The Effect of Copper, Zinc, Cobalt and Manganese on the Growth of the Marine Diatom Nitzschia closterium

RoSKO, JOHN J., and JOSEPH W. RACHLIN (Dept. Biol. Sciences, Lehman Coll., City Univ. of New York, Bronx, New York 10468). The effect of copper, zinc, cobalt and manganese on the growth of the marine diatom Nitzschia closterium. Bull. Torrey Bot. Club 102: 100-106. 1975.-ATn extension of a previously pnblished algal cell technique (Rachlin and Farran 1974) was used in this study to monitor the effects of copper, zinc, cobalt ancd manganese on the growth of the diatom Nitzschia closterium which had been isolated from the western end of Long Island Sound. The concentration of each metal which depressed the growth rate of this speeies by 50% (EC,0) after a 96 hr exposure was calculated to be 0.0329+0.00005 ppm for Cu, 0.271+0.0003 ppm for Zn, 10.2+0.0164 ppm for Co and 25.7+0.0237 ppm for Mn. The effects of chelation on the toxicity of each metal were also determined. The results of this testing procedure indicate the potential effects of heavy metal stress on primary productivity. This may be of particular concern in waters nearlarge urban centers like New York City, where heavy industrialization may discharge metal toxicants into the aquatic environment.