CONCENTRATIONS AND TEMPORAL VARIATIONS OF PO-210, PB-210, AND AL IN THE SURF ZONE ECOSYSTEM OF COPALIS BEACH, WASHINGTON

Surf diatoms monitored during a 21-month period at Copalis Beach, Washington, contained elevated concentrations of Al, 210Pb, and supported 210Po compared to net phytoplankton from Washington coastal waters and Puget Sound. Aluminum concentrations of several per cent dry weight found in the surf diatoms were not a reflection of contamination by discrete inorganic particulate matter but were the result of a natural coating of clay-sized particles on Chaetoceros armatum, the predominant diatom in the surf blooms. A high correlation between Al and 210Pb in the surf diatoms suggests 210Pb and supported 210Po were also associated with the clay-sized particles. During fall through spring, the unsupported 210Po concentrations in the surf diatoms were correlated with the input of 210Po by precipitation. A summer maximum in unsupported 210Po concentrations in the surf diatoms may reflect upwelling that causes higher dissolved 210Po concentrations in the summer surf relative to those of late spring and early fall. The consumers of the surf diatoms exhibited larger 210Po-activity-to-210Pb-activity ratios than their food, indicating 210Po was preferentially accumulated in the higher trophic level. © 1979.