Dynamics of Microbial Communities in an Earthen Shrimp Pond during the Shrimp Growing Period

Abstract

Correlations between the activities of microbial communities and water quality in an earthen pond were investigated monthly during the shrimp growing period. The TAN gradually decreased compared to the beginning time, thereby resulting in an overall decrease of 81.3%. In contrast, the overall nitrate concentration increased 46.3% over this same period. Microbial community analysis using PCR-DGGE showed that changes in community dynamics that occurred during the shrimp growing period might be correlated to water quality. Overall, there were 3 groups of microbial dynamics. The 1st was observed in all investigations, was microflora found in the shrimp culturing system, which included the following: Nitrosomonas eutropha, Exiguobacterium SKRP 5, and Exiguobacteria sp. CNJ771. The 2nd involved the replacement of bacteria from one type to another, such as from Flavobacteriales bacterium to Aquiflexum balticum, which are involved in shrimp shell degradation. The 3rd consisted of microbes observed at only one time point, such as Synechococcus sp. Y0011 (W0), and Stenotrophomonas maltophilia (W3), or at several time points, such as Pseudomonas lanceolata (W0 and W3) and Burkholderia sp. WBF2 (W1 and W2). Although this third group of bacteria was not found at all time points tested, the group was important for balancing the shrimp culturing system, which is important for a successful shrimp cultivation.