here are so invested in teaching and you see that throughout the community.

      Desirée: It’s a labor of love for sure.

      Sally: Exactly. You talked a little bit about the passion for teaching. Were there teachers along your way that you really think impacted you and changed the direction of what you’re doing?

      Desirée: Yes, absolutely. I could name all of them. I had a kindergarten teacher who would stay after school and wait for my mom to be done work. I was raised by a single mom and her siblings and that was amazing. I had a fourth-grade teacher who helped promote me through school and taught me to love the environment. If you ask fourth graders if they saw any trash on the way to school, they’ll all say, “No.” You take them outside and give them a trash bag to fill up and it’ll be full by the end of the hour. This is something I’ve done with students in Cambridge to this day and this was many years on now. She really got me aware and thinking about environmental problems and how we might change systems.

      Sally: I think it’s really great for faculty to think about their own experiences, but also to hear people who become faculty members reflect on the great impact their own teachers had. I think the things folks are doing here are going to reverberate in their student’s minds for many, many years. It also is interesting in terms of thinking about the pipeline and when you get students interested in science. You talk about your own early years of education that really ultimately had an impact.

      It’s funny, when I became president at MIT, I got a note from my second-grade teacher. I remembered her like it was yesterday. These are people that really had an impact. It’s great that we honor teaching here at MIT and we acknowledge that this is going to have a really big impact on our student’s lives.

      Desirée: Yes, absolutely. It’s a privilege to teach these top talents. At many schools around the country, it’s just young people that have so much potential. I feel like when we walk into that classroom, we’ve got to bring inspiration with us along with the tangible, practical skills. It’s been great to see what they become.

      Sally: Tell me a little bit about what you do outside of work. When you ask faculty hobbies, sometimes I go, “Hobbies?” There must be something you spend your time on. I’m just curious.

      Desirée: We’re worried we’re going to fail this part of the Q&A. Yes. I have four children.

      Sally: You don’t need any hobbies then.

      Desirée: I know. It’s been the good graces of the academic institution. Just for those people who are out there thinking about going into academia and say, “It’s too hard. I couldn’t possibly have the work and life that I seek if I go into academia,” I don’t think that’s true anymore. I know there are a lot of women who paved the way for me, and men for that matter. I remember my PhD advisors being fully present for their children. I’ve been very fortunate to be able to do the same thing. I spend lots of time taking care of them right now. But we love being out in nature hiking, skiing, and kayaking and enjoying what the Earth gives us.

      Sally: It’s also fun to see that “aha” moment in your children when they start to learn a little bit about science and they get the idea that you really can discover things by observing closely. I don’t know if they realize they benefit from having parents who think that way, but I think that also stays with them through their lives.

      Desirée: My son is just waiting for the phone call to be able to be part of MIT’s toy design class.

      Sally: That’s fantastic.

      Desirée: As an official evaluator. Yes.

      Sally: In the last five years or so, we’ve been through the pandemic. In practical terms, how you think about your work and your life, what do you do that has improved your life? I always hate the words of “work-life balance” because they’re so intermeshed, but just for the broader community, how have you thought about that?

      Desirée: I’ve been thinking about my Zoom world and how I am still able to do quite a bit of talking to my colleagues and advancing the research mission and talking to my students that I wouldn’t have been able to do. Even pre-pandemic, it would’ve been pretty hard. We’re all really trained to interact more efficiently through these media and mechanisms. I know how to give a good talk on Zoom, for better or worse. I think that that’s been something that has been great.

      In the context of environment, I think a lot of us—this might be cliched at this point—but realize that there are things that we don’t need to get up on a plane for and perhaps we can work on the computer and interact in that way. I think that’s awesome. There’s not much that can replace real, in-person human interaction, but if it means that you can juggle a few more balls in the air and have your family feel valued and yourself feel valued while you’re also valuing your work that thing that is igniting for you, I think that’s a great outcome.

      Sally: I think that’s right. Unfortunately, though, your kids may never know the meaning of a snow day.

      Desirée: You got it.

      Sally: They may be on a remote school whenever we would’ve been home building snow forts.

      Desirée: As a Mainer, I appreciate this fully, and almost had to write a note this year. Just let them go outside.

      Sally: Exactly, exactly. As we’re wrapping up, just thinking about the future of climate work and coming back to the science, I think you’ve thought a lot about what you’re doing and impact on the climate. I’m just wondering, as you look around MIT, where you think we might have some of the greatest impact? How do you think about what some of your colleagues are doing? Because I’m starting to think a lot about what MIT’s real footprint in this area is going to be.

      Desirée: The first thing I want to say is that I think for a long time, the world’s been looking for a silver bullet climate solution. That is not how we got into this problem and it’s not how we’re going to get out of it.

      Sally: Exactly.

      Desirée: We need a thousand BBs. Fortunately, at MIT, there are many thousands of minds that all have something to contribute. I like to impose, especially on the undergraduates and the graduate researchers, our student population out there, think, “How can I bring my talents to bear on this really most pressing and important problem that’s facing our world right now?” I would say just whatever your skill is and whatever your passion is, try to find a way to marry those things together and find a way to have impact.

      The other thing I would say is that we think really differently about problems. That’s what might be needed. If you’re going to break systems, you need to come at it from a different perspective or a different angle. Encouraging people to think differently, as this community does so well, I think is going to be an enormous asset in bringing some solutions to the climate change challenge.

      Sally: Excellent. If you look back over your career, and even earlier than when you became a faculty member, what do you think the best advice is that you’ve ever been given?

      Desirée: There’s so much. I’ve been fortunate to have a lot of really great mentors. What is the best piece of advice? I think this notion of balancing work and not work. I’ve gotten two really key points of advice. One is about travel. I think that ties into this concept of COVID and whether now we can actually go remote for a lot of things. It was from an MIT professor. He said, “You know, the biggest thing you can do to protect your personal life and your life with your family is to say no and travel less. Travel eats up time on the front, in the back, and it’s your family that’s paying the price for that, so be really judicious about your choices.” That was excellent advice for me.

      Another female faculty member of mine said, “You have to prioritize your family like they are an appointment on your calendar and it’s okay when you do that.” I think those have been really helpful for me as I navigate and struggle with my own very mission-oriented self where I want to keep working and put my focus there, but know that it’s okay to maybe go for a walk and talk to real people.

      Sally: Go wild.

      Desirée: Yes, that’s right.

      Sally: This issue, actually, of saying no, not only to travel but thinking about where you really place your efforts and when there’s a finite amount of time. When I think about this—and advising junior faculty in terms of service—every faculty member is going to be asked way more things than they’re going to want to do. Yet, their service to the department, service to the Institute, is important, not only for their advancement but in how we create a community. I always advise people to say yes to the things they’re truly interested in and they’re passionate about, and there will be enough of those things.

      Desirée: I have a flowchart for when to say yes and when to say no. Having an interest is at the top of the list and then feeling like you’re going to have an impact. That’s something I think, when we do this service at MIT, we really are able to have an impact. It’s not just the oldest people in the room that get to drive the bus. They’re really listening and want to hear that perspective from everybody.

      Sally: That’s excellent. Thanks again, Desirée. I really enjoyed that conversation. To our audience, thanks again for listening to Curiosity Unbounded. I very much hope you’ll all join us again. I’m Sally Kornbluth. Stay curious. More

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      in Environment

      Even as temperatures rise, this hydrogel material keeps absorbing moisture

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      The vast majority of absorbent materials will lose their ability to retain water as temperatures rise. This is why our skin starts to sweat and why plants dry out in the heat. Even materials that are designed to soak up moisture, such as the silica gel packs in consumer packaging, will lose their sponge-like properties as their environment heats up.

      But one material appears to uniquely resist heat’s drying effects. MIT engineers have now found that polyethylene glycol (PEG) — a hydrogel commonly used in cosmetic creams, industrial coatings, and pharmaceutical capsules — can absorb moisture from the atmosphere even as temperatures climb.

      The material doubles its water absorption as temperatures climb from 25 to 50 degrees Celsius (77 to 122 degrees Fahrenheit), the team reports.

      PEG’s resilience stems from a heat-triggering transformation. As its surroundings heat up, the hydrogel’s microstructure morphs from a crystal to a less organized “amorphous” phase, which enhances the material’s ability to capture water.

      Based on PEG’s unique properties, the team developed a model that can be used to engineer other heat-resistant, water-absorbing materials. The group envisions such materials could one day be made into devices that harvest moisture from the air for drinking water, particularly in arid desert regions. The materials could also be incorporated into heat pumps and air conditioners to more efficiently regulate temperature and humidity.

      “A huge amount of energy consumption in buildings is used for thermal regulation,” says Lenan Zhang, a research scientist in MIT’s Department of Mechanical Engineering. “This material could be a key component of passive climate-control systems.”

      Zhang and his colleagues detail their work in a study appearing today in Advanced Materials. MIT co-authors include Xinyue Liu, Bachir El Fil, Carlos Diaz-Marin, Yang Zhong, Xiangyu Li, and Evelyn Wang, along with Shaoting Lin of Michigan State University.

      Against intuition

      Evelyn Wang’s group in MIT’s Device Research Lab aims to address energy and water challenges through the design of new materials and devices that sustainably manage water and heat. The team discovered PEG’s unusual properties as they were assessing a slew of similar hydrogels for their water-harvesting abilities.

      “We were looking for a high-performance material that could capture water for different applications,” Zhang says. “Hydrogels are a perfect candidate, because they are mostly made of water and a polymer network. They can simultaneously expand as they absorb water, making them ideal for regulating humidity and water vapor.”

      The team analyzed a variety of hydrogels, including PEG, by placing each material on a scale that was set within a climate-controlled chamber. A material became heavier as it absorbed more moisture. By recording a material’s changing weight, the researchers could track its ability to absorb moisture as they tuned the chamber’s temperature and humidity.

      What they observed was typical of most materials: as the temperature increased, the hyrogels’ ability to capture moisture from the air decreased. The reason for this temperature-dependence is well-understood: With heat comes motion, and at higher temperatures, water molecules move faster and are therefore more difficult to contain in most materials.

      “Our intuition tells us that at higher temperatures, materials tend to lose their ability to capture water,” says co-author Xinyue Liu. “So, we were very surprised by PEG because it has this inverse relationship.”

      In fact, they found that PEG grew heavier and continued to absorb water as the researchers raised the chamber’s temperature from 25 to 50 degrees Celsius.

      “At first, we thought we had measured some errors, and thought this could not be possible,” Liu says. “After we double-checked everything was correct in the experiment, we realized this was really happening, and this is the only known material that shows increasing water absorbing ability with higher temperature.”

      A lucky catch

      The group zeroed in on PEG to try and identify the reason for its unusual, heat-resilient performance. They found that the material has a natural melting point at around 50 degrees Celsius, meaning that the hydrogel’s normally crystal-like microstructure completely breaks down and transforms into an amorphous phase. Zhang says that this melted, amorphous phase provides more opportunity for polymers in the material to grab hold of any fast-moving water molecules.

      “In the crystal phase, there might be only a few sites on a polymer available to attract water and bind,” Zhang says. “But in the amorphous phase, you might have many more sites available. So, the overall performance can increase with increased temperature.”

      The team then developed a theory to predict how hydrogels absorb water, and showed that the theory could also explain PEG’s unusual behavior if the researchers added a “missing term” to the theory. That missing term was the effect of phase transformation. They found that when they included this effect, the theory could predict PEG’s behavior, along with that of other temperature-limiting hydrogels.

      The discovery of PEG’s unique properties was in large part by chance. The material’s melting temperature just happens to be within the range where water is a liquid, enabling them to catch PEG’s phase transformation and its resulting super-soaking behavior. The other hydrogels happen to have melting temperatures that fall outside this range. But the researchers suspect that these materials are also capable of similar phase transformations once they hit their melting temperatures.

      “Other polymers could in theory exhibit this same behavior, if we can engineer their melting points within a selected temperature range,” says team member Shaoting Lin.

      Now that the group has worked out a theory, they plan to use it as a blueprint to design materials specifically for capturing water at higher temperatures.

      “We want to customize our design to make sure a material can absorb a relatively high amount of water, at low humidity and high temperatures,” Liu says. “Then it could be used for atmospheric water harvesting, to bring people potable water in hot, arid environments.”

      This research was supported, in part, by U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy. More

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      in Environment

      MIT PhD students honored for their work to solve critical issues in water and food

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      In 2017, the Abdul Latif Jameel Water and Food Systems Lab (J-WAFS) initiated the J-WAFS Fellowship Program for outstanding MIT PhD students working to solve humankind’s water-related challenges. Since then, J-WAFS has awarded 18 fellowships to students who have gone on to create innovations like a pump that can maximize energy efficiency even with changing flow rates, and a low-cost water filter made out of sapwood xylem that has seen real-world use in rural India. Last year, J-WAFS expanded eligibility to students with food-related research. The 2022 fellows included students working on micronutrient deficiency and plastic waste from traditional food packaging materials. 

      Today, J-WAFS has announced the award of the 2023-24 fellowships to Gokul Sampath and Jie Yun. A doctoral student in the Department of Urban Studies and planning, Sampath has been awarded the Rasikbhai L. Meswani Fellowship for Water Solutions, which is supported through a generous gift from Elina and Nikhil Meswani and family. Yun, who is in the Department of Civil and Environmental Engineering, received a J-WAFS Fellowship for Water and Food Solutions, which is funded by the J-WAFS Research Affiliate Program. Currently, Xylem, Inc. and GoAigua are J-WAFS’ Research Affiliate companies. A review committee comprised of MIT faculty and staff selected Sampath and Yun from a competitive field of outstanding graduate students working in water and food who were nominated by their faculty advisors. Sampath and Yun will receive one academic semester of funding, along with opportunities for networking and mentoring to advance their research.

      “Both Yun and Sampath have demonstrated excellence in their research,” says J-WAFS executive director Renee J. Robins. “They also stood out in their communication skills and their passion to work on issues of agricultural sustainability and resilience and access to safe water. We are so pleased to have them join our inspiring group of J-WAFS fellows,” she adds.

      Using behavioral health strategies to address the arsenic crisis in India and Bangladesh

      Gokul Sampath’s research centers on ways to improve access to safe drinking water in developing countries. A PhD candidate in the International Development Group in the Department of Urban Studies and Planning, his current work examines the issue of arsenic in drinking water sources in India and Bangladesh. In Eastern India, millions of shallow tube wells provide rural households a personal water source that is convenient, free, and mostly safe from cholera. Unfortunately, it is now known that one-in-four of these wells is contaminated with naturally occurring arsenic at levels dangerous to human health. As a result, approximately 40 million people across the region are at elevated risk of cancer, stroke, and heart disease from arsenic consumed through drinking water and cooked food. 

      Since the discovery of arsenic in wells in the late 1980s, governments and nongovernmental organizations have sought to address the problem in rural villages by providing safe community water sources. Yet despite access to safe alternatives, many households still consume water from their contaminated home wells. Sampath’s research seeks to understand the constraints and trade-offs that account for why many villagers don’t collect water from arsenic-safe government wells in the village, even when they know their own wells at home could be contaminated.

      Before coming to MIT, Sampath received a master’s degree in Middle East, South Asian, and African studies from Columbia University, as well as a bachelor’s degree in microbiology and history from the University of California at Davis. He has long worked on water management in India, beginning in 2015 as a Fulbright scholar studying households’ water source choices in arsenic-affected areas of the state of West Bengal. He also served as a senior research associate with the Abdul Latif Jameel Poverty Action Lab, where he conducted randomized evaluations of market incentives for groundwater conservation in Gujarat, India. Sampath’s advisor, Bishwapriya Sanyal, the Ford International Professor of Urban Development and Planning at MIT, says Sampath has shown “remarkable hard work and dedication.” In addition to his classes and research, Sampath taught the department’s undergraduate Introduction to International Development course, for which he received standout evaluations from students.

      This summer, Sampath will travel to India to conduct field work in four arsenic-affected villages in West Bengal to understand how social influence shapes villagers’ choices between arsenic-safe and unsafe water sources. Through longitudinal surveys, he hopes to connect data on the social ties between families in villages and the daily water source choices they make. Exclusionary practices in Indian village communities, especially the segregation of water sources on the basis of caste and religion, has long been suspected to be a barrier to equitable drinking water access in Indian villages. Yet despite this, planners seeking to expand safe water access in diverse Indian villages have rarely considered the way social divisions within communities might be working against their efforts. Sampath hopes to test whether the injunctive norms enabled by caste ties constrain villagers’ ability to choose the safest water source among those shared within the village. When he returns to MIT in the fall, he plans to dive into analyzing his survey data and start work on a publication.

      Understanding plant responses to stress to improve crop drought resistance and yield

      Plants, including crops, play a fundamental role in Earth’s ecosystems through their effects on climate, air quality, and water availability. At the same time, plants grown for agriculture put a burden on the environment as they require energy, irrigation, and chemical inputs. Understanding plant/environment interactions is becoming more and more important as intensifying drought is straining agricultural systems. Jie Yun, a PhD student in the Department of Civil and Environmental Engineering, is studying plant response to drought stress in the hopes of improving agricultural sustainability and yield under climate change.  Yun’s research focuses on genotype-by-environment interaction (GxE.) This relates to the observation that plant varieties respond to environmental changes differently. The effects of GxE in crop breeding can be exploited because differing environmental responses among varieties enables breeders to select for plants that demonstrate high stress-tolerant genotypes under particular growing conditions. Yun bases her studies on Brachypodium, a model grass species related to wheat, oat, barley, rye, and perennial forage grasses. By experimenting with this species, findings can be directly applied to cereal and forage crop improvement. For the first part of her thesis, Yun collaborated with Professor Caroline Uhler’s group in the Department of Electrical Engineering and Computer Science and the Institute for Data, Systems, and Society. Uhler’s computational tools helped Yun to evaluate gene regulatory networks and how they relate to plant resilience and environmental adaptation. This work will help identify the types of genes and pathways that drive differences in drought stress response among plant varieties.  David Des Marais, the Cecil and Ida Green Career Development Professor in the Department of Civil and Environmental Engineering, is Yun’s advisor. He notes, “throughout Jie’s time [at MIT] I have been struck by her intellectual curiosity, verging on fearlessness.” When she’s not mentoring undergraduate students in Des Marais’ lab, Yun is working on the second part of her project: how carbon allocation in plants and growth is affected by soil drying. One result of this work will be to understand which populations of plants harbor the necessary genetic diversity to adapt or acclimate to climate change. Another likely impact is identifying targets for the genetic improvement of crop species to increase crop yields with less water supply. Growing up in China, Yun witnessed environmental issues springing from the development of the steel industry, which caused contamination of rivers in her hometown. On one visit to her aunt’s house in rural China, she learned that water pollution was widespread after noticing wastewater was piped outside of the house into nearby farmland without being treated. These experiences led Yun to study water supply and sewage engineering for her undergraduate degree at Shenyang Jianzhu University. She then went on to complete a master’s program in civil and environmental engineering at Carnegie Mellon University. It was there that Yun discovered a passion for plant-environment interactions; during an independent study on perfluorooctanoic sulfonate, she realized the amazing ability of plants to adapt to environmental changes, toxins, and stresses. Her goal is to continue researching plant and environment interactions and to translate the latest scientific findings into applications that can improve food security. More

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      in Security

      Scientists uncover the amazing way sandgrouse hold water in their feathers

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      Many birds’ feathers are remarkably efficient at shedding water — so much so that “like water off a duck’s back” is a common expression. Much more unusual are the belly feathers of the sandgrouse, especially Namaqua sandgrouse, which absorb and retain water so efficiently the male birds can fly more than 20 kilometers from a distant watering hole back to the nest and still retain enough water in their feathers for the chicks to drink and sustain themselves in the searing deserts of Namibia, Botswana, and South Africa.

      How do those feathers work? While scientists had inferred a rough picture, it took the latest tools of microscopy, and patient work with a collection of sandgrouse feathers, to unlock the unique structural details that enable the feathers to hold water. The findings appear today in the Journal of the Royal Society Interface, in a paper by Lorna Gibson, the Matoula S. Salapatas Professor of Materials Science and Engineering and a professor of mechanical engineering at MIT, and Professor Jochen Mueller of Johns Hopkins University.

      The unique water-carrying ability of sandgrouse feathers was first reported back in 1896, Gibson says, by E.G.B. Meade-Waldo, who was breeding the birds in captivity. “He saw them behaving like this, and nobody believed him! I mean, it just sounded so outlandish,” Gibson says.

      In 1967, Tom Cade and Gordon MacLean reported detailed observations of the birds at watering holes, in a study that proved the unique behavior was indeed real. The scientists found that male sandgrouse feathers could hold about 25 milliliters of water, or about a tenth of a cup, after the bird had spent about five minutes dipping in the water and fluffing its feathers.

      About half of that amount can evaporate during the male bird’s half-hour-long flight back to the nest, where the chicks, which cannot fly for about their first month, drink the remainder straight from the feathers.

      Cade and MacLean “had part of the story,” Gibson says, but the tools didn’t exist at the time to carry out the detailed imaging of the feather structures that the new study was able to do.

      Gibson and Mueller carried out their study using scanning electron microscopy, micro-computed tomography, and video imaging. They borrowed Namaqua sandgrouse belly feathers from Harvard University’s Museum of Comparative Zoology, which has a collection of specimens of about 80 percent of the world’s birds.

      Bird feathers in general have a central shaft, from which smaller barbs extend, and then smaller barbules extend out from those. Sandgrouse feathers are structured differently, however. In the inner zone of the feather, the barbules have a helically coiled structure close to their base and then a straight extension. In the outer zone of the feather, the barbules lack the helical coil and are simply straight. Both parts lack the grooves and hooks that hold the vane of contour feathers together in most other birds.
      Video of water spreading through the specialized sandgrouse feathers, under magnification, shows the uncoiling and spreading of the feather’s barbules as they become wet. Initially, most barbules in the outer zone of the feather form tubular features.Credit: Specimen #142928, Museum of Comparative Zoology, Harvard University © President and Fellows of Harvard College.

      When wetted, the coiled portions of the barbules unwind and rotate to be perpendicular to the vane, producing a dense forest of fibers that can hold water through capillary action. At the same time, the barbules in the outer zone curl inward, helping to hold the water in.

      The microscopy techniques used in the new study allowed the dimensions of the different parts of the feather to be measured. In the inner zone, the barb shafts are large and stiff enough to provide a rigid base about which the other parts of the feather deform, and the barbules are small and flexible enough that surface tension is sufficient to bend the straight extensions into tear-like structures that hold water. And in the outer zone, the barb shafts and barbules are smaller still, allowing them to curl around the inner zone, further retaining water.

      While previous work had suggested that surface tension produced the water retention characteristics, “what we did was make measurements of the dimensions and do some calculations to show that that’s what is actually happening,” Gibson says. Her group’s work demonstrated that the varying stiffnesses of the different feather parts plays a key role in their ability to hold water.

      The study was mostly driven by intellectual curiosity about this unique behavioral phenomenon, Gibson says. “We just wanted to see how it works. The whole story just seemed so interesting.” But she says it might lead to some useful applications. For example, in desert regions where water is scarce but fog and dew regularly occur, such as in Chile’s Atacama Desert, some adaptation of this feather structure might be incorporated into the systems of huge nets that are used to collect water. “You could imagine this could be a way to improve those systems,” she says. “A material with this kind of structure might be more effective at fog harvesting and holding the water.”

      “This fascinating and in-depth study reveals how the different parts of the sandgrouse’s belly feathers — including the microscopic barb shafts and barbules — work together to hold water,” says Mary Caswell Stoddard, an evolutionary biologist at Princeton University, who was not associated with this study. “By using a suite of advanced imaging techniques to describe the belly feathers and estimate their bending stiffnesses, Mueller and Gibson add rich new details to our understanding of the sandgrouse’s water-carrying feathers. … This study may inspire others to take a closer look at diverse feather microstructures across bird species — and to wonder whether these structures, as in sandgrouse, help support unusual or surprising functions.”

      The work was partly supported by the National Science Foundation and the Matoula S. Salapatas Professorship in Materials Science and Engineering at MIT. More

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      in Environment

      Detailed images from space offer clearer picture of drought effects on plants

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      “MIT is a place where dreams come true,” says César Terrer, an assistant professor in the Department of Civil and Environmental Engineering. Here at MIT, Terrer says he’s given the resources needed to explore ideas he finds most exciting, and at the top of his list is climate science. In particular, he is interested in plant-soil interactions, and how the two can mitigate impacts of climate change. In 2022, Terrer received seed grant funding from the Abdul Latif Jameel Water and Food Systems Lab (J-WAFS) to produce drought monitoring systems for farmers. The project is leveraging a new generation of remote sensing devices to provide high-resolution plant water stress at regional to global scales.

      Growing up in Granada, Spain, Terrer always had an aptitude and passion for science. He studied environmental science at the University of Murcia, where he interned in the Department of Ecology. Using computational analysis tools, he worked on modeling species distribution in response to human development. Early on in his undergraduate experience, Terrer says he regarded his professors as “superheroes” with a kind of scholarly prowess. He knew he wanted to follow in their footsteps by one day working as a faculty member in academia. Of course, there would be many steps along the way before achieving that dream. 

      Upon completing his undergraduate studies, Terrer set his sights on exciting and adventurous research roles. He thought perhaps he would conduct field work in the Amazon, engaging with native communities. But when the opportunity arose to work in Australia on a state-of-the-art climate change experiment that simulates future levels of carbon dioxide, he headed south to study how plants react to CO2 in a biome of native Australian eucalyptus trees. It was during this experience that Terrer started to take a keen interest in the carbon cycle and the capacity of ecosystems to buffer rising levels of CO2 caused by human activity.

      Around 2014, he began to delve deeper into the carbon cycle as he began his doctoral studies at Imperial College London. The primary question Terrer sought to answer during his PhD was “will plants be able to absorb predicted future levels of CO2 in the atmosphere?” To answer the question, Terrer became an early adopter of artificial intelligence, machine learning, and remote sensing to analyze data from real-life, global climate change experiments. His findings from these “ground truth” values and observations resulted in a paper in the journal Science. In it, he claimed that climate models most likely overestimated how much carbon plants will be able to absorb by the end of the century, by a factor of three. 

      After postdoctoral positions at Stanford University and the Universitat Autonoma de Barcelona, followed by a prestigious Lawrence Fellowship, Terrer says he had “too many ideas and not enough time to accomplish all those ideas.” He knew it was time to lead his own group. Not long after applying for faculty positions, he landed at MIT. 

      New ways to monitor drought

      Terrer is employing similar methods to those he used during his PhD to analyze data from all over the world for his J-WAFS project. He and postdoc Wenzhe Jiao collect data from remote sensing satellites and field experiments and use machine learning to come up with new ways to monitor drought. Terrer says Jiao is a “remote sensing wizard,” who fuses data from different satellite products to understand the water cycle. With Jiao’s hydrology expertise and Terrer’s knowledge of plants, soil, and the carbon cycle, the duo is a formidable team to tackle this project.

      According to the U.N. World Meteorological Organization, the number and duration of droughts has increased by 29 percent since 2000, as compared to the two previous decades. From the Horn of Africa to the Western United States, drought is devastating vegetation and severely stressing water supplies, compromising food production and spiking food insecurity. Drought monitoring can offer fundamental information on drought location, frequency, and severity, but assessing the impact of drought on vegetation is extremely challenging. This is because plants’ sensitivity to water deficits varies across species and ecosystems. 

      Terrer and Jiao are able to obtain a clearer picture of how drought is affecting plants by employing the latest generation of remote sensing observations, which offer images of the planet with incredible spatial and temporal resolution. Satellite products such as Sentinel, Landsat, and Planet can provide daily images from space with such high resolution that individual trees can be discerned. Along with the images and datasets from satellites, the team is using ground-based observations from meteorological data. They are also using the MIT SuperCloud at MIT Lincoln Laboratory to process and analyze all of the data sets. The J-WAFS project is among one of the first to leverage high-resolution data to quantitatively measure plant drought impacts in the United States with the hopes of expanding to a global assessment in the future.

      Assisting farmers and resource managers 

      Every week, the U.S. Drought Monitor provides a map of drought conditions in the United States. The map has zero resolution and is more of a drought recap or summary, unable to predict future drought scenarios. The lack of a comprehensive spatiotemporal evaluation of historic and future drought impacts on global vegetation productivity is detrimental to farmers both in the United States and worldwide.  

      Terrer and Jiao plan to generate metrics for plant water stress at an unprecedented resolution of 10-30 meters. This means that they will be able to provide drought monitoring maps at the scale of a typical U.S. farm, giving farmers more precise, useful data every one to two days. The team will use the information from the satellites to monitor plant growth and soil moisture, as well as the time lag of plant growth response to soil moisture. In this way, Terrer and Jiao say they will eventually be able to create a kind of “plant water stress forecast” that may be able to predict adverse impacts of drought four weeks in advance. “According to the current soil moisture and lagged response time, we hope to predict plant water stress in the future,” says Jiao. 

      The expected outcomes of this project will give farmers, land and water resource managers, and decision-makers more accurate data at the farm-specific level, allowing for better drought preparation, mitigation, and adaptation. “We expect to make our data open-access online, after we finish the project, so that farmers and other stakeholders can use the maps as tools,” says Jiao. 

      Terrer adds that the project “has the potential to help us better understand the future states of climate systems, and also identify the regional hot spots more likely to experience water crises at the national, state, local, and tribal government scales.” He also expects the project will enhance our understanding of global carbon-water-energy cycle responses to drought, with applications in determining climate change impacts on natural ecosystems as a whole. More

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      in Energy

      How to pull carbon dioxide out of seawater

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      As carbon dioxide continues to build up in the Earth’s atmosphere, research teams around the world have spent years seeking ways to remove the gas efficiently from the air. Meanwhile, the world’s number one “sink” for carbon dioxide from the atmosphere is the ocean, which soaks up some 30 to 40 percent of all of the gas produced by human activities.

      Recently, the possibility of removing carbon dioxide directly from ocean water has emerged as another promising possibility for mitigating CO2 emissions, one that could potentially someday even lead to overall net negative emissions. But, like air capture systems, the idea has not yet led to any widespread use, though there are a few companies attempting to enter this area.

      Now, a team of researchers at MIT says they may have found the key to a truly efficient and inexpensive removal mechanism. The findings were reported this week in the journal Energy and Environmental Science, in a paper by MIT professors T. Alan Hatton and Kripa Varanasi, postdoc Seoni Kim, and graduate students Michael Nitzsche, Simon Rufer, and Jack Lake.

      The existing methods for removing carbon dioxide from seawater apply a voltage across a stack of membranes to acidify a feed stream by water splitting. This converts bicarbonates in the water to molecules of CO2, which can then be removed under vacuum. Hatton, who is the Ralph Landau Professor of Chemical Engineering, notes that the membranes are expensive, and chemicals are required to drive the overall electrode reactions at either end of the stack, adding further to the expense and complexity of the processes. “We wanted to avoid the need for introducing chemicals to the anode and cathode half cells and to avoid the use of membranes if at all possible” he says.

      The team came up with a reversible process consisting of membrane-free electrochemical cells. Reactive electrodes are used to release protons to the seawater fed to the cells, driving the release of the dissolved carbon dioxide from the water. The process is cyclic: It first acidifies the water to convert dissolved inorganic bicarbonates to molecular carbon dioxide, which is collected as a gas under vacuum. Then, the water is fed to a second set of cells with a reversed voltage, to recover the protons and turn the acidic water back to alkaline before releasing it back to the sea. Periodically, the roles of the two cells are reversed once one set of electrodes is depleted of protons (during acidification) and the other has been regenerated during alkalization.

      This removal of carbon dioxide and reinjection of alkaline water could slowly start to reverse, at least locally, the acidification of the oceans that has been caused by carbon dioxide buildup, which in turn has threatened coral reefs and shellfish, says Varanasi, a professor of mechanical engineering. The reinjection of alkaline water could be done through dispersed outlets or far offshore to avoid a local spike of alkalinity that could disrupt ecosystems, they say.

      “We’re not going to be able to treat the entire planet’s emissions,” Varanasi says. But the reinjection might be done in some cases in places such as fish farms, which tend to acidify the water, so this could be a way of helping to counter that effect.

      Once the carbon dioxide is removed from the water, it still needs to be disposed of, as with other carbon removal processes. For example, it can be buried in deep geologic formations under the sea floor, or it can be chemically converted into a compound like ethanol, which can be used as a transportation fuel, or into other specialty chemicals. “You can certainly consider using the captured CO2 as a feedstock for chemicals or materials production, but you’re not going to be able to use all of it as a feedstock,” says Hatton. “You’ll run out of markets for all the products you produce, so no matter what, a significant amount of the captured CO2 will need to be buried underground.”

      Initially at least, the idea would be to couple such systems with existing or planned infrastructure that already processes seawater, such as desalination plants. “This system is scalable so that we could integrate it potentially into existing processes that are already processing ocean water or in contact with ocean water,” Varanasi says. There, the carbon dioxide removal could be a simple add-on to existing processes, which already return vast amounts of water to the sea, and it would not require consumables like chemical additives or membranes.

      “With desalination plants, you’re already pumping all the water, so why not co-locate there?” Varanasi says. “A bunch of capital costs associated with the way you move the water, and the permitting, all that could already be taken care of.”

      The system could also be implemented by ships that would process water as they travel, in order to help mitigate the significant contribution of ship traffic to overall emissions. There are already international mandates to lower shipping’s emissions, and “this could help shipping companies offset some of their emissions, and turn ships into ocean scrubbers,” Varanasi says.

      The system could also be implemented at locations such as offshore drilling platforms, or at aquaculture farms. Eventually, it could lead to a deployment of free-standing carbon removal plants distributed globally.

      The process could be more efficient than air-capture systems, Hatton says, because the concentration of carbon dioxide in seawater is more than 100 times greater than it is in air. In direct air-capture systems it is first necessary to capture and concentrate the gas before recovering it. “The oceans are large carbon sinks, however, so the capture step has already kind of been done for you,” he says. “There’s no capture step, only release.” That means the volumes of material that need to be handled are much smaller, potentially simplifying the whole process and reducing the footprint requirements.

      The research is continuing, with one goal being to find an alternative to the present step that requires a vacuum to remove the separated carbon dioxide from the water. Another need is to identify operating strategies to prevent precipitation of minerals that can foul the electrodes in the alkalinization cell, an inherent issue that reduces the overall efficiency in all reported approaches. Hatton notes that significant progress has been made on these issues, but that it is still too early to report on them. The team expects that the system could be ready for a practical demonstration project within about two years.

      “The carbon dioxide problem is the defining problem of our life, of our existence,” Varanasi says. “So clearly, we need all the help we can get.”

      The work was supported by ARPA-E. More

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      in Environment

      Moving water and earth

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      As a river cuts through a landscape, it can operate like a conveyer belt, moving truckloads of sediment over time. Knowing how quickly or slowly this sediment flows can help engineers plan for the downstream impact of restoring a river or removing a dam. But the models currently used to estimate sediment flow can be off by a wide margin.

      An MIT team has come up with a better formula to calculate how much sediment a fluid can push across a granular bed — a process known as bed load transport. The key to the new formula comes down to the shape of the sediment grains.

      It may seem intuitive: A smooth, round stone should skip across a river bed faster than an angular pebble. But flowing water also pushes harder on the angular pebble, which could erase the round stone’s advantage. Which effect wins? Existing sediment transport models surprisingly don’t offer an answer, mainly because the problem of measuring grain shape is too unwieldy: How do you quantify a pebble’s contours?

      The MIT researchers found that instead of considering a grain’s exact shape, they could boil the concept of shape down to two related properties: friction and drag. A grain’s drag, or resistance to fluid flow, relative to its internal friction, the resistance to sliding past other grains, can provide an easy way to gauge the effects of a grain’s shape.

      When they incorporated this new mathematical measure of grain shape into a standard model for bed load transport, the new formula made predictions that matched experiments that the team performed in the lab.

      “Sediment transport is a part of life on Earth’s surface, from the impact of storms on beaches to the gravel nests in mountain streams where salmon lay their eggs,” the team writes of their new study, appearing today in Nature. “Damming and sea level rise have already impacted many such terrains and pose ongoing threats. A good understanding of bed load transport is crucial to our ability to maintain these landscapes or restore them to their natural states.”

      The study’s authors are Eric Deal, Santiago Benavides, Qiong Zhang, Ken Kamrin, and Taylor Perron of MIT, and Jeremy Venditti and Ryan Bradley of Simon Fraser University in Canada.

      Figuring flow

      Video of glass spheres (top) and natural river gravel (bottom) undergoing bed load transport in a laboratory flume, slowed down 17x relative to real time. Average grain diameter is about 5 mm. This video shows how rolling and tumbling natural grains interact with one another in a way that is not possible for spheres. What can’t be seen so easily is that natural grains also experience higher drag forces from the flowing water than spheres do.

      Credit: Courtesy of the researchers

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      Bed load transport is the process by which a fluid such as air or water drags grains across a bed of sediment, causing the grains to hop, skip, and roll along the surface as a fluid flows through. This movement of sediment in a current is what drives rocks to migrate down a river and sand grains to skip across a desert.

      Being able to estimate bed load transport can help scientists prepare for situations such as urban flooding and coastal erosion. Since the 1930s, one formula has been the go-to model for calculating bed load transport; it’s based on a quantity known as the Shields parameter, after the American engineer who originally derived it. This formula sets a relationship between the force of a fluid pushing on a bed of sediment, and how fast the sediment moves in response. Albert Shields incorporated certain variables into this formula, including the average size and density of a sediment’s grains — but not their shape.

      “People may have backed away from accounting for shape because it’s one of these very scary degrees of freedom,” says Kamrin, a professor of mechanical engineering at MIT. “Shape is not a single number.”

      And yet, the existing model has been known to be off by a factor of 10 in its predictions of sediment flow. The team wondered whether grain shape could be a missing ingredient, and if so, how the nebulous property could be mathematically represented.

      “The trick was to focus on characterizing the effect that shape has on sediment transport dynamics, rather than on characterizing the shape itself,” says Deal.

      “It took some thinking to figure that out,” says Perron, a professor of geology in MIT’s Department of Earth, Atmospheric and Planetary Sciences. “But we went back to derive the Shields parameter, and when you do the math, this ratio of drag to friction falls out.”

      Drag and drop

      Their work showed that the Shields parameter — which predicts how much sediment is transported — can be modified to include not just size and density, but also grain shape, and furthermore, that a grain’s shape can be simply represented by a measure of the grain’s drag and its internal friction. The math seemed to make sense. But could the new formula predict how sediment actually flows?

      To answer this, the researchers ran a series of flume experiments, in which they pumped a current of water through an inclined tank with a floor covered in sediment. They ran tests with sediment of various grain shapes, including beds of round glass beads, smooth glass chips, rectangular prisms, and natural gravel. They measured the amount of sediment that was transported through the tank in a fixed amount of time. They then determined the effect of each sediment type’s grain shape by measuring the grains’ drag and friction.

      For drag, the researchers simply dropped individual grains down through a tank of water and gathered statistics for the time it took the grains of each sediment type to reach the bottom. For instance, a flatter grain type takes a longer time on average, and therefore has greater drag, than a round grain type of the same size and density.

      To measure friction, the team poured grains through a funnel and onto a circular tray, then measured the resulting pile’s angle, or slope — an indication of the grains’ friction, or ability to grip onto each other.

      For each sediment type, they then worked the corresponding shape’s drag and friction into the new formula, and found that it could indeed predict the bedload transport, or the amount of moving sediment that the researchers measured in their experiments.

      The team says the new model more accurately represents sediment flow. Going forward, scientists and engineers can use the model to better gauge how a river bed will respond to scenarios such as sudden flooding from severe weather or the removal of a dam.

      “If you were trying to make a prediction of how fast all that sediment will get evacuated after taking a dam out, and you’re wrong by a factor of three or five, that’s pretty bad,” Perron says. “Now we can do a lot better.”

      This research was supported, in part, by the U.S. Army Research Laboratory. More

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      in Environment

      Looking to the past to prepare for an uncertain future

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      Aviva Intveld, an MIT senior majoring in Earth, atmospheric, and planetary sciences, is accustomed to city life. But despite hailing from metropolitan Los Angeles, she has always maintained a love for the outdoors.

      “Growing up in L.A., you just have a wealth of resources when it comes to beautiful environments,” she says, “but you’re also constantly living connected to the environment.” She developed a profound respect for the natural world and its effects on people, from the earthquakes that shook the ground to the wildfires that displaced inhabitants.

      “I liked the lifestyle that environmental science afforded,” Intveld recalls. “I liked the idea that you can make a career out of spending a huge amount of time in the field and exploring different parts of the world.”

      From the moment she arrived at MIT, Intveld threw herself into research on and off campus. During her first semester, she joined Terrascope, a program that encourages first-year students to tackle complex, real-world problems. Intveld and her cohort developed proposals to make recovery from major storms in Puerto Rico faster, more sustainable, and more equitable.

      Intveld also spent a semester studying drought stress in the lab of Assistant Professor David Des Marais, worked as a research assistant at a mineral sciences research lab back in L.A., and interned at the World Wildlife Fund. Most of her work focused on contemporary issues like food insecurity and climate change. “I was really interested in questions about today,” Intveld says.

      Her focus began to shift to the past when she interned as a research assistant at the Marine Geoarchaeology and Micropaleontology Lab at the University of Haifa. For weeks, she would spend eight hours a day hunched over a microscope, using a paintbrush to sort through grains of sand from the coastal town of Caesarea. She was looking for tiny spiral-shaped fossils of foraminifera, an organism that resides in seafloor sediments.

      These microfossils can reveal a lot about the environment in which they originated, including extreme weather events. By cataloging diverse species of foraminifera, Intveld was helping to settle a rather niche debate in the field of geoarchaeology: Did tsunamis destroy the harbor of Caesarea during the time of the ancient Romans?

      But in addition to figuring out if and when these natural disasters occurred, Intveld was interested in understanding how ancient communities prepared for and recovered from them. What methods did they use? Could those same methods be used today?

      Intveld’s research at the University of Haifa was part of the Onward Israel program, which offers young Jewish people the chance to participate in internships, academic study, and fellowships in Israel. Intveld describes the experience as a great opportunity to learn about the culture, history, and diversity of the Israeli community. The trip was also an excellent lesson in dealing with challenging situations.

      Intveld suffers from claustrophobia, but she overcame her fears to climb through the Bar Kokhba caves, and despite a cat allergy, she grew to adore the many stray cats that roam the streets of Haifa. “Sometimes you can’t let your physical limitations stop you from doing what you love,” she quips.

      Over the course of her research, Intveld has often found herself in difficult and even downright dangerous situations, all of which she looks back on with good humor. As part of an internship with the National Oceanic and Atmospheric Administration, she spent three months investigating groundwater in Homer, Alaska. While she was there, she learned to avoid poisonous plants out in the field, got lost bushwhacking, and was twice charged by a moose.

      These days, Intveld spends less time in the field and more time thinking about the ancient past. She works in the lab of Associate Professor David McGee, where her undergraduate thesis research focuses on reconstructing the paleoclimate and paleoecology of northeastern Mexico during the Early Holocene. To get an idea of what the Mexican climate looked like thousands of years ago, Intveld analyzes stable isotopes and trace elements in stalagmites taken from Mexican caves. By analyzing the isotopes of carbon and oxygen present in these stalagmites, which were formed over thousands of years from countless droplets of mineral-rich rainwater, Intveld can estimate the amount of rainfall and average temperature in a given time period.

      Intveld is primarily interested in how the area’s climate may have influenced human migration. “It’s very interesting to learn about the history of human motivation, what drives us to do what we do,” she explains. “What causes humans to move, and what causes us to stay?” So far, it seems the Mexican climate during the Early Holocene was quite inconsistent, with oscillating periods of wet and dry, but Intveld needs to conduct more research before drawing any definitive conclusions.

      Recent research has linked periods of drought in the geological record to periods of violence in the archaeological one, suggesting ancient humans often fought over access to water. “I think you can easily see the connections to stuff that we deal with today,” Intveld says, pointing out the parallels between paleolithic migration and today’s climate refugees. “We have to answer a lot of difficult questions, and one way that we can do so is by looking to see what earlier human communities did and what we can learn from them.”

      Intveld recognizes the impact of the past on our present and future in many other areas. She works as a tour guide for the List Visual Arts Center, where she educates people about public art on the MIT campus. “[Art] interested me as a way to experience history and learn about the story of different communities and people over time,” she says.

      Intveld is also unafraid to acknowledge the history of discrimination and exclusion in science. “Earth science has a big problem when it comes to inclusion and diversity,” she says. As a member of the EAPS Diversity, Equity and Inclusion Committee, she aims to make earth science more accessible.

      “Aviva has a clear drive to be at the front lines of geoscience research, connecting her work to the urgent environmental issues we’re all facing,” says McGee. “She also understands the critical need for our field to include more voices, more perspectives — ultimately making for better science.”

      After MIT, Intveld hopes to pursue an advanced degree in the field of sustainable mining. This past spring, she studied abroad at Imperial College London, where she took courses within the Royal School of Mines. As Intveld explains, mining is becoming crucial to sustainable energy. The rise of electric vehicles in places like California has increased the need for energy-critical elements like lithium and cobalt, but mining for these elements often does more harm than good. “The current mining complex is very environmentally destructive,” Intveld says.

      But Intveld hopes to take the same approach to mining she does with her other endeavors — acknowledging the destructive past to make way for a better future. More