Stanford University
Students on hike

Stanford Earth Summer Undergraduate Research

Photo by Kate Maher

2013 Projects

Nicole Ardoin and Amanda Cravens- SESUR  

The Role of Decision Support Software in Resolving Contentious Environmental Issues

When developing plans for managing public lands and waters such as California’s coastline and the state-managed ocean that extends out to 3 nautical miles from shore, resource managers encounter stakeholders with a wide variety of perspectives. Mapping and visualization software are a promising new tool for helping bridge these diverging views to make management decisions, but as yet we do not fully understand the cognitive mechanisms by which these software help users do their work. This overall project is focused on one specific case of such tool use, exploring how decision support software influenced decision-making during a 7-year-long policy process that determined where to locate new marine protected areas along California’s coast. The goal of this summer project is to determine to what extent computer experience and access affects if people used the software tool. Despite anecdotal evidence suggesting that technological literacy is important, an initial online survey showed little difference between users and non-users on measures of technological literacy. In order to determine whether computer access actually matters or not, the student will administer a parallel mail survey. Comparing the results from the two surveys should allow us to determine whether the results from the first survey are accurate or an artifact resulting from how the survey was administered (using the internet). Useful skills include previous background in statistics (SPSS would be especially helpful), previous work with surveys, and most importantly, an interest in thinking about research methodology.

Adam Brandt- SESUR  

Greenhouse Gas Reduction Potential from Natural Gas Flaring

Oil production facilities in remote locations often flare produced natural gas instead of selling the gas.  This gas flaring results in about 1% of global greenhouse gas emissions, or 300 million tonnes of CO2 per year. Flaring occurs when it is uneconomic to attempt to sell the produced gas (as is sometimes the case in offshore oil, or in locations far from gas pipelines).  This project will investigate the case of Nigeria, a major gas flaring region, to examine the potential for flaring emissions reductions.  This project will involve data gathering and analysis using our Stanford-developed emissions model called OPGEE (the Oil Production Greenhouse Gas Emissions Estimator).

Adam Brandt- SESUR  

Understanding the Role of Oil Depletion in Increasing Greenhouse Emissions

As oil fields age, it becomes more and more challenging to produce the oil from them.  This depletion effect not only affects the economics of producing oil, but also affects the environmental impacts from oil production.  This environmental impact of depletion is very poorly understood.  We will to gather historical data from regions around the world to understand the following things: a) as oil runs out in different regions, how do production characteristics change? b) as production changes, how does this affect the associated greenhouse gas emissions from producing the oil?  This project will involve data gathering and analysis using our Stanford-developed emissions model called OPGEE (the Oil Production Greenhouse Gas Emissions Estimator).

Gretchen Daily and Gregory Bratman- SESUR 

The Influence of Natural Environments on Human Cognitive Processes and Emotion 

After being present within natural environments, many individuals report feelings of “cognitive recharge”, decreased negative emotions, and increased positive emotions.  Several previous studies have used tools from psychology to measure the impact on human cognitive abilities and emotional capacities that may result from experience in nature.  But a great deal of research is still needed to further isolate and define these effects, and to answer the fundamental question: Do humans benefit in a measurable way from contact with nature?  And if so, why, and in what ways?  This study will employ a thorough and robust interdisciplinary experimental design, using tools and approaches from ecology and psychology, to consistently address the impacts that nature experience may provide for individuals’ cognitive components and emotion regulation.  Students will be learning how to administer – and collaborate on the development of – confidential tests that measure memory, attention, impulse inhibition, and mood in subjects. 

Rob Dunbar and David Koweek- SESUR 

Coral Reefs and Climate Change: Impacts of Rising Temperature and CO2 levels

The project involves studying coral reef ecosystem response to global climate change, particularly to ocean acidification. One undergraduate intern will become involved in a combination of modeling and lab studies designed to enhance our understanding of coral reef biogeochemistry at several field sites in the Pacific. Most work will take place on campus, but an opportunity may exist for travel to one of these field sites as part of research team recovering, servicing, and redeploying an array of physical oceanographic instrumentation. The intern will be mentored both by the faculty member and a graduate student. Quantitative experience (esp. MATLAB) is preferred.

Eric Dunham and Kenneth Duru- SESUR 

Computational tools for accurate simulations of seismic wave propagation and dynamic earthquake rupture models

There is a quest to accurately solve the elastic wave equation in realistic earth models. Examples are numerical simulations of elastic wave equations to explore natural minerals from the subsurface, to detect cracks and faults in solid structures, and to predict or investigate strong ground motions such as earthquakes.  In an ongoing project we are developing reliable numerical methods and computational tools to simulate the elastic wave equation for realistic, earth, fault and frictional law models. In our group we have several competencies, including mathematical modeling, numerical analysis, high performance computing and parallel programming.

We are looking for an enthusiastic undergraduate student who will work on a summer project within our group. The particular details of the project will depend on the student's interest and background. For a student with a computer science or programming interests the project can involve developing parallel visualization tools, parallel implementation of nite dierence or nite volume algorithms. While a student with numerical analysis interests can work on developing automatic error control schemes, accuracy evaluation for nite volume schemes. There are also applied mathematics projects involving deriving solutions for integro-dierential equations resulting from the perfectly matched layer in stratied elastic (and acoustic) media. The primary supervisor of this project is Kenneth Duru. We encourage interested students to contact Kenneth Duru (Email: kduru@stanford.edu) directly in order to schedule an initial meeting.

Scott Fendorf and Annika Alexander-Ozinskas- SESUR or SURGE

The Chromium Project

Millions of people in California face elevated lifetime exposure to Chromium(VI), a known carcinogen, via drinking water from Californian aquifers. This project explores correlations between irrigation practices in California and Cr(VI) formation in order to call attention to the issue, inform water management decisions, and protect the public from Cr(VI) exposure. Students involved may work on any of the following: data acquisition, geospatial statistical data analysis, map making, results publication, and journalism to communicate the topic more broadly. The project may involve affected communities and stakeholders in future participatory research, depending on student interest and initiative. We aim to complete the first paper by June 2012, with ongoing research after June. We encourage students to apply who have experience or interest in the following areas: GIS, statistical analysis, groundwater contamination, public health risks, science communication, and participatory research.

Scott Fendorf- SURGE

Projecting Groundwater Arsenic Contamination in Cambodia

Spatial variability of arsenic concentrations in Cambodian aquifers hinders the development of a comprehensive policy to limit consumption of contaminated ground water. Resource Development International (RDI) is an NGO in Cambodia that has systematically tested wells throughout Cambodia to develop an index for drinking water quality with a focus on arsenic, manganese, fluoride, and nitrate concentrations. In the last year, we have been working with a local well driller to document where new wells are being installed and to log sediment profiles for each new well.  We propose a project for an undergraduate researcher to investigate whether links exist between sediment characteristics (depth profiles) and the spatial distribution of groundwater contaminants. Skills in GIS or other spatial analysis programs would be helpful. The end goal of this project is to advance our ability to predict groundwater hazard based on sediment distribution.

Scott Fendorf, Eric Lambin, Samantha Ying - SURGE

Impact of fly ash on agricultural yield in China

Poor air quality from coal combustion in China is a nation wide problem that is adversely affecting human health via many routes. One of the routes that we are interested in investigating is the effect and geography of coal combustion-derived particulates on crop production in China.  These particulates, often containing very high concentrations of toxic heavy metals, may deposit onto croplands and gradually release heavy metals into the soil aqueous phase, which can be taken up and accumulated in plant tissue during the growing season.  Unlike contaminated water and polluted air, which impact local populations the greatest, these crops can be harvested and distributed throughout the country, affecting both local and far reaching areas. However, aside from coal combustion by-products, other anthropogenic and natural sources of metals also contribute to the metal concentrations in soils. We propose a project for an undergraduate summer intern to determine the contribution of different sources of heavy metals in soil samples collected from farmlands near a power plant in Wuhan, China. The researcher will use a combination of laboratory and computer modeling techniques to accomplish this task. The undergraduate researcher will have the opportunity to acquire skills in the laboratory performing isotopic analysis followed by spatial analysis using GIS. Chemistry or related laboratory skills highly recommended.

Chris Field and Charlotte Stanton- SURGE

Identifying Cost-Effective Policies for Conservation and Development: Conditional Cash Transfers for Environmental Services in Uganda

Solving the partially related problems of poverty, social inequity, loss of biodiversity, and climate change is perhaps the most pressing contest of our time. Winning it requires an interdisciplinary approach that incorporates the most advanced knowledge and methods from land-change science, applied ecology, experimental economics, and policy analysis, among others. Blending recent innovations in these fields, our research investigates the formulation of a policy that encourages environmental sustainability coupled with economic development; Specifically, a subsidy that pays people for conserving trees in Uganda.

Description of research position: The summer research associate will support several aspects of this research. S/he will assist in the preparation for and preliminary analysis of household survey data (which was collected in Uganda in June 2011), including the generation of descriptive statistics. In parallel, the associate will conduct an annotated review of recent literature in conservation science, land-change science, development economics, and behavioral economics, identifying substantive and methodological findings, current thinking, knowledge gaps, and the presence of puzzling anomalies.

Skills required: Interested applicants should have an interdisciplinary background in environmental studies, spanning the social and natural sciences. A basic level of statistics training and a willingness to learn new statistical and geographic research analysis tools is required, as well as excellent writing and communication skills. Familiarity with conservation and development issues as they pertain to Uganda a huge plus. 

Chris Field and Kelly McManus- SESUR

Investigating the spatial dynamics of plant defense among tropical canopy trees on Barro Colorado Island, Panama 

Plant-herbivore interactions play an important, but poorly understood, role in creating and maintaining biodiversity in tropical forests.  Mortality of juvenile trees is often greatest near conspecific adults which harbor large populations of host-specific herbivores, but there is inconclusive evidence of the influence of biotic interactions on community diversity. Plant defensive traits may provide evidence for the role of plant-herbivore interactions in structuring tropical plant communities. This study investigates the spatial dynamics of physical, chemical, and tactical defenses within and between three populations of canopy trees on Barro Colorado Island (BCI), Panama.  We seek two highly motivated undergraduate students to assist with the collection and processing of canopy foliage to measure plant defenses during the summer of 2013 (training provided).  Training and laboratory work will be based at the Department of Global Ecology at the Carnegie Institution for Science on Stanford’s campus. Collection and field work will be based at the Smithsonian Tropical Research Institute (STRI) facilities on BCI.  Chemical laboratory experience is preferred, and candidates must be amenable to very strenuous fieldwork in a tropical environment.

Chris Field- SESUR or SURGE

Restoring Ecosystem Services in an Era of Global Change

The Jasper Ridge Global Change Experiment is a long-running study that uses temperature, carbon dioxide, and precipitation manipulations to understand the ways that California grasslands respond to a changing climate.  In the summer of 2010, manipulated and unmanipulated grasslands were subjected to controlled wildfire.  In the summer of 2013, two years after the fires, we will be looking at the consequences of the wildfires and the climate change for the survival of the restoration target – native perennial grasses, and the invasive we hope to control, yellow star thistle.  There will be opportunities in the summer of 2013 for one student to focus on the grasses and one to focus on the start thistle.  The work will be primarily located at Jasper Ridge, Stanford’s biological field station on the western edge of the campus.

Chris Field and Rebecca Hernandez- SESUR or SURGE

Solar Energy in California: Ecological Impacts and Land Use and Land Cover Changes (LULCCs)

California is a model system for assessing solar energy technical potential and associated LULCCs due to its unique constraints on land availability, immense energy demand, and vulnerability to climate change. California includes, in part, the Mojave, Sonoran, and Great Basin Deserts, areas notable for high solar resources and ecosystem services. Currently, California has over 150 utility-scale solar energy projects, either in operation or planned, and on both private and public lands. These characteristics render the understanding of utility-scale solar energy in the context of LULCCs in California instructive for other global regions that share similar resource demands and limitations. We seek an undergraduate with GIS and ArcGIS experience to assist in this exciting project. Students will be based at the Department of Global Ecology at the Carnegie Institution for Science on Stanford’s campus.

Chris Field and Rebecca Hernandez- SESUR or SURGE

What Will Happen Belowground? The Impact of Climate Change on Mycorrhizal Fungi

Arbuscular mycorrhizal (AM) fungi are the most abundant plant symbionts, forming an intimate relationship with plant roots in over 90% of all terrestrial plant families. AM fungi are highways of carbon (C) inputs into the soil, which they receive directly from plant roots (i.e., up to 20% of total assimilated C). But determining C inputs requires a careful measure of production and turnover, which is determined by accurate measurement of continuous growth and mortality dynamics over various spatiotemporal scales. Advances in soil imaging automation, environmental sensor technology, and digital image processing, together, have conferred the opportunity to observe extra-radical AM fungal hyphae directly, at unprecedented temporal scales, and in concert with measurements of variables that characterize the mycelium environment. The primary goal of this study is to quantify seasonal and annual standing crops of AM fungal hyphae dynamics in US aridlands.  By better understanding these relationships we can subsequently model how changes in climate might alter AM fungal hyphae regimes, and how this may impact carbon sequestration and host plant success. This project seeks an undergraduate to assist with novel machine learning-based image analyses (training provided) and/or the processing and analysis of soils in a lab environment (previous experience a plus but not required). The student may have the opportunity to conduct field work in the Mojave Desert in collaboration with the University of California at Riverside. Students will be based at the Department of Global Ecology at the Carnegie Institution for Science on Stanford’s campus. 

Chris Field- SESUR or SURGE

Working Group II of the IPCC

The Intergovernmental Panel on Climate Change (IPCC) is tasked by the world’s governments with providing definitive assessments of the state of knowledge about climate change science.  Working Group II of the IPCC is based at Carnegie.  During the summer of 2013, there will be opportunities for two undergraduates to work on science support for the 2014 assessment.  One student project will involve working with authors to fine tune a series of frequently asked questions.  The other will focus on assuring the scientific integrity of graphs and tables.  The work will be based at the Department of Global Ecology of the Carnegie Institution for Science. 

Chris Francis and Jessica Lee- SESUR or SURGE

Microbially-mediated nitrogen cycling in San Francisco Bay

The San Francisco Bay-Estuary is an amazing place to study microbially-driven nutrient cycles, right in our own backyard. Our lab runs multiple projects aimed at understanding how nitrogen works in the different parts of San Francisco Bay—from the freshwater Delta to the salty South Bay—and the bacteria and archaea that transform that nitrogen. We would love to have help processing our monthly samples, and we’ll give you the opportunity to learn a wide variety of techniques that are standard to molecular biology and environmental science: PCR; molecular cloning; DNA sequencing and sequence analysis; growing bacteria in culture; chemical analyses of both sediment and water samples; and rate measurements of microbially-mediated processes such as denitrification and ammonia oxidation. There may even be an opportunity for field sampling on the Bay. Prior biology lab experience is helpful but not required; absolutely necessary is an enthusiasm for DNA, microbes, environmental chemistry, or all three.

Steve Gorelick and Laura Erban- SESUR or SURGE

Exploring Drivers of Groundwater Use in Mekong Delta, Vietnam

In the Mekong Delta, Vietnam, groundwater exploitation has risen dramatically over the past several decades, influencing the distribution of naturally-occurring arsenic contamination in unknown ways.   We aim to quantify the influence of groundwater extraction on arsenic contamination throughout the aquifer system.   We further seek to understand the socio-economic drivers of groundwater exploitation in order to forecast potential future contamination outcomes in the Delta.  The student will conduct literature-based research into the history of groundwater resources management in the Delta and relate findings to our existing spatial databases of physical landscape, socio-economic and water use variables.   According to the student’s interests, skills in programming (Matlab, Python or R), remote sensing, and GIS may be acquired.  Ability to read and write in Vietnamese is required. 

Steve Gorelick and Julie Padowski- SESUR or SURGE

Water Scarcity Issues in Cities

By 2050, 70% of the global population will be residing in urban areas.  Rapid urbanization is expected to create large localized demands for water, and therefore the sustainable management of water for human and environmental purposes will be one of the major challenges of the next century.  Much of the current information on global water scarcity is focused on water availability and does not specifically account for urban interactions with the hydrologic system.  This project will address urban water vulnerability by characterizing urban-hydrologic system dynamics in terms of how cities are using water, which factors contribute to urban vulnerability, and how systems adapt to water scarcity.  The student working on this project would be responsible for 1) updating a geospatial database of urban water quantity and quality information using ArcGIS (no previous experience necessary), and 2) estimating hydrologic vulnerability in urban areas using water budget analyses.

Jerry Harris and Shela Aboud- SURGE 

Computational Quantum Chemistry for Environmental Applications

Computational approaches based on quantum chemistry such as density functional theory (DFT) provide detailed information about the physical structure, electronic properties, and vibrational characteristics of rocks and minerals, both manmade and in the natural environment.  These tools can also be used to examine how potentially harmful atoms or molecules will adsorb or dissociate on the surface of these materials, which can provide important information for a variety of environmental applications.  The following is a list of several topics available:

Natural sequestration processes of actinides (such as Uranium) in the soil.
Catalytic decomposition of Nitrous Oxide (a greenhouse gas with 310 times the global warming potential as Carbon Dioxide).
Nitrogen and/or Sulfur interactions with mineral dust in the atmosphere.

George Hilley and Anne Sanquini - SESUR or SURGE

Earthquake Hazards: Reducing Vulnerability in Kathmandu

Building collapse following an earthquake can cause significant human and economic loss. For example in Haiti, nearly 250,000 fatalities resulted from the 7.0 earthquake of 2010. This is avoidable. Earth scientists can identify where earthquakes are likely to occur and engineers can design and build structures that resist ground shaking. Sociologists understand how people perceive risk, and marketing and communications experts can create programs that motivate people to take action. Kathmandu has a history of large earthquakes and, similar to Haiti, a building inventory that increasingly consists of non-engineered, unreinforced masonry. As is common in developing countries, building codes are not enforced and the skill to implement earthquake-safe construction is lacking. Our research brings together cross-discipline expertise to develop and implement an integrated communications program targeted at the affected population with the goal to create measurable demand for earthquake-safe schools in Kathmandu. Pre and post testing will produce a cost-benefit measurement of our methodology. During the summer, we plan to map actionable risk findings to messages required in our program, evaluate media analysis per the demographics of the affected population, and design pre-program attitude and belief testing. The supervisor of this project is Anne Sanquini. The student interested in this work should be comfortable with statistical analysis. Familiarity with the culture of Nepal or neighboring countries, GIS skills and Matlab skills may also be helpful, but are not required. 

George Hilley and Gus Seixas- SESUR 

Landscape Evolution and Active Tectonics in the Zagros Mountains, Iran

Can we use easily-observable patterns in topography to understand, and perhaps predict, geologic hazards? This project in the Tectonic Geomorphology Laboratory will examine this question by investigating the relationship between uplifting folded rock and rivers that either incise or are displaced around growing geologic structures. Our thesis is that rivers that traverse active structures will be progressively deflected around the tips of associated uplifts due to the strain gradient across the deforming region. In contrast, geologically inactive structures should not exhibit progressive diversion but should instead localize incision in entrenched bedrock channels. If this is true, it suggests that the incision and diversion history of some rivers may allow quantities associated with geologic hazards, such as surface displacement rates, to be imaged using widely available topographic datasets. Thus, information gathered from such a method will increase core scientific knowledge of landscape and tectonic processes, and has the potential to aid those trying to discern between active vs. inactive geologic structures. Such characterization would provide information regarding the activity of faults that is often too difficult, or too costly, to gather by other means.

This summer we will focus on the Zagros range, a geologically active fold and thrust mountain belt in southwestern Iran that demonstrates remarkable patterns in the relationship between large rivers and growing folds. The student may expect to learn GIS skills, topographic data processing, the basics of tectonic geomorphology and perhaps coding in Matlab. Applicants should possess interest in learning mathematical description of earth processes and some basic geology. 

George Hilley and Sam Johnstone- SESUR 

Quantifying the Transient Response of Landscapes to Valley Alluviation 

Broadly generalized, landscapes are the product of the influx of rock by tectonic processes and erosion by processes acting at the surface. Much work has been done to understand the conditions by which these two competing effects are in equilibrium. However, to appreciate the consequences of surface processes on the geologic record and to utilize landscape morphologies as a means of detecting recent changes (for example in local climate or tectonics) it is critical to also understand the processes by which landscapes grow to and decay from equilibrium conditions.  We propose that changes to equilibrium landscape conditions that lead to rivers becoming choked with sediment can drive the widening of river valleys through lateral migration of channels. We seek a student to help quantify the response of a landscape in the California Coast Ranges to one of these situations.

This work will involve 1) the use of high-resolution topographic data and aerial photography and 2) the integration of existing data to interpret, document, and quantify diagnostic features of disequilibrium topography. Through direct experience and discussions students will become familiar with common principles and active research in geomorphology, techniques for geospatial analysis of landscapes, and general techniques and strategies for data analysis. Students should be comfortable learning new software or have some experience with ArcGIS and Matlab or Microsoft Excel. This project includes the possibility of complementing observations made in elevation data and imagery with field observations from a site in the California Coast Ranges.  

Simon Klemperer - SESUR

Electromagnetic monitoring of earthquake precursors

Scientists expect that a major earthquake is likely to strike San Francisco Bay Area between 2008 and 2032, and we want to detect signals from it, ideally before it occurs! The student will be involved in any or all phases of the project, from maintaining the field equipment around the Bay Area, through computer-baseddata validation and analysis, and eventual scientific publication (AGU poster). The student should know something about Fourier signal analysis, and have some familiarity with Matlab and willingness to develop further knowledge. Also will not be averse to digging holes in the ground, soldering and plumbing, to maintain and develop our field stations. Driving license desirable.

Simon Klemperer - SESUR 

Geochemistry of Hot Springs to Study Geothermics, Carbon-cycle, and Tectonics of Continental Collision

Hot springs are surface manifestations of deep-seated groundwater flows that can carry chemical and isotopic species from great depths, allowing us to fingerprint their sources. Continental collision between India and Asia built Tibet, Earth's highest plateau, but fundamental questions remain about the 3D geometry of the interacting plates, and about metamorphic reactions within the orogenic zone. We are using 3He to distinguish cratonic Indian mantle from tectonically active Tibetan mantle. We will use carbon isotopes to distinguish mantle, subducted sedimentary, and organic sources of CO2. We are measuring CO2 fluxes to constrain orogenic degassing as a component of the carbon cycle: estimates from the Himalaya suggest the CO2 emissions range from 0.01% of the global carbon budget (irrelevant) to 10% (a major component), but no-one has yet measured the CO2 emissions of springs in northern or western Tibet. Because many of the hot-springs we plan to sample have not been methodically studied, we plan also t o analyze major cation/anions to estimate geothermal reservoir temperatures to improve assessment of resource potential in western Tibet.At Stanford the student researcher will carry out major-element analyses using ICP-OES spectrometry and determine ionic species using ion chromatography and interpret these results in terms of geothermal reservoir temperatures. There is also potential to be involved in isotopic analyses at Lawrence Berkeley National Labs. The opportunity to participate in the one-month sampling trip to western Tibet in early summer 2013 would require physical fitness commensurate with strenuous fieldwork at high altitude, as well as a commitment to ongoing participation in the project in the following academic year (e.g. senior thesis or co-term research), ideally leading to peer-reviewed publication.

Simon Klemperer, Greg Beroza, Shahar Barak - SESUR

Temporal and spatial evolution of the Aug.-Sept. 2012 Brawley Earthquake Swarm from near-field broadband seismographs

The Salton Trough is an active tectonic rift (where the earth’s crust is pulling apart to form a new ocean basin) in southern California at the southern terminus of the San Andreas strike-slip fault. It is an area of recent magmatism, and current geothermal energy production.   Stanford's IRIS-PASSCAL passive seismology deployment of the Salton Sea Imaging Project (https://pangea.stanford.edu/researchgroups/crustal/research/broadband-s… ) was active during the Brawley seismic swarm.  The Southern California permanent network located over 600 events, but their closest stations are >15km distant from the epicenters of these earthquakes that are mostly at 5 to 8 km depth.  Of our 25 temporary stations active during the swarm, we have 8 broadband stations closer than the closest network station, including one within 5 km of the swarm.  The student will detect and associate the earthquakes, and carry-out double-difference locations, to be able to show the spatio-temporal evolution of seismicity within the Brawley fault zone.  The availability of nearby stations will be particularly helpful in constraining the depth, and depth evolution, of seismicity.  This may allow us to differentiate among possible driving mechanisms for the swarm and alternative models of earthquake triggering.

Rosemary Knight, Tara Moran, and Andrew Parsekian- SESUR or SURGE

Using Emerging Technologies to Address Groundwater Management Questions in California

Groundwater provides approximately 30% of California’s water supply in average years.  This percentage increases to more than 80% of the water supply in some areas of the state during dry conditions.  Despite the State’s dependence on groundwater, very little quantitative information is known about the resource.  This project provides groundwater managers and consultants throughout California with access to new and emerging geophysical technologies being developed at Stanford University, in order to better understand and manage groundwater resources throughout the state.  Demonstrations of emerging technologies will be used to demonstrate the value of these technologies to address groundwater management questions in water management districts throughout California.  Students will help with fieldwork for at least one technology demonstration during a weeklong field campaign.  Once the data is collected, they will be responsible for organizing a community outreach event to share information on the value of geophysical technologies for groundwater management with the public and other groundwater management districts.  Students will also help with grant writing, the development of a value assessment for each technology and website design.

Anthony Kovscek and Christophe Duchateau- SESUR or SURGE

Immiscible Displacements in Porous Media

Even though multiphase flow in porous media has huge implications (oil and gas production, carbon geological sequestration…), and has been studied over the last few decades, multiphase flow in porous media is still very far from being completely understood. By performing an experimental study over a wide range of flow conditions in artificial porous media, you will help us to obtain more data on which newly developed theories rely, and thus improve the description of multiphase flow.

More precisely you will use several experimental apparatuses (i.e.: viscometer, interfacial tensiometer, syringe pump, microfluidic devices, digital microscope), first to characterize the fluids used, second to visualize the pattern along which one fluid is displaced by the other in a microfluidic device called a micromodel. After that, an image analysis will allow you to extract several descriptive parameters of particular interest for future modeling.

Eric Lambin and Ximena Rueda - SESUR

Enhancing Smallholder’s Livelihoods Through High Quality Cacao Varieties

Objective
Cacao is one of the most widely traded commodities around the world, produced by millions of smallholders in the tropics. Most of the value is added in consuming countries, leaving many farmers in poverty. In recent years, cacao has experienced a process of market differentiation since chocolate makers and consumers are appreciating traditional cacao varieties for their fine taste. Differentiation is creating two alternative value chains: i) the bean-to-bar model; and ii) the differentiated-within-mainstream model. These two new business models offer an opportunity to engage farmers in shared-value chains that could potentially lift them out of poverty, while at the same time promoting the conservation of cacao’s biological diversity. This study aims at evaluating the effectiveness of the three models—mainstream, bean-to-bar, and differentiated-within-mainstream—in improving farmers’ livelihoods and protecting cacao’s diversity. It also seeks to offer a set of recommendations to these new business models, based on our expertise on certification and other market-based mechanisms, to deliver the value promise of the triple bottom line: people, planet, profit.

Type of Work and Skills
Students will work at the Land Change Science group, they will conduct field work interviewing farmers and key actors in the cacao value chains in one or two locations: Tabasco, Mexico (where cacao was domesticated for consumption in pre-Columbian times) and Guayas, Ecuador  (center of origin of the Nacional landrace, Ecuador’s distinctive high quality cacao). Our purpose is to assess the potential of these new models to improve farmers’ wellbeing and alleviate poverty. We seek to understand the organization of the mainstream and high-quality value chains, the benefits farmers receive from participating in these different chains, and the socio-economic and environmental benefits of such engagement.  A sample of farmers will be selected and surveyed. The survey will contain a socio-economic component and an assessment of the diversity of local landraces in the crop. The survey will capture specific location of farms to further link socio-economic and bio-physical characteristics of the farms, setting up a platform for all actors in the value chains to connect and share information and practices and to facilitate traceability and scaling up.

Students must be fluent in Spanish. They must also have some basic knowledge of multivariate statistics. GIS skills and experience working with rural communities are a plus.

Jesse Lawrence- SESUR or SURGE

Ambient Noise Imaging of Geysers

It is possible to convert ambient seismic noise (vibrations from ocean waves, mine blasts, wind, micro-earthquakes) into useful signal. We can then convert this signal into useful travel-time measurements for mapping out the speed that seismic waves travel through the Earth. In this project we aim to process a large amount of seismic data to generate an image of subsurface wave speeds. In particular we want to understand how the subsurface changes beneath a set of geysers in the El Tatio Geyser Field (in Chile). El Tatio is the world's third largest geyser field. There are several goals: A) we want to determine if there is a shallow heat source (such as a magma pocket); B) We would like to gain a better picture of the plumbing (or conduit) that allows geysers to frequently erupt; C) We want to create a robust seismic velocity model that will help with investigations of the signal coming from the geyser eruption. The results from this experiment will help us understand how/why frequently erupting geysers work. The student will use a set of computer programs and scripts to process the data and generate images in a Unix environment. The student should have basic computer skills, advanced math skills, and a desire to learn. This project can be adapted to an 8 week SURGE or 10 week SESUR student.

Jesse Lawrence- SESUR or SURGE

Imaging Seismic Attenuation

This project aims at imaging the Earth mantle through measurements of seismic attenuation. Attenuation is the energy that a seismic wave looses as it travels through the Earth. By measuring this energy loss, we can map out where the properties of the Earth are different. In particular, attenuation increases in the mantle when volatiles (such as water) are abundant. By mapping out attenuation we aim to understand how the extremely deep water cycle influences the way the Earth cools itself through convection. The student will work with a seismic program on a Unix computer. The student will use this semi-automated code to make thousands of travel-time and attenuation measurements for regional and global maps of attenuation variation. The student should have basic computer skills, advanced math skills, and a desire to learn. This project can be adapted to an 8 week SURGE or 10 week SESUR student.

Jesse Lawrence and Stew Levin-  SURGE

Investigate Subsurface Geology with Vibrations from Bridge Traffic

In recent years seismologists have become increasingly capable of using different types of noise to investigate the interior structure of the Earth.  Nearly anything that causes a vibration within the Earth can now be used as a source for investigating the subsurface geology.  These noise types include, mine blasts, ocean waves, wind, building vibrations, and now freeway traffic.  With many seismic sensors, new techniques can yield results where fewer sensors could not and where the use of traditional vibrational sources is not possible.

This study will focus on a grid of 3000 seismic stations that passively recorded vibrations in and around the city of Long Beach.  The goal is to tease out coherent signals coming from the 405 freeway (a nearly constant source of noise) to learn more about the subsurface structure.  This will be accomplished by cross-correlating records made near the 405 freeway with the rest of the stations to see if we can recover reflection and, more importantly, refraction arrivals.  The project will yield 3D pictures of seismic wave speed variation. 

Furthermore, we will determine what it would take to repeat this experiment with the Golden Gate Bridge in San Francisco (i.e., how many stations? And for how long?). The subsurface structure beneath the San Francisco Bay has many unanswered questions that cannot be resolved with more conventional analyses because such analyses could jeopardize marine mammals and bridge safety.

(Some experience with Unix/Linux and programming is desirable, but not required.)

David Lobell- SESUR or SURGE

Identifying Hotspots and Analogues to Guide Wheat Breeding Strategies

A student is sought to join a project on adapting irrigated wheat systems in developing countries to climate change. The main task of the student will be to take maps identifying hotspots of future impacts around the world, and find locations that are currently good analogues for the future climate at each of these hotspots. The student will then seek to identify a handful of sites that represent good analogues for a large number of hotspots.  Time permitting, the student will also investigate the current areas, yields and varieties of wheat grown in these analogue areas as a way of scoping the possibilities for adaptation. The results of the project will be used by a wheat breeding center to locate future screening trials to improve varieties for the hotspots. Experience with statistics and the R programming language is strongly desired.

David Lobell- SESUR or SURGE

Modeling Crop Adaptation to Climate Change and Variability in the Sahel

A student is sought to evaluate adaptation options for sorghum production in the Sahel. The approach will involve running a calibrated crop model for various climate scenarios and management options. The goal is to identify strategies that are robust to future climate scenarios and also help to deal with current climate variability. Results will be fed into climate adaptation investment decisions. Experience with statistics and the R programming language is required.

Kate Maher and Cynthia McClain- SESUR

Modeling Hexavalent Chromium Groundwater Contamination in California’s Central Valley

Hexavalent chromium (Cr(VI)) is a toxic carcinogen when ingested. Unfortunately, it has recently been found in drinking water sources in California’s Central Valley. The ultimate goal of this project is to understand processes controlling Cr(VI) release to groundwater and to determine whether human activities such as land use and water management are accelerating Cr(VI) release to drinking water sources. We hypothesize that 1) manganese and nitrate distribution is closely tied to the locus of Cr(VI) generation from natural sources in the subsurface; and 2) that increased flow rates (due to groundwater pumping) accelerate Cr(VI) release to groundwater. We seek an undergraduate researcher to conduct laboratory and/or computational modeling experiments testing either one of these probable mechanisms for Cr(VI) release from natural aquifer sediments. Participation in water and sediment sampling at one of our established field sites is possible as well. Laboratory experience and/or computational skills (e.g. Matlab, ArcGIS) are desired, but not required.

Kate Maher and Jenny Druhan- SESUR

Stable Isotope Fractionations due to Transport in Porous Media

Many chemical reactions that commonly take place in groundwater systems are associated with fractionations in the stable isotope ratios between reactant and product species. This fractionation is a useful indicator of the reactions taking place, and can even be used to quantify the extent of a reactive process. However, the stable isotopes of dissolved species also differ very slightly in their masses. As a result, the physical transport of these isotopes through a porous media can lead to separation that may be misinterpreted as evidence of a chemical reaction. To understand the relative importance of this process, we are constructing a series of flow-though column experiments. We seek a motivated undergraduate interested in participating in the construction, parameterization and analysis of these experiments. Activities will include hydrologic and chemical characterization of the porous media and chemical analysis of effluent samples. Laboratory experience and some background in fluid mechanics will be useful, but is not required.

Kate Maher, Jenny Druhan, Laura Nielsen and Cynthia McClain- SESUR or SURGE

Reactive Transport Modeling of Isotope Systematics in CO2 Sequestration, Paleohydrology and Groundwater Contamination

Reactive transport models use both mathematical descriptions of chemical reactions that take place in flowing solutions and the laws that govern fluid motion.  These models track the physical motion of the chemical species themselves as well as the chemical reactions that take place along the way. However, very few reactive transport models explicitly calculate the distribution of individual isotopes of reactive chemical species. Monitoring individual isotopes of elements such as C, Ca, S, Cr and Fe is useful for measuring the reaction rates that govern subsurface transformations such as mineralization of CO2 and reduction of toxic hexavalent chromium. We are seeking a motivated undergraduate to help develop an isotope-specific reactive transport code (CrunchFlow).  A background in programming (e.g. Matlab) and/or in quantitative chemistry is preferred. Applicants may work on: 1) adding individual isotopologues of reactive species to a geochemical database, 2) literature review for relevant parameters, 3) developing a graphical user interface, 4) generalizing the code for flexibility in modeled isotope systems, or 5) controlled laboratory mineral precipitation experiments to validate the model.

Jonathan Payne and Adam Jost- SESUR or SURGE

Carbon Cycling During the End-Guadalupian Extinction

Understanding mass extinctions in the geologic past and their causes is critical for predicting the effects of modern climate change on our biosphere. The end-Guadalupian mass extinction (260 million years ago) is a relatively minor event, providing us with a unique opportunity to explore the how smaller extinctions may be triggered, and how these events may be recorded in the fossil and geochemical record.  The aim of this study is to distinguish between global and local ocean carbon cycle signals in Guadalupian-age carbonate sediments by measuring organic carbon isotopes.  The student involved in this project will 1) prepare and dissolve rock samples for organic carbon isotope analysis; 2) compare newly collected data with existing geochemical data; and 3) perform statistical analyses with all geochemical data.  Knowledge of historical geology is preferred.

Jonathan Payne and Matthew Knope- SESUR or SURGE

Does Ecological Mode of Life Govern the Evolution of Body Size?

Body size is widely recognized as one of the most ecologically and physiologically important traits of an organism. Size varies by many orders of magnitude across all species, but the selective factors that have produced this huge range of body sizes remain poorly understood. The primary objective of this research project is to constrain the relationship between habitat affinity, feeding ecology, locomotion, and the evolution of body size over the past 540 million years. To accomplish this goal, we are assembling the largest time-calibrated fossil data set of body size ever compiled and seeking to unravel the ecological mode of life of each of these fossil species. Students involved in this research would contribute primarily by collecting data on the ecology of both living and extinct species from published records.  They would then spend time in the laboratory conducting statistical analyses to assess the role of ecology (e.g., feeding, motility, life habit) in determining the relationship between size and fitness. Interested students would ideally have strong interest in ecology and evolution and experience with statistics. However, enthusiasm is the primary requirement, as most of the skills can be taught within the timeframe of the project. This project presents a unique opportunity to not only learn about the history of life on Earth through the fossil record, but to gain research and statistical skills that are foundational to almost all of the sciences.

Jonathan Payne and Caitlin Keating-Bitonti - SESUR or SURGE

The Environment’s Role in Shaping Patterns of Diversity and Size Distribution

How does the environment influence and drive patterns in species diversity and the distribution of sizes among species? The goal of this research is to identify and better understand patterns in the distribution of sizes among modern foraminifera (marine protists) living in vastly different environments. Foraminifera are an excellent study group because they are incredibly diverse and occur in all ocean basins at all depths, thereby providing the unique opportunity to tackle questions like: Are size distributions in the tropics similar to distributions in the arctic, or are patterns along the continental coast similar to those in the deepest ocean? Here we seek to identify the oceanographic variables (e.g., dissolved oxygen concentrations and temperature) that are shaping these large-scale evolutionary patterns. A student working on this research will help with data collection, map foraminiferal occurrences using ArcGIS, and conduct statistical analyses. This project integrates data and concepts across biology, paleontology, and oceanography.  It is also flexible such that the student may focus on mapping, statistical analyses, or both based on his/her interests.

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