Ecosystem Dynamics of a Microbial Biofloc Community Used to Culture Pacific White Shrimp (Litopenaeus vannamei)

Abstract

Microbial biofloc systems are increasingly important to raising Pacific white shrimp (Litopenaeus vannamei), because they efficiently remove wastes produced by high density cultivation and have the potential to provide supplemental nutrition and oxygen to the shrimp population. Gross primary productivity (GPP) and community respiration (RESP) can easily be measured and used to characterize the dominant processes in a system and how they relate to shrimp growth, microbial productivity, and survival. Photoautotrophic, "green water", systems are algal dominated as evidenced by high daytime GPP. By contrast in heterotrophic or chemoautotrophic, "brown water", systems, the respiratory costs exceed the photosynthetic rate even during daylight hours. RESP can also be used to better understand the relative contribution of the microbes and the shrimp to the total oxygen demand of the system. Finally, clarifiers allow cropping of sludge in hopes of promoting algal growth and a "green", photoautotrophic system.