Influences of Diurnal Sampling Bias on Fixed-Point Monitoring of Plankton Biodiversity Determined Using a Massively Parallel Sequencing-Based Technique

Abstract

In this study, we investigated the influence of diurnal sampling bias on the community structure of plankton by comparing the biodiversity among seawater samples (n = 9) obtained every 3 h for 24 h by using massively parallel sequencing (MPS)-based plankton monitoring at a fixed point conducted at Himedo seaport in Yatsushiro Sea, Japan. During seawater sampling, the semidiurnal tidal current having an amplitude of 0.3 m s−1 was dominant, and the westward residual current driven by the northeasterly wind was continuously observed during the 24-h monitoring. Therefore, the relative abundance of plankton species apparently fluctuated among the samples, but no significant difference was noted according to G-test (p > 0.05). Significant differences were observed between the samples obtained from a different locality and at different dates, suggesting that the influence of diurnal sampling bias on plankton diversity is acceptable and data taken at a certain time in a day can be used as the representative one.