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...
We used data from Cascadia Initiative and Blanco Transform Fault Zone array of ocean bottom seismometers and hydrophone to look at the seismicity and specially depth of the Central Cascadia Continental Margin events. Events were detected and located automatically with Antelope software package (Boulder Real Time Technologies). We looked at...
We used data from Cascadia Initiative and Blanco Transform Fault Zone array of ocean bottom seismometers and hydrophone to look at the seismicity and specially depth of the Central Cascadia Continental Margin events. Events were detected and located automatically with Antelope software package (Boulder Real Time Technologies). We looked at...
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....
Natural habitats have the ability to protect coastal communities against the impacts of waves and storms, yet it is unclear how different habitats complement each other to reduce those impacts. Here, we investigate the individual and combined coastal protection services supplied by live corals on reefs, seagrass meadows, and mangrove...
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 Marinoan Snowball Earth ended 635 Ma ago during the Neoproterozoic Era, after an interval in which the Earth was completely covered by glaciers. Thawing of these glaciers formed cap carbonates across shallow marine depositional environments. The Noonday Formation is a cap carbonate that formed after the deglaciation of the...
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 Ratio Mountain Quadrangle is located in Southwest Montana, East of the city of
Butte. This quadrangle features two major geologic units; the Elkhorn Mountain
Volcanics, a series of several ignimbrites of varying composition, and the Boulder
Batholith, a large granite pluton that rose through the EMV. Previous studies in...
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...
A three-dimensional, process-based model of the ocean’s carbon and nitrogen cycles, including 13C and 15N isotopes, is used to explore effects of idealized changes in the soft-tissue biological pump. Results are presented from one preindustrial control run (piCtrl) and six simulations of the Last Glacial Maximum (LGM) with increasing values...
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....
Numerous investigations demonstrate that mantle convective processes such as upwelling affect the surface topography of the overriding plate. The surface expression of mantle flow has been coined ‘transient topography’. Transient topography in the North American plate is thought to result from a mantle thermal anomaly beneath the Yellowstone volcanic center,...
As the effect of ocean acidification (OA) on marine calcifiers is better understood, a range of potential mitigative strategies have been proposed, many of which are plagued by concerns of scale and feasibility. One oft-cited option is to increase the biomass of photosynthetic organisms to remove CO₂ from the water...
Over 70% of the Antarctic krill population exists along the Antarctic Peninsula, a region undergoing rapid climate change. Recent studies have shown a clear correlation between krill recruitment each spring and the timing and coverage of sea ice the winter before, with less sea ice and a shorter duration being...
Over the last several years, the Northwest Fisheries Science Center, in collaboration with the Pacific States Marine Fisheries Commission and Oregon State University, has been sampling young-of-the-year groundfishes and other small demersal fishes along the Newport Hydrographic (NH) line. An important question concerning these surveys is whether the NH line...
This dissertation uses argon geochronology and cosmogenic nuclide surface exposure dating methods to address three research questions. The first question concerns a geomagnetic instability recorded in lava flows on the island of Floreana in the Galapagos Archipelago. Changes in the Earth’s magnetic field (intensity and orientation) occur frequently throughout geologic...
The purpose of this thesis is to analyze an abrupt case of climate change in the past as a means to understand the mechanisms that force climate change. By looking to past analogs of climate change, we hopefully will gain an understanding of these events, which could be used to...
Lau Basin basalts host an array of geochemical signatures that suggest incorporation of enriched mantle source material often associated with intraplate hotspots, but the origin of these signatures remain uncertain. Geochemical signatures associated with mantle material entrained from the nearby Samoan hotspot are present in northwest Lau Basin lavas, and...
Atmospheric pressure changes do not stop at the permeable snow surface but rather propagate into it. These pressure changes range from high-amplitude, low-frequency events caused by seasonal cycles and synoptic weather systems to small-amplitude, high-frequency events caused by topographic features and turbulence. The effect of pressure changes on interstitial air...
Understanding controls on the stable isotopic composition of precipitation and vapor in the West Pacific Warm Pool is vital for accurate representation of convective processes in models and correct interpretation of isotope-based paleoclimate proxies, yet a lack of direct observational evidence precludes the utility of these isotopic tracers. Results from...
In situ observations of tidally driven turbulence were obtained in a small channel that transects the crest of the Mendocino Ridge, a site of mixed (diurnal and semidiurnal) tides. Diurnal tides are subinertial at this latitude, and once per day a trapped tide leads to large flows through the channel...
Thorough understanding of the mechanisms controlling the temperature structure in the surface mixed layer of the ocean and, in particular, accurate values of sea surface temperature are critical for properly parameterizing air-sea heat exchange and quantifying the amount of heat redistributed below the surface. It is however difficult to obtain...
Wildfire greatly impacts the composition and quantity of organic carbon stocks within watersheds. Most methods used to measure the contributions of fire altered organic carbon–i.e. pyrogenic organic carbon (Py-OC) in natural samples are designed to quantify specific fractions such as black carbon or polyaromatic hydrocarbons. In contrast, the CuO oxidation...
Signals from the R/V Langseth’s tuned airgun array were recorded on an array of 33 EarthScope FlexArray seismometers deployed in the Oregon Coast Range from 43.5° to 45°N as part of the 2012 Ridge2Trench experiment to image the structure of the Juan de Fuca plate. This segment of the Juan...
Coastal sand dunes and beaches offer a variety of ecosystem services such as coastal protection, sand stabilization, species conservation, and recreation. However, the management and balance of ecosystem services offered by dunes and beaches is challenging when ecosystem services interact across the landscape. Management focusing only on one ecosystem service...
This dissertation examines the spatial distribution of park access by type in relation to trajectories of gentrification in Seattle from 1990 to 2010. The dissertation includes 5 Chapters. The first chapter provides an overview of the literature that motivated this research. The second, third and fourth chapters are research papers...
The mouth of the Columbia River (MCR) is an intersection of more than a river and ocean, but also multiple economically valuable activities including dredging to maintain a deep draft shipping channel and an active Dungeness crab (Metacarcinus magister) fishery. More than three million cubic meters of sediment are annually...
Changes in environmental conditions in marine ecosystems could directly or indirectly influence distribution, abundance, settlement, and size at settlement of flatfish. Understanding species-specific and age-specific responses to environmental variability is important for managing commercially important flatfish stocks. Slope-spawning flatfish whose offspring rely on extensive drift from the slope (spawning) to...
The Eastern California Shear Zone (ECSZ) is a broad zone of dextral shear inboard of the North American - Pacific plate boundary. Despite decades of study, the significance of a mismatch between geodetic velocities and geologic fault slip rates across the ECSZ remains incompletely understood. Geodetically determined interseismic strain across...
The Nearshore Assessment Tool for Alaska: Southeast (NATAK-SE) is a standardized protocol for rapidly assessing the habitat and functions of a particular marine or estuarine shore segment (intertidal zone and immediately adjoining upland) anywhere in Southeast Alaska. It consists of data forms and a spreadsheet. It has a Rapid component...
The central Oregon coast was selected as an ideal site for wave energy
development and establishment of the Pacific Marine Energy Center (PMEC). PMEC will consist of two nearshore sites, one north (NETS) and one south (SETS) of the Yaquina River, Oregon. Our study aims to assess how the development...
Contains ground-truthed wetland maps and scores representing ecosystem services of a large portion of the wetlands in Juneau, Alaska. LiDAR imagery was used extensively.
The Juneau Wetland Management Plan (JWMP), Volume 1, provides results of wetlands mapping and wetland functional assessments for currently undeveloped parcels within the City and Borough of Juneau (CBJ). The study areas were selected for their potential for future development based on low elevation and proximity to existing infrastructure. During...
Interest in understanding long-term coastal morphodynamics has recently increased as climate change impacts become perceptible and accelerated. Multiscale, behavior-oriented and process-based models, or hybrids of the two, are typically applied with deterministic approaches which require considerable computational effort. In order to reduce the computational cost of modeling large spatial and...
Proceedings of the Eighteenth Biennial Conference of the International Institute of Fisheries Economics and Trade, held July 11-15, 2016 at Aberdeen Exhibition and Conference Center (AECC), Aberdeen, Scotland, UK.