Light‐Induced Hg Volatilization and O₂ Evolution in Chlorella and the Effect of DCMU and Methylamine

The rate of volatilization of Hg 2+ as metallic Hg is accelerated by illumination of Chlorella cells. In the presence of the uncoupler methylamine the rate of volatilization in the light is greatly but transiently increased. DCMU (3‐(3,4‐dichlorophenyl)‐1,1‐dimethyl urea) prevented the light response. In the presence of Hg 2+ , O 2 evolution by the cells was not completely inhibited by DCMU. Hg 2+ appears to prevent DCMU reaching its binding site. Light seems to increase the amount of or leakage from the cells of a metabolite capable of reducing Hg 2+ to Hg°.