Variation in contents of carbon, nitrogen and heterotrophic bacteria in intensive shrimp ponds and their correlation

We studied the variation in contents of carbon (C), nitrogen (N) and heterotrophic bacteria in the intensive shrimp ponds in Shanwei Red Bay of Guangdong Province, and analyzed the effects of C and N on heterotrophic bacteria, so as to provide theoretical references for a reasonable regulation for water quality during culture period. The results show that carbon content gradually reaches the maximum during pre- and mid-culture periods but declines to stability in late period; the nitrogen content is relatively low during pre- and mid-culture periods but reaches the maximum in later period; the content of heterotrophic bacteria peaks in mid-culture period for 56 d and later period for 98 d, but reaches the lowest point after 70-day culture. The heterotrophic bacteria show a very significant positive correlation to TIC and TC. In late culture period, the heterotrophic bacteria show a very significant negative correlation to C/N (TOC/TN).Mainly carbon limits the propagation of heterotrophic bacteria in mid and late culture periods. Thus, addition of carbon in the ponds can promote propagation of heterotrophic bacteria, absorption and transformation of inorganic nitrogen, and reduce the concentration of inorganic nitrogen, finally improve the efficiency of material recycling.