The physicochemical properties and bacterial diversity of the sediment of sea cucumber Apostichopus japonicus culture ponds atsummerhigh temperature

In this study, six sea cucumber culture pondsoffthe coast of Weihai in the north of the Yellow Sea, China, wereselected, andmeasured the physicochemical properties of the sediment ofculture pond at high temperature (HT) stage andthe end of the high temperatures(EHT) stage in summer. High-throughput sequencing was used to analyze the bacterial diversity and community composition of the sediment ofculture pond. The results of physicochemical properties of the sediment in the culture ponds showed that the contents of TN, TC, TOC, NH4+, TS, SO42-, and S2- of Geziling (GZL)sediment were the lowest in bothstages, and the sediment environment was the best. The contents of TN, TC, TOC, and NH4+ in the sediments ofWulei Island (WLD) decreased significantly at EHT stage, and the self-purification ability of sediment was the highest. The contents of various physicochemical properties were higher in Rushankou (RSK) and Xiaoxun Village (XHC) sediments, and the sediment environment was the worst. In addition, the results of high-throughput sequencing showed that the bacterial diversity in the sediments of six culture ponds at HT stage was higher than those of at EHT stage. The bacterial community compositions in the sediment samples were similar in the six culture ponds at HT stage, of which phylum Proteobacteria accounted for the largest proportion.At EHT stage, the bacterial community compositions in the sediment samples were different in the six culture ponds.