Leads are long fractures wide enough for a ship to travel through the ice pack. Sea ice acts as a barrier between the ocean and the atmosphere, whereas leads allow the transfer of heat and moisture between the two. Leads play a role for marine mammals and are hunting grounds...
Seafood is one of the most diverse and highly traded natural resources worldwide. Widespread evidence of increased seafood fraud and IUU fishing has placed enormous pressure on industry and governments to determine the authenticity, safety, and sustainability of seafood. The recently established US National Ocean Council has addressed several gaps...
In this thesis, high resolution ocean models are used to evaluate and forecast coastal ocean variability in two different applications. In the first study, the 2-km resolution ocean circulation model for the Eastern Bering Sea is utilized to understand whether slope-interior exchange along the path of the Aleutian North Slope...
Management goals for restoring populations of the federally-threatened northern spotted owl currently include experimental lethal removals of barred owls from demographic study areas within the overlapping ranges of the two species to examine northern spotted owl population response. As lethal removals of a bird species are time- and cost-intensive, predictive...
This dissertation works towards determining the mechanisms driving the Mo isotopic composition of soils, and how these signals may be used to refine the use of Mo as a proxy of biogeochemical processes. The first step towards quantifying Mo fractionation in soils is to determine the mechanisms controlling Mo accumulation,...
Understanding groundwater flow in faulted and fractured rock is an important frontier in the field of environmental remediation and in the management of water resources. One example of a site where this is particularly evident is the Santa Susana Field Laboratory (SSFL) in Ventura County, CA where environmental remediation activities...
This dissertation is divided into two major chapters. The first chapter covers the geologyof the Encuentro deposit with emphasis in the intrusion sequence, vein mineral assemblages and distribution, and age of mineralization. The data used for this section includes field mapping, petrography, elemental analysis of biotite, and isotopic geochronology. The...
The Columbia River delivers the greatest amount of freshwater to the coastal ocean along the U.S. Pacific coast. This freshwater forms the Columbia River plume, a mesoscale plume with significant implications on coastal ocean physical, biological, chemical, and geological processes. The plume is transported south and offshore during the upwelling...
Arctic cod (Boreogadus saida) is an ecologically significant species that plays a critical role channeling energy throughout the Arctic marine food web. Arctic cod is uniquely adapted to occupy ice edge habitats, however, a basic understanding of its larval physiology and habitat requirements is lacking due to widespread sea ice...
Understanding the ecological role of Pacific oyster aquaculture (Crassostrea gigas) and eelgrass (Zostera marina L.) as important habitats in US Pacific Northwest estuaries is critical for management and regulatory decisions. The oyster aquaculture industry is currently restricted by regulations concerning impacts of their activities on Z. marina. This seagrass is...
Arctic sea ice concentration and volume have declined due to greenhouse gas radiative forcing and an overall positive climate feedback. At the same time, there have been noteworthy weather and climate circulation anomalies both within the Arctic and extending through the midlatitudes and even into the tropics, leading some studies...
Childhood cancers are rare diseases that affect 188 children in Texas for every million born. Leukemia is the most common childhood cancer and accounts for roughly one third of childhood cancer cases. However, it is estimated that only 10% of childhood cancer cases can be explained by known risk factors....
During the Last Glacial Maximum (LGM, ∼ 21 ky before present) the atmospheric CO2 concentration was about 100 ppm lower than its pre-industrial (PI)value. The missing carbon from the atmosphere must have been stored in thedeep ocean during this period, but the mechanisms driving such re-distribution ofthe carbon cycle are...
Commercial fishing is a culturally and economically significant industry on the Oregon coast. The importance of this industry to human communities is often neglected in fisheries research, with economic and ecological data being favored by managers and decision makers. Recent observations in many coastal communities have indicated aging of fishermen...
In this thesis, the spatial patterns of vegetation and soils of reference and restored tidal marshes were compared to determine the extent to which restored sites differ from the reference site after 40 years of restoration. Vegetation surveys of 1m x 1m plots were conducted along previously-established transects of salt...
The eruptive history of the Quaternary Cascades arc has been relatively well characterized. However, much less is known about the frequency and sizes of explosive eruptions produced by earlier stages of the arc. The Late Neogene Deschutes Formation of Central Oregon preserves a remarkable record of heightened pyroclastic activity during...
Geomagnetically Induced Currents (GICs) are quasi-DC signals that are induced in the ground during geomagnetic disturbances (GMDs) and pose a large threat to power grid infrastructure. The power industry currently attempts to mitigate GIC effects by utilizing 1-D ground electrical conductivity based electric field predictions, though conductivity can vary in...
Evacuation strategies have been established for most user groups in tsunami inundation zones; however, surprisingly little information is available for a growing visitor group - surfers. For near-shore tsunami events, Oregon surfers, who recreate in the nearshore region, must make life or death choices when deciding what to do in...
The Toba Caldera Complex is the youngest resurgent caldera in the last 100 kyrs, formed from four overlapping eruptions starting 1.2 Myrs ago. The last caldera-forming eruption, the Youngest Toba Tuff eruption, occurred ~74 kyrs ago, emitting 2800 km3 of ash and pumice into the atmosphere and forming the caldera...
This thesis describes the results of a linear stability analysis conducted on a simulated wind-forced ocean front. The ocean surface boundary layer regulates exchanges between the ocean and atmosphere, and the presence of turbulence in the surface layer can greatly impact climate and ocean life. Past research has shown that...
Quantification of contemporary sediment and carbon accumulation within Oregon tidal saline wetlands will: (1) fill a critical knowledge gap, and (2) naturally test without complicating variables whether sea level rise or sediment supply primarily control wetland growth. Here we measure vertical accretion rates and carbon burial rates in three Oregon...
The spatial distribution and geologic histories of submarine volcanoes provide insight into submarine eruptive behavior, deep earth processes and plate tectonics. This dissertation examines the evolution of individual submarine volcanic edifices as well as linear trails of seamounts at three spatial and temporal scales.
In order to understand constructive and...
In this thesis, I investigate the organization of eelgrass (Zostera marina L.) and mesograzer communities across local and regional scales in three upwelling- influenced estuaries located along the Oregon coast, USA. Eelgrass ecosystems are an important source of primary production in estuarine systems, providing numerous ecosystem services, including nursery habitat...
The rare earth elements (REEs) have been established as powerful tracers for a range of physiochemical processes occurring in the natural environment. They also hold significant economic importance as many technological advancements are reliant upon the REEs for their unique magnetic, luminescent, and electrochemical characteristics. In sedimentary settings, understanding the...
Large ensembles of regional climate simulations were generated from the weather@home distributed volunteer computing project over the western US domain. Weather@home uses the U.K. Met Office Hadley Centre’s regional climate model HadRM3P (~0.22°) nested within the atmospheric global model HadAM3P (1.875 longitude° by 1.25 latitude°). Simulations from HadRM3P were evaluated...
Marine bacteria play vital roles in every niche of the ocean, from small-scale symbioses to large-scale productivity and the regulation of Earth’s climate. Recent advances in molecular tools now allow us to probe the genetic potential of entire microbial communities. The next step is linking these diverse communities to the...
Earth’s mantle extends to nearly 3000 km depth, comprises >80 % of Earth’s total volume, and has the largest influence on the primordial and radiogenic heat budget. Despite its importance, the structure and composition of the mantle is still debated. There are three primary models for Earth’s mantle structure that...
In volcanic systems, magma is generally stored in the shallow crust prior to eruption. The conditions of this storage directly impact whether the magma eventually erupts, or crystallizes within the crust to form a pluton. In this dissertation I present four studies that investigate the storage conditions of a number...
Developing accurate predictive distribution models requires adequately representing relevant spatial and temporal scales, as these scales are ultimately reflective of the relationships between distributions and influential environmental conditions. In this research, we considered both spatial and temporal scale and the influence each has on predicting broad-scale distributions of two disparate...
Phytoplankton are a sentinel class of organisms in the marine environment. Through their photosynthetic activity in sunlit waters worldwide, phytoplankton shape the health and productivity of marine ecosystems and impact the global climate. In this work a range of ocean sensing technologies (via ships, surf zone sampling, moorings, gliders, and...
Observations of the Oregon coast’s physical oceanography over the last few decades have revealed falling dissolved oxygen levels associated with seasonal upwelling, as well as rising water temperatures. In extreme cases, these changes have been associated with die-offs, redistribution, and decreased abundance and diversity of benthic fish and invertebrates. Many...
Measuring surface heat flow at the Hikurangi Trough is key toward characterizing the local thermal regime and the influence of thermally sensitive processes such as fluid flow and slow slip. Marine heat flow data were collected during May– June 2015 in the northern Hikurangi Trough at sites seaward and landward...
The Juan de Fuca plate system is what remains of Farallon plate subducting under the continental North American plate. Blanco Transform Fault Zone (BTFZ) consists of a network of strike-slip faults discontinued by pull apart depressions which o↵sets the Juan de Fuca Ridge and the Gorda Ridge. Detailed analysis of...
As highlighted in this study, shallow-water habitats and the prey they provide are important for juvenile salmon in the Columbia River estuary, but the spread of invasive species and large-scale changes to the estuary influence how these habitats are utilized. Reed canarygrass (Phalaris arundinacea) (“PHAR” hereafter) is a highly invasive...
Visualizing large movement datasets with flow maps is difficult because overlapping flows create significant graphical conflicts that make accurate interpretation difficult or impossible. Interactive flow mapping applications allow users to explore large movement datasets by automatically generating flow maps from subsets of the data in response to queries by the...
This dissertation explores one overarching question relevant to the
paleoclimate of the latest Pleistocene glacial cycle (approximately the last
130,000 years): “How did spatial and temporal evolution of ocean
temperature, both at the surface and interior, relate to other parts of the
climate system in the late Pleistocene?” Results from...
There are many different organizations and agencies which share responsibility for educating the public about responsible use of aquatic and marine resources. However, organizations specifically focused on particular dimensions of water use, such as Oregon State Marine Board (OSMB), often face challenges when attempting to recruit teachers to implement educational...
For hundreds of years, coastal and marine ecosystems have experienced increasing threats due to the cumulative effects of increasing population growth and dependence on these ecosystems. Thus, there has been increased enthusiasm to mitigate the negative effects of human actions through the use of cleaner sources of energy, like marine...
The aggregate industry is responsible for the extraction and production of crushed stone, sand, and gravel— the literal building blocks of our society. Across the U.S. there are tens of thousands of quarries and sand and gravel pits, the majority of which are left abandoned or with minimal reclamation efforts....
The Botija Cu-Mo-Au porphyry deposit is located in the Cobre Panamá mining district, which contains several deposits with a global measure and indicated and inferred resource of 14.8 MT of Cu. These deposits are associated with the Cerro Petaquilla batholith, which has U/Pb zircon ages of 26-33 Ma (Whattam et...
Arctic soils are warming, making vast stores of organic carbon available for conversion to CO₂. This could create a positive feedback loop and accelerate global warming, but the processes that convert this carbon into CO₂ are not well understood. We investigated how the combined activities of sunlight and microbes degrade...
The goals of this dissertation are centered on understanding changes in Earth surface and climate systems through the use of geologic proxies as records of past changes in these systems. Specifically, this dissertation (1) establishes a new chronology for retreat of the Ross Sea sector of the West Antarctic Ice...
Despite more than two centuries of exploration, including more than six million deep wellbores with depths exceeding 40,000 feet in some parts of the world, our ability to constrain subsurface processes and properties remains limited. Characteristics of the subsurface vary and can be analyzed on a variety of spatial scales....
The rapid decline of marine ecosystems worldwide and the failure of traditional single species management pushed for the development of ecosystem-based conservation measures such as marine protected areas (MPA) to slow the loss of marine biodiversity. One approach to MPA creation advocates targeting marine megafauna (e.g., marine mammals, seabirds, sharks,...
Contiential margins on plate boundaries are complex systems with morphologies and characteristics dictated by the interplay of sediment deposition and erosion, tectonic faulting, folding, and strong ground motion generating mass wasting events. With ever increasing advances in high-resolution remote sensing techniques these systems are increasingly becoming illuminated.
A ~120 km...
Education programs at zoos and aquariums provide opportunities for visitors to learn and garner information on animal natural history and, hopefully, conservation messaging. Fee-based programs (programs with an additional fee on top of admission prices), which are commonly employed by zoos and aquariums to foster learning opportunities for visitors, are...
Montane meadows in the Cascade Range of Oregon have been declining due to tree establishment since records began. Montane meadow complexes in the H.J. Andrews Experimental Forest shrank by 60 to 75% from 1949 to 2005, but fine scale temporal and spatial processes of tree establishment in these meadows are...
Microplastics, plastic marine debris less than 5 mm in size, is a threat to the health of our oceans. One important way to reduce microplastics in our oceans is to educate people about the issue, particularly future decision-makers. In this study, a middle school curriculum was developed using current scientific...
The goal of dissertation research was to use geochemical, statistical and geological methods to constrain and understand climate variability over several different time scales. Specifically, I have addressed three questions regarding past climate change: (1) how does the record of Irish cirque glaciers constrain the dimensions of the Irish Ice...
This PhD dissertation describes and evaluates a geographical analysis of candidate areas for siting nuclear plants utilizing a wet cooling tower in the Columbia River Basin (CRB). It focuses on the analysis of water availability for cooling and how it may be limited by climate change effects on river streamflow....