Harmful Algae Blooms at Oaks Bottom
by John Sparks In April 2025, Oregon Health Authority experts tested the waters of Wapato Marsh at Oaks Bottom and found a “concerning” level of microcystins at 191 μg/l (micrograms per liter). (Microcystins are toxins produced by cyanobacteria; the other major cyanotoxin is cylindrospermopsin.) Accordingly, in May, warning signs were posted on the trails at …