Time‐dependent buoyant plumes form at the outflow of tidally dominated estuaries. When estuary discharge velocity exceeds plume internal wave speed c, a sharp front forms at the plume’s leading edge that expands from the time‐dependent source. Using observations of the Columbia River tidal plume from multiple tidal cycles we characterize...
Copper and iron are essential micronutrients that are required by marine primary producers for a variety of metabolic processes. Over 99% of both copper and iron are bound within organic complexes in the marine environment, however the molecular identity of many of these complexes remains unknown. The speciation of these...
Internal tides on the continental shelf can be intermittent as a result of changing hydrographic conditions
associated with wind-driven upwelling. In turn, the internal tide can affect transports associated with upwelling.
To study these processes, simulations in an idealized, alongshore uniform setup are performed utilizing
the hydrostatic Regional Ocean Modeling...
A reduced-gravity model is presented of the warm-water branch of the middepth meridional overturning circulation in a rectangular basin with a circumpolar connection. The model describes the balance between production of warm water by Ekman advection across the circumpolar current, dissipation of warm water by eddy fluxes southward across the...
Numerical simulations of the Hudson River estuary using a terrain-following, three-dimensional
model (Regional Ocean Modeling System (ROMS)) are compared with an
extensive set of time series and spatially resolved measurements over a 43 day period with
large variations in tidal forcing and river discharge. The model is particularly effective at...
Observations of turbulence, internal waves, and subinertial flow were made over a steep, corrugated continental slope off Virginia during May–June 1998. At semidiurnal frequencies, a convergence of low-mode, onshore energy flux is approximately balanced by a divergence of high-wavenumber offshore energy flux. This conversion occurs in a region where the...
The initial composition of a river plume depends on the cumulative turbulent
entrainment within the estuary and how this dilutes the supplied freshwater. Here we
examine the relative roles of turbulence and freshwater input using observations from the
Columbia River estuary and plume during two periods with contrasting river flow....
The subtidal salt balance and the mechanisms driving the downgradient salt flux in the Hudson River estuary are investigated using measurements from a cross-channel mooring array of current meters, temperature and conductivity sensors, and cross-channel and along-estuary shipboard surveys obtained during the spring of 2002. Steady (subtidal) vertical shear dispersion,...
Resource managers at the state, federal, and tribal levels make decisions on a weekly to quarterly basis, and fishers operate on a similar timeframe. To determine the potential of a support tool for these efforts, a seasonal forecast system is experimented with here. JISAO’s Seasonal Coastal Ocean Prediction of the...
Chemical and biological sensor technologies have advanced rapidly in the past five years. Sensors that require low power and operate for multiple years are now available for oxygen, nitrate, and a variety of bio-optional properties that serve as proxies for important components of the carbon cycle (e.g., particulate organic carbon)....
Modifications of an ocean model are described, as the objective for which the model was used changed to study the kinematics and dynamics of an eastern-boundary poleward undercurrent.
The accumulation of domoic acid (DA) and saxitoxins (STX), phycotoxins produced by some species of Pseudo-nitzschia and Alexandrium, respectively, in coastal food webs are a focus of research on the West Coast of the United States due to the deleterious effects they have on coastal ecosystems and economies. Results are...
Two bloom-detection products were developed for the Oregon coast that describe the relative percent change observed between successive pairs of 8-day chlorophyll-a (CHL) and fluorescence line-height (FLH) products obtained from the MODerate Resolution Imaging Spectroradiometer aboard the Aqua spacecraft (MODIS-Aqua). The CHL[subscript dev] and FLH[subscript dev] products, respectively, were optimized...
Velocity measurements from 17 deployments of moored acoustic Doppler current
profilers obtained during four summer upwelling seasons are used to describe the crossshelf
divergence of Ekman transport in the inner shelf off Oregon. For each deployment
the measured surface and bottom cross-shelf transports were compared with estimates
of the theoretical...
Measurements of inherent optical properties (IOP) were conducted over bottoms with different substrates by use
of a sampling package mounted on and operated by a SCUBA diver. It was found that in areas of low ambient
currents the distribution of IOP varies with bottom type in (1) its value relative...
Harmful algal blooms (HABs) are a problem for coastal communities, the fishing industry, and coastal organisms. Pseudo-nitzschia spp. is a regularly occurring diatom in Oregon’s coastal waters. At times, Pseudo-nitzschia spp. can facultatively produce domoic acid, a neurotoxin that can bioaccumulate in the food chain. While regular shore-based sampling provides...
Freshwater discharge from large rivers into the coastal ocean creates tidally-driven frontal systems
known to enhance mixing, primary production, and secondary production. Many authors suggest that
tidal plume fronts increase energy flow to fish-eating predators by attracting planktivorous fishes to feed
on plankton aggregated by the fronts. However, few studies...
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...
Structured estuarine habitats, such as salt marshes, seagrass beds, and oyster reefs, are recognized as critical nurseries for juvenile fish and crustaceans. Estuarine habitat usage by fish, including juvenile Pacific salmon Oncorhynchus spp., was characterized by sampling with a modified tow net in Willapa Bay, Washington, where 20% of the...
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model without
that effect; the P-values function was used for individual fac-
tor levels.
RESULTS
A high volume sampling system, employing Nuclepore filters and
designed for sampling particulate in the plumes from industrial
sources using a light aircraft, is described. The effluent of kraft
paper mills was sampled using this system and then analyzed by
electron microscopy.
Size distributions of particles were obtained at several...