Climate models predict a decrease in oceanic dissolved oxygen and a thickening of the oxygen minimum zone, associated with global warming. Comprehensive observational analyses of oxygen decline are challenging, given generally sparse historical data. The Newport hydrographic (NH) line off central Oregon is one of the few locations in the...
MicroSoar, an undulating profiler capable of measuring turbulence parameters such as Thorpe scales and thermal dissipation rate while being towed at speeds of up to 4 m s⁻¹, offers the possibility of obtaining a close-to-synoptic image of mixing over large spatial areas. In this paper, the method of calculating Thorpe...
As part of the Coastal Ocean Processes (CoOP) project Coastal Ocean Advances in Shelf Transport (COAST), this was the second of two cruises in 2001 to study cross-shelf transport processes in a wind-driven coastal ocean. The project includes field experiments off the Oregon coast and coordinated ocean circulation/ecosystem and atmospheric...
As part of the Coastal Ocean Processes (CoOP) project Coastal Ocean Advances in Shelf
Transport (COAST), this was the first of two cruises in 2001 to study cross-shelf transport
processes in a wind-driven coastal ocean. The project includes field experiments off the Oregon
coast and coordinated ocean circulation/ecosystem and atmospheric...
Small-scale turbulence is a random phenomenon, and theoretical relationships about turbulent processes are often only crude approximations. There are relatively few accurate statements that can be made about a turbulent flow without recourse to experimental evidence from flow itself (Tennekes and Lumley, 1972). In the atmosphere, turbulent flows are relatively...
Two physical oceanography cruises on the R/V Endeavor were conducted by the co-PIs Jack Barth and Mike Kosro as part of the ONR-sponsored Coastal Mixing and Optics (CMO) Accelerated Research Initiative. The objective was to rapidly survey a region around 40.5N, 70.5W where a set of moorings and a stationary...
Currently, forecasts produced by the Oregon-Washington (OR-WA) Coastal Ocean Forecast System are constrained by assimilation of only surface observations. The 4-dimensional variational (4DVAR) data assimilation (DA) algorithm is utilized to combine the model and the data, with the time-independent forecast ("background'') error covariance B. In this study, two possible improvements...
From mid-May to August 2011, extreme runoff in the Columbia River ranged from 14,000 to over 17,000 m³/s, more than two standard deviations above the mean for this period. The extreme runoff was the direct result of both melting of anomalously high snowpack and rainfall associated with the 2010–2011 La Niña....
A new high-frequency turbulence measuring instrument, MicroSoar, has been developed, tested, and used to make scalar variance dissipation rate measurements. MicroSoar was mounted on the undercarriage of SeaSoar, a depth-programmable winged platform, and towed by a ship, at speeds up to 7 kt, in a depth range of the sea...
The primary objectives of R/V Wecoma cruise W9907C were to: 1) collect threedimensional fields of temperature, salinity, and light absorption and attenuation using the towed, undulating vehicle SeaSoar; 2) collect 3-D fields of velocity using shipboard ADCP; 3) to make turbulence profiles along a single cross-shelf transect; and 4) locate,...
During fall/winter off the Oregon coast, oceanographic surveys are relatively scarce because of rough
weather conditions. This challenge has been overcome by the use of autonomous underwater gliders deployed
along the Newport hydrographic line (NH-Line) nearly continuously since 2006. The discharge from the
coastal rivers between northern California and the...
The commercial groundfish fishing industry and groundfish research have a long concurrent history of activity on the Oregon continental margin. Within the non-whiting groundfish fishery, the target species are primarily flatfishes, sablefish, lingcod, and rockfishes, though landings of each have fluctuated over time. Recent work shows that over the past...
Lateral stirring is a basic oceanographic phenomenon affecting the distribution of physical, chemical, and biological fields. Eddy stirring at scales on the order of 100 km (the mesoscale) is fairly well understood and explicitly represented in modern eddy-resolving numerical models of global ocean circulation. The same cannot be said for...
This paper details a method to compute absolute water velocity profiles from glider-based acoustic Doppler current profiler (ADCP) measurements based on the "shear method" developed for lowered ADCPs. The instrument is a 614-kHz Teledyne RDI ADCP integrated into the body of a Teledyne Webb Research Slocum Glider. Shear is calculated...
Quantification and comparison of morphological changes over the last ~300 y in Oregon salt marshes provide valuable insights into the tectonic, hydroclimatic, and anthropogenic processes shaping this important intertidal zone. Understanding of the rates and drivers of salt marsh change contextualizes intertidal habitats within the sediment routing system (i.e., source...
Wind-driven coastal upwelling brings subsurface water onto the central-Oregon shelf after the spring transition each year. This cold and salty source water is oxygen-poor, yet above the hypoxic threshold, dissolved oxygen < 1.4 ml l⁻¹. Once on the shelf, dissolved oxygen (DO) concentrations of upwelled near-bottom waters are modified by...
Freshwater provided from river discharge influences the dynamics and circulation of most continental shelves around the world. It has profound effects on the transport and fate of materials and substances originated from rivers and estuaries, as well as on the ocean biogeochemistry and marine ecosystems. The effect of buoyancy forcing...
Advances in mobile autonomous vehicles for oceanographic sensing provide new opportunities for passive acoustic monitoring of marine mammals. Acoustically equipped mobile autonomous platforms, including gliders, deep-water profiling floats, and drifting surface buoys can survey for a variety of marine mammal species over intermediate spatiotemporal scales. Additionally, such mobile platforms may...
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, from the Oregon continental shelf, describe the slumping of a coastal
upwelling front in response to a reversal of winds from upwelling-to downwelling-favorable.
Initially, the front outcropped in a surface mixed layer of depth 10–20 m with a
pronounced cross-shelf density gradient. Following wind reversal, both the unbalanced
cross-shelf...
The focus of this dissertation is the analysis of submesoscale and finescale features measured at oceanic fronts and the role they play in the transport of heat and salt. Two different geographical areas were used to analyze this transport: one, an area on the western side of the North Atlantic...
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...
As ocean ecosystems continue to deteriorate in the face of human induced pressures, marine management professionals are increasingly being urged to predict the impacts of various activities on ocean ecosystems. Many ecosystem interactions are still not adequately understood, so managers often turn to scientists to provide data and analysis on...
During summer 2001, high-resolution hydrographic, velocity, and bio-optical surveys
were conducted over Heceta Bank off central Oregon. North of the bank, upwelling
over simple bottom topography exhibited a classic response with a midshelf, baroclinic
coastal jet and upwelled isopycnals. The coastal upwelling jet follows the bank
topography as it widens...
The Coastal Ocean Advances in Shelf Transport (COAST) program conducted an
interdisciplinary study of coastal upwelling off central Oregon during summer 2001.
Two intensive field efforts during May–June and August 2001 were coordinated with
ocean circulation, ecosystem, and atmospheric modeling of the region. A primary
goal was to contrast the...
Repeated mesoscale surveys of waters over the shelf and slope off Oregon were
conducted during spring and summer of 2001 to study the spatial structure of the velocity
and hydrographic fields. The ocean response to wind forcing is compared between a
region of relatively simple topography with alongshore uniformity and...
This investigation is an exploration of the use of inherent optical properties towards further elucidation of coastal circulation processes occurring on the continental shelf and slope in the Middle Atlantic Bight, south of Cape Cod Massachusetts, during 14-Aug to 1-Sep 1996 and 25-Apr to 15-May 1997. Assessing the possibility of...
Cherenkov detectors have been developed and used in several fields since the discovery of Cherenkov radiation. They do have several advantages compared with other detector types, such as low noise due to the low-energy threshold of Cherenkov radiation, and short decay constant (on the order of picoseconds). However, the light...
By mapping the three-dimensional density field while simultaneously tracking a subsurface, isopycnal float, direct observations of upwelling along a shelfbreak front were made on the southern flank of Georges Bank. The thermohaline and bio-optical fields were mapped using a towed undulating vehicle, and horizontal velocity was measured with a shipboard...
Three-dimensional ecosystem response to wind forcing on the continental shelf off Oregon is studied using a five-component nitrogen-based ecosystem model coupled to a high-resolution circulation model. We investigate, in particular, the influence of timedependent winds and alongshore variations in shelf topography for summer 2001 during the time period of the...
In the productive central-Oregon coastal upwelling environment, wind-driven upwelling, tides, and topographic effects vary across the shelf, setting the stage for varied biogeochemical responses to physical drivers. Current, temperature, salinity, and dissolved oxygen (DO) measurements from three moorings deployed during the upwelling seasons of 2009–2011 off the central-Oregon coast are...
Nearshore hypoxia within the Northern California Current (NCC) system is a seasonal phenomenon caused by coastal upwelling and occurs mainly during late-summer and early fall. The effects of low oxygen levels on fish and invertebrate communities, particularly during early-life history stages, however, are poorly known for this area. I investigated...
Various ocean-climate models driven by increased greenhouse gases and higher temperatures predict a decline in oceanic dissolved oxygen (DO) as a result of greater stratification, reduced ventilation below the thermocline, and decreased solubility at higher temperatures. Since spreading of low oxygen waters is underway and predicted to increase, understanding impacts...
We examined the feasibility of using a video beam trawl system to assess behavioral responses of juvenile flatfishes in relation to co-occurring habitat features, most notably dissolved oxygen (DO) concentrations. Sixteen samples were collected along a cross shelf transect in the central Oregon coast during summer 2008. We found that...
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...
This study addresses the occurrence, severity, and extent of hypoxia over the continental shelf of the northern
California Current (40–48.5°N latitude) from 1998 to 2012. Clear seasonal trends exist in the timing and duration
of hypoxia. The highest bottom-water dissolved oxygen concentrations occurred from November to March, and
levels below...
Nearshore hypoxia along the coast of Oregon and Washington is a seasonal phenomenon that has generated concern among scientists studying this temperate upwelling ecosystem. These waters are affected by coastal upwelling-induced hypoxia mainly during late summer and fall, but the effects of low oxygen levels on fish and invertebrate communities,...
Meanders of the shelf break front in the Mid-Atlantic Bight (MAB) during April and May of 1997 were associated with chlorophyll enhancement along a hydrographic and a topographic feature. The hydrographic feature was the surface outcrop of the front, which ranged from ~10 to >100 km seaward of the shelf...
As in many regions of the world, the shelf waters of the western United States have experienced large increases and high interannual variability in jellyfish populations in recent decades. The northern California Current (NCC) is a productive upwelling zone that is home to large populations of medusae, particularly during some...
We present observations from deployments of a microstructure turbulence instrument
(the Towed Microstructure and Auxiliary Sensor Instrument) aboard a pumping profiling
vehicle (the Lamont Pumping SeaSoar) towed behind a research vessel at the New
England shelf break front in August 2002. From these we determined coincident fine-scale
vertical eddy diffusivity...
As part of an experiment to study wind-driven coastal circulation, 17 hydrographic
surveys of the middle to inner shelf region off the coast of Newport, OR (44.65°N, from
roughly the 90 m isobath to the 10 m isobath) were performed during Summer 1999
with a small, towed, undulating vehicle. The...
The Pacific coast groundfish fishery is a diverse, important and lucrative commercial and recreational fishery. Part of this fishery’s monitoring process includes regular fishery-independent surveys for stock assessment. Although these fishery-independent surveys are cost-effective, they are susceptible to scientific uncertainty, and they do not currently sample in nearshore (water depth...
A study of the effect of catalyst properties on the synthesis of carbon nanotubes (CNTs) is done in this thesis. Three different metal alloy catalysts, Fe/Ti, Ni/Ti, Co/Ti, have been studied. Various atomic concentrations and thicknesses were cosputter deposited on clean Si wafers using AJA Orion 4 RF Magnetron sputter...
Time‐dependent, three‐dimensional, upwelling circulation on the continental shelf off the Oregon coast is studied using a primitive equation numerical model. A limited area domain with a high‐resolution curvilinear grid is utilized. The response of the coastal ocean to forcing by observed wind stress and heat flux during the summer 2001...
An international Coupled Ocean-Atmosphere Response Experiment (COARE)
was conducted in the warm-pool region of the western equatorial Pacific Ocean over a four-month period from November 1992 through February 1993 (Webster and Lukas, 1992). Most of the oceanographic and meteorological observations were concentrated in the Intensive Flux Array (IFA) centered at...
Oregon Fishermen in Ocean Observing Research (OrFIOOR) is a cooperative research program between ocean scientists and fishermen in the Pacific Northwest. Dungeness crab fishermen attach sensor packages (temperature and dissolved oxygen) to crab pots. The pots serve as platforms of opportunity for ocean observing. This study examines three principle questions...
Athletic workout clothing is designed to help the wearer stay comfortable, cool,
and dry. There are several different styles of athletic apparel available at retailers and each individual has a preference as to what is comfortable for him or her. Comfort of clothing has traditionally been related to the fabric...
Coastal hypoxia, or low oxygen episodes pose a threat to marine resources in the Pacific Northwest. Previous research into nearshore oxygen dynamics have linked coastal upwelling to this seasonally occurring phenomenon, however the manifestation of hypoxic waters over coastal fishing grounds was not well understood. Through a partnership with Dungeness...
In the past two decades, occurrences of summertime upwelling-driven low dissolved oxygen (DO) events, or hypoxia, have increased along the northeast Pacific coast. If hypoxic events are severe enough to cause marine species mortality, the areas affected are often called "dead zones." In 2002 and again in 2006, the events...
In recent years, there has been an increase in episodic coastal hypoxia along the mid to inner-shelf waters off the Oregon Coast. Wind-driven coastal upwelling events can exacerbate the magnitude of these hypoxic events, causing extremely hypoxic bottom water (<0.5ml l-1 dissolved oxygen) to move onshore towards the inner shelf....
Horizontal current measurements from an array of moored acoustic Doppler profilers are assimilated sequentially into a model of coastal wind-driven circulation off Oregon during the upwelling season of May–August 2001. Model results are compared against independent moored and ship survey data to document a positive effect of velocity data assimilation...
The International Handbook of Evaluated Reactor Physics Benchmark Experiments contains detailed descriptions of many different reactor facilities. A large portion of these experiments have not been fully modeled due to the unavailability of computational power at the time of the experiment’s execution. With the advent of renewed interest in Sodium...
A data assimilation system (DAS) of the wind‐driven, mesoscale shelf circulation off the Oregon coast is developed. The DAS assimilates low‐pass filtered surface velocity measurements, obtained from land‐based high‐frequency coastal radar arrays, into a primitive equation coastal ocean model using a sequential optimal interpolation scheme. Inhomogeneous and anisotropic estimates of...
Continental shelf sediments are sinks for dissolved oxygen and sources of many major and minor nutrients required for oceanic surface primary production, resulting in a strong coupling between benthic and pelagic biogeochemical cycling. However, the influence and spatiotemporal variability of benthic remineralization on bottom-water chemistry and the supply of nutrients...
In this report, we present climate projections for Douglas County that are relevant to specified natural hazards for the 2020s (2010–2039) and 2050s (2040–2069) relative to the 1971–2000 historical baseline. The projections are based on multiple global climate models for both a lower greenhouse gas emissions scenario (RCP 4.5) and...
Connectivity of fish populations is a crucial question for fisheries conservation and the development of spatial management plans. Both adult and larval movement define the extent and direction of ecological and evolutionary overlap between geographic regions and, therefore, how we define stocks for management purposes. Within that context, my work...
Marine and coastal sedimentary archives show that the Cascadia Subduction Zone can generate great earthquakes of ~M9, most recently in 1700 CE, yet we still know little of the impacts of these events inland of the Pacific coast. Inland lakes have recently been exploited for their use as paleoseismic records...
The group of scientists that make up the Intergovernmental Panel on Climate Change found in 2007 that the warming of Earth’s climate is unequivocal and largely due to human activity. Earth’s climate has changed in the past, though the recent magnitude and pace of changes are unprecedented in human existence....
The purpose of Oregon's Nearshore Research Inventory (NRI) project was to inventory and map the current and future use of Oregon's nearshore environment by the scientific research community for use in Oregon's marine spatial planning process. Spatial and qualitative data on the use of Oregon's ocean and coast by the...
Changes in ocean conditions influenced by climatic fluctuations have lead to changes in individual species distributions, which alter the diversity, communities and species interactions across marine ecosystems worldwide. Assessing the species composition and identifying regions and habitats that can safeguard the persistence of biota are critically important. In this dissertation,...
Small rivers, such as those that line the Oregon coast, have been shown to deliver significant concentrations of suspended sediments and nutrients to estuaries and the coastal ocean during wet seasons during which winds are predominantly downwelling-favorable. The fate of the buoyant source water and of any suspended or dissolved...
Nonthermal plasmas generate high concentrations of excited species that can simultaneously exist at high energy and far from thermodynamic equilibrium, making them useful tools in chemistry and engineering. Microplasmas, roughly defined as plasmas that are generated within sub-millimeter dimensions, provide enhanced stability, improved excited species density, increased nonequilibrium properties, higher...
Biotic and abiotic processes at continent-ocean interfaces cycle a disproportionate mass of carbon and nutrients relative to their global surface area, and microbial activity is a principal determinant of organic and inorganic matter flux in these transition zones. Most studies using modern high-throughput ‘omics techniques to link microorganisms with costal...
Coastal communities in the U.S. Pacific Northwest (PNW) are rapidly engaging with the idea that hazards and environmental pressures are changing and may be characteristically different in the near future. This has led to a need for scientific knowledge and tools that can help coastal communities prepare and build resilience...
Through this dissertation, the quality of freely available physical activity promotion web articles that lay adults would likely locate online was critically appraised and theoretically analyzed. Three broad categories were considered. They were 1) message consistency with national health guidelines for physical activity; 2) suitability for health-related communication; and 3)...
Wave energy has the potential to power large and small factions of economies around the world alike. Current methods for determining the amount of wave energy resource available to wave energy converter (WEC) devices entail capturing the look of the sea state at large by presenting characteristic wave heights, periods,...
Consistent with its charge under Oregon House Bill 3543, the Oregon Climate Change Research Institute (OCCRI) conducts a biennial assessment of the state of climate change science, including biological, physical, and social science, as it relates to Oregon and the likely effects of climate change on Oregon. This fifth Oregon...