An approach to optimizing sampling effort for bioassessment surveys based on periphytic ciliates according to water depths in marine ecosystems

Abstract

The expectation analysis on taxonomic sufficiency of a community is a useful tool to optimize sampling effort for bioassessment of environmental/ecological quality status. To identify the taxonomic breadth for monitoring surveys based on periphytic ciliate communities at different layers in water columns, the taxonomic breadth was studied based on a 2-week baseline survey at four depths of 1, 2, 3.5 and 5 m in coastal waters of the Yellow Sea, northern China. Using glass slides with 17.5 cm2 for each, samples with five sample sizes (1, 2, 3, 5 and 10 slides) were collected at each depth after a 14-day exposure. The ciliates represented a clear variability in taxonomic composition/breadth from surface layer to deep in the water column. The taxonomic diversity/distinctness measures generally showed a weak increasing trend from the low sampling effort to high. Analysis on homogeneity in taxonomic breadth demonstrated that 10 slides (175 cm2) were required for collection of periphytic ciliates at depths 1–5 m, 3–5 slides (52.5–87.5 cm2) were sufficient to collect the ciliates at depths of 1–3.5 m. It is suggested that an optimal sample size should be determined in monitoring programs using periphytic ciliates according to water depths in marine ecosystems.

Keywords

• Sampling effort
• Monitoring program
• Taxonomic distinctness
• Periphytic ciliates
• Marine ecosystems