The marine climate of the Galapagos is spatially and seasonally
heterogeneous. A taxonomically comprehensive study of Galapagos zooplankton has
never been done. This study is an initial effort to establish the distribution and
community structure of zooplankton in the Archipelago. I collected zooplankton
samples by vertical tows over the Galapagos...
Models for surface gravity wave propagation in the presence of currents often assume the current field to be quasi-stationary, which implies that the absolute wave frequency is time invariant. However, in the presence of unsteady currents or time-varying water depth, linear wave theory predicts a time variation of the absolute...
The stable nocturnal boundary layer is commonly viewed or modelled as a balance between the temperature tendency (cooling) and vertical heat-flux divergence. Sometimes the radiative-flux divergence is also included. This perspective has dictated the design of field experiments for investigating stable nocturnal boundary layers. Tower-based micrometeorological data from three field...
Discrete layers of phytoplankton and zooplankton were observed over the Oregon continental shelf in summer and fall of 2001 and summer 2002 using optical and acoustical technologies and a pump sampling system. Layers of phytoplankton had steep vertical gradients which were associated with gradients in density and local peaks in...
Data from three micronetworks with eddy correlation data and three additional micronetworks without eddy correlation data are analyzed to study the spatial variability of surface air temperature in complex terrain. A simple similarity relationship is constructed to relate the spatial variation of air temperature along the slope to the thermal...
Wind stress variability over the Benguela upwelling system is considered using 16 months (01 August 1999 to 29 November 2000) of satellite-derived QuikSCAT wind data. Variability is investigated using a type of artificial neural network, the self-organizing map (SOM), and a wavelet analysis. The SOM and wavelet analysis are applied...
In eastern boundary current upwelling ecosystems, mesoscale circulation features such as eddies and upwelling filaments play a prominent role in the transfer of water and the associated plankton from the productive nearshore to the oligotrophic deep sea. The relationship between mesoscale circulation, zooplankton distributions, and the across-shelf transport of coastal...
A benthic microbial fuel cell (BMFC) is an electrochemical device that
generates current from the redox gradient at the sediment-water interface. Early
prototypes had anodes buried in anoxic sediments and cathodes in overlying water.
The BMFCs described in this dissertation are based on a chamber design that enables
the use...
Outreach is a key element in natural resource public participation processes in order to create an engaging, thoughtful, and productive environment for citizen involved decision-making. This project examined the utility of a needs assessment as an initial outreach tool within the context of the National Oceanic and Atmospheric Administration Fisheries...
1-km MODIS observations of ship tracks off the west coast of the U.S. are used to characterize changes in cloud visible optical depths, cloud droplet radii, cloud cover fraction, and column cloud liquid water amount as low-level marine clouds respond to particle pollution from underlying ships. This study re-examines the...
Dramatic declines in many species of demersal fishes off the West Coast have resulted in the designation of nine commercially important species as being overfished. While the causes of those declines are not clearly understood, the fact remains that a paucity of life history and abundance data exists for many...
Quantitative assessments of many West coast rockfish stocks of both major and
minor importance to commercial fisheries have shown varying declines in abundances. The population sizes of less-abundant, co-occurring unassessed species may also be
declining. However, determining stock status of the many non-targeted, minor species with high levels of certainty...
High‐resolution three‐dimensional (3‐D) seismic reflection data acquired on the R/V Thomas G. Thompson in 2000 reveal a pair of bottom simulating reflections (BSRs) across a broad region of southern Hydrate Ridge, offshore Oregon. The primary BSR (BSRp) is a regionally extensive reflection that lies 120–150 m below seafloor and exhibits...
As part of the U. S. GLOBEC NorthEast Pacific Program we made repeated seasonal hydrographic surveys in the northern California Current system (Figure 1) between July 1997 and September 2003. These surveys included early spring sampling along a pair of hydrographic sections, one north (at 44.6ºN) and one south (at...
As part of the U. S. GLOBEC NorthEast Pacific
Program we made repeated seasonal hydrographic surveys in
the northern California Current system between July
1997 and September 2003. These surveys included sampling
along a pair of hydrographic sections, one north (at 44.6ºN)
and one south (at 41.9ºN) of Cape Blanco...
Microphysical and chemical aerosol measurements collected during DYCOMS‐II research flights in marine stratocumulus clouds near San Diego in 2001 were used to evaluate the partitioning of 18 organic and elemental components between droplet residuals and unactivated particles. Bulk submicron particle (between 0.2 and 1.3 μm dry diameter) and droplet residual...
Anoxic sediment overlain by oxic seawater establishes a voltage gradient on the order of 0.7-0.8V across the sediment-water interface. This study follows Reimers et al. (2001) and Tender et al. (2002) who reported the development of a seafloor fuel cell to harvest electrical energy from this potential difference. Prototype fuel...
A pair of hydrographic sections, one north and one south of Cape Blanco at 42.9N, was sampled in five summers (1998–2000 and 2002–2003). The NH line at 44.6N lies about 130 km south of the Columbia River, and spans a relatively wide shelf off Newport, Oregon. The CR line at...
Motivated by the tendency of high-Prandtl-number fluids to form sharp density interfaces, the authors investigate the evolution of Holmboe waves in a stratified shear flow through direct numerical simulation. Like their better-known cousins, Kelvin–Helmholtz waves, Holmboe waves lead the flow to a turbulent state in which rapid irreversible mixing takes...
Vessel traffic places the sensitive environmental, natural, and cultural resources of Washington’s outer coast at risk of oil or hazardous materials spills. In 1995, International Maritime Organization established the Area to be Avoided off the Washington Coast (ATBA) to reduce this risk. Annual estimates of vessel compliance with the ATBA...
The origin of the Pacific Decadal Oscillation (PDO), the leading mode of sea surface temperature variability for the North Pacific, is a matter of considerable debate. One paradigm views the PDO as an independent mode centered in the North Pacific, while another regards it as a largely reddened response to...
Tidal mixing over a slope was explored using moored time series observations on Kaena Ridge extending northwest from Oahu, Hawaii, during the Survey component of the Hawaii Ocean Mixing Experiment (HOME). A mooring was instrumented to sample the velocity and density field of the lower 500 m of the water...
Measurements of tidal currents on the central Oregon shelf are available from several sources, including recent high frequency (HF) coastal radar and Acoustic Doppler Profiler (ADP) deployments, and historical current moorings. In this paper we use a generalized inverse (GI) approach to compare these data to, and then assimilate them...
An analytical model of subtropical mode water is presented, based on ventilated thermocline theory and on numerical solutions of a planetary geostrophic basin model. In ventilated thermocline theory, the western pool is a region bounded on the east by subsurface streamlines that outcrop at the western edge of the interior,...
Loss of wetlands within Oregon has led to strong interest in restoring wetlands that once existed. Restoration practitioners are currently using knowledge they have gained from many years of working with wetlands to design and carry out restoration projects. There is much variability between tidal wetlands within coastal
Oregon and...
The inherent and apparent optical properties of different ocean regimes are the basis for all optical remote sensing of the ocean. Ecological information derived from remote sensors therefore relies on having a detailed understanding of how particulate backscattering and absorption contribute to the bulk optical signal. The absorption
characteristics of...
The local and remote sources of variability of the South Atlantic Ocean are investigated using a set of numerical experiments and satellite data. A global, eddy-permitting, numerical simulation is analyzed to investigate the dynamical links between the Antarctic Circumpolar Current (ACC) and the Malvinas Current (MC). The model results indicate...
Using wave and wind data from nearby buoys and gauges, real time
kinematic global positioning system (RTK-GPS) and light detection and ranging
(lidar) topographic survey data, and a robust video record, we have quantified the
Large Scale Coastal Behavior (LSCB) of a dissipative end member beach in the
Pacific Northwest....
This study assesses the role of the atmospheric dry fallout as a source of new nitrogen and phosphorus to the surface Levantine seawater. Leaching experiments of inorganic nitrogen (LINO-3, LINH+4) and phosphorus (LIPO4), using SE Mediterranean surface seawater, were performed on 41 aerosol (hereafter dust) samples collected on Whatman 41...
A high-resolution numerical model with idealized topography is used to investigate the degree to which a coastal upwelling jet separates from the shelf as it flows around a submarine bank depending on the wind strength and the horizontal scale of the bank. Experiments were run using several wind forcing magnitudes...
One year of collocated, rain-free normalized backscatter cross-section measurements from the Tropical Rainfall Mapping Mission (TRMM) precipitation radar (PR) and wind speed estimates from the TRMM Microwave Imager are used to construct fully empirical model functions relating cross section to wind speed for incidence angles from 0° (nadir) to 18°....
The Lamprey Eel Decline project conducted by the Confederated Tribes of Siletz Indians (CTSI) combined traditional ecological knowledge, scientific research and geographic information science. CTSI wanted to learn why the Pacific lamprey (Lampetra tridentata), a culturally and ecologically important species, was declining in the streams within their native land area....
Research on the ecology of salmon in the northeast Pacific Ocean began in the early 20th century. Charles Gilbert and Willis Rich demonstrated the basis for the stock concept and were instrumental in changing common misconceptions of the times. Later in the 1900s, research endeavors, primarily under the auspices of...
A linearized baroclinic, spectral-in-time tidal inverse model has been developed for assimilation of surface currents from coast-based high-frequency (HF) radars. Representer functions obtained as a part of the generalized inverse solution show that for superinertial flows information from the surface velocity measurements propagates to depth along wave characteristics, allowing internal...
The Inverse Ocean Modeling (IOM) system constructs and runs weak-constraint, four-dimensional variational data assimilation (W4DVAR) for any dynamical model and any observing array. The dynamics and the observing algorithms may be nonlinear but must be functionally smooth. The user need only provide the model and the observing algorithms, together with...
Precise in situ measurement of the spectral absorption and scattering coefficients in several regions has revealed patterns in the distribution of the inherent optical properties on spatial scales that were previously unobtainable. The precision of the measurements was found to be consistent and unbiased across a variety of oceanic regimes...
Westward propagating Gaussian eddies with statistical characteristics estimated from altimeter observations but with purely random starting locations and times produce striated features in time-averaged maps of zonal velocity. The striations in these simulations have magnitudes and meridional scales comparable to those reported from time-averaged altimeter observations and model output in...
In most estuarine systems it is assumed that the dominant along-channel momentum balance is between the integrated pressure gradient and bed stress. Scaling the amplitude of the estuarine circulation based on this balance has been shown to have predictive skill. However, a number of authors recently highlighted important nonlinear processes...
This thesis investigates the influence of early diagenesis on trace metal and
molybdenum isotope behavior in marine and lacustrine environments. Chapter one is a
synthesis of previous research in all the marine environments investigated, providing an
essential geochemical context for interpreting the observed behavior of Mo in these settings.
Chapter...
Oceanic waves have been found to contribute enhanced back-scattering in the direction of the illumination source in studies that assumed the ocean surface to be a random sum of waves. Here we investigate enhanced back-scattering by coherent capillary-gravity wave trains that co-exist near the crests of short gravity waves in...
The reflectance of the bottom is of importance when interpreting optical data in shallow water. Closure studies of radiative transfer, interpretation of laser line scanner data, lidar, and remote sensing in shallow waters require understanding of the bottom reflectance. In the Coastal Benthic Optical Properties experiment (CoBOP), extensive measurements of...
During two cruises in February and June of 2003, the erodibility of sediment along the western Adriatic Sea was measured using a "Gust erosion chamber". In addition, the surficial sediment properties were characterized through a suite physical and biological measurements including porosity, grain-size, inorganic carbon, organic carbon and colloidal carbohydrate....
Upwelling jets flow alongshore in approximate geostrophic balance with the onshore pressure gradient induced by coastal upwelling. Observations of such jets have shown that they often move offshore downstream of capes, leaving a pool of upwelled water inshore. Comparisons are made between this behavior and the hydraulic transition of a...
Hydrographic observations made with an undulating vehicle carrying a CTD and concurrent shipboard ADCP velocity observations over a 12‐day period are combined to investigate vertical mixing and cross‐frontal fluxes on the Northern Flank of Georges Bank. The CTD density time series is analyzed to detect the presence of vertical overturns,...
This research focuses on the development of new techniques to explore terrestrial-ocean climate linkages along the Pacific Northwest-northeast Pacific Ocean margin. This is done by investigating river response to climate change and by unraveling this history preserved in continental margin sediments. A significant component of this work centers on developing...
The time evolution of mixing in turbulent overturns is investigated using a combination of direct numerical simulations (DNS) and microstructure profiles obtained during two field experiments. The focus is on the flux coefficient Γ, the ratio of the turbulent buoyancy flux to the turbulent kinetic energy dissipation rate ϵ. In...
The purpose of this research is two-fold: to evaluate the success of the new emergency procedures promulgated in 1998 and to characterize the erosion event that precipitated the emergency during January, February and March 1999. These two purposes support each other and provide a holistic understanding of how emergencies arise...
Ocean observing groups are currently making efforts to work with well-defined end-user groups, like boaters and fishermen, to provide meaningful and effective real-time data (RTD) products and visualizations. However, providing meaningful data products for undefined groups such as the general public is not straightforward. In Oregon, several industry, science, and...