Sustainability, Engineering and Science - Undergraduate Research (SESUR) Program Spend your summer on science and engineering

Undergraduate Research Symposium 2024

Friday, October 25, 2024 
Hartley Conference Center and Patio
Mitchell Earth Sciences Building

Research presented by students of the SDSS undergraduate research programs:

Program Schedule

2:00-3:00 pm - Select oral presentations in Hartley Conference Center 
3:00-5:00 pm - Poster presentations on the Patio 
5:00 pm - dinner as part of the SDSS Alumni Awards Reception and Dinner - RSVP Required

Oral Presentations

Long-Distance Ranging and Velocity Estimation for the NASA Europa Clipper Mission Using REASON
Michelle Park, SESUR

Using Ordinal Regression Analysis For Probabilistic Ranking And Identification Of Sustainable Carbon Capture Utilization And Storage Sites In California
Rudraksh Mohapatra, SUPER

Gandules, Yuca, and Malanga: Understanding Nitrogen Availability and Food Sovereignty in Puerto Rico
Diego Gutierrez, MUIR

Comparative Techno-Economic Analysis for Emerging CDR Technologies
Eva Geierstanger, SUPER

Investigating Environmental Conditions On Earth One Billion Years Ago Through Stable Carbon And Oxygen Isotopic Compositions In The Coal Creek Inlier, Yukon, Canada
Caroline Dee, SESUR

 

Abstracts of Posters and Oral Presentations

Calculating Emissions Factors for the U.S. Electricity System
Nomin-Erdene Bayarsaikhan, SUPER

In response to climate change, there is growing interest in promoting renewable energy generation and other interventions within power systems, alongside implementing energy policies. Strategies such as installing efficient building lighting, integrating energy storage technologies, and deploying demand response programs can significantly reduce emissions of carbon dioxide and criteria air pollutants like SO₂, NOₓ, and PM2.5. Emission factors—average and marginal—are key metrics used to assess the emissions reductions achieved through these interventions. While average emissions rates reflect the average emissions per MWh of energy consumed, marginal emissions rates focus on the emission intensities of the marginal generators, which are the last units dispatched to meet electricity demand. This work employs linear regression analysis on hourly generation and emissions data up to the year 2023 to investigate trends in marginal emissions factors and compare them with average emissions factors. A major contribution of this work is the development of an open-source codebase that integrates publicly accessible data from the Public Utility Data Liberation Project. The code automatically updates electricity emissions factors, making it a valuable resource for researchers and policymakers interested in tracking and analyzing the environmental impacts of energy interventions. This approach provides a comprehensive understanding of how different strategies affect emissions, enabling more informed decision-making.

Industrial Energy Tariff Structures Database
Casey Chen, MUIR

Decarbonizing the grid relies on a significant increase in grid-scale storage solutions that allow greater flexibility to utilize low-carbon energy supplies. One way to supply this energy storage is using demand-side energy flexibility, which incentivizes consumer behavior to align with use during times of lower stress or greater renewable energy availability. Industrial facilities account for 30% of the primary energy consumption in the US. Grid operators incentivize industrial energy flexibility using price-based incentives and complex, time-varying tariff structures. Energy flexibility benefits both participants and the grid— reducing the peak demand increases grid stability, saves costs, and allows for lower carbon impact. For participants, varying flexibility incentives present opportunities to decrease costs and increase reliability when aligning usage habits with the health of the grid. However, when it comes to electricity tariffs for the industrial sector, the structure is largely heterogeneous with various methods for determining total cost. Varying tariff structures provides an opportunity to incentivize operational alignment with grid health financially. Through these incentives to align power consumption to grid dynamics, grid operators can indirectly manage distributed energy flexibility. We show a database that captures tariffs in the US across 45 states and 90% of industrial energy use. It contains over 70,000 tariff structures within the database and the ability to capture varying structures on three distinct time scales (hourly, daily, and monthly) drawn from the 257 largest industrial energy providers. We provide an explainable and machine-readable database that can be integrated with industrial facility dynamics models. The dataset offers a perspective into the variation in structures across the US. With this data, we can better understand how industrial facilities can provide demand-side flexibility, understand the trade-offs in operational cost and emissions, and how to design industrial facilities for “grid-interactive” operations.

Low-Cost Manual Greenhouse Gas (GHG) Flux Chamber
Vanessa Chen, MUIR

The natural environment is a major source of greenhouse gas (GHG) emissions. Automatic and manual flux chambers are deployed to measure GHG concentrations over time from soil, tree, and water surfaces around the world. However, existing scientific instruments are expensive and difficult to deploy, especially in tropical wetlands. Therefore, a low-cost manual GHG flux chamber is desired to improve accessibility to measurements. Reliability, durability, adaptability, mass efficiency, stackability, simplicity, and ease of assembly were prioritized to address current limitations of existing instrumentation and incorporate desired design features. Researchers were interviewed and design reviews were held throughout the summer to produce an intentionally designed low-cost manual GHG chamber. Leak tests were performed by evaluating decreases in carbon dioxide concentration over 10 minute intervals and presented a consistently satisfactory leak rate of approximately 1%. Validation tests of the manual chamber housing and electronics were executed by comparing manual chamber measurements side-by-side with smart chamber measurements at the Stanford Arboretum, Lake Lagunita, and Jasper Ridge Biological Preserve. Promising data analysis and an r-squared value of 0.97 corresponding to fluxes ranging approximately from 150 to 3500 [(ppm * mol) / (m2 * s)] conclude this low-cost manual GHG flux chamber could be implemented on larger global scales!

An Investigation of Environmental Justice and Timber Tree Health for LAPA
Isabella Cruz-Krahn, SESUR

Palm oil is one of Costa Rica’s most important and profitable exports, however the income generated from palm plantations is not evenly distributed. Instead, profits are tightly concentrated among wealthy corporate owners who take advantage of small-scale farmer labor. In 2013, a set of partner studies was conducted in the Osa-Golfito region of Costa Rica to evaluate the role of palm plantations on native ecosystems and the livelihoods of local people. In response to suggestions provided by the case studies, an experimental program called the African Palm Laboratory (LAPA) was initiated to directly compare the social and environmental effects of monocultures versus polycultures on seven experimental sites. As part of Stanford’s Undergraduate Research Program under direction of LAPA’s founder, Dr. Rodolfo Dirzo, I visited LAPA’s seven experimental plots with the intent of following up on the initial social and ecosystem case studies conducted in 2013. I set out to evaluate LAPA’s environmental justice progress through social surveys of participants in addition to gathering feedback on LAPA as a community-centered sustainability program. I also set out to evaluate various aspects of ecosystem services and crop success in the experiment. While various types of biodiversity and ecosystem surveys had been conducted throughout LAPA’s lifetime, I specifically updated timber tree measurements in order to estimate carbon sequestration/storage, evaluated apparent disease or unsuitable growing conditions for timber trees in the sites, and took basic evaluations of essential soil nutrients for plant growth in each plot. Overall, I sought to evaluate whether LAPA was achieving its goals as a program: whether the polyculture portions of the experimental sites were providing greater positive impacts on farmers’ sustained financial and social well-being as well as enhancing ecosystem services more so than the palm monoculture portions of experimental sites.

Investigating Environmental Conditions On Earth One Billion Years Ago Through Stable Carbon And Oxygen Isotopic Compositions In The Coal Creek Inlier, Yukon, Canada
Caroline Dee, SESUR

This study aims to investigate environmental conditions on Earth prior to animal evolution by analyzing the stable carbon and oxygen isotopic compositions (𝛅13C and 𝛅18O, respectively) of carbonate rocks deposited during the late Mesoproterozoic, (ca. 1.3 –1.0 billion years ago [Ga]). Additionally, these analyses will be used to evaluate proposed correlations of Mesoproterozoic strata in Yukon. Previous studies have analyzed the 𝛅13C and 𝛅18O values of the ca. 1.1 Ga Pinguicula Group exposed in the Wernecke inlier in the northeast of Yukon but there is still disagreement regarding the correlation of the Pinguicula Group to informal Mesoproterozoic units PP1 and PP2 exposed in the northwest of Yukon in the Coal Creek inlier. To investigate this dispute, we measured sections of PP1 and PP2 and collected carbonate samples which were analyzed for their 𝛅13C and 𝛅18O values. Our findings help resolve correlations of Yukon stratigraphy and provide insight into how carbonate 𝛅13C and 𝛅18O values change through time. By studying these rocks, we can discover more about supercontinent cycles and how they affect paleoenvironmental conditions.

Developing Agrobacterium-Mediated Transformation in an Ectomycorrhizal Fungus?
Anastacia Del Rio, MUIR

Suillus pungens is an ectomycorrhizal fungus (EMF) that associates with Pinus muricata and rhizobacteria in a symbiotic relationship. Ectomycorrhizal fungi play an essential role in forest health across boreal, temperate, and tropical forests, but climate change threatens the ectomycorrhizal tree population globally. This mycorrhizal symbiosis regulates photosynthesis, carbon sequestration, and general resiliency against environmental pressures. The ecological prevalence of S.pungens makes it an attractive species to study for developing technologies focused on ecosystem services and forest resilience against climate change. However, there is inadequate technology to study and engineer ectomycorrhizal fungi such as S.pungens. This project aims to close this technical gap by developing an agrobacterium-mediated transformation protocol for the expression of autofluorescence in Suillus pungens. Developing a standard transformation protocol would increase the capabilities of mycologists and bioengineers to understand relevant mechanisms in S.pungens and tackle sustainability challenges.

A Geospatial Dashboard For Carbon Storage Transparency
Samuel Desai, SUPER

Carbon Capture and Sequestration (CCS) can remove emissions from flue gas streams at hard-to-abate pollution sources such as cement production, refineries, and heavy manufacturing. California's regulators will deploy CCS to reach the state’s 2045 carbon neutrality goal. Yet, only 19 percent of Americans understand this technology. Those legislating or experiencing its effects must be well-informed to advocate for community benefits and develop projects based on facts, not conjecture. To promote access to information, we created an ArcGIS Story Map and Web Experience data dashboard to provide objective information to poorly informed communities, developers, and policymakers about the risks and opportunities of CCS. We addressed knowledge gaps by meeting with environmental justice organizations like the Center for Biological Diversity (CBD) and sought input from CCS expert researchers in Stanford’s Center for Carbon Storage. Their diverging viewpoints provided a complete picture of the landscape for CCS projects in California. A recent McKinsey analysis found that 130 billion dollars of annual investment in CCS is required to meet emissions goals. However, it will be challenging for unknowledgeable communities to reap the benefits of deployment. By promoting transparency, the Story Map will accelerate the deployment of CCS, protect communities, and help California meet its climate goals.

Prescribed Fire Effects on Chaparral Soil Biogeochemistry at Jasper Ridge ‘Ootchamin ‘Ooyakma Biological Preserve
Kiara Fufunan, SESUR

Wildfires across California are growing in frequency, size, and intensity. Pile burning, a form of prescribed fire, can reduce the risk of severe wildfires while promoting ecosystem health and the biogeochemical cycling of nutrients. The impacts of prescribed fire on soils vary depending on factors such as vegetation and soil characteristics. While previous studies have shown ecological benefits of prescribed fire in forest systems, fire-prone chaparral ecosystems remain understudied, despite their abundance across California. In March 2024, Jasper Ridge ‘Ootchamin ‘Ooyakma Biological Preserve conducted pile burns within chaparral landscapes, offering the unique opportunity to assess the immediate and extended impacts on soil biogeochemistry, such as soil physiochemistry (pH, water content) and nutrient availability. We collected surface (soil and ash) and deep (>10 cm) soil samples from 10 pile sites within the chaparral landscape in February (pre-fire) and revisited sites for monthly post-fire sampling through August. Our findings show that prescribed fire had a significant impact on soil pH and nutrient content. Overall, each pile exhibited a significant (P<0.05) difference in pH. The average soil pH pre-fire was 5.64, which increased to 8.95 (a 1.6-fold increase) in surface soil and ash and remained alkaline in subsequent months. We also observed a significant (P<0.05) increase in water-extractable (or bioavailable) calcium, potassium, magnesium, sodium, and sulfur levels in surface soil and ash from all pile sites. These elevated nutrient levels may have significant implications for future vegetation recovery. Continued monitoring of long-term biogeochemical changes in fire-altered soil is essential for guiding wildfire management and predicting chaparral ecosystem recovery after prescribed burning.

Comparative Techno-Economic Analysis for Emerging CDR Technologies
Eva Geierstanger, SUPER

Since the start of the Industrial Revolution, carbon dioxide levels have almost doubled due to human activity, from about 280 to 427 parts per million. As a greenhouse gas, carbon dioxide has contributed to the warming of the planet, and consequently the drastic changes of climate patterns worldwide. According to the 2022 Intergovernmental Panel on Climate Change, to limit global warming to 2 degrees celsius or lower, carbon dioxide removal (CDR) needs to be employed, especially in hard-to-abate sectors where immediately reducing fossil fuel use is difficult. The research question to be explored is how four different CDR technologies (Enhanced Rock Weathering (ERW), Biomass Carbon Removal and Storage (BiCRS), Bioenergy with Carbon Capture and Storage (BECCS), and Direct Air Capture (DAC)) differ across techno-economic performance indicators. This research aims to develop an analytical tool for investors and companies to employ when deciding which CDR technologies to include in their carbon offset portfolios. The tool will aggregate data for each technology across quality-adjusted measures and present a scoring metric that allows stakeholders to compare different technologies. This project is in its beginning stages and efforts so far have established a thorough review of current literature in the field, a database of carbon removal projects, and calculations for life-cycle costs for BiCRS. The next steps are to continue collecting techno-economic data on the four different CDR technologies and developing the calculating tool.

Gandules, Yuca, and Malanga: Understanding Nitrogen Availability and Food Sovereignty in Puerto Rico
Diego Gutierrez, MUIR

Puerto Rico faces an unstable food system, leading to high food insecurity rates. Additionally, the island is prone to natural disasters which disrupt domestic agriculture. As a colony of the United States, Puerto Rico is economically and politically limited, with the main food supply coming through imported food and widespread barriers to land ownership. There are also limited studies on small-scale solutions to the food crisis in Puerto Rico. The guiding question was whether a pathway toward regaining autonomy in the food system was possible using legumes and root vegetables. Through a field trial in Aibonito, Puerto Rico, staple crops for the Puerto Rican diet were planted on a slope to understand the path of nitrogen produced from a legume, in this case, pigeon peas. In addition to the legume, root vegetables like cassava and taro were also planted. There were four treatments in this field trial: (1) fallow, or a bare field, (2) pigeon peas planted alone, (3) root vegetables (cassava and taro), and (4) pigeon peas, cassava, and taro. Composite soil samples were taken bi-weekly at 10, 15, and 30 centimeters and analyzed for plant-available nitrogen content (nitrate + ammonium). Additionally, plant characteristics, like canopy cover and height, were measured weekly. The plant characteristic data from the final sampling day shows greater plant biomass growth and canopy cover in the pigeon peas that were planted with the root vegetables than by the pigeon peas planted alone. At the end of the experiment, we found no discernable treatment effect concerning soil nitrogen content. Therefore, it is likely that planting pigeon peas and root vegetables together has no significant impact on their growth or nitrogen availability and could be a viable option for Puerto Rican people to both reduce erosion and improve their food security.

Understanding Local Perspectives on Land Use and Management in the Eastern Sierra to Improve Social-Ecological Resilience of Dryland Systems to Climate Change
Lela Hanson, SESUR

Landscapes are changing due to trends in land use practices and global climate. Indigenous and rural communities are particularly affected by these changes, and yet in the American West most of these landscapes are managed by chronically under-resourced federal agencies. As a result, there exists a lack of regional specificity to land management policy that can be detrimental to ecosystem health as well as to local livelihoods and well-being. In the Eastern Sierra region of California (ie. Inyo, Mono, and Alpine Counties), increased outdoor recreation tourism and climate change have intensified pressure on vulnerable landscapes, particularly water resources and dryland forests, imperiling traditional practices and profoundly impacting how residents experience social belonging and place attachment. This community-led research effort is the first to engage residents of all three counties in order to provide inclusive and equitable insight into the needs and values of Eastern Sierra communities. Mixed qualitative methods of semi-structured interviews and focus groups were used to examine land and forest use, landscape values and cultural ecosystem services, place attachment and social belonging, intergenerational knowledge, and environmental change and land management in the Eastern Sierra. This study seeks to identify generalizable landscape values and stewardship priorities to guide sustainable land management that supports vibrant and resilient communities and landscapes across the Eastern Sierra region.

Using Non-linear Fermi-Ulam Model to Investigate Stochastic Heating of Electrons in Partially Magnetized Plasma
 Kae Heller, SUPER

Our study investigated how the Fermi-Ulam acceleration model can be used to understand the conditions for stochastic heating of electrons in low-temperature, partially magnetized plasmas. Stochastic heating of electrons is the unpredictable energy gain due to instabilities in plasma, making Hall thrusters, which use this type of plasma, potentially less efficient. We built two computational models, one which modeled the individual behavior of particles in plasma and one which modeled the behavior of particles in the Fermi-Ulam Model. We calculated the energy gain under different conditions for both models and compared those results to previous literature and theoretical predictions. We found that using a measure of energy gain for the plasma model that more accurately reflected the plasma’s conditions recorded slightly higher measures of energy gain than previous work by Mandal et al. Phys. Plasmas 27, 032301 (2020). Furthermore, our model also observed energy gain for electric fields that had wavenumbers, ky, and amplitudes, ϕ0, which were below the condition for stochastic behavior in literature, i.e., ky2 ϕ0≥ωcB0, where ωc is the cyclotron resonance and B0 is the magnitude of the constant magnetic field. Using the Fermi-Ulam model, we verified that there was stochastic heating of the particles, and there was a saturation point for the heating of particles under a stochastic transition velocity as predicted by the work of Lieberman and Lichtenberg. Moving forward, we hope to create an analogy between the stochastic transition velocity from the Fermi-Ulam problem and the conditions for energy gain in the plasma model. Additionally, we plan to measure the degree of chaos of particles under different equations using their trajectories, all to understand the origins of wave-driven electron transport in partially magnetized plasmas.

The size distribution of toxic particulate matter in wildfire smoke and their impacts on California farmworkers
Jonathon Howell, SESUR

Wildfires have increased in abundance and severity in the Western US. Wildfire smoke contains toxic particulate matter (PM), which have significant health impacts on people exposed to it. The health effects of PMs are controlled by their size, which is poorly understood. We collected smoke samples from 11 wildfires from the 2024 wildfire season in the western US, ranging from southern California to Idaho. Particles from wildfire smoke were collected on pre-weighed filters using an active air sampler. The filters were then weighed and compared with the pre-weight values to calculate the mass of particles collected at each size range. Our results reveal that for all the smoke from varied wildfires, the mass of particles increased with decreasing size, with the majority (more than 50%) being less than 0.25 μm. To address the broader impacts of our research, we have conducted interviews with farmworkers in Watsonville, California, to understand their experiences working during wildfires. These interviews have inspired the creation of a play, which is to be performed at Stanford’s campus in October 2024. We are using performing arts techniques to initiate a conversation and raise awareness about the environmental justice implications of California wildfires. This approach will help to inform local communities who are impacted by wildfire smoke and policymakers about the results of this work and how PM in wildfire smoke can threaten human health.

Earth, Wind, and a Volcanic Eruption: Peering Into the Earth’s Structure Using an Atmospheric Shock Wave
Jason Hu, SESUR

The Earth, like all other solid materials, has elastic properties. Seismologists are particularly interested in two of these properties: the pressure wave (P-wave) speed and the shear wave (S-wave) speed. These closely-related variables determine how quickly waves propagate through a material, and thus how the ground behaves during an earthquake. Previous research has used atmospheric pressure fluctuations to measure these elastic properties in the subsurface. When the air pressure changes, the ground deforms a miniscule amount. However, these small movements can get lost in the seismic ambient noise spectrum that seismometers record. Only a sudden, drastic change in air pressure can create larger movements that are distinct from seismic noise. This sudden change in air pressure arrived on January 15, 2022, in the form of an atmospheric shock wave generated by the Hunga Tonga-Hunga Ha‘apai volcano eruption. The Hunga volcano eruption was the largest explosion ever recorded with modern instruments. As the shock wave circled the globe, the ground at the Pinyon Flat Seismic Array in Pinyon Flat, CA responded to this sudden atmospheric pressure change. Observations during the passage of the pressure wave show consistently high coherence (>0.8) between atmospheric pressure and vertical displacement. By combining recorded data with existing models of atmospheric-solid earth coupling, we obtain an estimate for a vertical seismic/acoustic coupling coefficient (Sv/A) which corroborates existing models of the ground properties at Pinyon Flat. The P-wave speed and S-wave speed can be estimated from the vertical seismic/acoustic coupling coefficient using empirical relationships. We then extend this work to the Alaska Geophysical Network, creating a map of Alaskan whole-crust subsurface structure. Ultimately, we propose the potential of using this technique to verify currently-existing whole-crust velocity models anywhere in the world with co-located barometer-seismometer instruments.

Quantifying Source Contributions to Seasonal PM2.5 Pollution in Northern Thailand
Nachat Jatusripitak, MUIR

Fine particulate matter (PM2.5) poses a serious threat to public health, tourism, and economic productivity in Northern Thailand. Previous studies quantifying PM2.5 source emissions have limited spatio-temporal resolution, failing to capture potentially significant variations in emission behavior at the local level. The unclear role of long-range pollutant transport from neighboring countries complicates the use of existing results for domestic air quality interventions. This ongoing study aims to develop a machine learning model to predict how PM2.5 concentrations vary across space and time using data from Thailand, Myanmar, and Laos. By integrating high-resolution data over a large geographic region, this model aims to account for long-range transport and provide more reliable, localized quantification of source contributions for targeted air quality management. Our research involves two major efforts: conducting systematic literature reviews to evaluate current PM2.5 research in Thailand and developing a data processing pipeline to feed data into the model. The literature reviews guided the selection of key data sources, highlighting forest fires and open burning of rice and maize residue as major emission sources. Accordingly, our pipeline integrates terrain, meteorological, active fire, land cover, and PM2.5 data into daily multi-band raster images with 1km pixel resolution from 2017 to 2022, which will serve as inputs for model training and prediction. Moving forward, we plan to incorporate additional data sources, such as vehicle traffic and agricultural production, and conduct correlation analyses to support the feature engineering process.

Uncovering Magnetic Properties of Mantle and Crustal Rocks along the Mid-Atlantic Ridge
Olivia Ju, SESUR

The Mid-Atlantic Ridge is a slow-spreading ridge with thinned oceanic crust. Located 30° North along this ridge, the Atlantis Massif, host of the Lost City Hydrothermal Field, exhibits anomalous magnetic properties in part due to a chemical fluid-rock process known as serpentinization. The recent success of International Ocean Discovery Program Expedition 399 involved drilling into the massif and recovering core samples extending from the oceanic crust to the upper mantle. To further understand the effects of serpentinization, we conducted susceptibility and imaging tests on spatially distributed recovered core samples. We ran high and low-temperature magnetic susceptibility tests, noting clear Verwey transitions at ~120K. This supports the interpretation that magnetite, a common serpentinization reaction mineral, is the primary magnetic carrier. Imaging techniques, including scanning electron microscopy and energy dispersive x-ray spectroscopy, helped identify the spatial relationships between magnetic carriers with associated minerals and features. We found that deeper rocks (~740m) displayed primary olivine relict with magnetite, suggesting high, albeit incomplete degrees of serpentinization, aligning well with the current view of a km-scale hydrothermal system. However, the coexistence of iron sulfides with iron oxides in varying depths complicates the alteration history, indicating periods of time that were reducing (conducive to iron sulfides) and oxidizing (conducive to iron oxides). Our work helps contextualize ongoing demagnetization experiments, thereby providing key insights that will help elucidate past magnetizing events in this region.

Socio-Environmental Factors Influencing Malaria in Costa Rica
Julieta Lamm-Perez, MUIR

Prior to 2015, malaria was nearly eradicated in Costa Rica. In the last decade, the disease has resurged to cause hundreds of cases annually, however, the drivers of contemporary malaria transmission in Costa Rica remain poorly understood. Plasmodium parasites (Plasmodium spp.) are the causative agent of malaria and, in Costa Rica, the parasites are primarily transmitted by Anopheles albimanus mosquitoes. The environmental dependence of the vector and reliance of the parasite on humans for transmission suggest that socio-environmental factors may contribute to the recent resurgence. This research seeks to measure the influence of socio-environmental changes on the recent resurgence of malaria, focusing on climatic factors and agricultural activities as a proxy for changes in mosquito breeding habitat, human-vector contact, and human mobility.We compare annual (2015-2023) district-level and canton-level malaria incidence with annual summaries of rainfall, temperature, and pineapple plantation area using geospatial and linear regression analyses. Preliminary findings indicate a positive correlation between precipitation levels and malaria cases. Malaria transmission is concentrated in district-years where average temperatures were around 25°C, which aligned with the thermal optimum for malaria transmission identified in previous observational and laboratory settings. There is a weak but positive relationship between plantation area and malaria cases when examining within district variability, however, we do not find clear signals across districts. The research highlights the critical influence of environmental factors, such as rainfall and temperature, on malaria resurgence and points to potential links between agriculture and disease spread.

Challenges and Opportunities to Mitigate Tradeoffs in WEFE Nexus under Climate Change - taking Yangtze River Basin, China as the example
Yuer Liu, MUIR

The Yangtze River Basin in China exemplifies the challenges of balancing the demands of the interconnected water, energy, and food sectors while ensuring ecosystem conservation. Climate change exacerbates water use conflicts, particularly between the food and hydropower sectors, and agricultural adaptation strategies, such as cropland expansion and increased irrigation, are likely to intensify competition between food production and ecological restoration. Nature-based solutions, such as forest restoration, present significant opportunities to improve water availability and enhance ecosystem resilience. However, the implementation of collaborative climate adaptation strategies to mitigate trade-offs within the water-energy-food-ecosystem (WEFE) nexus remains uncertain. Current sectoral management is hindered by challenges in policy integration, farmer engagement, and ensuring long-term sustainability, limiting efforts toward collaborative management. This research develops a framework to examine climate adaptation strategies in the Yangtze River Basin, with a focus on effectively managing WEFE conflicts and balancing competing demands. The findings aim to contribute to governance and infrastructure planning for a more resilient and sustainable future.

Using Ordinal Regression Analysis For Probabilistic Ranking And Identification Of Sustainable Carbon Capture Utilization And Storage Sites In California
Rudraksh Mohapatra, SUPER

California’s total greenhouse gas (GHG) emissions for 2021 was roughly 381.3 Million Metric Tons of CO2 (CARB 2023). Reductions in these emissions are carried out in three main ways - improving energy efficiency, increasing usage of renewables and carbon capture utilization and storage (CCUS). CCUS is key in reducing large emissions from industrial and power sectors. In order to effectively utilize and allocate resources for this technology, it is important to identify potential storage sites and quantitatively rank them. This project employs several data-driven approaches such as geospatial algorithms in ArcGIS and machine-learning in Python to do so. An initial classification stage used several tree-based machine-learning models to effectively identify the input factors used for the final ranking result. The input factors were prepared from various data-sources. These factors include: distance to faults, pipelines, and power plants, CO2 intensity, saline aquifers, and seismic moment. The next stage involved ranking sites using regression methods. Finally, an ordinal regression method was employed, which is used to provide the probability of an input being a certain classification (in our case, if it’s a suitable site or not). This probability value allowed us to quantitatively rank the sites. In this method, several different solvers were compared in the optimization step. An additional analysis involving exclusion zones (areas that are densely-populated, protected lands, critical habitats, near faults) was also conducted. The results of this project, therefore, will promote more efficient and just emission reduction efforts. It will also help policymakers meet California’s emissions reduction goals.

The Soil Remembers: Using Fallout Radionuclides to Trace Soil Erosion in Puerto Rico Before and After Hurricane Maria
Jason Navarro-Lopez, SESUR

In 2017, a two-punch series of hurricanes, Maria and Irma, severely impacted Puerto Rico’s El Yunque rainforest – changing the processes of soil erosion and the evolution of the landscape, among other economic and social devastations across the island. By employing fallout radionuclides (~7Be, ~137Cs, and ~210Pb) as tracers through gamma spectroscopy, we can measure variations in soil erosion and sediment flows prior to and following these storms. With a half-life of about 53 days, ^7Be tracks short-term processes, while \210Pb and ^137Cs, with half-lives of 30 and 22.3 years, respectively, enable the study of soil loss at the decadal scale. In order to evaluate sediment export, this study compares pre- and post-hurricane radionuclide inventories by resampling soils from sites this past summer (June 2024) that were initially examined in 2011–2012. Reduced ~210Pb and ~137Cs inventories, as well as preliminary data, point to a net loss of soil and sediment from El Yunque watersheds during decadal timescales. El Yunque’s unique ecological productivity and biogeochemical cycling have facilitated rapid recovery following the hurricane, as seen by near-background ~7Be concentrations in modern soils. According to measured radionuclide patterns, El Yunque's soil systems recovered quickly from Hurricane Maria, suggesting that the area is resistant to severe ecological and geomorphological disruption. Our research explores how intense weather affects tropical ecosystems and how soil erosion and landscape disruption models might be developed by using radioactive tracers and gamma spectroscopy. This research provides opportunity to build knowledge on ecosystems sensitive to natural disasters such as El Yunque, a culturally important forest to the Taino people of Puerto Rico.

Characterizing the Evolution of an Outgassed Secondary Atmosphere on 55 Cancri e
Barron Nguyen, SESUR

55 Cancri e (55 Cnc e) is a mature planet with an age of ~8 Ga, having a radius and mass of 1.95REarth and 8.8MEarth respectively. Considered an “ultra short period” planet, or USP for short, it orbits a K0IV-V/G8V type star on a period less than a day leading to interpretations of the planet being a lava world or a hot sub-Neptune. Observations suggest it may host an atmosphere composed predominantly of carbon-based species such as CO2 or CO. The presented research suggests that any observable CO2 dominant atmosphere on 55 Cnc e, alongside minor associated H2O and O2 species, will be supplied through outgassing of its initial volatile content, with outgassing rates and evolution regulated by supplementary or delayed tidal heating. Without the addition of tidal heating, 55 Cnc e must have had an initial 5% water mass fraction (WMF) inventory or 2 wt% of CO2 to delay cooling of its magma ocean by ~10 Mya through the greenhouse effect. Our model suggests the addition of tidal heating will decrease the initial volatile threshold needed to retain an elevated global mean temperature that sustains a planet-wide magma ocean, while slowing outgassing of its >2 bar secondary atmosphere to the present-day.

Long-Distance Ranging and Velocity Estimation for the NASA Europa Clipper Mission Using REASON
Michelle Park, SESUR

Europa, one of Jupiter's moons, is a promising candidate for habitable conditions as it harbors a global subsurface ocean heated by gravitational interactions with Jupiter. NASA’s upcoming Europa Clipper mission is equipped with the powerful Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON) instrument to penetrate Europa’s ice shell and explore its ocean. Here, we refine the orbital information of Europa Clipper using REASON, which can be implemented outside the closest approach of each flyby. We construct radar simulations of REASON’s radar pings to determine the maximum altitude for surface echo detection. We enhance the received signal’s power by maximizing pulse length, targeting Europa’s most reflective (leading sub-Jovian) hemisphere, and summing many compressed pulses. Next, we explore a phase shift approach for velocity measurements, which uses existing ranging pulses. Using Clipper’s most recent trajectory design, we identify the best flybys that meet the best working scenarios for this objective. Our anticipated range and velocity resolution will supplement existing radio science measurements, offering a new level of orbital precision for spacecraft navigation and insights into Europa’s evolution for habitable conditions.

Study of Dual Control Systems Involved in Chromogenic Behavior of Doryteuthis opalescens
Nguyen Pham, MUIR

Doryteuthis opalescens, or the California market squid, and other squid species exhibit chromogenic patterns for camouflage, mating, or antagonistic displays by expanding and contracting pigment-containing sacs–chromatophores–in their skin. The radial muscle fibers connected to the chromatophores receive electrical signals from the brain and activate or relax these cells accordingly, which constitutes the vertical control component of the dual control system over the chromatophores. The horizontal control of chromatophores relies on the spread and mechanical pulling exerted by the radial muscle fibers to activate one network of chromatophores to another, resulting in asynchronous expansion of chromatophores within the region exposed to an electrical or mechanical stimulus. The study aims to characterize the horizontal control component in the dual control system and develop a more comprehensive understanding of chromogenic behavior. To remove axonal input from the brain to the radial muscle fibers, the chromatophore sample dissected from the squid’s skin is treated with tetrodotoxin (TTX), which blocks voltage-gated sodium channels in nerve cell membranes. Consequently, the sample is treated with tetraethyl ammonium chloride (TEA) to enhance muscle fiber excitability, yielding better demonstrations of horizontal control among chromatophores. Video recordings of electrical or mechanical stimulus administered to the sample and the resulting chromatophore patterns go through a video-processing software to measure changes in chromatophore areas over time. Video analysis indicates that samples treated with TTX and TEA have longer latencies after the stimulus, than those only in seawater, and that the chromatophore networks appear to activate in random orders and directions.

Encapsulation of Hybrid Organic-inorganic Halide Perovskite Solar Cells to Maintain Performance in Damp-heat Conditions.
James Pullinger, SUPER

Silicon based solar cells have been the market standard since solar cells have been popularized and deployed. Increasing demand for silicon for these and other electronic devices has meant that prices of these cells are still prohibitive for widespread adoption. It is necessary to provide comparable solar cells at a lower cost. Hybrid organic-inorganic halide perovskite describes the composition of a new material that challenges the power conversion efficiency of silicon cells and could provide energy at half of the cost. Perovskites are limited by their instability, resulting in degradation and poor performance when exposed to heat, oxygen, or moisture. The best way to delay this degradation is to protect the devices from oxygen and moisture by encapsulating them with barriers including glass and polymers. This research project aimed to optimize the encapsulation conditions, including the temperature, time, and pressure that the devices were encapsulated for, as well as the polymer used. To determine the optimal encapsulation conditions, a range of JV (efficiency) tests were performed in a solar simulator, before, during, and after the encapsulation and accelerated aging. The results demonstrated the role that time under pressure plays in protecting the devices, with an optimum time of around 2 minutes, as well as the limitations on the polymer that can be used based on its thermal and mechanical properties. Dynamic mechanical analysis was used to observe the properties of different polymers both unaged and aged to determine the effect of aging on the polymer and how that would affect the quality of the encapsulation.

Observing Fluid Dynamics of Microplastics Upon Various Bed Material
Evelyn Pung, SESUR

Microplastic pollution originating from land and carried through rivers and streams can contribute as much as 0.8-2.7 million metric tons of plastic waste to marine ecosystems each year [Meijer, et al., 2021]. As we come to realize how microplastic pollution is rapidly affecting the natural processes of our ecosystems and wildlife, the urgency to better understand rivers as a vector for plastic transport grows. In this study, we simulated microplastic transport in riverine systems using a flume in the Bob and Norma Street Environmental and Fluid Mechanics Lab at Stanford University. The microplastics, consisting of approximately 2.5mm pre-production nylon pellets (known as nurdles), were randomly distributed across three types of bed materials installed in the flume floor: a sand bed, sandpaper floor, and flat acrylic floor. By using different types of floor materials, we were able to imitate the various ecosystems that microplastics will be traveling through. Qualitative results revealed characteristics related to sediment transport; for example, the behavior of microplastic transport was strikingly similar to historically observed barchan dunes found in deserts. These microplastics of lighter density and uniform size traveled along the bed for a short period until they clustered in crescent-shaped groups, which dispersed slowly as water flow increased. Acknowledging these findings enhance our overall understanding of microplastic transport in rivers, and therefore can help shape future interventions for aquatic ecosystems. Thus, observing the behavior of microplastic transport is an important aspect in creating sustainability solutions.

eDNA Data Analysis and Synthesis to Support Palau's Marine Sanctuary
Anika Quon, MUIR

In 2020, The Republic of Palau set aside 80% of its exclusive economic zone as a national marine sanctuary (NMS), closed to fishing, mining, and any other extractive activities. This established one of the largest marine protected areas in the world and represents one of the greatest efforts by an individual nation at marine protection. However, monitoring and management of such a large marine area proves difficult. This project aims to understand how environmental DNA (eDNA) can be used to monitor the biodiversity of the Palau NMS in an effective, quick, and cost efficient manner, and to understand how biodiversity composition shifts over time. The author generated a pipeline for intaking and visualizing large eDNA datasets in order to understand the connectivity of species between marine zones. Preliminary results showed that commercially-important species tended to be found more often in nearshore environments than offshore environments, and nearshore environments housed greater numbers of cosmopolitan species (species found in more than one zone across the NMS). The pipeline allows for streamlined analysis and communication in the future as well, as data continues to be collected for the project.

24/7 Carbon-Free Electric Fleets
Juan Bautista Romaniuk, SUPER

The Stanford Marguerite Shuttle, a fully electric fleet, currently relies on a combination of solar energy generated at the bus depot and grid electricity from natural gas when the former is not available. This project aims to align the shuttle system's electricity consumption with campus renewable energy resources, promoting sustainable practices and reducing reliance on carbon-intensive energy sources. To achieve this, an automated charging schedule was developed to maximize the use of available solar energy through dynamic charging periods. My research focused on 1) enhancing the post-processing of the output charging optimization model to ensure feasibility with real-life bus operations; 2) improving the model’s legibility for straightforward implementation; 3) maintaining a comprehensive database to track charger reliability; 4) liaison between the research team and Marguerite Shuttle operators. A script was created to condense scattered charging times into contiguous blocks, and adjust battery percentage displays, while simultaneously improving the visual output of the schedule to enhance its legibility. A modified schedule for operational feasibility is able to achieve weekly savings of $5,310.75 during January, while emissions only increase by 5.5% compared to a perfect optimized scenario. Additionally, an interactive database was developed to analyze charger reliability across all bus-charger combinations, uncovering key trends and patterns with respect to charging issues. Charger reliability remains a challenge, with only 32% of chargers and 34% of tested combinations achieving a reliability rate of 75% or higher, highlighting the need for comprehensive infrastructure upgrades.

Comparing Urban and Agricultural Water Security in Santiago Amidst an Uncertain, Changing Climate
Danny Sallis, MUIR

Droughts, characterized by prolonged periods of dry conditions, are among the most widespread and expensive natural disasters globally. Their impacts are far-reaching and can affect a wide range of economic sectors and water users. Climate change may exacerbate future droughts in many regions around the world, necessitating updated drought management plans to help to mitigate impacts. However, climate change uncertainty poses a challenge to designing drought management plans, as it is unclear exactly how droughts and their impacts may evolve over the century. This project focuses on a case study of the Maipo Basin in Central Chile, which is currently facing its fifteenth consecutive year of drought. This has led to the declaration of an agricultural state of emergency and unprecedented urban water use restrictions in Santiago. Drought management is overseen by the Chilean national government and is in the process of being updated. This project explores how urban and agricultural water users in the Maipo Basin may be impacted differently across alternative future climate change scenarios and drought management plans. We first develop a systems model of the Maipo Basin that explicitly models urban and agricultural water supply reliability. We next create alternative drought management plans that include either urban water use restrictions or water rights contracts between urban water utilities and agricultural users as response actions. We then simulate the performance of drought plans across fifteen different climate scenarios to examine how water supply reliability varies for urban and agricultural water users. Our preliminary findings suggest that urban water use restrictions can enhance urban water reliability with minimal effect on agricultural water supply reliability. This work seeks to help inform updates to Chile’s drought management strategies.

Surface flux equilibrium-derived ET across CONUS and its validation using triple collocation
Lillian Sanders, SESUR

Evapotranspiration (ET) is an essential component of the terrestrial hydrologic cycle, and significantly influences the carbon cycle. However, remote sensing measurements of ET typically require numerous assumptions and parameters, many of which are poorly known and heterogeneous across the land surface. This results in large errors. Here, we release a new dataset of daily ET at 4 km resolution across the continental US by leveraging the surface flux equilibrium theory and its approach to estimating ET. This data-driven approach makes only one assumption, that the Bowen ratio can be approximated for inland regions using only boundary layer temperature and humidity. We implement this using data from GridMET, which, when combined with net radiation from ERA5-Land, allows us to estimate ET without making assumptions on root-zone soil moisture, vegetation dynamics, or land surface properties. While surface flux equilibrium-derived ET has previously been tested at catchment scale, a gridded product has not been released nor statistically evaluated. Therefore, we use triple collocation to calculate the random error and bias of this ET dataset in comparison to ET products from GLEAM and FluxCom. We analyze how the error varies seasonally as well as spatially as a function of topography, proximity to the ocean, and climate to provide recommendations on the strengths and limitations of our surface flux equilibrium-derived ET.

Should Pillar Point Be Closed To Harvesting? Integrating Social And Ecological Perspectives
Eva Shen, MUIR

Pillar Point State Conservation Marine Area, a 6.5 mile haven for marine and intertidal species along the California coast, has long been an important area for recreational and subsistence harvesting. It is unique for being very accessible to the public, with rocky reef, kelp forest, and surfgrass habitats supporting more than 650 species. However, there have been increasing reports of Pillar Point’s ecosystem being in decline, with some groups calling for a complete closure of the area in order to protect the habitat. As harvesting regulations were created before a dramatic increase in visitors over the years, petitions are currently underway to designate Pillar Point as a no-take zone. Because no previous data regarding biodiversity and abundance had been analyzed for the area, meaning that neither the petition request, nor current management recommendations were based on available quantitative data, we hoped to synthesize citizen science, ecological fieldwork, and oral histories and narratives in order to highlight underrepresented local users’ perspectives and inform current policy-making. We approached different users either in person at the intertidal or by email. We also put up posters at the Half Moon Bay Library, the Pillar Point Harbor, Spangler’s Market, Princeton’s Landing, and Cafe Society with QR codes to the project website and Google Form, so that anyone could reach out and contact the team. We conducted 11 semi-structured questionnaires both in-person and over Zoom, and transcribed and analyzed the transcripts using Otter.ai and Nvivo. While questionnaires are still in progress, we found over the summer that many individuals referenced concerns about the overall health of Pillar Point’s intertidal and marine ecosystems, and expressed interest in tightening regulations and/or enforcement. We highlight a need for improved signage and better communication of existing regulations.

Prototyping Technology for Personal Health Aides
Eliza Siebers, SESUR

While developing new technology, creating prototypes is an important step that allows potential stakeholders to visualize and interact with the idea. These prototypes vary in fidelity and modality, and serve different purposes throughout the design process. Low fidelity prototypes can spark feedback on broad ideas and implications, while high fidelity prototypes allow potential users to picture the finished product and how it may fit into their life. Our prototyping project revolved around the Stanford HP+DS lab’s idea for an intelligent home sensing system to support the care of older adults aging in place and the work and upskilling of their PHAs (personal health aides). We decided to research the following questions: What physical, social, and professional components should be considered when designing an upskilling app for PHAs? What attributes of the interactive voice assistant (IVA) and ambient display are suitable for high fidelity versus low fidelity prototyping? Once developed, our prototypes will be used in a collective speculation workshop with PHAs to gain insight into what they feel are the ethical implications of such a system. To achieve these objectives, we conducted a literature review to extract empirical data, then performed an expert analysis to gather feedback on our initial prototypes. We learned that the aesthetics of the app and display screens, as well as which functions are available to which users, will affect how warmly they are received. These steps produced our final medium-fidelity prototypes, designed in Figma, a collaborative design tool.

The Impact of a California Water Efficiency Program (SWEEP) on Agricultural Water Use
Wyatt Sklarin, SESUR

Agricultural operations dominate water usage in California, and increasing drought and water stress have prompted government policies that attempt to reduce water consumption, such as the State Water Efficiency & Enhancement Program (SWEEP). This program provides grants to implement water-saving irrigation systems (CDFA, 2024). Despite SWEEP’s focus on water conservation, its overall impact on consumptive water use in California remains unclear. To assess SWEEP’s effect on water usage, we analyzed yearly evapotranspiration (ET) across fields; ET is a measure of water that will not be returned to the fields during the growing season, and therefore is lost for that year. Given the observational nature of the data, we employed two causal inference methods, matching and synthetic control, which are used in econometrics to analyze cause-and-effect relationships without a controlled experiment. The overall analysis indicates an increase in evapotranspiration in SWEEP-funded fields; however, this effect varies by intervention type. Fields adopting drip irrigation systems showed reduced evapotranspiration, while those who implemented smart irrigation systems or sensors exhibited an increase. These results suggest that the effectiveness of the SWEEP program is influenced by the technology being funded. Further research is needed to understand why certain technologies may increase evapotranspiration and how we can optimize both policy and technology for more effective water conservation and sustainable agriculture practices.

Sea-Slug Solar Power: Applying Insights From Kleptoplasty To Biophotovoltaics Technology
Haley Solis, SUPER

Global energy demand is projected to increase 32% by 2040, far outpacing renewable energy deployment. Due to the high resource costs and heavy metal consumption of some conventional technologies like photovoltaic solar cells, the pace of renewable energy development cannot keep up with that of energy consumption. New sustainable technologies must be considered, such as biophotovoltaics (BPV) which have the potential to diversify, stabilize, and accelerate the clean energy transition without exploiting rare earth metals and other finite resources. Current limiting factors for this technology relate to the efficiency and useful lifespan of BPV cells. Kleptoplasty may hold some insight as to how we can support photosynthetically active chloroplasts in an artificial BPV cell after isolating them from their host algae. This study aims to demonstrate the viability and increased efficiency of a BPV cell that uses isolated chloroplasts (instead of the more conventional entire algal cells) as photosynthetic drivers of electricity production. We construct bio-”bottle”-voltaic devices, one using intact algal cells to produce electric current and another using a novel biofilm constructed from isolated chloroplast suspension. Electrical power output will be measured from both devices to compare energy efficiency and organismal longevity. If an isolated suspension of chloroplasts demonstrates higher photoelectric efficiency than intact algal cells, prolonging the useful life of isolated chloroplasts becomes essential to BPV technology. Biochemical, behavioral, and physiological mechanisms contributing to sacoglossan kleptoplasty can provide inspiration and insight for future BPV engineering applications.

Testing The Tsunami Hypothesis For The Formation of Boulder Deposits Around Chryse Planitia, Mars, From Boulder Morphometrics
Euclid Soringa, SESUR

Extensive boulder fields in the northern lowlands of Mars, specifically along Tempe Terra, Chryse Planitia, and Arabia Terra, have been hypothesized to result from large tsunami events in an ancient ocean. However, several other processes that do not require the presence of an ocean (including impact cratering, glaciers, or megafloods) can generate boulder fields. Yet, these boulder deposits have been used to argue for the existence of a past ocean. To test the hypothesis that the boulder fields were deposited by a tsunami, we compiled a boulder morphometric dataset by manually mapping approximately six thousand individual boulders within the deposit. From boulder outlines, we calculate their size, shape, and orientation across large areas to identify and characterize any spatial trends. The spatial distribution of the detected boulders was then assessed using sediment transport mechanics to test the tsunami hypothesis quantitatively. Preliminary findings indicate a preferential northwest-southeast orientation of boulders in Arabia and Tempe Terrae. In contrast, boulders display variable orientations in Chryse Planitia, roughly following the strike of a putative paleoshoreline, consistent with deflection of a tsunami wave as it traveled through the Chryse Planitia embayment. Additionally, larger boulders are observed where the tsunami wave would have most directly impacted the shoreline in Tempe and Arabia Terrae, if the impact source was located hundreds to thousands of kilometers to the northeast. While our results so far are possibly consistent with a tsunami origin, we have not ruled out other possible formation mechanisms. Future steps include expanding the dataset across the entire deposit through automated boulder detection using machine learning. Such a more expansive and continuous dataset across the study area will be required to unravel the origin of these boulder fields, offering new insights into Mars’ geological history and the potential presence of ancient oceans.

Aligning Carbon Dioxide Removal Policy with Climate Justice: Understanding Stakeholder Perceptions of Climate Technologies across Countries
Sinmiloluwa Sowande, MUIR

We are conducting a study on policies and legislation for large-scale carbon dioxide removal (CDR) technology, in the Global South. In doing so, we seek to explore the research question: what are the social, political, and economic enablers or catalysts for communities to engage in CDR projects, especially in service of local "just transitions"? Specifically, our project involves planning and facilitating virtual focus groups with Climate stakeholders in countries around the world, gaining knowledge on local experiences, strategies, and barriers. Our research will produce the first cross-country regional analysis of CDR opportunities to meaningfully involve country-level stakeholders in implementing CDR policy. We hope to provide insights into community-based policy development for effective, equitable clean infrastructure deployment to guide project development.

Screening Bacteriophages And Polymers For Sustainable, Natural, And Effective Sunscreen Formulations
Tyler Tam, SUPER

Large amounts of UV radiation severely damage the stratum corneum (SC), the outermost layer of human skin. Current sunscreens, our primary safeguard, contain harmful chemicals, such as oxybenzone, that can harm the environment, particularly coral reef ecosystems. The potential for climate change to exacerbate the damage has highlighted the need for sustainable, natural, and effective sunscreens. In this study, we explore, separately, the impact of UV-inhibiting bacteriophages and sustainable polymers in moisturizing formulations on the biomechanical properties of the SC. Pieces of stratum corneum (SC) were adhered onto a reflective glass substrate. As the SC dries, substrate curvature is related to SC stress by Stoney’s equation. Stresses were measured before and after application of a treatment. The change in stress can be correlated with how effective the treatment protects and influences the SC’s biomechanical properties. Our study shows that bacteriophages diminish the stress increase that develops as a result of the damage to the underlying SC structure that UV exposure causes. Additionally, polymers in moisturizing formulations increase emollient penetration by stabilizing the formulation and preventing phase separation of oil and water. Understanding the effects of bacteriophages as UV inhibitors and the mechanisms of polymers in moisturizing formulations will allow for rapid engineering of a complete and novel sunscreen formulation that is sustainable, natural, and effective.

Machine Learning Cloud Microphysics
Gabriel Tsai, SESUR

State-of-the-art global climate models (GCMs) continue to inaccurately predict rainfall (Jing et al 2017), overestimating drizzle precipitation while underestimating heavy precipitation. These inaccuracies are largely caused by mischaracterizations of cloud microphysics, particularly autoconversion, the rate at which cloud droplets collide and coalesce into larger rain droplets. Properly parameterizing autoconversion is essential for accurately predicting rain formation but the process is difficult to model - cloud droplet sizes come in irregular and non-uniform distributions. Chiu et al (2020) have shown that carefully configured neural networks predict autoconversion rates with greater accuracy than standard rain parameterizations. They were able to more precisely capture the non-linear patterns of direct cloud observations because well-trained deep neural networks inherently learn complex non-linearities in data unlike typical autoaccretion and autoconversion prediction models. In this project, we aim to build off of and improve Chiu et al’s work. We explore a wide range of machine learning architectures to identify the best model for autoconversion prediction and determine the most meaningful, physics-based input parameters. The result is a lightweight and efficient deep neural network that operates within the computational constraints of and can be easily integrated with GCMs. Our model predicts autoconversion in multiple regions across the globe with much greater accuracy than GCMs.

Biophysical Implications of Lipid Modification via MD simulations
Minh Tu, SESUR

Glycerol dialkyl glycerol tetraether lipids (GDGTs) are archaeal membrane lipids widely found in the environment. Over the past few decades, GDGT molecules and the specific degree of cyclization (ring formation) have been linked to sea surface temperatures, functioning as proxies for past temperature reconstruction. A higher degree of GDGT cyclization is associated with higher temperatures, suggesting that ring formation in GDGT molecules likely leads to increased rigidity in the membrane at higher temperatures. However, the exact biophysical understanding of how ring formation (known as GDGT0-8) in GDGT molecules contributes to membrane dynamics remains unclear. To better understand this, we ran molecular dynamics simulations of 8x8 membranes consisting of GDGT0-8 each, as well as a mixed membrane approach, which to our knowledge, has not been previously explored in the literature. Our results will indicate to us how different structural properties in archaeal GDGT membranes such as order parameter, membrane density, radial distribution, hydrogen bonding are influenced by ring formation.

Salinity Dependent Variations in Ephydra Morphology
Andrew Wang, MUIR

Phenotypic variation is a commonly observed phenomenon among organisms as an adaptation or product of exposure to stressful environmental conditions. However, the specific response of the Ephydra genus and its various life stages is poorly understood. It has been observed that one potential adaptation of Ephydra is an elongation of the respiratory structures of pupal-stage organisms in response to increased salinity. This study aims to quantify the relationship between salinity and spiracle length while developing a systemic method of measuring Ephydra pupae. Pupal specimens along with salinity measurements were taken from salt ponds around the Bay area. From these specimens, we identified 3 major sets of landmarks (2nd anterior leg, base of the respiratory structure, and spiracle tip) that were either consistently free of damage or provided measurement data even in the case of deformation. Utilizing the 2nd anterior leg as a landmark, measurements of the body and respiratory structures were taken from a profile view and combined into a ratio. This metric compares the spiracle relative to body size, which limits the impact of variations in overall specimen size. These measurements will hopefully provide insight into the adaptation behavior of an extremophile species in haline conditions, which may vary in the face of anthropogenic influences.

Numerical Simulations of Carbon Scrubbing Salt Fountains
Jaime Yu, SESUR

The development of strategies for easily scalable ocean-based carbon dioxide removal (mCDR) strategies has become a recent focus in our global effort towards minimizing global warming. Our proposed strategy involves the use of salt fountains, a simple structure that facilitates the perpetual upwelling of nutrient-rich deeper waters into the shallow mixed layer, thus fertilizing the surface layer and increasing photosynthetic activity and carbon drawdown. A key benefit of salt fountains as opposed to alternative mCDR strategies is that they are energy neutral as their kinetic energy is derived entirely from natural oceanic salinity variations that are prevalent throughout the subtropics and other regions. However, to prevent the outgassing of CO2 from the carbon-rich deeper waters, the salt fountain must incorporate some carbon-scrubbing material. In order to perform a detailed system design and determine the efficacy, scale and cost of this strategy, it is necessary to have a numerical model of the salt fountain system that can incorporate the fluid physics, chemistry, and eventually biogeochemistry. We developed a model of the fluid physics in Oceananigans, a software package generally used for small-to-large scale ocean modeling. By using Oceananigans, this model provides a foundation upon which chemistry and/or biogeochemistry can be implemented through either offline processing or packages like OceanBioME, thus providing a tool for further research and analysis on whether salt fountains are a viable method of mCDR.