Phytoplankton community succession in relation to water quality changes in the indoor industrial aquaculture system for Litopenaeus vannamei

Abstract

Phytoplankton is an important component of aquaculture ecosystem. The succession of dominant species often dominates the trend of phytoplankton community structure balances, which affects the healthy development of aquaculture. To comprehensively assess phytoplankton community succession and explore the major driving factors of this succession in the indoor industrial aquaculture system for Litopenaeus vannamei, a combination of the traditional morphological analysis and high-throughput sequencing were used in the present study. A total of 9 phyla were detected by both methods. Bacillariophyta, Chlorophyta and Cyanophyta were the dominant groups. During the whole process of aquaculture, the succession of phytoplankton community composition in the flowing waters did not follow a clearly regular trend, and ammonia-N and DIN/DIP were the main driving factors. In the aquaculture waters, the dominant species of phytoplankton changed from Thalassiosira to Actinocyclus and Picochlorum. The increase in salinity and decrease in silicate-SiO2 concentrations were the main factors that drive this temporal succession. Some picophytoplankton (≤2 μm) and small nanophytoplankton (>2 μm and ≤ 10 μm) were detected by high-throughput sequencing but not observed by morphological analysis. Picophytoplankton represented 22.22% of total phytoplankton sequence abundance, and small nanophytoplankton accounted for 27.45% of total phytoplankton.