Importance of biofilm for water quality and nourishment in intensive shrimp culture

• Published in: Aquaculture 2002-01, Vol.203 (3), p.263-278
• Main Authors: Thompson, Fabiano Lopes, Abreu, Paulo Cesar, Wasielesky, Wilson
• Format: Article
• Language: English
• Subjects: Animal aquaculture; Animal productions; Aquaculture; Bacillariophyta; Biofilm; Biological and medical sciences; Crustacea; Crustaceans; Cyanophyta; Farfantepenaeus paulensis; Food; Fundamental and applied biological sciences. Psychology; Invertebrate aquaculture; Microorganisms; Shrimp; Water; Water quality
• ISSN: 0044-8486; 1873-5622
• DOI: 10.1016/S0044-8486(01)00642-1

Experiments were conducted to test the usefulness of biofilms—a microbial consortium associated with extracellular polymeric substances attached to submersed surfaces—in reducing the levels of ammonium and phosphate of rearing system water, and as a food source for the shrimp Farfantepenaeus paulensis. A mature biofilm, which is able to keep ammonium and phosphate at low levels, occurred 10–15 days after tank cleanup, and was characterized by chlorophyll- a concentration around 5 μg/cm 2. It was mainly composed of pennate diatoms ( Amphora, Campylopyxis, Navicula, Sinedra, Hantschia and Cylindrotheca; ca. 9×10 4 cells/mg of biofilm) and filamentous cyanobacteria ( Oscillatoria and Spirulina; ca. 2×10 5 cells/mg), though bacteria (max. 1.48×10 7/mg), flagellates (max. 1.08×10 3/mg) and ciliates (max. 3.51×10 2/mg) were also present. Pennate diatoms and filamentous cyanobacteria were responsible for the largest uptake of ammonium from the water, but nitrifying bacteria also played an important role. The presence of a biofilm lead to reduced exportation of phosphorus (33% less phosphate) and to a higher output of nitrate+nitrite, instead of ammonium. Biofilm was also an important complementary food source for the shrimp, increasing their growth.