Fall 2019
Caleb Fried '22
Advisor: Peter Huybers
I worked under professor Peter Huybers to try to develop new methods of reconstructing solar variability, with the end goal of supplementing our understanding of the climate forcings that contributed to the Little Ice Age and Medieval Warm Period. I spent the semester investigating the potential of reconstructing past solar variability using solarization- the sunlight-induced photochemical alteration of the absorption spectrum of any silicate glass. For this purpose, I collected old stained glass window samples from a local church and cut and polished them to compare glass that has been exposed to sunlight to glass that has remained mostly unexposed over its lifetime (hidden under plaster moldings or the shadow of the building). I analyzed these samples using visible and near-infrared spectroscopy to compare the concentration of Fe2+ in the samples, and thus the extent that the solarization reaction had progressed in each part of the glass. In addition to designing and setting up the experiments, I learned how to modify my instruments and setups to perform transmission spectroscopy measurements on glass surfaces rather than liquid samples.
Maddie Goldberg ’21
Advisors: David Johnston, Jordon Hemingway
This semester, I continued as a research assistant in Dave Johnston’s isotope geochemistry lab. I worked with Jordon Hemingway to set up and initiate a series of experiments aimed at examining the rate and mechanism of pyrite oxidation under various conditions. Pyrite (FeS2), often known as “fool’s gold,” is a valuable mineral when it comes to investigating Earth’s environmental conditions, especially on an ancient planet. Because pyrite is so readily oxidized, its presence or absence in the rock record can lend insight into the oxidizing capacity of the early Earth. And this is only one dimension in which pyrite has proved a compelling mineral to study; Jordon’s measurement of the oxidation products’ isotopic composition (particularly an unexpected ∆17O result) has raised a number of intriguing questions about the precise mechanism by which pyrite is oxidized--and suggests that the process may actually be quite different from what is typically assumed. The series of experiments that I started this semester with Jordon will hopefully help to clarify that mechanism. We are using a chemostat setup, which allows us to monitor and toggle various chemical parameters while the reaction in question--oxidation of pyrite--is running. A few of the variables that we hope to investigate are pH (our input solution has thus far been buffered around 7), dissolved oxygen content of the input reservoir, flow rate of the input reservoir, and the presence of hydrogen peroxide. All of these parameters allow us to imitate various environmental conditions, and, alongside isotope analysis, can lend insight into the role of those parameters in the reaction mechanism. To be sure, getting the chemostat framework to run smoothly was a bit of a challenge! The semester has provided an excellent lesson in the intricacies of experimental design- and the fact that it’s okay to diverge from the original plan when something isn’t working! For instance, we discovered that what we thought was a collection of pyrite grains of a single size fraction- we’d sieved it--contained a good deal of smaller grains, possibly of a different mineral. It took many more rounds of sieving, as well as a heavy liquid separation, to achieve the correct size fraction. Trying out different methods and thoughtfully adjusting our approach was an exciting aspect of the lab work for me--it meant I got to engage firsthand in the scientific process, and I learned new skills, like conducting methylene iodide separation or wrangling an anoxic glove bag, as a result. I’m looking forward to continuing these experiments in the coming semester!
Elida Kocharian ’21
Advisor: Kaighin McColl
Every year, 8 million metric tons of plastic is dumped into the ocean. The vast majority of this waste are microplastics, 5mm or smaller plastic particles that float throughout the water column and accumulate at the surface. The effects of plastic accumulation on marine life and ecosystems has been an area of increasing research--but is it possible that the buildup of plastic at the surface ocean effects the greater oceanic hydrological cycle? This semester, I've been exploring this theoretical question experimentally in the lab by designing and building a toy ocean model to test whether agglomerations of microplastics at the surface dampen ocean evaporation. The experimental method I developed involves measuring changes in mass, surface temperature, and relative humidity of an ocean-simulating tub under different weather conditions by varying wind speed and solar radiation and under different amounts of microplastics using a precision balance, anemometer, and IR camera. The majority of my work this semester has been devoted to building, piloting, and fine-tuning the experimental setup, but our preliminary results suggest a negative correlation between the amount of plastic in the system and the evaporation rate, meaning plastic may be slowing ocean evaporation in our small-scale approximation. Future work will develop these initial results and we hope to include potential findings in larger, global-scale ocean hydrological models that don't currently account for the effects of plastics on circulation.
Tyler Moulton '20
Advisors: Robin Wordsworth, Kaitlyn Loftus
In the fall 2019 semester, I started a research project under the supervision of Professor Robin Wordsworth and a 3rd-year PhD student in his group, Kaitlyn Loftus. My project’s overall goal is to examine and model the atmospheric evolution of carbon dioxide and water on planets in the habitable zones of M dwarfs. M dwarf stars are less luminous than our sun but make up 80% of the stars in the Milky Way and burn for much, much longer than our own sun—making them extremely interesting candidates for having potentially Earth-like or habitable planets. To examine and model this evolution, I have been working with Kaitlyn and Professor Wordsworth to construct a model to examine how a planet distributes a set input amount of carbon and water between its ocean and atmosphere. Along the way, I’ve also reviewed literature enabling me to fine tune my model and explore how different stellar and planetary parameters affect the atmospheric evolution of carbon dioxide. Moving forward, I’m hoping to improve this model and see whether I can incorporate other earth and planetary science softwares and theory so as to create a rigorous model for how planetary habitability can be maintained around M dwarf stars!
Jacob Ott ’20
This fall term I worked on two projects in the Fu Lab, one planetary in focus and one terrestrial. The planetary project--a study into the ancient magnetic fields of the asteroid Vesta--involved preparation of two meteorite thin sections and analysis on Quantum Diamond Microscope, a state-of-the-art magnetic field imaging instrument. QDM analysis is ongoing but so far it is unclear whether the particular meteorite sections being analyzed have retained substantial magnetic remanence. The terrestrial project is an investigation into the chemistry of impact ejecta deposits in South Africa called "spherule beds." Spherule beds are thought to retain chemical signatures of the Archean crust and mantle. I have analyzed a dozen spherule samples using Laser-Ablation Inductively-Coupled-Plasma Mass-Spectrometry and have developed a program to aid in processing the large amounts of spectrometry data produced. So far, my data suggests that the spherules which have escaped significant post-deposition alteration do indeed possess some Archean crust and/or mantle components, although specific compositions for these components are yet to be determined.
Summer 2019
Aidan Crawford ’22
Advisor: David Keith (SEAS)
Aidan Crawford (Environmental Engineering S.B. with an EPS Secondary) spent the summer working on a solar geoengineering research program as a part of the Keith Group at Harvard SEAS. His project examined the potential effect of a Marine Cloud Brightening (MCB) geoengineering scheme on various natural climate mechanisms. In particular, he focused on the ability of a general or targeted MCB deployment to alter the tracks of tropical cyclones before they make landfall. The project utilized NCAR's Community Earth System Model (CESM) to simulate climate response.
Will Flanagan ’20
Advisors: Marine Denolle, Brad Lipovsky
While taking Dr. Brad Lipovsky’s course in Glaciology last fall, I used seismological tools and methods to try to measure ice sheet thickness. The project involved downloading and analyzing data from existing seismic stations in Antarctica, and it introduced me to the intriguing field of glacier seismology. I quickly decided to dig deeper by doing summer research with Brad and Professor Marine Denolle. We soon began to look into potential glaciers for a project in which we would gather original data to attempt to couple seismology to subglacial hydrology. In July, I traveled with Brad and Stephanie Olinger (G2) to Valais, Switzerland, where we deployed small, three-component Raspberry Shake seismometers on three different glaciers over the course of a week. On Gorner Glacier and Rhône Glacier (the first and last glaciers we visited), we deployed instruments overnight. Conversely, on the pancake-shaped Glacier de la Plaine Morte, we visited two different sites — spending the first day near a human-engineered channel and the second near the large terminus — and conducted multiple shorter deployments for each instrument on both days (and stayed at a cool alpine hut in between!). We generally deployed the seismometers near features such as moulins, superglacial rivers, and termini. Additionally, we flew a drone at all sites except Rhône Glacier (where flying is prohibited) to construct digital elevation models (DEMs) of the glaciers in their current forms, which have diverged drastically from even the most recent Google imagery. Since returning to Cambridge, I have been processing the Swiss data: plotting spectrograms, relating the results to weather and hydrological features, and cross-correlating signals to analyze various events. Many thanks to Brad, Marine, and Stephanie, for their tremendous guidance and dedication all summer; to EPS and HUCE (and their wonderful staff members) for funding and supporting this research adventure; to Professor Fabian Walter and his group at ETH Zürich, for their collaboration at Plaine Morte and for providing us with mountaineering gear; and to Dr. Adam Soule of WHOI, for lending us his awesome drone and for helping with the DEMs.
Thomas Lee ’19
Advisor: Miaki Ishii
This summer, I spent time working in EPS with Professor Miaki Ishii on both building further upon my thesis work, and wrapping up a project on time corrections for analog seismograms. My thesis work was on imaging the subsurface of Kīlauea, Hawai`i during the volcanic eruption of summer 2018 using ambient seismic noise, this work has since expanded to investigate the volcanic tremor detected in the seismic noise and ways to track it. As work progresses, this work could bring great benefit to both the volcano-monitoring and volcanic-hazard communities. The time correction project involved using the symmetry present in seismic noise correlation functions to generate relative time corrections between stations. This method was applied to digitized paper seismograms, and opens up more opportunities for the use of such legacy data.
Ethan Manninen ’21
Advisor: Steve Wofsy
I spent this summer working in the Wofsy group on data from the ATom campaign. My project meandered a fair bit over the course of two months, before I settled on a plume of carbon monoxide that is flowing off the west coast of Africa into the air above the Atlantic. Specifically, I am interested in the different sources of CO, and how the trace gasses associated with the emissions from those sources affect hydroxyl chemistry. OH is crucial to the atmosphere's ability to remove methane and other pollutants, and understanding how human emissions are changing atmospheric OH is an important and challenging problem. I have deeply enjoyed learning technical skills including how to use the Harvard Odyssey Computing Cluster, as well as how to interact with data structures I had not seen before outside of EPS research. Perhaps more important has been my growth in terms of the research mindset: being flexible, and knowing when to ask for help. The best part of the summer has definitely been meeting all sorts of wonderful people, both at Harvard and in the broader EPS community.
Robert Powell ’20
Advisor: Kaighin McColl
My research this summer is if focusing on how microwave satellite observations could greatly improve our ability to monitor fuel moisture content, and to predict wildfire risk. The Soil Moisture Active Passive (SMAP) satellite, an L-band microwave satellite mission launched in 2015, provides global retrievals of surface soil moisture (SM) and vegetation water content (VWC) at 9-km resolution. In this study, we will test the added utility of SMAP observations on several recent wildfires, including California’s 2018 Camp Fire. Wildfires are identified using observations from the Moderate resolution Imaging Spectroradiometer (MODIS) burned area product. For each wildfire case study, time series of SMAP-observed SM and VWC in the days preceding the fire will be compared to corresponding time series of weather-based fuel moisture content proxies currently used in wildfire risk predictions. By comparing current prediction models with data from the SMAP instrument, this project aims to assess the potential for improving wildfire predictions with microwave satellite observations.
Vladislav Sevostianov ’19
Advisor: Scot Martin
I spent the summer building a drone based photoionization detector (PID) to measure volatile organic compounds (VOCs). I spent much of the summer in the Physics/SEAS Machine Shop where I also received my green certification manufacturing the sensor and performing laboratory testing afterwards. This is all for my senior thesis, which I will be presenting in November, and I also plan on presenting my work at AGU in December afterwards. The instrument I've built currently detects to around 3ppb, and I hope to soon have it at 1ppb detection as I keep evolving my design. The trickiest part is proving to be the electronics, as I am measuring fractions of nano amps, so I am having to quickly learn other skills to help solve the atmospheric measurement problem I set out to solve initially!
Kendra Wilkinson ’20
Advisor: Jerry Mitrovica
I am working in Professor Mitrovica’s research group with graduate students Marisa Borreggine and Evelyn Powell. The overarching goal of our project is to determine the most likely pathway for the first human migration from Sunda to Sahul. Within the greater project, my focus is determining whether or not one island is visible from another island, a variable also known as inter-island visibility. This variable impacts the probability of human movement from one island to another; greater visibility lowers the risk involved in a potential crossing and consequently heightens the probability of movement. Over the summer, I have been developing a code that will create several maps we will use to determine inter-island visibility and the likelihood of travel from one island to another. This will allow us to evaluate potential pathways between the two major landmasses and brings us one step closer to determining the most likely migration pathway from Sunda to Sahul.
Joseph Winters ’20
Advisor: Ann Pearson
Past research has reliably found that elevated levels of CO2 (eCO2) cause protein, zinc, and iron reductions in agricultural crops like rice and wheat, but there has been much less research about how eCO2 might affect food sources that are important for pollinators — that is, flowers. Bees depend on pollen protein for larval development, but researchers are worried that, like with cereal grains, eCO2 could bee causing flowers’ pollen protein concentrations to drop. Senior Researcher at the USDA Lew Ziska recently confirmed this was the case for goldenrod, an important source of pollen for bees that overwinter — the apian equivalent of hibernating. So this summer, I joined his lab at the Agricultural Research Service near Washington, DC to find out how eCO2 might affect other flowers. We used growth chambers to grow eight flower species from seeds, half of them in a 400ppm environment and the other half in a 600ppm environment. Then we transplanted them to eight outdoor plots, sealed them off in a mesh enclosure, and placed a bumblebee colony in each plot, allowing the worker bees to collect pollen from each plot’s flowers. Just like the bees, I have spent much of my time hand-collecting flower samples, then dissecting and storing them for later analysis. We also plan to run analyses on each of the eight beehives — we‘re going to flash freeze them in the final days of the experiment so they can be shipped back to Harvard. This fall, my advisor and I will assay the flower samples for protein content, among other things. In this photo you see me in the bee suit — a vital tool for my research! When provisioning the bees with pollen, you have to remove the hive’s entry box, open the lid, and force pollen pellets through small slits in the top of the box. It’s for their benefit, but they can get pretty angry about the intrusion!
Spring 2019
Maddie Goldberg ’21
Advisor: David Johnston
This semester, I've been working with Jordon Hemingway in the Johnston lab on a series of experiments related to pyrite oxidation under a number of conditions. So far, the experiments have involved oxic conditions--namely, rate calculations at varying pH. We also produced a calibration curve so that we can reliably use the spectrophotometer as a measure of sulfate production; this will likewise let us determine the reaction rate. Next, we will do these experiments in a chemostat setup, which allows for the maintenance of extremely constant chemical conditions, like pH and dissolved oxygen concentration. I haven't done much lab work before, so most of the steps involved are unfamiliar to me. As a result, this has been an excellent learning process, and I feel far more capable in a lab setting than I did at the beginning of the semester.
Hillman Hollister ’19
Advisor: John Shaw
This semester, I collaborated with John Shaw’s group on a project focusing on the geology of the Andes Mountains. By interpreting this geology, we hoped to inform the search for energy resources in the subsurface. We began at a high level, reading papers and learning about how these mountains formed, with a specific interest in the Andean orocline–the bend in the mountain chain. I then began to collect high resolution satellite imagery of regions that we identified as important. I learned to stitch together the images using GIS software, and then layer different types of images on top of each other to create a 3D, true color representation of local geological formations. This new imagery will be used to improve existing seismic reflection data of the area and will likely be used to inform upcoming field expeditions.
Elida Kocharian ’21
Advisors: Ann Pearson, Jenan Kharbush
This spring, I’ve been working with Dr. Jenan Kharbush as a research assistant in the Pearson lab on a project that analyzes the fractionation of nitrogen isotopes in photosynthetic microorganisms, specifically diatoms and cyanobacteria. I’ve been happy to work as a primary caretaker of the lab’s critters, including growing, transferring, and harvesting diatom and cyanobacteria cultures; developing cryopreservation methods to maintain the cultures; developing growth curves for each culture based on optical density and cell count; and measuring nitrogen and chlorophyll concentrations at different growth stages with nitrogen/chlorophyll assays. During my time in the lab, I’ve learned how to grow and analyze cultures, how to mix and create different kinds of media, how to perform various procedures including isotope assays, and how to develop and follow a scientific procedure in an experiment—along with countless other valuable scientific skills that I’m immensely grateful to have learned in a hands-on, active environment. Here I am transferring a cyanobacteria culture in the sterile hood! (photo creds to Jenan)
Jacob Ott ’20
Early this semester in Roger Fu’s paleomagnetics lab, I prepared a meteorite from the asteroid Vesta for analysis under the cutting-edge Quantum Diamond Microscope. The QDM was then used to map the meteorite’s magnetization, which it received while under the influence of Vesta’s ancient dynamo. Preliminary results suggest the magnetization is contained within vein-like features, but the magnetic carrier minerals themselves have been elusive. I am gathering more data now to puzzle this out. I have also assisted in the preparation of zircon samples, the oldest magnetic recorders on Earth. The magnetization of these zircons will tell the latitude of their formation site (paleolatitude) and provide novel constraints on ancient plate tectonic motion.
Sophie Webster ’21
Advisors: Ann Pearson, Felix Elling, Shelley McCann
Over this semester, I've worked on two separate projects with Shelley and Felix, in Ann Pearson’s lab. Shelley is trying to grow archaea under different conditions (both autotrophically and heterotrophically) to eventually analyze their membranes for GDGTs, lipids whose concentrations have been shown to covary with temperature. This could be important for reconstructing paleoclimate using the TEX86 variable (a ratio established from concentrations of different GDGTs). I assisted Shelley by working with the archaea grown on iron, calculating their day-to-day growth with Fe-oxidation assays. Felix is working to understand nitrogen cycling at the PETM (Paleocene-Eocene Thermal Maximum). In the three different sediment cores we are using, there are notable carbon excursions that denote the PETM, and we are wondering if we will notice a similar trend in nitrogen. I have been massing and preparing core samples to run on the EA. This process has been slightly trial and error, as we are trying to find the appropriate mass to deliver a large-enough N peak for analysis. Pictured: Me wrangling New Jersey sediment core samples, massing them and dexterously loading them into tiny tin foil cups.