Eukaryotic plankton size structure and species composition in the wetland lakes

Eukaryotic plankton play an important role in the wetland lake ecosystems. However, the size structure and species composition of eukaryotic plankton in shallow wetland lake ecosystems remains largely unexplored. To address this gap, our study employed high-throughput sequencing and quantitative PCR techniques to investigate the size structure (pico-0.7–5 μm and nano-5–20 μm) and species composition of eukaryotic plankton in two shallow wetland lakes in China during August 2016. Our findings reveal that the diversity index values of the pico-size fraction were significantly higher than those of the nano-size fraction. Additionally, there was a significant difference in community structure between these two size fractions. Furthermore, different dominant taxa were associated with each particle size, with certain lineages being enriched exclusively in one of the size fractions. In particular, biomarkers differed between the pico- and nano- fractions. The abundance of the 18S rDNA gene did not differ significantly between the two fractions. However, there was a significant difference in the abundance of gene transcripts. Moreover, the pico- fraction exhibited a significantly higher rRNA: rDNA ratio compared to the nano- fraction. It is important to note that certain taxa had lower absolute abundance in specific samples, despite their higher relative abundance.