Oceanography and Atmospheric Sciences and Meteorology Commons^™

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 …

Wave Attenuation Through Submerged Oyster Aquaculture Cages, Liam T. Hanley

Electronic Theses and Dissertations

Coastal erosion presents a growing issue to shorelines around the world and is especially harmful to Maine, a region where sea-level rise is higher than the global average. Green and hybrid coastal defense strategies are being implemented around the country to provide sustainable, habitat-friendly solutions to erosion control. Maine is a hotspot for commercial aquaculture, with an estimated $13.6 million economic impact. This study looks to bridge the gap between Maine aquaculture and the living shorelines initiative, by determining the wave attenuating properties of submerged oyster cages. The project will be able to inform local oyster farmers, resource planners, and …

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 …

The Response Of The Zooplankton Community In The Western Gulf Of Maine To A Shift In Oceanographic Conditions: 2005-2017, Emma Cecile Dullaert

Electronic Theses and Dissertations

The Gulf of Maine (GoM) harbors a productive ecosystem that supports a wide variety of marine life, providing services upon which local communities rely. The GoM ecosystem supports many important commercially harvested species, including the American lobster (Homerus americanus) which is the most valuable fishery in the US, Atlantic herring (Clupea harengus) and a variety of groundfish. The GoM is also home to the critically endangered North Atlantic right whale (Eubalaena glacialis), which has historically been known to feed in the eastern GoM and Bay of Fundy during the summer and fall months. In …

Collaborative And Engaged Research To Strengthen Equity And Adaptive Governance In Co-Managed Fisheries, Gabrielle V. Hillyer

Electronic Theses and Dissertations

Small-scale, co-managed fisheries are found throughout the world and often represent intertwining cultures, societies, communities, economies, institutions, and governments. They face complex issues, derived from ecological and social sources. Solving these issues requires diverse expertise, often developed through engaged methodologies which can facilitate collaborative solution creation between researchers, community members, and others. In this dissertation, I demonstrate the benefits of these engaged methodologies and review how they, when coupled with anticolonial approaches to research, can create more equitable solutions to complex issues. This dissertation focuses on multiple projects within the wild clam fishery in Maine including: (1) the creation of …

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 …

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. …

Simulations Of Coastal Currents, Transport And Population Connectivity Of Blue Mussel (Mytilus Edulis) In The Gulf Of Maine, Denghui Li

Electronic Theses and Dissertations

Sections of the coastal Gulf of Maine (GoME) differ in circulation, temperature, salinity, and primary production. These regional differences as well as their temporal changes, together with biological factors, such as the vertical migration, pelagic larval duration, etc., determine marine larval transports, and further affect the population connectivity, and community assembly in the intertidal GoME. To investigate the variations of coastal currents in the GoME, we built a high-resolution circulation model covering the shelf seas from Long Island Sound to the Gulf of St. Lawrence, This model was quantitatively validated with observed sea surface height (SSH), time series of temperature, …

Archaeological Bivalves As El Niño-Southern Oscillation (Enso) Proxies, Frankie St. Amand

Electronic Theses and Dissertations

El Niño-Southern Oscillation (ENSO) is a climate phenomenon with periodic events that impact humans in the study area along the North Coast of Peru. In this region, Eastern Pacific and Coastal El Niño events are associated with anomalously high sea surface temperature (SST), reduced upwelling, and heavy precipitation (Grados et al., 2018; Sandweiss et al., 2020). Major changes in ENSO occurred during the Mid- to Late-Holocene, ca. 5.8 and 2.9 ka, resulting in rapid increases in event frequency to modern conditions. To better identify human adaption to changing climate during the Holocene, we must improve our understanding of ENSO. Though …

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 …

Remotely Sensed Assessment Of The Preferred Habitat Of Alexandrium Catenella In The Gulf Of Maine And The Bay Of Fundy, Andre F. Bucci

Electronic Theses and Dissertations

Harmful Algal Blooms (HABs) of the toxic dinoflagellate Alexandrium catenella are an annually recurring problem in the Gulf of Maine (GoM), resulting in risks to human health and substantial economic losses due to shellfish harvesting closures. The monitoring approaches in the region are restricted to real-time identification of the HABs events, when they are clearly underway and already causing deleterious effects to the environment. To fully function as an early warning system rather than an immediate response, monitoring strategies need to be focused on environmental conditions preceding A. catenella HABs. However, the current understanding of the preferred habitat for A. …

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 …

The Effects Of Rising Ambient Temperatures On Thermoregulation And Range Shifts Of Northern Flying Squirrels, Elise K. Gudde

Electronic Theses and Dissertations

Climate change may potentially alter a species’ range distribution and thus the relationship between environmental temperatures and animal performance as a response to climate warming has become an important area of research. Two species of flying squirrel in North America, the southern flying squirrel (Glaucomys volans) and the northern flying squirrel (Glaucomys sabrinus) have undergone northward range shifts, with climate warming being the suspected driver. Because they are nocturnal and tree nesting, flying squirrels may be particularly susceptible to warmer temperatures, as they will experience the highest daily ambient temperatures during their resting phase. I used G. sabrinus as a …

Sustainability As Justice Engaging With North American Alternative Seafood Networks Through Participatory Action Research, Paloma Henriques

Electronic Theses and Dissertations

Transformations in the ways we relate to the ocean are long overdue given the myriad of anthropogenic problems that exist – from overfishing to plastic pollution and acidification to ‘slavery-at-sea ’ and loss of access and fishing rights. Yet alongside the hegemonic modes of ocean exploitation exist diverse alternative economies, including those associated with alternative seafood networks, that aim to create different and more-than-economic relationships with marine systems. To situate my research within the broader literature, I interpret the widely used Brundtland Report definition of sustainability, “meet[ing] the needs of the present without compromising the ability of future generations to …

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 …

High Resolution Remote Sensing As A Tool To Improve Coastal Habitat Mapping In The Gulf Of Maine, Gabriel Hesketh

Electronic Theses and Dissertations

The derivation of oceanographic and biological parameters from remote sensing is well documented across decades of research. Careful evaluation of satellite products provides insight into the optimal algorithms for image processing, research, and various biogeographical applications. Archived multi-satellite data from the United States Geological Survey offers users decades of continuously updated global data, and the agency has recently updated the Landsat portion of its catalog with Collection 2 files, which offers both Level 1 and Level 2 processed data products. Here, we evaluate the Collection 2 improvements using several published algorithms currently used to derive sea surface temperature, chlorophyll, and …

Anthropogenic Impacts To Essential Habitats In The Gulf Of Maine: A Case Study Of The American Lobster, Homarus Americanus, And Its Fishery, Andrew Goode

Electronic Theses and Dissertations

The Gulf of Maine has been fundamentally altered by anthropogenic forcings for decades and offers an ideal study system to monitor response to change. Through complex interactions between ocean warming, altered demographic bottlenecks, and reduced top-down controls, the American lobster (Homarus americanus Milne Edwards) capitalized on favorable conditions and proliferated within the Gulf of Maine. These changes catalyzed the expansion of the lobster fishery, elevated its status as North America’s most valuable marine resource, and shifted coastal communities towards a virtual lobster monoculture. The same processes that facilitated lobster to capitalize on favorable conditions may come with unintended consequences …

Hydrodynamic Impacts Of Expanding Aquaculture, Zhilong Liu

Electronic Theses and Dissertations

Climate change may potentially change aquatic systems and bring certain risks for aquaculture development. Understanding interactions between aquaculture and the environment helps to ensure aquaculture expansion is sustainable in the future. It is critical to determine how farms influence tidal flow patterns, turbulence, mixing and material transport in estuaries. This research aims to determine the flow response of an oyster farm, predict how expanding farms and farm placement will alter estuarine dynamics, and understand how the design of a farm influences material transport.

The hydrodynamic response of a floating oyster aquaculture farm in a low inflow estuary (the Damariscotta River …

Variations In Zooplankton Communities As Indicators Of Biological Responses To Climate Change And Recovery From Acidification In Northeastern And Maine Mountain Lakes, Stephanie Dykema

Electronic Theses and Dissertations

Since the Clean Air Act Amendments of 1990, lakes in Maine and much of the Northeastern US have seen significant shifts in response to reduced atmospheric deposition as well as climate change. The organisms that inhabit lakes are susceptible to environmental change, but our understanding about how biological communities react to simultaneous changes in geochemistry and climate is incomplete. This research investigates how zooplankton communities respond to geochemical changes and warming, on both long-term and seasonal scales. These small organisms are sensitive to changes in physical lake conditions, and variation within zooplankton communities could indicate larger ecosystem shifts. We evaluated …

Farmer Engagement Through Mental Modeling: Opportunities For Climate Change Outreach, Ruth S, Clements

Electronic Theses and Dissertations

Climate change poses a challenge to farming systems worldwide. Effective adaptation and mitigation may be facilitated by outreach that is locally tailored and framed in terms of farmers’ perceptions and values. However, existing research suggests that farmers and those providing outreach may have different climate change perspectives, and there is little understanding of how farmers consider and prioritize climate change in relation to other aspects of their farming system. Furthermore, the diverse agricultural, economic, social, and environmental challenges farmers face require agricultural research and engagement efforts that can identify and adapt to farmers’ dynamic priorities and perceptions. Mental modeling is …

Deciphering The Ecology Of Aulacoseira Taxa In Alpine Lakes: Implications For Paleoclimate Reconstructions, Edna Luz Pedraza Garzon

Electronic Theses and Dissertations

Diatoms of the genus Aulacoseira are thought to bloom during enhanced lake mixing. Thus, changes in their relative abundances in lake sediment records may track lake thermal conditions and be used to reconstruct past climate. However, the lack of species-specific ecological information for the genus, and taxonomical conflicts for low-height mantle taxa, generates uncertainty about the conditions in which they occur. As many of the environmental reconstructions analyzing alpine lake sediments report species from this genus, it is relevant to understand the factors that control their growth and persistence to improve climate inferences. This research focused on low-mantle species, particularly …

Fostering Coastal Destination Resilience In Maine: Understanding Climate Change Risks And Behaviors, Lydia Horne

Electronic Theses and Dissertations

Tourism is an increasingly important global industry. Coastal and nature-based tourism destinations are especially vulnerable to climate change. Trends in visitation are expected to shift under changing climate conditions, influencing tourist travel behaviors related to destination selection, timing of visits, and activity participation. Tourism suppliers’ adaptation and mitigation behaviors have the potential to alleviate negative shifts in visitation and respond to negative climate change impacts, while also enabling suppliers to take advantage of emerging opportunities. The purpose of this dissertation is to understand how tourism stakeholders, including tourism suppliers (i.e., business owners, managers) and consumers (i.e., visitors), perceive their risk …

Optical Signatures Of Plankton In The Open Ocean: From Individual Cells To Global Patterns, Nils Haentjens

Electronic Theses and Dissertations

Marine plankton ecosystems play a major role on Earth, having implications for the global carbon cycle and the food-web structures. Ocean color satellites and networks of autonomous platforms equipped with optical sensors are the primary tools used to study phytoplankton dynamics. They provide long term records while offering a synoptic view of our oceans, enabling to study impact of climate variability on planktonic ecosystems. Interpretation of these observations rely heavily on optical theory and how light propagating through the water is affected by particles who absorb and scatter light (e.g. phytoplankton, sediments). However, the complexity of the optical properties of …

Variations In The Southern Hemisphere Westerlies Over The Last 23,000 Years From Lake Records In The Falkland Islands, Meghan M. Spoth

Electronic Theses and Dissertations

The Southern Hemisphere Westerlies (SHW) are an important driver of climate in the mid-latitudes of the Southern Hemisphere. Abrupt latitudinal migration of this coupled atmospheric-oceanic system is thought to be linked to the onset of the Termination at the end of the last ice age and to subsequent climatic variation through the late-glacial period and Holocene. However, the timing and spatial extent of these shifts, as well as variations in wind intensity, are poorly constrained, hindering our understanding of abrupt climate change in the Southern Hemisphere. In addition, future changes in the position and intensity of the SHW are a …

Extratropical Cyclones And Associated Climate Impacts In The Northeastern United States, Julia Simonson

Electronic Theses and Dissertations

There is growing concern that some aspects of severe weather could become more frequent and extreme across the northeastern United States (USNE) as a consequence of climate change. Extratropical cyclones and frontal systems are a common factor in a variety of severe weather hazards in the region. This dissertation examines three types of meteorological events impacting the USNE – ice storms, heavy rainfall, and high-wind events. The first research topic utilizes the Weather Research and Forecasting (WRF) model in a case study of the December 2013 New England ice storm. In this analysis, a series of tests are conducted to …

Assessing The Factors That Alter Ecological Responses Of Cold, Oligotrophic Lakes To Nutrient Subsidies, Benjamin Burpee

Electronic Theses and Dissertations

Arctic and alpine areas experience rapid environmental changes that are altering nutrient delivery to lakes. I review the current state of lake ecosystem subsidization research and summarize Arctic and alpine lake subsidies, their ecological importance, and ways they are changing. I identify current knowledge gaps in Arctic and alpine lake subsidization research and highlight the importance of Arctic and alpine lakes for ecosystem subsidy research. Meltwater from the Greenland Ice Sheet (GrIS) exports sediment and nutrients to lakes, but the ecological effects of this subsidy remain unclear. To assess the effects, four glacially fed (GF) lakes that receive GrIS meltwater …

Phytoplankton Community Composition In The Surface Ocean: Methods For Detection Using Optical Measurements, Pigment Concentrations, And Flow Cytometry, Alison P. Chase

Electronic Theses and Dissertations

Phytoplankton are microscopic photoautotrophs living in the surface ocean waters and help support all life on earth via photosynthetic production of oxygen. Thousands of species make up the bulk phytoplankton community, and the spatial and temporal distribution of different types of phytoplankton has relevance for many ocean ecosystem questions including marine food web dynamics, and carbon flux and sequestration. Methods to detect phytoplankton community composition (PCC) on the vast scale of the global ocean require estimates of PCC from remote platforms, namely earth-observing satellites. The use of satellite data to observe and interpret PCC in the surface ocean requires significant …

An Algorithm To Estimate Suspended Particulate Matter Concentrations And Associated Uncertainties From Remote Sensing Reflectance In Coastal Environments, Juliana Tavora

Electronic Theses and Dissertations

Suspended Particulate Matter (SPM) is a major constituent in coastal waters, involved in processes such as light attenuation, pollutant propagation, and waterways blockage. The spatial distribution of SPM is an indicator of deposition and erosion patterns in estuaries and coastal zones and a necessary input to estimate the material fluxes from the land through rivers to the sea. In-situ methods to estimate SPM provide limited spatial data in comparison to the coverage that can be obtained remotely. Ocean color remote sensing complements field measurements by providing estimates of the spatial distributions of surface SPM concentration in natural waters, with high …