2025 Potential Projects

1. Quantifying calcium carbonate burial in different sediment phases over time
2. Reconstructing organic carbon production in the surface ocean and burial on the sea floor
3. Investigating how carbon storage affects oxygen concentrations in the deep ocean
4. Examining the foraminiferal assemblage response to changing climate conditions over glacial-interglacial cycles.

The SSF will join ongoing collaborations within our lab, and they will have the opportunity to learn multiple analytical techniques in geochemistry (230Th-normalization, major and trace elemental sediment geochemistry, metal to calcium ratios  in foraminifera (ICP-MS) and micropaleontology (foraminiferal assemblages, d18O, d13C). These projects are lab based, and so students should be prepared to leave their computers behind to work with mud, acids, microscopes, and more. All techniques are accessible to students without prior experience but with the motivation to learn. Kassandra Costa's website

• training and using an unsupervised machine learning algorithm to identify and measure cracks in SEM images
• using a Matlab program to measure crystallographic twins from electron backscatter diffraction (EBSD) maps
• receive hands-on training in the acquisition of SEM images and EBSD data at WHOI/MBL
• participate in virtual meetings with project collaborators at WHOI, MIT, and GFZ Potsdam
• travel to MIT to meet with collaborators and participate in a deformation experiment on Carrara marble
• interact with graduate students and postdoctoral investigators in WHOI’s Rock and Ice Deformation Laboratory

Interested students are encouraged to contact Dr. Andrew Cross (https://www.whoi.edu/profile/across/) to learn more about the project.

Example of surface deployed DAS recording of a seismic shot vs. a multichannel geophone recording (Harmon et al., 2022).

Distributed Acoustic Sensing (DAS) uses backscattered light from lasers transmitted through fiber optic cable to measure ground motions along the fiber, essentially turning the cable into hundreds to thousands of seismic sensors. This allows for the measurement of seismic and other environmental signals such as ocean waves and whale song at high spatial (cm-scale) and temporal scales (kHz). This technique is exploding because of its wide applications and versatility. Fiber optic cable is relatively inexpensive and easy to deploy in the field, opening up a wide range of environmental applications such as seismic and volcanic hazard monitoring to biological and oceanographic observation. In other words, surface deployed DAS is a new technique and there is an enormous opportunity to develop optimal field methods and advance or scientific understanding in a wide range of fields. The summer fellow will participate in a series of field deployments of DAS in field sites on Cape Cod including onshore offshore environments (beaches) to examine the feasibility of this type of surface deployment. The DAS will be deployed for passive and active seismic experiments to examine sensitivity of the DAS to a wide range of anthropogenic and environmental signals. The student will process the active seismic data and perform analysis on the continuous recordings to examine known signals such as ocean waves and nearby car and small boat noise. In addition, legacy datasets from land and submarine cables will be available for the student to explore, compare and interrogate. The ideal student will have a background in geophysics, geology, oceanography, physics, or mathematics. The student should have a basic knowledge of MATLAB or python and a willingness to deepen their skillset with computer programming. The student will develop skills in seismic network array processing and signal processing. The student will also develop skills in near surface geophysics survey design and execution, as well as oral and written presentation skills by presenting their work at group meetings. The student will work in a wider group at WHOI with Dr. Catherine Rychert, Dr. Madison Smith, Dr. Wenbo Wu, and PhD students and postdocs across the Geology and Geophysics and Applied Ocean Physics and Engineering departments. Nicholas Harmon Catherine Rychert Maddie Smith Wenbo Wu

Shot gather of the vertical component with reduced time at station CELP from the Puerto Rican Seismic Network.

Puerto Rico is part of the relict Greater Antilles Arc that was constructed in the Cretaceous as the Caribbean Plate converged on the North and South American plates. The island has also been subjected to large tectonic motions, which has further shaped the region. Subduction is still occurring to the north of the island at the Puerto Rico trench at a very oblique angle, as well significant seismicity associated with the Muertos Trough to the south, making Puerto Rico a region of high seismic hazard. The crustal structure of Puerto Rico is important for our understanding of the evolution of the Greater Antilles Arc and the development of the Caribbean as well as understanding the seismic hazard of the region. In late fall 2023, the “Collaborative Research: Seismic Hazard, Lithosphere Hydration, and Double-Verging Structure of the Puerto Rico Subduction Zone: A Seismic Reflection and Refraction Perspective” project collected multichannel seismic and refraction data using airgun shots from the RV Marcus G Langseth to study the structure of the Puerto Rico Trench and Puerto Rico for a better understanding of hazard on the region. Several thousand shots were recorded on the permanent seismic network on land. The three component seismic data provides an opportunity to examine P-to-S wave conversions beneath the station generated at seismic velocity discontinuities below the station. The student will use the receiver function method to examine seismic velocity discontinuity structure beneath the seismic network and understand the construction the crust of Puerto Rico. The receiver function data will then be migrated to depth to construct a 2-D image of the structure beneath the station, which can be used to understand the layering with the crust and its construction. This is an amazing opportunity to provide tight constraints on Earth structure which are imperative to earthquake hazard mitigation in the region, with broader implications for our understanding of regional tectonics and the tectonic plate. The ideal student will have a background in geophysics, geology, oceanography, physics, or mathematics. The student should have a basic knowledge of MATLAB or python and a willingness to deepen their skillset with computer programming. The student will develop skills in seismic network array processing and signal processing. The student will also develop skills in active source seismics, as well as oral and written presentation skills by presenting their work at group meetings. The student will work in a wider group of scientists at WHOI and at the University of Puerto Rico, University of Texas and the US Geological Survey with Dr. Pablo Canales, Dr. Elizabeth Vanacore (UPR), Dr. Uri Ten Brink (USGS), Dr. ShuoShuo Han (UT), Dr. Catherine Rychert and PhD students and postdocs across the Geology and Geophysics Department at WHOI. Nicholas Harmon Pablo Canales Catherine Rychert Uri Ten Brink (USGS Woods Hole)

High-resolution numerical simulation of the coastal current produced by the discharge of glacial meltwater from the Laurentian Channel during a glacial period of low sea level. Shown is the distribution of surface horizontal velocity after 150 days of sustained discharge. The maximum speed of the current is 1.3 m/s. The current has developed eddies all along the continental slope. This project will be concerned with the analysis of a similar simulation but for a larger domain including the oceanic region east of the Grand Banks of Newfoundland (GB) (O. Marchal and A. Condron, unpublished)

Paleoclimate records suggest that the last glacial period was punctuated by a series of rapid climatic changes. Although these changes were first documented in the circum North Atlantic, subsequent studies indicated that they may have been at least hemispheric in extent. The estimated magnitude of these changes is truly impressive. For example, ice core records from Central Greenland suggest that local air temperature increased repeatedly by 8-16^oC in only about a century. With such a discovery, the once-traditional view that climatic changes are slow, with time scales far exceeding a human lifespan, has been overthrown, and understanding the processes leading to these changes has emerged as a most pressing question in climate research. A popular idea to explain rapid past climate changes involves the recurrent release of glacial melt water from the Laurentide Ice Sheet (LIS) – the ice cap that covered northern North America during the last glaciation. The introduction of glacial water into the ocean would have lowered the salinity of surface waters, particularly at high latitudes in the North Atlantic, thereby leading to enhanced vertical density stratification, reduced deep water formation, and ultimately, abated meridional overturning circulation and northward heat transport. The abated northward heat transport would have produced a rapid climate change, with cooling in parts of the northern hemisphere, such as in the northern North Atlantic. The goal of this project is to analyze detailed simulations of the transport of glacial meltwater in the North Atlantic which will be produced from a high-resolution numerical model of ocean circulation. In contrast to previous studies, our simulations will represent oceanic eddies with scales of 10-100 km, thereby allowing a detailed calculation of the pathway of the glacial water in the North Atlantic. Emphasis will be put on the entrainment of glacial water emanating from the LIS with the North Atlantic Current – the northeastern extension of the Gulf Stream east of the Grand Banks of Newfoundland – and on the transport of the glacial water to critical regions of deepwater formation. The student working on this project will be exposed to concepts emanating from various disciplines, including physical oceanography, the numerical modeling of ocean circulation, and paleoclimatology. Although prior exposure to branches such as physics and calculus would be desirable, the most important quality the student working on this project should have is motivation! This project will be co-supervised by WHOI scientists Olivier Marchal and Alan Condron. Olivier Marchal's profile Alan Condron's profile

Schematic of Hawaiian Plume Lithosphere interaction (Rychert et al., 2013).

Hawaii is the classic example of a mantle plume, where hot focused upwelling in the mantle leads to a volcanic island chain. Yet the origin and the processes that give rise to the Hawaiian volcanos are still the subject of vigorous debate. For example, where does the plume originate from, how wide is the plume is and how hot is it? One of the primary ways for investigating the nature of the Hawaiian plume come from seismic observations of the lithosphere-asthenosphere boundary (the boundary at base of the tectonic plate) and the mantle transition zone at 410 and 660 km depth. Interactions of the plume with the plate and also the mantle transition zone, the gate keeper of the mantle which plays a primary role in dictating mantle convection, are fundamental to our understanding of mantle dynamics and Earth’s evolution. Yet, the characteristics of the plume are debated, in part because most constraints come from a single methodology or dataset. Here we will develop an interdisciplinary and wholistic view of Hawaii and its plume. The student will use existing ocean bottom and land seismic data to examine the lithosphere-asthenosphere and mantle transition zone boundaries. The student will use existing SS wave precursor stacks, S-to-P and P-to-S receiver functions to develop a unified velocity discontinuity model for Hawaii. The student will use synthetic seismogram modelling to determine the optimal models and data combinations that produce a unified Earth structure. This will yield a high resolution image of the mantle structure beneath Hawaii and constrain the location, width, structure and temperature of the Hawaiian plume. The ideal student will have a background in geophysics, geology, oceanography, physics, or mathematics. The student should have a basic knowledge of MATLAB or python and a willingness to deepen their skillset with computer programming. The student will develop skills in seismic network array processing and signal processing. The student will also develop skills in passive source seismology specifically the receiver function method and SS precursor imaging, as well as oral and written presentation skills by presenting their work at group meetings. The student will work in a wider group of scientists at WHOI and Scripps Institution of Oceanography with Dr. Nicholas Harmon, Prof. Peter Shearer (SIO) and PhD students and postdocs across the Geology and Geophysics Department at WHOI. Nicholas Harmon Catherine Rychert

Microfossil fish teeth and denticles, approximately 50 million years in age, from DSDP Site 596, a marine sediment core from the South Pacific ocean. The scale bar is 500 microns, and the fossils were imaged using a high resolution digital microscope.

Understanding how life has responded to past global change events is vital to predicting and mitigating anthropogenic impacts on the planet. The Paleo-Biological Oceanography lab explores how marine ecosystems have responded to environmental changes in earth’s history, going back hundreds of millions of years. This work lies at the intersection of biological oceanography, ichthyology, paleobiology, and paleoceanography, and is driven by big-picture questions, including: How have marine ecosystems evolved throughout Earth’s history? How did past climate and biotic events impact the structure, function, and evolution of marine ecosystems, and what can that tell us about potential impacts of future global change? How has the evolution of pelagic marine vertebrates, particularly fish and sharks, interacted with changes in the Earth system? To investigate these questions, we leverage an interdisciplinary toolkit that centers around microfossil fish teeth and shark scales (ichthyoliths) preserved in marine sediments in conjunction with fish biology, paleo-proxies, ecological models, and evolutionary tools, to study how fish, sharks, and marine ecosystems have evolved in concert with climatic and biotic changes throughout Earth’s history. Interested students are welcome to propose a particular time or event in Earth’s past to investigate, or can pick up a project that is currently ongoing. Ongoing projects include looking at fish and shark biodiversity and abundance across the Cretaceous-Paleogene Mass Extinction and to several major global warming and cooling events in earth’s past, developing a catalog of modern shark scale and fish tooth morphological diversity, machine learning applications to identifying and cataloging microfossils. No prior microscopy, fossil prep, sediment processing, or computer coding experience necessary, but a willingness to learn and develop these skills is essential. A student project would likely be primarily lab based with some computer programming and image processing, though the exact scope is determined by the student’s research interests. The work generally includes sediment processing (sieving and chemical separation), picking for fossils using a dissection microscope, high resolution digital imaging, dissection of collections-based fish and shark specimens, morphological characterization, and data analysis and interpretation using R. Students will work in a fully wheelchair-accessible laboratory space and collaborate with a multidisciplinary research team committed to high-quality research and effective mentoring in STEM.
Elizabeth Sibert profile Paleo-FISHES Lab

National Park Service scientist Petra Zuniga deploys a temperature profiler at the Herring River restoration site in Wellfleet, MA.

Understanding the interaction between surface water and groundwater is a fundamental aspect of ecosystem and biogeochemical cycling studies in aquatic environments. Surface water penetrating into sediments (infiltration), groundwater discharging into the water column (discharge), and surface water that flows through shallow sediments before returning to the water column (hydrodynamic exchange), all play an important role in modulating solute and nutrient fluxes, but these fluxes are very difficult to measure, and they often exhibit considerable spatial and temporal variability. The simplest way to constrain fluxes is by measuring the sediment thermal gradient because fluid flux modulates both the steady state gradient and the downward diffusion of surface water temperature changes into the sediment. Heat is thus a tracer that can be used to constrain flux rates, and in contrast to other methods, temperature sensors are robust, inexpensive, and essentially maintenance-free. This project involves using newly developed, state-of-the-art, thermal instrumentation to measure groundwater fluxes in natural environments around Cape Cod, and to conduct controlled experiments in a newly built test tank in the AVAST facility. The ideal student will have a background in physics and some experience using Matlab software, though neither is strictly speaking necessary if there is a willingness to learn. Rob Sohn's profile