Simple electrometric methods for estimating microbial activity in aquaculture ponds

Simple electrometric methods were tested to estimate microbial activity in hypereutrophic aquaculture ponds using equipment common at aquaculture facilities for biochemical oxygen demand (BOD) measurements. Activity measurements tested included net photosynthesis based on changes in dissolved oxygen (DO) concentrations in samples incubated under light and dark conditions; general microbial activity as indicated by oxygen consumption rates in the dark; nutrient limitations as indicated by changes in DO consumption rates with nutrient additions; and nitrification based on the difference in DO consumption rates between samples incubated with and without a nitrification inhibitor. Method evaluations in intensive shrimp culture ponds suggest that simple electrometric methods are a good index of water column microbial activity under a range of conditions.