Global increases in ultraviolet-B radiation (UVBR:290-
320 nm) resulting from decreases in stratospheric ozone
concentration have the potential to alter marine primary
production and affect global climate and marine trophic
dynamics. Effects of UVBR on phytoplankton carbon fixation
were determined from open ocean exposure studies conducted
off the coast of...
The Critical Depth Hypothesis formalized by Sverdrup in 1953 posits that
vernal phytoplankton blooms occur when surface mixing shoals to a depth shallower than a
critical depth horizon defining the point where phytoplankton growth exceeds losses. This
hypothesis has since served as a cornerstone in plankton ecology and reflects the...
The ¹⁴C-uptake method is the most common approach employed for estimating primary production in the ocean. Normalizing ¹⁴C-uptake to chlorophyll a and time yields a value termed the assimilation number, which is thought to reflect phytoplankton physiology. It is often assumed that the measured rate of ¹⁴C-uptake is between net...
The fluorescence signal emitted from phytoplankton exposed to natural sunlight has been considered a potentially useful tool to examine phytoplankton physiology from in situ radiometers and satellites, but variability in the fluorescence signal is confounded by non-photochemical quenching (NPQ). This pathway dissipates excitation energy as heat rather than fluorescence. It...
The effects of broadcast gypsum on infiltration rates, crusting,
aggregate stability, and runoff and sediment yields were analyzed
during the winter months on three West Oregon soils. The results were
used to evaluate its utility as a management tool to help control
erosion.
An application rate of two metric tons...
I examined two amphibian communities to assess factors
that may impact amphibian biodiversity. The results suggest
that the potential factors which influence the maintenance
of amphibian biodiversity are multi-faceted and thus,
attempts to understand these factors must reflect these
complexities.
I investigated factors that influenced the susceptibility
of western toad...
The effects of improved oral hygiene on the nutrition of 23
elderly institutionalized men and women were investigated. An experimental
group of 12 received professional oral hygiene treatments
three times weekly for a period of five weeks, while a control group
of 11 received only placebo work. Changes in taste...
Freshwater (FW) and seawater (SW) acclimated yearling coho salmon, Oncorhynchus kisutch, were subjected to severe confinement stress in FW, SW, or a medium (1/3 SW) that was approximately isosmotic to the fish's blood. Chronic stress caused osmotic imbalances in FW and SW, but not in 1/3 SW. In SW, blood...
Mean weights, lengths, and condition factors of three isozyme
phenotypes of lactate dehydrogenase (LDH) enzyme differed significantly
for experimentally reared winter steelhead trout (Salmo
gairdneri) fry. Time of emergence from the gravel was unrelated
to LDH phenotype. Relative mortality of the phenotypes between
eyed-egg stage and emergence was unaffected by...
There are well over 200 species of fishes which are known to be venomous, and which are capable of inflicting serious and
potentially fatal wounds. Within this group, less than 5% have been studied even in the most preliminary manner and, to date, the
basic chemical structure of even a...
