Herbicide effects on the population growth of some green algae and cyanobacteria

Abstract

Six herbicides were tested for their effects on the population growth of a range of green algae and cyanobacteria by an easily replicated low‐volume liquid culture technique using Repli‐dishes. Diuron, propanil and atrazine were most inhibitory, chlorpropham was intermediate and MCPA and glyphosate were least inhibitory. Chlorpropham was more inhibitory to green algae than to cyanobacteria. The effects of chlorpropham and 3‐chloroaniline, a metabolite, on populations of the cyanobacterium Anacystis nidulans and the alga Chlamydomonas reinhardii were monitored in larger scale batch cultures. Both compounds reduced the growth rate although in some cases there was partial recovery. 3‐Chloroaniline was less inhibitory than the parent herbicide chlorpropham.