Application of Micro-nutrients Affects Planktonic Quality and Quantity

Abstract

An experiment was conducted for 90 days in outdoor, circular, 1000 L, cement cisterns with soil base for evaluating the effect of nutrient supplementation on planktonic quality and quantity. All the cisterns were manured with cow dung (400 g), Urea (1 g) and single super phosphate (1.5 g) at fortnightly intervals. Water-soluble forms of Magnesium (Mg), Manganese (Mn), Zinc (Zn) (100 mg each) and Silicon (Si, 0.2 ml) were applied separately to cisterns, maintained in triplicate for each treatment, once in 10 days. Planktonic quality and quantity and water quality were analysed at monthly intervals. The population of diatoms, rotifers and plankton belonging to Chlorophyceae, Euglenophyceae and Trebouxiophyceae were the highest in tanks supplemented with Si. The next higher density of plankton belonging to Trebouxiophyceae was recorded in Mg treatment. The highest density of planktonic Cyanophyceae was recorded in Zn treatment. The density of planktonic crustacean was higher in control and Mn treatment. Excepting a lower yield with Zn treatment, the plankton biomass recorded during the experimental period in different treatment tanks did not differ significantly. The study revealed that the supplementation of nutrients to the culture system affects the taxonomic quality of plankton produced.