Calanoid copepod diet was investigated in Oregon coastal waters to determine
the trophic significance of phagotrophic protists as copepod prey within an ecosystem
where the microplankton biomass is typically dominated by large diatoms. Prior to and
during the 1991 upwelling season, clearance rates on phytoplankton and phagotrophic
ciliates were measured...
The ecological interaction between the largest coastal predator, the gray whale (Eschrichtius robustus) and the most abundant shallow water marcrozooplanktonic prey, mysids, were examined in a poorly-understood predator-prey relationship along the central Oregon coast. From 2002-2008, 83 seasonal gray whales were identified. These whales returned each year around Memorial Day...
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...
In situ optical measurements of spectral absorption and beam attenuation provide information on the fine scale horizontal and vertical variations in phytoplankton pigments and other measures of phytoplankton photophysiology and ecology in coastal waters. Phytoplankton pigment ratios from discrete sample analyses with High Performance Liquid Chromatography were compared to in...
Mesoscale surveys to examine the relationship between the physical processes and biological response along the Antarctic Polar Front (PF) were conducted as part of the US JGOFS Southern Ocean Program during austral spring and summer 1997/98. Multiple crossings of the PF near 170° W, using a towed undulating instrument, provided...
Bi-weekly sampling of zooplankton and environmental parameters was conducted along a cross-shelf transect off the coast of Newport, OR, USA (44.65°N) from 1996 to present. Results have demonstrated the feasibility of using copepod community structure as an early indicator of ecosystem response to seasonal and large scale environmental changes in...
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...
How certain aspects of the swimming behavior of the copepod Calanus
marshallae vary as a function of different food conditions of Thalassiosira weissflogii
was examined. A two video camera recording and controlled food environment
aquaria system were used to record long-term swimming behavior and to determine 3-
dimensional swimming paths...
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...
Wireless networking equipment was installed on three research vessels and at three shore stations during the 1998 Thin Layers Experiment in East Sound, Washington. This wireless network provided high-speed data communication between scientists on separate vessels and permitted rapid transfer of data from vessels and from moored instruments to a...
Cytokinin oxidase activity in callus tissues of
Phaseolus vulgaris L. cv. Great Northern has been examined
using an assay based on the oxidation of radioactively
labeled N⁶ -(Δ² -isopentenyl) adenine (i⁶Ade) to adenine
(Ade). Conditions for the quantitative extraction and
assay of the enzyme have been established. The substrate
specificity...
Small pelagic fish represent a critical trophic link between plankton and large predators in marine upwelling ecosystems such as the California Current System. Populations of these fish are highly variable over time and are characterized by extreme fluctuations in abundance, which have significant ecosystem impacts. The causes driving
this instability...
At the Costa Rica Dome (CRD), upwelling associated with cyclonic circulation and the presence of a shallow thermocline support a highly productive biological habitat, exploited by marine fauna at several trophic levels. During January 2008, a cruise to the CRD by the R/V Pacific Storm was conducted to relocate blue...
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...
Physical, optical, and acoustical data from Monterey Bay, California, USA, describing the distributions of phytoplankton, zooplankton, and small fish as well as gradients in the physical habitat were used to examine the interactions between vertically compressed plankton structures (thin layers), their consumers, and the local physical forces they experience. The...
We present velocity observations from a shipboard acoustic Doppler current profiler (ADCP) on RJV Revelle during cruises R9710 (20 October to 23 November 1997) and R9801 (9 January to 7 February 1998). The cruises were conducted as part of the Southern Ocean JGOFS (Joint Global Ocean Flux) Antarctic Polar Frontal...
The first seagoing test of a prototype laser/fiber-optic system for in situ detection of ocean chlorophyll fluorescence is described. Radiation at 488 nm originating from a shipboard argon laser was transmitted through 20 of 200-µm core optical fiber to the distal tip mounted on the microstructure profiler, the Rapid Sampling...
A new in situ fluorometer for the detection of oceanic photosynthetic pigment fluorescence is described.
Emission spectra from 546 to 733 nm are recorded for each of three different visible excitation bands ten
times a second. A Spectralon cell is used to improve the excitation coupling to and the collection...
As part of the U.S. Joint Global Ocean Flux Study Southern Ocean
program, high-resolution surveys of the Antarctic Polar Front near 170øW were
conducted during October-November 1997 with a towed undulating system equipped
with conductivity-temperature-depth and bio-optical sensors. Transects along
170°W and two successive mapping surveys revealed zonal bands with...
Variation in bacterial abundance and activity was assessed by sampling the upper 35 to 80 m of the water column during 2 to 5 d periods at 3 sites: eutrophic-mesotrophic midshelf, mesotrophic-oligotrophic slope, and oligotrophic gyre edge, off the Oregon coast in late summer 1997 and 1998. Bacterial abundances varied...
The spectral dependency of the particulate backscattering ratio is relevant in the fields of ocean color inversion, light field modeling, and inferring particle properties from optical measurements. Aside from theoretical predictions for spherical, homogeneous particles, we have very limited knowledge of the actual in situ spectral variability of the particulate...
The implementation and characterization of backscatter and forward-scatter fiber-optic fluorescence sensors attached to a microstructure profiling instrument are described. By using an optical multichannel array detector to record emission spectra, eight profiles per hour of chlorophyll fluorescence spectra at 2-cm intervals can be obtained throughout the upper 100 m of...
We present velocity observations from a shipboard acoustic Doppler current profiler (ADCP) on RIV Revelle during cruises R9711 (30 November 1997 to 3 January 1998) and R9802 (13 February 1998 to 19 March 1998). The cruises were conducted as part of the Southern Ocean JGOFS (Joint Global Ocean Flux) Antarctic...
Diatoms are a ubiquitous group of plankton responsible for 20-40% of oceanic
primary production, and a higher fraction of organic matter export to the ocean
interior. Diatoms actively transport dissolved inorganic silicon into their cells, and
through the process of silicification (i.e. biogenic silica production) they build tough
and intricate...
Calanus finmarchicus (Gunnerus) stratify narrowly near 500 m depth during their fifth copepodite resting phase in North Atlantic Slope Water off southern New England, USA. They probably achieve this by migration to a specific, daytime isolume. Photoperiod information provided by light intensity at depth could serve as a cure for...
Our view of phytoplankton has historically revolved around their inability to
control their location in space. The term phytoplankton itself underscores this
particular difference between phytoplankton and their sessile terrestrial counterparts.
Yet there are other differences between land plants and the phytoplankton that are
perhaps equally important, beyond this sessile-planktonic...
Using techniques that permit the direct observation of
fetuses in vivo, prenatal behavioral development was
compared among four species in the rodent family Muridae:
the Norway rat (Rattus norvegicus), Mongolian gerbil
(Meriones unguiculatus), cotton rat (Sigmodon hispidus), and
spiny mouse (Acomys cahirinus). Rattus and Meriones bear
altricial offspring, as do...
We measured iron concentrations off the Oregon coast in spring (May–June) and summer (August) of 2001 as part of the Coastal Ocean Advances in Shelf Transport (COAST) program. Dissolvable and total dissolvable iron levels in surface waters were generally higher in spring (mean of 2.1 and 33.9 nmol L¯¹, respectively)...
The backscattering properties of marine phytoplankton, which are assumed to vary widely with differences in size, shape, morphology and internal structure, have been directly measured in the laboratory on a very limited basis. This work presents results from laboratory analysis of the backscattering properties of thirteen phytoplankton species from five...
Ribonucleotide reductase from Rhizobium meliloti has been
partially purified and characterized. The enzymatic reduction of
ribonucleotides to deoxyribonucleotides is dependent upon B₁₂ coenzyme
and dihydrolipoate.
B₁₂ coenzyme was more effective than B₁₂ coenzyme analogues
in the reductase reaction. The affinity of the R. meliloti
reductase system for B₁₂ coenzyme was...
Childhood tooth decay is a prevalent and concerning public health issue that is often misunderstood or dismissed. In Oregon specifically, over 50% of children have experienced at least one instance of tooth decay and these rates are even higher for marginalized communities such as children living in poverty, children of...
High concentrations of chlorophyll are found in the California Current System over
300 km offshore, far from the productive coastal upwelling region, and between 150 and
250 m, well below the depth to which photosynthetically active solar radiation penetrates.
This exceptionally deep chlorophyll feature is formed near the coast and...
People will spend a large amount of their lifetime indoors where the air is filled with both indoor and outdoor allergens. Exposure to allergens can have a range of effects on the health of building occupants. Textiles make up a vast majority of the surfaces, such as draperies, sofas, pillows,...
The objectives of the experiment were to: 1) determine the relationship
between overstory canopy cover and ungulate herbivory on understory production
composition and diversity and 2) determine the effects of timber harvest, ungulate
herbivory and season of use on botanical composition and nutritional quality of
beef cattle diets. Three randomly...
Two experiments were conducted to evaluate the effects of forage quality and supplemental undegradable intake protein (UIP) level on intake, digestibility, and performance of beef cattle. In Exp. 1, five ruminally cannulated steers (BW = 456 ± 6 kg) were used in a 6 x 5 incomplete Latin square with...
This study quantified the magnitude and timing of summer streamflow deficits in paired-watershed experiments in the Cascade Range of Oregon where mature and old-growth conifer forests were subjected to clearcutting, patch cutting, and overstory thinning treatments in the 1960s and 1970s. Hydrologic effects of clearcutting, small-patch cutting, and overstory thinning...
SeaWiFS estimates of surface chlorophyll concentrations are reported for the region of the U.S. JGOFS study in the Southern Ocean (∼ 170 °W, 60 °S). Elevated chlorophyll was observed at the Southern Ocean fronts, near the edge of the seasonal ice sheet, and above the Pacific Antarctic Ridge. The elevated...
Observations during the Coastal Transition Zone (CTZ) experiment in summer 1988 reveal the
presence of deep phytoplankton layers in a coastal upwelling system. The layers occur throughout the
CTZ study area, including a strong baroclinic jet which was present over the period of the experiment.
On the basis of a...
The objective of this study is to analyze empirically the demand
structure for the following important farm production inputs in
Oregon: hired labor, chemical fertilizer, farm machinery, repairs
and operating costs of motor vehicles and other machinery designated
as "machinery supplies," purchased feed and miscellaneous inputs.
Twenty-year data (1950-69 except...
Satellite-derived data provide the temporal means and seasonal and nonseasonal
variability of four physical and biological parameters off Oregon and Washington
(41°–48.5°N). Eight years of data (1998–2005) are available for surface chlorophyll
concentrations, sea surface temperature (SST), and sea surface height, while six years of
data (2000–2005) are available for...
