EFFECT OF TURBIDITY ON PRIMARY PRODUCTIVITY AT 2 STATIONS IN THE AREAOF THE COLORADO RIVER DELTA

Most coastal lagoons that present high tide intervals and high turbule nt kinetic energy have high turbidity and, therefore, light is a limit ing factor for primary productivity. The Colorado River Delta has been reported with high turbidity values. Our purpose is to estimate the e ffect of turbidity on primary productivity. We took water samples from two locations within the Colorado River Delta (one turbid and another less turbid). We carried out daily experiments on primary productivit y with the C-14 technique during spring and neap tides, from 15 to 22 May, 1991. We used artificial light incubators with lamps of cool whit e constant light with 66.33 mu E m(-2) s(-1) of irradiance and another with a stroboscopic lamp with white xenon light with 66.17 mu E m(-2) s(-1) of irradiance. In general, in the samples from the high turbid location we found a higher concentration of chlorophyll alpha and a hi gher concentration of chlorophyll alpha per cell. In the incubations w ith the stroboscopic lamp, the samples from the turbid station showed higher assimilation rates and assimilation rates per cell than the sam ples from the clear station. Meanwhile, for the samples from the clear station, the assimilation rates and assimilation rates per cell were higher in the incubations with constant light.