Mentor: Mara Freilich

Ocean eddies shape biodiversity and plankton productivity. Eddies cause water parcels to move in and out of the sunlit upper ocean into the darker ocean interior. This process supplies nutrients to the surface ocean and organic carbon to depth. Eddy dynamics are not fully resolved in global models so their effects must be parameterized. Recent observations have shown that advection of organic carbon to depth supplies energy and nutrients to the deep ocean in subtropical oceans. However, the ways that eddy dynamics affect the biogeochemical processing of this carbon remain to be understood.

This project will explore how eddies influence dissolved organic carbon (DOC) in the ocean using models and observations. You will analyze data from satellites and ships in subtropical oceans. You will also learn how to develop an idealized model of DOC reactions and implement this model in a physical eddying flow field. The results will provide insight into the ways that ocean biology and physics are coupled.

Mentor: Chris Horvat

Anthropogenic climate change is a global public health emergency. Changes to tropical cyclones, and associated waves, winds, storm surge, and extreme rainfall have direct impacts on the health of individuals and the healthcare facilities that serve them. These risks are particularly relevant to geographically dispersed Pacific Island Countries and Territories (PICTs) -  which bear an inequitable fraction of climate change impacts and whose healthcare infrastructure is expected to be under pressure in the coming decades. Policymakers must have interpretable, geographically specific, and statistically sound information about future climate-related risks, but face real challenges when accessing relevant data for making decisions. PICTs comprise more than 10,000 islands and atolls, of which several hundred are inhabited. Yet fewer than 5 are large enough to be properly represented by climate models. The contrast between highly localized PICT geographies and coarse climate projections frustrates the ability of stakeholders to evaluate climate-sensitive health risks and consequently climate-change-associated impacts on healthcare infrastructure.

In the EMPIRIC project, which you will join, we are attempting to address this need. Here we are using machine learning to merge scientific developments in high-resolution state estimates of Pacific climate, and statistical modeling of tropical cyclones to build AI-driven estimates of cyclone impacts and extreme weather in PICTs and specifically for the major healthcare facilities that serve them. Your role will be to work with us and with our Pacific partners to develop an AI-driven tool for cyclone and wave inundation by combining several datasets produced by the EMPIRIC and visualizing them using GIS software. It is expected that this will involve communication and collaboration with stakeholders in the Pacific and team members in the region, and will culminate in a contribution to an online data portal hosted by the South Pacific Community (www.spc.int). 

Mentor: Colleen Dalton

The viscosity of mantle rocks controls solid Earth dynamics across a vast range of timescales, including: the melting of ice sheets; the annual cycle of groundwater recharge and extraction; and the draining of large lakes. Propagating seismic waves after an earthquake cause mantle deformation at higher frequencies than these processes, and this study will measure seismic wave attenuation to probe the high-frequency response in the mantle beneath Iceland. 

You will download seismic data from several broadband networks across Iceland and measure the travel times and amplitudes of surface waves generated by large earthquakes located around the globe. You will be guided to write simple computer programs in Matlab or Python to determine maps of surface wave velocity from the travel times and maps of attenuation from the amplitudes, which will form the main product of the project. You will consider how their results can be used to estimate temperature and partial melt content in the Icelandic upper mantle. You will compare your attenuation values to other viscosity estimates from ocean tidal loading and GPS-measured deformation that are being collected by collaborators at other U.S. institutions. You will gain skills like writing computer programs, and analyzing seismic data.  You will also experience working as part of larger team by interacting with scientists at other institutions.

Mentor:  Harriet Lau

The collapse of the extinct North American ice sheet some 14,000 years ago triggered Melt Water Pulse 1A, an event captured in paleo-sea level records that point to a dramatic rise in global mean sea level of ~20 m within ~500 years. The pattern and rate of sea level rise rests on how the solid Earth (crust and mantle) deforms in response to the shifting of surface mass (ice and ocean). To date, investigations of the solid Earth response assume simple models of mechanical deformation: ice can melt steadily or quickly, and the same Earth properties (e.g., Earth’s rigidity and viscosity) are applied. Moreover, constraints on these properties are biased by slow melt processes for viscosity and very fast seismic processes for rigidity. Melt Water Pulse 1A and ongoing climate change represent intermediate ice mass changes, and to accurately predict sea level change in the face of diminishing ice sheets today, more complex Earth deformation must be considered. 

We will use Melt Water Pulse 1A as an analog for future sea level rise. By using computer-based modeling, to understand the role of complex Earth structure in the face of climate change, you will apply both the established and revised understanding of Earth deformation to analyze how different the two models predict sea level change in response to Melt Water Pulse 1A. This project will equip you with technical (mathematical and computational) skills and build an appreciation for the interdisciplinary nature of Earth science research today.

Mentor: Karen Fischer

In the western Antarctic rift system, extension over more than 85 million years has thinned the crust and the mantle lithosphere of the continent, and adjacent to the northern tip of the Antarctic Peninsula, ongoing subduction of lithosphere continues to release water and promote melting in the shallow mantle, also likely thinning the lithosphere of the upper plate.  Existing models of seismic wave velocities indicate that warm and low viscosity asthenosphere at relatively shallow depths beneath these regions, but more precise estimates of lithospheric thickness are possible.  Better constraints on lithospheric thickness are important for modeling the strength (rigidity and viscosity) of the mantle beneath western Antarctic, and understanding how the solid Earth will respond to changes in surface loading from the melting ice sheet and how water will be redistributed, affecting sea-level rise.

You will analyze seismic body waves from distant earthquakes recorded at stations in the western Antarctic rift system and the Antarctic Peninsula to measure lithospheric thickness.  You will interpret observed variations in lithospheric thickness relative to the candidate tectonic processes that could have created them, for example rifting and the effects of subduction, and will assess their implications for models of mantle viscosity (a measure of the strength of mantle rocks).  Through this work, you will gain experience with the analysis of seismic data, working with existing computer codes, writing some new code, and interacting with a scientific team to interpret results.

Mentor: Chris Huber

Volcanism is ubiquitous on Earth and planetary bodies across the solar system. It plays a fundamental role in the formation of the crusts of Earth and other planetary bodies and the evolution of their surfaces. On Earth, volcanoes pose a major threat to our society with large population centers located nearby active volcanoes. The causes behind volcanic eruptions can be diverse, moreover volcanoes respond mechanically to the tectonic environment that hosts them. 

In this project, you will study the effect of tectonic stresses on magma chamber stability (number and frequency of eruptions) as well as magma chamber longevity. You will employ a numerical model for magma chamber thermal and mechanical evolution.  This project will also study the effect of tectonic stresses on the relative fraction of magma that reaches the surface compared to the fraction that remains trapped at depth.  Through this work, you will gain experience with numerical modeling of physical processes, coding, and the interpretation of modeling results.

Mentor: Stephen Parman

This project will use noble gases to trace how volcanoes degas and erupt. The broad goal is to constrain rates of magma degassing processes, particularly on short timescales. If successful, the results may allow more accurate predictions of eruptions. Degassing is what drives most eruptions. This should fractionate the noble gases from each other, and may be detectable in changing noble gas ratios emitted hours prior to an eruption. The specific question is how do noble gases diffusively fractionate from each other during degassing?  This depends on 1) a detailed understanding of their diffusivities (not currently available) and 2) a sufficiently accurate model of degassing to track bubble nucleation, growth, movement and coalescence. 

Options open to students working on this project include: 1) Lattice-Boltzmann modeling of degassing processes, 2) physical experiments on noble gas diffusion or 3) noble gas analysis of natural and synthetic samples. Depending on the project chosen, you will learn computer modeling, high-pressure laboratory skills and/or noble gas geochemical analyses, and will gain perspective on how large, complicated physical-chemical systems behave, and how to approach studying them.

Mentor: Alexander Evans

It has been well established that volcanic eruptions on rocky worlds can generate domical structures (i.e., volcanoes), where the slopes and sizes of the volcanoes are directly related to the properties of the magma and eruption events. Although volcanic eruptions have been suggested to have occurred on metal-rich planetary bodies like Psyche and ice-rich planetary bodies like Ceres, it remains unclear if such eruptions can also form volcanoes. Hence, the goals of this project will be 1) to rigorously examine the plausibility of volcanoes on icy and metal worlds by applying our understanding of the geomechanical and rheologic properties of volcanic edifice-forming eruptions on Earth and 2) to determine whether volcanoes are likely to be an exclusively characteristic landform of Earth and other rocky worlds. This project will provide important context for understanding Earth’s history, evolution, and long-lived volcanism.

Through computational modeling and analytical analyses, you will: 1) identify whether Earth-like volcanic eruptions can occur on planetary bodies like Psyche and Ceres, 2) examine the conditions necessary for volcanic edifices to form on Earth and other worlds, and 3) evaluate whether Earth and other rocky worlds are exclusively capable of forming volcanic edifices.  Through this project, you will: 1) develop an understanding of fundamental physical processes that operate across Earth and other planetary bodies, 2) develop the ability to simplify and approximate key physical processes that operate across Earth and other planetary bodies, and 3) develop an understanding of data commonly used to understand the physical processes related to the evolution of planetary bodies.

Mentor: Yan Liang 

Pyroxene is a major-rock forming mineral in mafic and ultramafic rocks. Major and trace element zoning in pyroxene has often been observed in natural samples. The goal of this project is to use major and trace concentrations in pyroxene, geothermometry, and diffusion modeling to unravel the thermal history of selected mafic and ultramafic rocks.  Potential samples include peridotites and pyroxenites from the Trinity ophiolite, mantle xenoliths from the North China Craton, and cumulate rocks from the Bushveld Igneous Complex.  

You will be involved in sample preparation, and will also use a petrographic microscope to identify pyroxene and associated minerals in the samples. You will use the electron microprobe to measure major and minor element concentrations and concentration profiles in the pyroxenes. You will work closely with the PI to interpret the measured chemical data through applications of geothermometry and diffusion modeling.

Mentor: Blake Hodgin

Pleistocene glacial ice sheet advance and retreat in North America was driven by climate change, which resulted in sea-level fluctuations of greater than 100 meters. Our understanding of Pleistocene climate change from recent geological deposits can inform ongoing challenges to understand, quantify, and predict the effects of human-induced climate change to existing ice sheets. A proposed case study at Block Island in southernmost Rhode Island can inform a poorly understood interval of glacial re-advance that took place during the last glacial maximum about 20,000 years ago.  Questions related to the re-advance include whether it was related to regional conditions or to a climate perturbation that could be correlated to re-advance elsewhere. 

To test these hypotheses, you will be involved in field work to characterize folding and faulting related to ice-sheet re-advance, radiocarbon and cosmogenic dating of the deformed sediments to constrain the timing of re-advance, and a synthesis of existing data related to ice re-advances around the time of the last glacial maximum. As Block Island is an important historical and ecological site, the research project will include opportunities for sharing findings with the community and engaging in ecological outreach.

Mentor: James Russell

The interactions between climate change, wildfire, and water cycling are well-studied in many mountain regions, such as the western United States, where forest fires are very frequent. In contrast, these interactions are poorly studied in tropical mountains, which are often considered to exist in a climate that is too cool and moist to burn. However, recent events suggest that wildfire may also be an emerging threat to tropical mountains and their unique ecosystems. This project seeks to assess the effects of changes in climate on fire frequency in tropical mountains, and the impacts of fire on tropical montane vegetation and flooding. A key goal is to test the hypothesis that changes in fire regimes in tropical mountain environments are influenced by temperature change, rather than precipitation changes that dominate fire frequency in the lowlands.

You will generate organic geochemical, sedimentological, and/or microfossil records of temperature and rainfall, flooding, and fire from lake sediment cores recovered from alpine environments in the Rwenzori Mountains, Uganda. Specific analyses can be tailored to your skills and interests, from isotope and geochemical records of climate to plant fossil records of fire.  You will develop skills in laboratory analyses, data analysis, hypothesis testing, and data visualization.

Mentor: Daniel Ibarra

The effects of future warming on water availability in arid to semi-arid regions is a key uncertainty in climate projections. The Mojave desert is a natural laboratory to study how past changes in climate affected water availability, as it contains numerous dry lake basins that are the remnants of periods when this area contained large pluvial lakes. Between the Last Glacial Maximum and the Holocene, lake levels fluctuated in response to changes in regional temperature, evaporation, infiltration, and groundwater tables. However, there remains no paleorecords that have the temporal resolution necessary to resolve how lake levels responded to centennial-scale climate change.

In this project we will collect and study lake cores and beach deposits from one of these ancient pluvial lakes: Glacial Lake Mojave. By combining geochronologic and stable isotope measurements on this archive we will construct a time series that describes the evolution of water levels and environmental conditions within that lake over the last 25,000 years.

Mentor: Timothy Herbert

This project will involve lab work and micropaleontology to study deep sea sediment cores along a transect (S-N) of sites in the flow path of the North Atlantic Current, the major source of heat to the North Atlantic and Arctic. The project will trace the evolution of ocean surface temperatures in relation to global cooling and the onset of ice ages over the time period 4 Million years to present. The major research question would be to determine whether temperature gradients, an index of heat transport, evolved in parallel with global climate change. 

You will learn organic biomarker geochemistry (our main proxy for ocean temperatures), a field that involves organic chemistry and the use of gas chromatography. Other skills learned would be stratigraphy (the ordering and dating of past events), statistical inference, and basic lab skills of accuracy and reproducibility of analytical data. Your ultimate learning goal will be to better understand how we reconstruct past climate change, and what these changes may imply for our future.

Mentor: Jung-Eun Lee

The Intergovernmental Panel on Climate Change (IPCC) report suggests that the interior of continents will be drier with anthropogenic warming. As a result, tree coverage is expected to become lower with increasing greenhouse gas concentration when the present-day climate-vegetation relationship obtained from machine learning is applied to the “business as usual” climate change scenario of the future climate. Our preliminary modeling study suggests that under higher CO₂ conditions, plants can grow better in hotter and drier regions, and also at higher latitudes due to longer growing seasons.  These changes occur because vegetation cover decreases high latitude albedo, and plants may be using water more efficiently in higher CO₂ conditions, suggesting that the vegetation-climate relationship is not static. Thus, we hypothesize that the warmer world is greener if we include the full vegetation feedback.

This project will explore how we can resolve the discrepancy between the model prediction of future browning and paleoproxy indication of past greenness using climate model simulations with the NCAR CESM (Community Earth System Model) with a dynamic vegetation model. You will run the NCAR CESM climate model using Eocene paleogeography and will analyze the climate model results. You will be able to learn how to run a climate model and how to analyze climate data using Python or Matlab.

Mentor: Meredith Hastings

The isotopic composition of various reactive nitrogen species is a powerful tool to investigate variations in sources, chemistry, atmospheric transport, and deposition. Our aim is to use geochemical techniques to fingerprint emission sources and track their impact, influence, and potential feedbacks in an urban landscape. Recent discoveries include a significant increase in ammonia in urban environments due to vehicles with implications for poor air quality, especially in winter, and poor water quality via local deposition and stormwater runoff to the largest estuary in New England.

You will be trained and involved in field sample collections, laboratory analyses, and data analysis and interpretation. Field collection will involve utilizing novel techniques for simultaneous collection of gases and particulate matter. You will learn: collection methods for gas and particulate samples; wet chemistry techniques for preparation of standards; general training in calibration and standardization; concentration analyses via spectrophotometric methods; isotope determination via isotope ratio mass spectrometry; experimental design and sampling strategy for field sampling; data analysis and interpretation of results based on background reading.

Mentor: Emily Cooperdock 

Nitrogen (N) is the most abundant element in the Earth’s modern atmosphere, is present in the structure of amino acids (the basic building blocks of life), is dissolved in the oceans, and fixed in the sediments and Earth’s crust by microbes and lightning. Nitrogen is also present in the deep Earth, as evidenced by its presence in the lattice of diamonds and recent studies have shown that it may also be present in the core. The subduction of N-rich materials along with volcanic degassing has enabled exchange between the surface and deep Earth reservoirs over Earth’s history. Previous studies have estimated the recycling efficiency of N in subduction zones (percentage of incoming N in subduction zones that escapes fore-arc and sub-arc release and enters deep mantle) by subtracting the outflux of volcanic degassing from the influx of subducted igneous crust and sediments. Depending on how well the inputs and outputs were constrained, this resulted in inferred efficiencies that vary from 0-80%.

Although many studies have measured N partitioning and devolatilization in metamorphic rocks, mélange matrix rocks remain under-characterized despite being key conduits for fluids and deformation that mobilize and redistribute volatiles. This project will use natural mélange rocks from different exhumed subduction complexes to study where N is hosted during forearc metamorphism. Specifically, the student will be involved in detailed sample characterization and broad chemistry, as well as N data analyses from published literature.

Mentor: Greg Hirth

The largest and most damaging earthquakes occur along plate boundaries where the lithosphere is subducted beneath the continents. Geoscientists have discovered that a wide range of fault slip processes occur in these regions. However, there are still gaps in our knowledge of the critical physical properties that lead to earthquakes. We have made new modifications to our experimental equipment that significantly improves our ability to characterize the fault slip behavior that occurs within subduction zones. Experiments will provide new constraints necessary to understand the conditions where earthquake slip initiates. The results will also provide data relevant for leveraging the potential of geothermal energy, and mitigating the danger of nucleating earthquakes while storing CO2 in the crust. 

In the lab, you will learn how to conduct experimental tests on the physical properties of rocks, how to characterize specimens using standard and electron microscopes, and how to analyze the experimental data with computer programs like MatLab. There is also the potential to interact with our larger community through CORD (Collaborative Organizations for Rock Deformation) – a group that includes scientists at MIT and the Woods Hole Oceanographic Institution. 

Mentor: Sam Birch

Comets represent some of the most primitive bodies of our solar system, holding significant importance as they preserve materials that ultimately went into building the planets and life itself. The Rosetta mission to comet 67P has opened the doors to a new era of small-body geology by allowing us to directly interrogate the processes that are responsible for modifying cometary surfaces at the meter scale over which they occur. For the first time, we can resolve sediment transport across a cometary surface in exquisite detail. Our goal is to study 67P’s landscape evolution by tracking its dominant sediment transport pathways. For this, we will be measuring the changes in sediment levels as a function of time, relative to static landforms such as boulders and cliffs in targeted regions of interest. The measurements will be made by employing the photoclinometry (or shape-from-shading) technique to generate digital terrain models (DTMs). 

This project will involve working with a large dataset of images for 67P's surface acquired by the Rosetta mission, and generating DTMs over several target regions on the comet. The student will gain experience working with planetary datasets, python, and Linux/Unix systems, along with learning how planetary topographic datasets are generated and used by scientists.