Scarratt, MGMoore, RM2013-06-192013-06-191999-05Scarratt, MG, and RM Moore. 1999. "Production of chlorinated hydrocarbons and methyl iodide by the red microalga Porphyridium purpureum." Limnology and Oceanography 44(3): 703-707. DOI:10.4319/lo.1999.44.3.07030024-3590http://hdl.handle.net/10222/27169http://dx.doi.org/10.4319/lo.1999.44.3.0703Two experiments were performed using axenic batch cultures of the red microalga Porphyridium purpureum. The cultures were grown in sealed 5-liter glass vessels under a high-purity artificial atmosphere and analyzed for the production of several halocarbons, including chloroform (CHCl(3)), methylene chloride (CH(2)Cl(2)), methyl iodide (CH(3)I), trichloroethylene (C(2)HCl(3)), and tetrachloroethylene (C(2)CL(4)). Two cultures and a control were used in each experiment. The first experiment followed the system for 17 d at low Light intensity (20 mu mol quanta m(-2) s(-1)), while the second was comprised of 7 d at low light followed by 24 h at high light intensity (800 mu mol quanta m(-2) s(-1)). In both experiments, only chloroform and methyl iodide were produced in measurable quantities. This is the first report of chloroform production in a microalgal species. The chlorophyll a (Chl a)-normalized production rate of chloroform in the various cultures ranged between 1.3 x 10(-7) and 7.8 x 10(-7) mol (g Chl a)(-1) d(-1) (15-93 mu g [g Chl a](-1) d(-1)). Chloroform production peaked during the logarithmic growth phase. Methyl iodide production ranged between 2.0 x 10(-7) and 1.2 x 10(-6) mol (g Chl a)(-1) d(-1) (28-170 mu g [g Chl a](-1) d(-1)). Exposure of the cultures to high irradiance (800 mu mol quanta m(-2) s(-1)) did not stimulate the production of any of the compounds. In contrast to an earlier published account involving this species of algae, the production of tri- and tetrachloroethylene was not detected in any of the cultures under either low or high irradiance.article443703