Diversity and Seasonality Dynamics of Ciliate Communities in Four Estuaries of Shenzhen, China (South China Sea)

Chuanqi Jiang,Bin Liu,Jie Xiong,Siyu Gu,Kai Chen,Yishan Lu,Jing Zhang,Xueyan Wang,Zhencheng Liu,Wei Miao

doi:10.3390/jmse9030260

Abstract

Ciliates are fundamental components of microzooplankton, with important ecological roles. However, ciliate communities are particularly difficult to monitor using conventional morphological approaches. New molecular tools, such as DNA metabarcoding, can facilitate the study of these communities. This study used high-throughput sequencing to examine the diversity and seasonal dynamics of ciliate communities in four estuarine ecosystems in the South China Sea from June 2019 to March 2020. The amplification of the V4 region of 18S rDNA using ciliate-specific primers identified a total of 1645 amplicon sequence variants (ASVs), corresponding to 13 ciliate classes, 97 families, and 157 genera. The dominant species across all four sampling stations were spirotrichs (including choreotrichs, oligotrichs, and stichotrichs), oligohymenophorean scuticociliates, litostomateans Didinium, and prostomateans Cryptocaryon. Significant differences in ciliate diversity and community composition in the four stations were mainly due to differences in rare, rather than abundant, ASVs. Analysis of the ciliate communities and seasonal patterns in their composition revealed that variations in habitat and environmental conditions have a greater effect than seasonal changes on community composition.

Highlights

Estuarine ecosystems form an important interface between terrestrial rivers and open marine ecosystems
This study analyzed the seasonal dynamics of ciliate diversity and community structures in four estuaries in similar geographical areas
The results show that estuarine ecosystems contain a high diversity of ciliates, including members of most ciliate classes

Summary

Introduction

Estuarine ecosystems form an important interface between terrestrial rivers and open marine ecosystems They undergo highly dynamic changes and have variable environments because of alternating inputs of freshwater and seawater. Ciliates are unicellular organisms that belong to the Alveolata supergroup; they have been found in freshwater, marine, soil, and extreme environments [2,3] They dominate many microeukaryote communities in terms of their diversity and abundance [4,5]. Ciliates display enormous functional diversity as producers, consumers, and decomposers of food webs [6]. Their diversity and community dynamics contribute to the ecosystem stability and function [4,7]. Studies on the community composition and dynamics of estuarine ciliates will improve our understanding of how the distribution and function of ciliates contribute to estuarine ecosystems and inform future assessments of the environmental status of estuaries

Methods

Results

Discussion

Conclusion