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Geology and Geography major, Rutgers University
CEOAS mentor: Erin Pettit
Understanding tidewater and lake-terminating glacier dynamics in creation of a historical time series of Bear Glacier Lagoon, Alaska
Bear Glacier Lagoon within Kenai Fjords National Park is a fast-changing lake at the terminus of Bear Glacier. The lake may only be 50-60 years old, but there is very little information on the history and evolution of this lake and the ecosystem it supports. Given limited existing data, what can we say about historical evolution and modern dynamics of this glacier-lake system? This work has two interrelated goals. The first is to visually describe the evolution of Bear Glacier Lake over the last half century using historical maps and satellite imagery in the context of historical climate data, and second, to describe the modern physical and environmental factors that may begin to explain the glacier’s fast retreat and overall circulation. Those factors include the shape of the lake, flow of water, location of the terminus, bathymetry, climate, and oceanic connections. Landsat imagery starting from 1984 allowed for the creation of yearly lake outlines to better observe the retreat of the glacier, as well as the changes to lake levels and circulation between lake, morainal spit, and ocean water. Here we present this historical analysis paired with recent elevation data and local weather statistics to help provide the platform to identify the major events and most likely key processes to focus the next stage of analysis. The creation of this history and initial analysis will ultimately give insight into how Bear Glacier lake was formed, the glacier’s effect on the entire Harding Icefield from which Bear Glacier branches from, and what future changes to expect that may affect ecosystems and recreation. Further, it provides a basis for more in-depth study of the circulation and dynamics of this and other glacial lake systems.
Physics major, Oregon State University
CEOAS mentors: Erin Pettit and Kiya Riverman
Ice flow analysis over Hiawatha impact crater
Hiawatha is a 30km diameter impact crater currently covered by as much as 1000m of ice along the northern margin of the Greenland Ice Sheet. The ice cover makes estimating the age and studying the structure of the crater challenging. The meteorite likely impacted directly onto the ice, melting a substantial amount of ice and disturbing the ice sheet flow dynamics, with subsequent ice flow back over the crater. Impacts onto ice sheets on Earth have not been studied as much as on other astronomical bodies (Kjaer 2018); Hiawatha provides, therefore, an opportunity to study impact processes as well as ice dynamics in this unique setting under a changing climate. Airborne radar profiles collected by the Center for Remote Sensing of Ice Sheets (CReSIS) of the ice structure within the crater show unusual englacial stratigraphy which may be the result of basal freezing and melting in a steady flow regime, or of temporal changes in the flow regime due to either Holocene climate change or recovery from the impact disturbance. Here, we use an ice flow-band model to study modern behavior of the ice sheet under different boundary conditions and compare results to the observed radar stratigraphy. Further, we estimate how long a recognizable signature of the impact disturbance will persist within the ice sheet. We expect that flow patterns from the radar profiles cannot be modeled by a steady state system with a simple distribution of basal freezing and melting, but this initial analysis will provide insight into the dynamic evolution of this region. We also expect that with the observed rate of ice flow, the modern stratigraphy is unlikely to retain evidence of the impact disturbance, yet will be the first step toward understanding the response of the ice sheet after the impact.
Physics and mathematics major, University of Wisconsin
CEOAS mentor: Jim Lerczak
Temperature modeling in an idealized estuary
Estuaries are biologically productive systems and are important for many biogeochemical processes. Temperature impacts the health of estuaries and the ecosystems they support, however, there is a significant gap regarding temperature behavior and variability in estuary research. In this project we constructed an idealized model of an estuary to describe the change in temperature along the estuary channel under a steady state assumption. Using this model we simulated temperature behavior in the Columbia, Hudson, and Yaquina estuaries varying the model's geometry and river behavior to approximate these three estuaries. The results of this model lead us to hypothesize that estuary geometry and river discharge are important factors in along channel temperature distributions. Lastly we compared our model to temperature data collected in the Columbia estuary. We saw for high discharges our model approximately agrees with data however some refining of the model is needed to capture the complete picture of temperature behavior.
Physics major, Oregon State University
CEOAS mentor: Erin Pettit
Measuring bubble pressure in glacial ice
Glacial ice melt predictions at near-vertical ice faces currently underestimate the observed melt rates. One process that can amplify the melt is the release of bubbles into the water from pressurized pores in the ice. This process disturbs boundary layer flow; it is missing from models because the conditions that lead to bubble-induced heightened melt rates (buoyancy and pressure forces) are still not well defined. Pressure is an important factor in the overall impact that bubbles have on glacial melt because higher pressure differences may lead to more disruptive bubble release events. To determine bubble pressure, we use a pressure chamber device with various pressure capabilities. Blocks of glacial ice will be placed in the pressure chamber and a glycerol solution will fill the remainder of the tank, producing a slow surface melt of the ice and allowing an up-close study of the air-bubble release. By describing glacier ice melt rates with bubble pressure as a contributing parameter, current models and understandings can improve, strengthening predictions of future sea level rise. Climate models will also become more reflective of true environmental conditions. Both of these implications will protect humans and enable more educated planning.
Biology major, Cabrillo College
CEOAS mentor: Rick Colwell
Characterization of microfauna along a geochemical gradient at the East Scotia Ridge E2 hydrothermal vent site
Many hydrothermal vents have been discovered near mid ocean ridges and back arc centres around the world and their fauna have been studied. However, a recently found vent site named E2 on the East Scotia Ridge (ESR) is yet to be microbiologically characterized. The objective is to extract DNA from sediment samples collected on the expedition led by Prof. G. Bohrmann (Univ. Bremen/MARUM) conducted on the Polarstern in 2019 (Expedition PS 119), to characterize microbial communities surrounding this hydrothermal vent site. The iron reduction functional genes omcA & mtrB of microfauna surrounding the ESR E2 hydrothermal vent site were quantified along a geochemical gradient and at varying depths using polymerase chain reaction (PCR) to amplify the target genes, a Qubit DNA Quantification HS Fluorometer to quantify the PCR results, and gel electrophoresis visualization of the amplicons was attempted. The Qubit values were analyzed in correlation with geochemical composition data and relative to the vent locations. Quantification of iron reducing functional genes in these hydrothermal vent sediments is a sensible way of seeing whether there are significant distributional patterns that could link to biogeochemical function. Microbial DNA was extracted and quantified from 18 sediment samples up and down gradient of the E2 hydrothermal vent site and six were used for the quantification of omcA & mtrB genes. In our preliminary results it was found that there were higher concentrations of omcA gene DNA after PCR at a core site with high levels of reduced iron down gradient from the E2 vent site and about a similar amount of mtrB gene DNA amongst all the 6 samples after PCR. PCR amplification done on extracted microbial genomes did not yield high enough concentrations of DNA to be visualized on a gel. This suggests that there is a low abundance of microbes that potentially have the ability to reduce iron at the ESR. Eventually, droplet digital polymerase chain reaction (ddPCR) will be used to amplify and more thoroughly quantify the mtrB and OmcA genes associated with iron reduction. Illumina MiSeq paired-end sequencing of the 16S rRNA gene of extracted sample DNA will also be done and would taxonomically characterize the microbial communities. Inference of biogeochemical function complemented with geochemical analyses would help better clarify the metal cycling process near hydrothermal vent systems and the taxonomic survey of the E2 hydrothermal vent sediment microbes would establish groundwork for further metagenomic and or metatranscriptome research at the ESR.
Geology and Environmental Science major, Western Washington University
CEOAS mentors: Alan Mix and Mo Walczak
Presenting at 2021 Geological Society of America meeting, October 10-13, Portland
Paleoceanographic perspectives on Columbia River discharge during the Holocene
The Columbia River is among the largest river systems in North America (fourth in terms of discharge). Its flow influences North Pacific climate and ecosystems, while serving as an essential resource for agriculture, hydropower, shipping, and fisheries. Future warming is expected to influence snowpack, seasonal precipitation, and both atmospheric and sea-surface temperatures, but model projections disagree about both the sign and magnitude of the effects, so the resulting impacts on seasonal and annual river flows remain uncertain. This study assesses past variations in sea-surface salinity from δ18O in planktonic foraminifera over the Holocene along the Oregon margin, to better understand the impact of warming on river flows. Newly collected marine sediment cores off the Columbia River record the influence of the freshwater plume near the sea surface. A chronology based on benthic foraminifera oxygen isotopes and supported by correlation of paleomagnetic secular variation features indicates preservation of a thick, bioturbated sediment sequence with sedimentation rates of 50-80 cm/kyr in the Holocene and 30-230 cm/kyr in the latest Pleistocene. Abundances of planktonic foraminifera are sufficient for developing a high-resolution (century-scale) record of changes in the Columbia Plume through much of the core. We utilize δ18O analysis of several planktonic foraminifera species in the seasonal succession to identify sea surface salinity variation in response to variations in Columbia River discharge over a 15,000-year period during the late Pleistocene and the Holocene, identifying two apparent episodes of freshening/warming of the surface ocean centered at ~14,000 and ~10,000 years ago.
Applied mathematics and environmental science major, University of California, Riverside
CEOAS mentors: Justin Wettstein, Melanie Fewings, Larry O’Neill
North Pacific momentum and heat flux variability: A bridge between ocean and atmosphere
One of the primary challenges in distilling coherent patterns of North Pacific variability and change may be the common use of sea surface temperature as the indicator variable. The change in ocean temperature, not the ocean temperature itself, is constrained by the conservation of energy and associated energy fluxes. We examine a new perspective on North Pacific atmosphere-ocean interaction in 1950-2020 ECMWF ERA5 surface ocean and atmosphere reanalysis data by: 1) focusing on the evolution of sea surface temperature rather than the sea surface temperature itself, and 2) exploring co-variability between the evolution of sea surface temperature and the four radiative and turbulent fluxes that comprise the surface energy balance. We find that the suggestion of fundamentally new regimes of North Pacific ocean-atmosphere interaction in recent decades may need to be more carefully investigated. We can also infer from our preliminary results that a focus on the time evolution of ocean and ocean-atmosphere coupling is likely to provide an insightful perspective on recent and future changes in the North Pacific, with consequences for a variety of natural and human systems.
Geology major, University of California, Riverside
CEOAS mentors: Mo Walczak and Joe Stoner
Do marine sediments from the Cascadia Margin record the geomagnetic field? A preliminary study of piston cores collected during OC2006A from the upper slope adjacent to Grays Harbor Canyon, WA
Magnetic minerals within marine sediments can record paleomagnetic secular variation, or past changes in Earth’s self-generating magnetic field. On the Cascadia Margin, prior work has shown that high levels of marine productivity led to magnetic mineral diagenesis that is thought to obscure and potentially obliterate the paleomagnetic record, thus limiting paleomagnetic and environmental magnetic studies in this region. However, careful evaluation of prior studies and new work as part of the Cascadia H.O.P.S. program suggests PSV signals may still be preserved in the specific depositional environment on the margin. The first paleomagnetic results from the upper continental slope of Sites OC2006A 16JC and 18JC, adjacent to Grays Harbor Canyon. were evaluated against established paleomagnetic criteria to discern the context of the sediment and sedimentation processes associated with that record. The sediments’ physical and magnetic properties were used to evaluate the paleomagnetic record, including shipboard multi-sensor track data and CT scans, along with alternating field demagnetization of the natural remanent magnetization, anhysteretic remanent magnetization, and magnetic susceptibility from u-channels. Common paleomagnetic features observed in coeval intervals of Sites 16JC and 18JC are considered likely to be geomagnetic in origin. These signals were compared to established paleomagnetic secular variation records from a regional stack (NEPSIAS), to explore and evaluate the magnetostratigraphic potential of Cascadia Margin sediments.
Environmental Sciences and Trumpet Performance major, Lawrence University
CEOAS mentors: Erica Fleishman and David Wrathall
A synthesis of global research since 2014 assessing the impact of climate change on people’s livelihoods
As greenhouse gases continue to accumulate in the atmosphere, climate change continues to significantly impact people’s livelihoods, especially those of poor and marginalized groups. We aim to synthesize scientific understanding of the effects of climate hazards on livelihoods of poor and marginalized people worldwide. We use Google Scholar to compile instances of climate hazard-livelihood asset relationships that have been published in the scientific literature since 2014. We aim to use these data to create confidence statements for each climate hazard-livelihood asset relationship. This work will be incorporated into the sixth Assessment Report of the Intergovernmental Panel on Climate Change, and may affect regional and global policy and action related to climate change.
Climate Science major, Oregon State University
CEOAS mentor: Ed Brook
The nitrous oxide record in the new CMC3 ice core from Allan Hills, Antarctica
New ice cores recently obtained from the Allan Hills Blue Ice region of Antarctica contain ice up to 2.7 million years old. Our project aimed to establish the reliability of Allan Hills cores for preserving concentrations of nitrous oxide, an important greenhouse gas and ozone-depleting substance, by obtaining a record of nitrous oxide concentrations for the penultimate glacial termination. This record may provide additional justification for analyzing nitrous oxide concentrations in much older ice from the Allan Hills site. We utilized gas chromatography and a vacuum extraction line to obtain nitrous oxide concentration data for 33 samples from the new CMC3 ice core from Allan Hills for a time period of roughly 127,000 to 146,000 years before present. Preliminary comparison of these data to existing records suggests that CMC3 cores reproduce the glacial to interglacial change in nitrous oxide from other ice cores, and may contain reliable concentration data for a glacial period with no previously established record.
Earth and Planetary Sciences major, Johns Hopkins University
CEOAS mentor: Brodie Pearson
Transfer of energy in Jupiter’s atmosphere
The dynamics energy transfer within Jupiter’s upper atmosphere provide a powerful means for exploring turbulence. Such an exploration can aid in understanding the properties of other turbulent systems including the oceans of Earth and the atmospheres of other planets. Many turbulent systems, including Jupiter’s atmosphere, are difficult, if not impossible to measure directly, however given information about velocity at two specified points separated by a vector of defined magnitude, r, the rate of transfer of kinetic energy can be calculated with the use of a structure function. A structure function is an easy-to-calculate statistic that can be used to ascertain information about the transfer rates at different scales in complex turbulent fluid systems. Several permutations of structure functions have been developed and applied to the study of turbulence using data derived from both computer models and empirical observations. Traditionally, a structure function adapted from Kolmogorov’s Law has been used, Young and Read (2017) however this method does not account for Jupiter’s anisotropic conditions. Recently, a new advective structure function has been developed to account for this anisotropy Pearson et al. (2021) and has been applied to simulated turbulent systems Pearson et al. (2021), but never has it been tested on a natural system like Jupiter. Using images from the NASA Cassini-Huygens mission which provide velocity and displacement data, this new advective structure function will assess transfer rates of energy across a range of displacements to be compared to Young and Read (2017) in their resulting values, trends, and variability.
Chemistry major, Indiana University of Pennsylvania
CEOAS mentor: Mary Santelmann
Investigation of Diurnal Stream Chemistry Patterns in Schooner Creek and Other Coastal Streams, OR
Oregon’s coastal range streams are geologically young, receive the state’s highest amounts of precipitation, and are diverse in nature. These streams have not been extensively studied, and it is of great interest to generate baseline data and discover if they exhibit diurnal chemistry patterns. Diurnal patterns in chemistry can be used to assess, understand, and monitor stream condition, implement conservation projects, and evaluate current sampling method integrities. Schooner Creek is an undammed coastal stream that meets the Pacific Ocean through Siletz Bay near Newport, Oregon. A case study was performed here on July 27th, 2021, from 7 a.m. to 6 p.m. to observe these patterns over a 12-hour period by recording field measurements and collecting samples for lab analysis at the Oak Creek Collaboratory. Results and past sonde data showed that Schooner Creek exhibits diurnal patterns in pH, specific conductivity, temperature, and dissolved inorganic carbon, but not dissolved organic carbon, generating more questions about stream condition and baseline data in Oregon’s coastal range.
Geology major, Western Washington University
CEOAS mentors: Mo Walczak and Alan Mix
Presenting at 2021 Geological Society of America meeting, October 10-13, Portland
A paleoceanographic perspective on the final days of Glacial Lake Russell, Puget Sound, Washington
During the Late Pleistocene, Glacial Lake Russell formed at the southern margin of the Puget Lobe of the Cordilleran Ice Sheet as it retreated out of the Puget Sound region. Fresh water from the lake flowed through what is now the Chehalis River and discharged into the Pacific Ocean out of Grays Harbor, depositing sediment offshore in and around Grays Canyon. The discharge from Glacial Lake Russell via Grays Harbor eventually shut-off as ice retreated and opened a new drainage route farther north via the Straits of Juan de Fuca. The timing of the final drainage of Glacial Lake Russell is not well constrained on land but it is preserved in the offshore sediment record where it can be readily identified and dated. Here we present results from the jumbo piston core OC2006A-18JC and its corresponding trigger core, recovered from a fine-grained hemipelagic sediment package accumulating on a rise near the southern slope of Grays Canyon. Downcore δ18O on benthic foraminifera places the timeline of regional glacial retreat into global context, suggesting the basal part of the studied sediment sequence dates to ~17,000 years before present. Salinity estimated from δ18O values on planktonic foraminifera as well as benthic and planktic foraminiferal faunal data identify millennial-scale oscillations in ambient ocean conditions and fresh-water discharge to the ocean during deglaciation. In conjunction with sediment physical properties, low-resolution faunal data, and depositional structures these data constrain the cessation of proximal glacial-marine sediment delivery, indicating that the Puget Lobe of the Cordilleran had retreated to the Strait of Juan de Fuca and Glacial Lake Russell had vanished by or before 12,000 years before present. This study provides insight into the retreat of the southwestern Cordilleran Ice sheet and the impact of regional freshwater inputs associated with drainage of Glacial Lake Russell on the adjacent marine environment.
Geology major, The College of Wooster
CEOAS mentor: Frank Tepley
Presenting at 2021 Geological Society of America meeting, October 10-13, Portland
How are they related? Determining the composition of biotite-bearing rhyolitic and dacitic tephra-fall deposits from Misti, Peru
Misti volcano in Peru has a long eruption history that continues into the present day. It has produced andesitic material for the vast majority of its history, however, there are four biotite-bearing units present in the stratigraphy (Cogollo, Anchi, Sacarosa, and Conchito) dating around 40-25 ka. Their specific compositions and relationship to each other are unknown. Petrography and geochemistry of the glasses and crystals in two of these units, Cogollo and Conchito, were used to determine the relationship between them, using a petrographic microscope and electron microprobe. Based on our analyses, the petrography of the Cogollo and Conchito are demonstrably different. The Conchito contains amphibole whereas the Cogollo does not, and the Conchito has a greater number of smaller, broken crystals than the Cogollo. Plagioclase crystals from the Conchito have a higher anorthite content, but there is abundant overlap in composition with the Cogollo. The Mg# of biotite in the Conchito is slightly higher than the Cogollo. While it is clear there is a difference between the Conchito and Cogollo, there are no strong indicators of the mechanism (such as mixing or fractionation) behind these unique eruptions. Based on these geochemical indicators, the Cogollo came from a more evolved magma (more Si content, lower An content), than the Conchito (lower Si content, higher An content), but it is unknown why this change occurred.