Horizontal Distribution of Geosmin in a Reservoir before and after Copper Treatment

Extracellular geosmin, chlorophyll a, and Anabaena circinalis filament density were measured at several stations on the surface of Lake Perris, a 1.62 × 10⁸ m³ (131,450 acre-ft) reservoir in southern California, before and after the reservoir was treated with copper sulfate. Samples were collected from 22 stations within three hours the day before copper was applied by helicopter to the reservoir, which was undergoing an odorous Anabaena bloom. The day after the copper application, 19 stations were sampled over the same short period of time to see how the copper application affected parameter distribution on the reservoir surface. The presence of higher geosmin concentrations in some areas of the lake after copper treatment suggests that additional geosmin was released into the water when Anabaena cells were lysed by the copper.