Microeukaryotic Community Structure and Dynamics During Macrobenthos Bioremediation in Intertidal Mudflat Sediments of Sansha Bay, China

Abstract

Background: Microorganisms play important roles in the macrobenthic bioremediation process. At present, studies regarding microeukaryotes in intertidal sediments are not enough, and studies of the microeukaryotic dynamics in the bioremediation process using macrobenthos have received much less attention. Objectives: This study aimed to reveal the microeukaryotic community structure and dynamics during the bioremediation process using macrobenthos in the intertidal sediments of Sansha Bay of China. Methods: Twenty sediment samples were collected before and after bioremediation respectively. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) as well as 18S rDNA clone libraries analyses were used. Results: The microeukaryotic communitywere divided into 10 phyla, in which Annelida and Arthropoda were the most dominant, and Gastrotricha and Nematoda were the second dominant groups. A small amount of Cercozoa, Bacillariophyta, Chlorophyta, Alveolata, Amoebazoa, Chytridiomycota, and some unknown eukaryotes were also present. The microeukaryotic community structure presented a clear variation with time. In June, Annelida was the most dominant, and Arthropoda, Nematoda, and Cercozoa were the subdominant phyla. While in September, phylum Annelida decreased dramatically, and Arthropoda and Gastrotricha increased greatly. December harbored a quite different and highest diversity of microeukaryotic community: the phylum Annelida, which was dominant in June and September, was not detected, while the phyla Bacillariophyta, Nematoda, and Alveolata increased greatly, and Amoebozoa and Chytridiomycota were only detected in December. The bioremediation using macrobenthos changed the microeukartotic community structure and increased the diversity. The phyla Annelida and Arthropoda increased, while Gastrotricha, Cercozoa, and Alveolata decreased during the bioremediation. Conclusions: The microeukaryotic community in the intertidal sediment of Sansha Bay of China, were divided into 10 phyla, and presented a clear variation with time. The bioremediation using macrobenthos changed the microeukartotic community structure and increased the diversity.