AEI prepress abstract  -  DOI: https://doi.org/10.3354/aei00311

Effects of the algicidal bacterium CZBC1 on microalgal and bacterial communities in shrimp culture

Xiaojuan Hu*, Guoliang Wen*, Wujie Xu, Yu Xu, Haochang Su, Keng Yang, Yunna Xu, Zhuojia Li, Yucheng Cao**

*Email: cyc_715@163.com

ABSTRACT: Algicidal bacteria may play a role in controlling algal blooms. Previously, a Bacillus cereus strain (CZBC1) has shown specificity against harmful Cyanophyta. To elucidate the characteristics of microalgal and bacterial communities in shrimp culture associated with the algicidal bacterium CZBC1 and its combined use with the addition of organic carbon, we established a shrimp culture system in which the dominant species were Oscillatoria chlorina (Cyanophyta) and Chlorella pyrenoidosa (Chlorophyta). We studied the water-column microalgal and bacterial communities in control (GC), bacteria (GB) and bacteria–carbon (GBC) groups in the early and mid-experiment (Days 28 and 56). The algicidal bacterium CZBC1 was able to regulate abundance of Cyanophyta on Days 28 and 56 in GB and GBC. Percentages of Cyanophyta on Days 28 and 56 were significantly lower in GB (<0.44%) and GBC (<0.37%) and those of Chlorophyta were significantly higher (86.83–99.94%) than those in GC (25.57–40.87% and 52.52–67.35%, respectively). Multiple linear stepwise regression analysis showed that the amount of applied algicidal bacterium CZBC1 had the most significant negative correlation with the percentage of Cyanophyta (R = 0.973, p < 0.01). On Days 28 and 56, the average well color development value (BIOLOG), bacterial count, and bacterial community structure were relatively stable in GB, while the addition of a carbon source increased the amount of bacteria and affected the composition of the bacterial community in GBC. Our findings suggest that algicidal bacteria could be used to regulate microalgal communities and stabilize metabolic potential of bacterial communities in the aquaculture water environment.