Bioremediation of shrimp (Litopenaeus vannamei) cultured effluent using copepod (Oithona rigida) and microalgae (Picochlorum maculatam & Amphora sp.)—An integrated approach

Abstract

Nitrogenous compounds are major contaminants in aquaculture effluent and thereby needs a potential candidate for removing these nutrients. The present study tested the efficacy of immobilized microalga, diatom Amphora sp. and copepod Oithona rigida to remove excessive nutrients from the shrimp (Litopenaeus vannamei) cultured effluents. Nutrient removal was evaluated with five different combinations: (1) copepod, O. rigida; (2) immobilized Picochlorum maculatum and copepod O. rigida; (3) immobilized P. maculatum; (4) immobilized Amphora sp. and copepod O. rigida; and only (5) immobilized diatom, Amphora sp. Preliminary studies showed maximum reduction of about nitrate 86% and nitrite 88% in treatment 2–4, respectively. The maximum phosphate (69%) and ammonia (91%) removal was recorded in the treatment 3. In disparity, the phosphate concentration recorded was significantly higher (6%) at the end of the experiment in the treatment 1 than other experiments. While in the treatments 1, 2, and 4 the copepod showed significant (ANOVA: p < 0.001) increases in phosphate from the previous concentration, it might be due to the rapid release of this nutrient from excreta of filter-feeding organism. The results showed that immobilized green alga and copepod performed well in absorbing phosphate, ammonia, and nitrogenous compounds, respectively.

Keywords:

• Adsorption
• Absorption
• Bioadsorption
• Picochlorum maculatum
• Oithona rigida
• Copepod

Acknowledgement

The authors thank the Head, Department of Marine Science and authorities of Bharathidasan University, Tiruchirappalli-24, for the facilities provided and one of the authors (SD) greatly acknowledge the DBT, Govt. of India, for Junior Research Fellowship.