Carolyn Schmitt | Department of Civil and Environmental Engineering
October 11, 2017
From optimizing food production to feed a growing population to discovering the fundamental behaviors and processes of biopolymers, faculty in the Department of Civil and Environmental Engineering (CEE) are leveraging the interdisciplinary nature of the department to establish two new, innovative projects.
H.M. King Bhumibol Professor Dennis McLaughlin, a hydrologist, and Mitsui Chair Professor Serguei Saavedra, a network and community ecologist, are working together to examine the impact of resource allocation and community ecology on crop productivity and resilience. Additionally, assistant professors Tal Cohen and Otto X. Cordero are joining forces in an effort to discover the relationship between the physical and biological processes that underlie how biopolymers are consumed by bacteria.
The projects are funded by CEE’s Cross-Disciplinary Seed Funds, which invites CEE faculty from differing disciplines to apply for funding to support the creation of research projects.
“Through the Cross-Disciplinary Seed Funds and department events such as CEE Research Speed Dating, I encourage faculty members to reflect on how their expertise could be used in conjunction with another faculty member in a disparate area of the department to create new and innovative approaches to a topic,” says Markus Buehler, head of CEE, McAfee Professor of Engineering, and creator of the initiative. “The aim of the Cross-Disciplinary Seed Funds is to allow faculty to act on these ideas and make them realities. Every year I look forward to seeing the creative applications and the exciting research and findings these collaborations produce.”
For McLaughlin and Saavedra, their new research project will allow them to carve out a new direction for approaching the increasing demand for land and water resources that are necessary to feed the growing global population. By combining Saavedra’s proven ecological theories with McLaughlin’s experience studying the optimization of resources, the pair are taking a new direction towards ecological diversity and food production.
“Questions that are relevant to this project are issues of land use in areas with high biological diversity that are fragile ecosystems, but that are attractive, at least superficially, for agricultural development,” McLaughlin said. “We’ve got this growing global population that is pushing food demand, so there’s a demand for more food, but it’s not clear where it’s going to be grown, except places where the local ecosystem might have to be greatly changed.”
Previous research on food production has considered factors such as climate, water, and soil. McLaughlin and Saavedra are adding factors of ecological and landscape diversity, including resource competition among plants and the ecosystem’s tolerance to environmental stresses, to this list of considerations. Through their newly launched project, the pair are attempting to identify the effects of plant diversity and plot scale on crop productivity and resilience. Using this information, they are aiming to create a model for allocating land and water resources in environments where ecological factors, such as biodiversity and environmental stress, are present.
“We are trying to combine our research into an ‘eco-optimization model’ that optimizes production, but at the same time takes into account the ecological implications of this growth. These two things cannot be separated, but so far they have been treated separately,” Saavedra explained.
The project, which has its genesis in a thesis project by one of McLaughlin’s graduate students, uses Hawaii as its case study. CEE faculty and students have been pursuing various research projects in Hawaii, including air quality sensing and plant health on farms, during the department’s Traveling Research Environmental eXperiences (TREX) program. McLaughlin and Saavedra’s project offers a new potential topic of research for TREX students in upcoming years.
The project will also be useful as supplementary case studies for Saavedra’s course 1.s977 (Modeling Community Diversity) and McLaughlin’s course 1.74 (Land, Water, Food, and Climate).
The other project funded by this year’s CEE Seed Fund award is being spearheaded by Cohen, who specializes in nonlinear solid mechanics and material instabilities, and Cordero, a microbiologist who studies micro-scale ecology.
By combining forces, the pair are initiating a project to understand how bacteria colonize and decompose complex biological materials, a process that is crucial to the global carbon cycle.
Materials such as plant fibers can only be broken down by microorganisms that release extracellular enzymes capable dissolving complex biopolymer networks. This breakdown of polymers releases into the environment considerable amounts of carbon, which are otherwise sequestered inside the biological material.
This decomposition of plant fibers fragments, which occurs in soils, oceans or animal guts, drives the carbon cycle of the planet. This process, however, depends on the interplay between mechanical instabilities that emerge within the plant tissue and the ecology of microbes growing on the surface of the material. Such interplay between physics and ecology has never been studied thus far, and it is unclear to what extent the speed of degradation depends on this relationship. To address this issue, Cohen and Cordero are seeking to integrate mathematical models and experiments, creating a multidisciplinary approach to tackle this question.
To fully understand how biopolymers are decomposed by bacteria, Cordero’s lab is creating a micro-scale model ecosystem to understand how the individual bacteria break down a controlled hydrogel, representing the biopolymer. An understanding of a single particle will provide insight into the fundamental principles that govern the global function of microbial ecosystems.
“It was clear to us that there were biological and ecological problems that were directly interfacing with physics. Some of this physics we can take care of in our lab, but once it starts to get to the physics of the materials and why they break and the forces at play, it becomes much more complicated. And that was actually something Tal was working on in different contexts,” Cordero said.
Thus, Cohen’s lab is creating a theoretical model to describe the mechanics of polymer surface growth and degradation such as the ones in Cordero’s controlled setting. The theoretical models of the system will then be applied to the model system developed by the Cordero lab to get a complete understanding of the process from both a biological and mechanical perspective.
Simultaneously, Cohen’s lab is creating a theoretical model to describe the mechanics of polymer surface growth and degradation, such as the ones seen in Cordero’s controlled setting. The theoretical models of the system will then be applied to the model system developed by the Cordero lab to get a complete understanding of the process from both a biological and mechanical perspective.
Together, the two labs plan to develop a mathematical model integrating the mechanical approach with biological observations.
“I think it would be super exciting if we find something that shows a non-trivial interaction between the physics and biology determining how fast those things can break up,” Cordero said. With a fundamental understanding of how the degradation process works using his model ecosystem and Cohen’s theories, Cordero notes that the model could potentially be used for more complex organisms.
“For me, primarily being a theoretician, anytime I get this opportunity to work with people who are working on ideas that are very different from the types of problems I’ve been working on, but I can apply the same tools to it, is a super exciting opportunity,” Cohen said.
The project stems from a conversation between graduate students from Cohen’s lab and Cordero’s lab at CEE’s annual Research Speed Dating event, and the students will be integral to the theoretical and experimental components of the research project.
“I think [the collaboration is] a great opportunity for students in the sense that they get acquainted with a different community and a different type of thinking. We tend to have these disciplines that think about problems in very specific ways but it’s very fruitful to talk and kind of cross-pollinate,” Cohen said.
Now in its fourth year, the Cross-Disciplinary Seed Funds support one graduate student from each of the selected projects for one year. The student is chosen by the faculty members to receive the funding, and will be subsequently mentored by both faculty members. This unique style of project also allows the graduate student to receive a wider perception of the project at hand. Selected projects also demonstrate the potential for a long-term collaboration beyond the one year of department funding.
CEE faculty often collaborate to create multi-faceted, comprehensive solutions to a variety of issues and to solve major problems. Researchers in CEE also partner with other departments, labs and centers at MIT and at other institutions, including universities, governmental organizations, and industry practitioners, to further the potential impact of their work and applying their work to other domains.
“In order to do good research, you have to collaborate with the experts in those fields. These days, science is not done by a single person, it has two or more people involved, so definitely that helps a lot,” Saavedra said. “There are many things that you don’t see because you’re so biased by your own expertise, that once you start explaining things to people that are not necessarily experts or see the world in a different way, that is hugely interesting and beneficial, not only for the project but also for your work.”