Screening of some fresh water phytoplankton for the requirement of iron, a micronutrient in terms of growth and productivity

The current project analyzes the requirement of iron for the growth, chlorophyll a content and productivity of three fresh water phytoplankton viz. Chlorococcum humicola, Chlorella ellipsoidea and Scenedesmus bijuga. The test organisms were treated with different concentrations of iron like 0.0075ppm, 0.015ppm, 0.03ppm, 0.06ppm and 0.12ppm supplied in the form of FeCl3. The culture devoid of iron was kept as control. Results obtained revealed the indispensable role of iron for the growth of these organisms as they showed decreased values for all the parameters in iron deficient medium. Optimum concentration of iron for the growth and productivity of Chlorococcum humicola was found to be in the range 0.0075ppm to 0.015ppm and it was 0.015ppm for Chlorella ellipsoidea and Scenedesmus bijuga. Iron scarcity exerted more retarding effect on the growth of Chlorella ellipsoidea. Chlorococcum humicola appeared as more susceptible to the toxic effect of higher concentrations of iron than other two test algae. The above observations suggest that algal species vary in their tolerance to iron.