Genus-specific relationships between the phytoplankton and bacterioplankton communities in Lake Taihu, China

Abstract

Phytoplankton is the main source of energy and material for bacterioplankton in eutrophic lakes, but little is known about the species-specific relationships between dominant phytoplankton and bacterioplankton. In this study, we examined the response of the bacterioplankton community composition (BCC) to phytoplankton succession at genus-level resolution in a eutrophic lake, Lake Taihu. BCC was analyzed using 16S rRNA gene terminal restriction fragment length polymorphism and high-throughput 454 pyrosequencing for selected samples collected monthly from January to December of 2009. Microcystis, Phormidium, Synedra and Asterionella dominated the phytoplankton community from January to March; then, Microcystis became the sole dominant genus, and a phytoplankton bloom occurred from June to October. Canonical correspondence analysis showed that phytoplankton abundance played a key role in shaping the variance of the BCC. The abundance of Microcystis was negatively correlated with the abundance of Micrococcineae and Burkholderiales but was positively correlated with that of Actinomycetales; the abundance of Synedra had a positive correlation with two operational taxonomic units (OTUs) of Actinomycetales as well as Planctomycetales, Rhodobacterales, Sphingomonadales, and Xanthomonadales, four OTUs that are affiliated with Burkholderiales. These results suggest that the responses of bacterioplankton to phytoplankton may be genus specific, even within the same order.