A 56-day study was conducted in which shrimp (Litopenaeus vannamei) were stocked at 300 m−3 into
16, 500-L tanks. Four treatments were created: chemoautotrophic (CA), heterotrophic sucrose (HS), het-
erotrophic molasses (HM), and heterotrophic glycerol(HG). The heterotrophic treatments were managed
such that the C:N ratio of inputs (feed and carbohydrate source) was 22:1. The chemoautotrophic treat-
ment received no added carbohydrate, only shrimp feed. Each treatment was assigned randomly to four
replicate tanks. Nitrate-N was significantly greater in the CA treatment, accumulating to a peak mean
concentration of 162 mg NO3-N L−1 and nitrate was typically below detection (