Processes Affecting Distribution and Dispersal of Suspended Matter in Columbia River Effluent System: ABSTRACT

Abstract

The sources of the suspended particulate matter derived from the summer mixing of Columbia River and ocean waters are river-borne particles, phytoplankton growing in the ocean near the river, and resuspended particles. The Columbia River contributes most of the particulate (>= 0.45µ) matter (8 to 40 mg/l) which consists of lithogenous particles (85-95 percent) and biogenous particles--primarily freshwater phytoplankton with lesser amounts of detritus. Biogenous matter, primarily phytoplankton and detritus ( Positive vertical gradients in particle concentrations are maintained in the low-salinity surface layers near the river mouth by vertical water movements (>= 1 m/day) and by the relatively greater turbulence of the low-salinity surface layers. The upward component of the water movements is sufficient to retain lithogenous matter (3 to 104 m/day). Concentrations and modal particle diameters (10 to 30µ) of river-borne lithogenous particles, which differ with the rate of river discharge, decrease seaward by progressive mixing with ocean waters with less suspended matter ( 4µ) suspended load. End_of_Article - Last_Page 464------------