Mathematical modeling of phytoplankton populations based on laboratory observations provides increased understanding of the interaction among the environmental and biological mechanisms. influencing growth dynamics. Such fundamental understanding is necessary to estimate the impact of man-made perturbations on natural population.
A three-compartment mathematical model was developed to represent a phytoplankton population...
Waters of various salinities were secured from the Umpqua
estuary, the Umpqua River, and the open ocean near the mouth of the
estuary. The rate of oxidation of sulfides in these various waters
was investigated to assess the potential longevity of free sulfides in
The rate of disappearance...
Spatial, diel and seasonal variations in dissolved oxygen and
temperature were measured in Triangle Lake, Oregon. Spatial dissolved
oxygen and temperature variations measured in the stratified
lake are presented to illustrate the horizontal uniformity of the lake
and to demonstrate the applicability of the one dimensional assumption
for sampling and...
A digital computer model was developed to simulate the time
and space distribution of a dissolved pollutant in an estuary. The program
is basically a one-dimensional finite-difference model, but two
dimensions can be represented by attaching together several one-dimensional
channels. The influence of convection, dispersion and
decay are included in...
Several dichotomous-response models of carcinogenesis are discussed and their implications for low-dose risk estimation are
examined. In addition, a pharmacokinetic model incorporating non-linear kinetics is studied and the results are investigated with
respect to multiple-pollutant exposures. None of these models appears to suggest the existence of "thresholds".
The analysis of...
A study of the effect of mixing on the oxygen uptake rate of
estuarine bottom deposits is presented. The method of study involved
the mixing of samples of bottom deposits with the overlying water to
result in concentrations of suspended matter in the same order as
observed in the estuary....
In situ light and dark planktonic and benthal respirometers were
used to measure the oxygen requirements of Yaquina estuary water
and benthal deposits. Respirometer devices were constructed so that
actual conditions of mixing could be simulated and benthal deposit
disturbance would be minimized.
A mathematical model of a benthal respirometer...