Physical Sciences and Mathematics Commons^™

Comstock Point, Lubec, Maine - A Natural And Photographic History, Willaim H. Schlesinger, Lisa M. Dellwo

Documents from Environmental Organizations

A natural and photographic history of our lands compiled by Lisa Dellwo and Bill Schlesinger, with the help of many friends and neighbors.

Quantifying Tidewater Glacier-Fjord Environments In The Rapidly Changing Regions Of West And South Greenland, Sydney Baratta

Electronic Theses and Dissertations

The Greenland Ice Sheet has undergone rapid mass loss over the last four decades, primarily through solid and liquid discharge at marine-terminating outlet glaciers. The acceleration of these glaciers is in part due to the increase in temperature of ocean water in contact with the glacier terminus. However, quantifying meltwater injection and heat transport can be challenging due to iceberg abundance, which threatens instrument survival and fjord accessibility. Additionally, acceleration and eventual retreat of tidewater glaciers onto land can change glacier forcing, completely altering fjord water-meltwater dynamics. Here, we couple in situ and remote sensing methods to quantify the upper-layer …

Spatial And Temporal Variability In Snow Properties And Firn Volume Across The Juneau Icefield In Southeast Alaska, Mikaila Mannello

Electronic Theses and Dissertations

Glaciers are important freshwater resources which have far reaching impacts on a range of local to global systems and processes, including ecosystems and societies. As global climate continues to change, the response of glaciers has largely been reductions in ice mass and widespread retreat. A high degree of accumulation and ablation occurs in the near surface which is exposed to the atmosphere. The Juneau Icefield (JIF) has, up until the mid-2010s, historically responded climate change anomalously where its main drainage, Taku Glacier (here forward referred to its native name T’aakú Kwáan Sít’i), has been advancing while all other JIF outlet …

Rheological Bridge Zones: A New Perspective To Explore Strain Localization And Rock Rheological Weakening, He Feng

Electronic Theses and Dissertations

Strain localization, a ubiquitous geological phenomenon, emerges when rock undergoes extensive weakening and accommodates disproportionate deformation. This phenomenon spans from brittle faulting to viscous flow, known as shear zones. Despite its prevalence, discussions on weakening primarily center on highly strained samples, rather than the initial deformation state. This research delves into the evolution of localization and rheology in intact rocks.

Heterogeneous mechanical properties within the lithosphere vary based on mineralogy, microstructure, and environmental conditions. Chapter 2 characterizes microscale structures termed "bridge zones." These zones, observed through optical and electron microscopy, exhibit distinctive morphologies. Comprising fine-grained aggregates, bridge zones link weak …

Kinematic Vorticity And Porphyroclast Rotation In Mylonites Of The Norumbega Fault System: Implications For Paleoviscometry, Hendrik Lenferink

Honors College

Crystallographic and shape preferred orientation (SPO) fabrics that develop in mylonitic shear zones can preserve the mean kinematic vorticity number (Wm) of bulk flow. Microstructural methods exploiting dynamically recrystallized quartz and porphyroclast SPO fabrics typically yield conflicting values of Wm. The Sandhill Corner Mylonite Zone of the Norumbega Fault System, Maine, USA, serves as a case study for investigating this discrepancy; Wm estimates range from 0.90 to 1.00 employing the former method (Method 1) and from 0.3 to 0.6 employing the latter method (Method 2). Using a numerical model, I show how a low-viscosity layer (LVL) surrounding clasts affects their …

Investigating Mercer's Paradox: A 10be Chronology Of Moraines Deposited During The Last Glaciation At Soda Lake, Wind River Range, Wyoming, U.S.A., Lauren M. Woods

Electronic Theses and Dissertations

Here I use geomorphic mapping and ¹⁰Be surface-exposure dating to address the paradox that lies within the general understanding of the mechanisms driving ice-age climate and glacial cycles. The long-standing and widely accepted Murphy-Milankovitch hypothesis suggests glacial cycles are controlled by the local intensity of summer-time insolation. By this hypothesis, glacier maxima should be achieved at times of low insolation intensity and asynchronously between the polar hemispheres, a pattern which is inconsistent with the glacial geomorphic record. The ¹⁰Be chronology I have constructed of moraines at Soda Lake, Wind River Range, Wyoming, U.S.A. shows nine glacial advances to …

A Bi-Hemispheric Perspective On The Last Glacial Maximum And Termination Using 10be Surface-Exposure Chronologies From An Interhemispheric Asia-Zealandia Transect, Peter Strand

Electronic Theses and Dissertations

Late-Pleistocene glacial cycles represent the largest natural changes to Earth’s climate over the past one million years, and yet determining the underlying drivers remains a major mystery in paleoclimate. The observation of generally synchronous glaciation and deglaciation between the polar hemispheres (Mercer, 1984) runs contrary to long-standing ice age theory (e.g. Milankovitch, 1941), and was recently dubbed ‘Mercer’s Paradox’ (Denton et al., 2021). In this thesis I derive regional climate records from mountain glaciers along an interhemispheric Australasian transect, extending from the Mongolian Altai to the Southern Alps of New Zealand, to test the existence of Mercer’s Paradox in the …

Scaling Up The Relevance Of Land-Sea Connections In Coastal Bacteria Pollution Vulnerability, Bea E. Van Dam

Electronic Theses and Dissertations

Bacteria pollution closures of Maine’s coastal shellfish harvest areas have substantial negative consequences for coastal businesses and communities. Sustainability solutions for Maine’s shellfish harvesting areas and businesses require new types of knowledge and information to protect water quality and public health while avoiding unnecessary fishery closures. Coastal management agencies have interests in tools to support science-based management decision-making related to pollution and sustainability solutions for businesses and communities.

Prior research into land-sea connections has demonstrated uses of geographic information and statistical methods to facilitate management and science communication. Research in Maine has focused on identification and comparison of attributes influencing …

The Upper Ocean At The End Of An Ice Age: Using Proxies In Benthic Foraminifera To Investigate Intermediate Water Changes During The Last Glacial Termination, Cassandre R. Stirpe

Electronic Theses and Dissertations

The ocean is an important component of the global climate system and plays a key role as a storage reservoir for heat and carbon. Under glacial conditions, the ocean sequestered carbon from the atmosphere, contributing to a cooler global climate. During the last glacial termination, that carbon was released back into the atmosphere, but the exact timing and mechanisms of this transfer are still not fully understood. This study examines waters from the intermediate depths of the Southern Ocean to gain insight into deglacial processes. Intermediate waters are capable of reacting to climate change on decadal timescales, making them a …

Stratigraphic Architecture Of Pozuelo Mounds As Revealed By Earth Resistivity Tomography, Caeli Connolly

Honors College

This study is a geoarchaeological analysis using earth resistance tomography (ERT) surveys of two of four mounds at Pozuelo (Formative Period, cal yr 3000 BP) in the Chincha Valley of coastal, southern Peru. Layers identified in the subsurface were to determine the presence or absence of regional continuity between the mounds. This effort is part of a larger investigation examining the paleoenvironmental setting of the site, and its influence on site location and use. Ten earth resistance tomography profiles were collected using an ABEM Terrameter LS2 and 81 pin array. These profiles were then topographically corrected using topographic survey data …

Lethal And Sublethal Effects Of Beauveria Bassiana On Maine Ticks Across Soil Ph, Alexander Mahar

Honors College

Ticks are obligate parasite arthropods that are becoming increasingly common in northern regions of the United States. Ticks such as the black-legged tick (Ixodes scapularis) and the American dog tick (Dermacentor variabilis) are vectors for pathogens that cause a wide range of diseases, and as these ticks increase their exposure to humans, the diseases they transmit become more prevalent. This upward trend in cases of tick-borne illnesses has necessitated the pursuit of tick control methods that can be used across the diverse environments that are present in tick habitat ranges. One such control method is the fungal biological control, Beauveria …

Assessing College Students' Understanding Of Geologic Timescales, Ethan Couture

Honors College

Geologic timescales are central to many concepts in the natural sciences, including evolution, climate change and plate tectonics. However, geologic time scales can be challenging to appreciate, especially for those who have not had exposure to such topics previously. During primary and secondary education (K-12) students are provided with foundational information about geology that is then further developed in specialized classes in college. Yet most students are not getting this foundation, which could arguably lead to deficits in their post-secondary education. Despite the importance of these concepts, especially for those interested in careers associated with geologic timescales, there have been …

Modeling Franconia Ridge, New Hampshire Using Structure From Motion And Developing New Techniques For Fracture Detection, Dane Johnson

Honors College

Bedrock fracture density is an important characteristic of bedrock that determines its structural formation, the potential for groundwater or fluid flow, and the capacity of erosion for exposed features. In the case of the Franconia Range, there are two primary bedrock lithologies that we wish to analyze. In this research, we conduct the first structural analysis and quantification of the bedrock fracture density of this region using Structure from Motion modeling and machine learning algorithms. Additionally, the algorithms were supplemented to be useful in determining fracture density in the subsurface geology of Ground-Penetrating-Radar (GPR) radargrams. The products of this work …

The Surprising Oceanography Of The Gulf Of Maine, Nicholas R. Record, Benjamin Tupper, Johnathan Evanilla, Kyle Oliveira, Camille Ross, Logan Ngai, Karen Stamieszkin

Maine Policy Review

The oceanography of the Gulf of Maine has changed in ways that have not been seen previously but that are likely to be more common in the future–changes like extreme rapid warming and declines in primary productivity. The changing oceanography has underpinned surprising losses in commercial stocks and endangered species. Because of the rapid rate of change, some have viewed the Gulf of Maine as a window into the ocean’s future, with the idea that lessons learned can be applied in places that have yet to experience similar rapid changes. We can examine the dynamics, origin, and implications of surprising …

Holocene And Last Glacial Period Atmospheric Dynamics And Biogeochemistry Based On South Pole Ice Core Microparticle And Trace Element Records, Aaron Chesler

Electronic Theses and Dissertations

I develop and interpret a record of dust deposition from the South Pole ice core (SPC14) to identify changes in atmospheric variability. The SPC14 core was drilled during 2014 – 2016 and provides a high accumulation (~7 cm w.e.q. per year) record in central Antarctica that reaches a depth of 1751 m (~54 ka). My analysis combines microparticle (dust) concentration, size, and shape metrics using continuous and discrete methodologies and high- and low-resolution multifractional Fe analyses that span the past 54 ka.

Results from my dust shape analysis suggest the common assumption of spherical dust particle shape in incorrect and …

First-Row Transition Element Distribution Across The Blueschist-Eclogite Transition: A Case Study From New Caledonia, Natalie M. Harmon

Electronic Theses and Dissertations

The first-row transition elements (FRTE), namely Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn, are potential redox tracers in the solid Earth due to their general compatibility during crustal processes, and the redox-sensitive nature of certain elements. Despite widespread interest in the FRTEs, their distribution and behavior in subduction zones, particularly across the blueschist-eclogite transition, are still poorly constrained. New Caledonia preserves a prograde subduction zone with largely coherent continuous progression in metamorphic grade. Although the metamorphic sequence has been disrupted to some extent, this is the closest natural example of blueschist and eclogite that was sourced …

Carbon Dioxide Emissions From Deadwood In Forests Of The Northeastern United States, Zoe Read

Electronic Theses and Dissertations

As the climate changes, understanding the sources and sinks of greenhouse gases such as carbon dioxide (CO₂) is increasingly important. However, several components of the carbon cycle within forests remain poorly understood. For example, knowledge gaps exist in our understanding of CO₂ emissions from coarse woody material (CWM; logs and stumps), including how emissions change over time, how they are influenced by environmental variables, and how they compare to soil and ecosystem-level CO₂ emissions.

To fill these knowledge gaps, we examined CO₂ emissions from CWM at three sites. We sampled 18 red spruce (Picea …

Regional Scale Generalizations Of Firn Thickness And Snow Accumulation In Southeast Alaska: An Applied Deep Learning Framework, Jonathan Maurer

Electronic Theses and Dissertations

High elevation mountain glaciers are referred to as the “water towers of the world” due to their ability to store water internally and release it later through melt and runoff. Much of the work to understand these complex environments has focused on cold based polar glaciers in high latitude regions, neglecting temperate glaciers and associated snowpack which are more responsive than polar systems to minor climatic changes. Advancements in the availability of open source data, deep learning theory, and computational efficiency has opened up new methods of “data hungry” modeling that may be well suited to the type of complex …

Investigation Of Cryptotephra In Polar Ice Cores, Meredith Helmick

Electronic Theses and Dissertations

Volcanic ash (tephra) present within polar ice cores greatly supplements our understanding of past volcanism and its impacts on society and the state of the climate system. This thesis investigates the utility and limitations of ice core tephrochronology in answering questions related to volcanic source identification of ice core glaciochemical signals, tephrostratigraphy of an Antarctic ice core, and the timing of major and climate forcing eruptions. This thesis explores the efficacy of SEM-EDS measurements on ultra-fine (µm) volcanic particles for the purpose of geochemically characterizing a non-visible ice-embedded tephra and the subsequent identification of the volcanic source. In combination with …

Anthropogenic Effects On Tidal Distortion In A Tidal River, Matthew D. Fischer

Electronic Theses and Dissertations

Tidal rivers are landward portions of estuarine systems constituting the union between coastal, tidally controlled settings and rivers, where fluvial processes dominate. In these reaches, river discharge (mean flow) and tides are the two most important mechanisms in controlling geophysical flows. The processes governing water levels and current amplitudes in tidal rivers are highly nonlinear and modulated by external forcings- thus requiring sophisticated techniques for accurate prediction and forecasting. Physical oceanographers and estuarine physicists tend to limit their study area to the maximum extent of the horizontal tide (salinity intrusion), not the most landward point influenced by tidal water levels. …

Arcmap Basics: Wpes, How Do I...? Quick Guide, Bea E. Van Dam

Non-Thesis Student Work

This document is a quick guide to performing common geospatial tasks in ArcMap 10.x (ArcGIS Desktop) for new users. Covered are basic navigation of the ArcMap window; importing, opening, querying, editing, and exporting data; and map preparation. In many cases, there are multiple ways to accomplish different tasks; presented here are the methods the author finds easiest or most straightforward. Mouse click sequences and menu/tool layout may differ if using previous versions of ArcMap.

Microstructural Analysis For Dynamic Pulverization And Asymmetric Damage At The Base Of Seismogenic Strike-Slip Faults, Bo Ra Song

Electronic Theses and Dissertations

Although the mechanics of continental, seismogenic strike-slip faults have been primarily studied around active faults near Earth’s surface, large earthquakes on these faults commonly extend to depths between 10 and 20 km. At the base of seismogenic strike-slip faults, interaction and feedback between coseismic brittle fracturing and post- and interseismic viscous flow affect transient and long-term changes in stress cycling, fluid and heat transport, fault strength, and associated strain localization and deformation mechanisms. A primary goal of my dissertation is to explore the deeper structures of damage zones near the base of the seismogenic zone and to better understand the …

Quantifying Spatial Heterogeneity Of Wild Blueberries And Crop Water Stress Monitoring Using Remote Sensing Technologies, Kallol Barai

Electronic Theses and Dissertations

The wild blueberry is one of the major crops of Maine, with significant economic value and potential health benefits. Due to global climate change, drought impacts have been increasing significantly in recent years in the northeast region of the USA, causing significant economic losses in the agricultural sectors. It has been predicted to increase further in the future. Changing patterns of the elevated atmospheric temperatures, increased rainfall variabilities, and more frequent drought events have made the wild blueberry industry of Maine vulnerable, suggesting the adoption of novel approaches to mitigate the negative impacts of global climate changes. Also, wild blueberry …

Assessment Of Historical Climate Variability In Maine With Implications For Future Agricultural Productivity And Adaptation, Carly Frank

Electronic Theses and Dissertations

Climate change is a wicked problem with global impacts, one of which being the sustainability of the existing global food system. As temperatures and variability in precipitation are projected to increase, the challenges to agriculture are expected to intensify. This thesis examines the Maine historical climate record over the growing season, in combination with future projections, to assess how conditions have changed and will change with agricultural implications. In this analysis, relevant climatic variables are analyzed, and agriculture-significant measures are derived for Maine’s three climate divisions using four decades of daily and monthly gridded datasets. In addition, this thesis explores …

Glaciochemical Investigations In Three Southern Hemisphere Mountain Sites, Mariusz Potocki

Electronic Theses and Dissertations

The research presented in this dissertation focuses on glaciochemical records of trace elements, major ions, and stable water isotopes from three mountain regions: the Antarctic Peninsula, the Central Chilean Andes, and South Georgia Island.

The first section reports a significant increase in U concentration over 27 years on Detroit Plateau, Antarctic Peninsula. U concentrations in the ice core increase by as much as 102 between the 1980s and 2000s, accompanied by increased variability in recent years. The U concentration increase coincides with expanded open pit mining in the Southern Hemisphere, most notably Australia. Since other land-source dust elements do not …

Structure From Motion Methodology Captures Seasonal Influences On Coastal Bluff Erosion And Landslide Hazards In Casco Bay, Me, Nicholas Whiteman

Electronic Theses and Dissertations

Shoreline erosion in response to rising sea level is a global problem. Recognizing the need for observational data on coastal bluff recession in Casco Bay, Maine, we employed Structure from Motion (SfM) photogrammetric methods in a dynamic intertidal environment. Evaluating the method as a means to measure and monitor dynamic geomorphological changes occurring at a coastal bluff shows that a spatial resolution of centimeters over an area of 10’s to 100’s of meters can be attained at relatively low cost. The efficient methodology allows for frequent surveys at an operational scale, leading to greater temporal resolution and quantification of bluff …

Overlapping Scales Of Place Based Indigenous Knowledge And Hydroclimate In Australia, Rachel L. Coleman

Electronic Theses and Dissertations

Indigenous Peoples have been monitoring and adapting to uncertainty and change in their local regions for millennia, resulting in a holistic view of the interlinkages within the occupied complex socio-environmental systems. This research consists of investigating the overlapping scales of knowledge within Indigenous Australian seasonal calendars and colonial methods of hydroclimate assessment for improving adaptability to climate change impacts.

The analyses began with a sample of 25 Indigenous seasonal calendars providing a glimpse into interlinkages among biota, environment, and meteorology of the localised regions. Across the calendars, five themes of information and multiple categories within these themes became apparent and …

Giving Form To Flow: Modeling The Paleohydrological Context For Human Settlement And Water Use In The North-Central Coast Of Peru, Elizabeth Leclerc

Electronic Theses and Dissertations

Within coastal Andean archaeology there is a growing emphasis on the roles of hydrology and hydrological knowledge in Andean strategies for water management, settlement, and land use. Hydrological methods can not only help reconstruct past water environments but also illuminate the influence of changing climates and conditions in the Andean highlands on coastal water flows. Through a case study of the Supe River basin in north-central coastal Peru, focusing on the period from 5000 to 3000 calibrated radiocarbon years before present (cal. BP), I review several hydrological methods useful for archaeological study. I then combine these to develop a paleohydrological …

Riders On The Storm: Using Satellite Transmitters To Quantify American Woodcock Movement Behavior Following Extreme Weather Events, Katherine Trebilcock

Honors College

The American Woodcock (Scolopax minor) has experienced steady declines in abundance over the past fifty years, which has raised questions as to why (Sauer et al. 1991). Migration for many birds, woodcock included, is energetically intensive, and may be the cause for greater mortality compared to other times of the year (Newton 2007). Despite this, there remains uncertainty in how conditions encountered during migration affect their movements and survival. One obstacle that birds must face is extreme weather, which has been increasing in intensity and occurrence due to climate change. How these events impact a migrating woodcock has been speculated …

S6e6: How Do Changing Conditions In The Arctic Affect Maine?, Ron Lisnet, Karl Kreutz, Kristin Schild

The Maine Question

Changes in the Arctic affect Maine, despite them being separated by more than 1,000 miles. Several scientists from the University of Maine study these shifting conditions of the climate and environment in the region and their impacts. In 2018, the UMaine Arctic Initiative was formed to build on their work and enhance collaboration in the campus community and with outside stakeholders.

In this episode of “The Maine Question” podcast, scientists Karl Kreutz and Kristin Schild from UMaine Arctic and the UMaine Climate Change Institute discuss their research, and elaborate on the region and its shifting conditions influence the state.