Phylogenetic diversity and spatiotemporal dynamics of bacterial and microeukaryotic plankton communities in Gwangyang Bay of the Korean Peninsula

Dukki Han,Hanseob Shin,Chang-Keun Kang,Dong-Gyun Kim,Ji-Hoon Lee,Hor-Gil Hur

doi:10.1038/s41598-022-06624-7

Abstract

Nutrient dynamics function globally, flowing from rivers to the ocean (estuarine–coastal zone), and are vulnerable to climate change. Microbial habitats can be affected by marine nutrient dynamics and may provide a clue to predict microbial responses to environmental heterogeneity in estuarine–coastal zones. We surveyed surface seawater in Gwangyang Bay, a semi-enclosed estuary in Korea, from 2016 to 2018 using a metabarcoding approach with prokaryotic 16S and eukaryotic 18S rRNA genes. Bacterial and microeukaryotic communities in these waters showed distinct local communities in response to environmental heterogeneity and community transition at spatiotemporal scales in the estuarine–coastal zone. The relative abundance of prokaryotic and eukaryotic operational taxonomic units suggested a microbial trophic interaction in the Gwangyang Bay waters. We found that the community assembly process in prokaryotic communities was primarily influenced by biological interaction (immigration–emigration), whereas that in eukaryotic communities was more affected by environmental stress (habitat specificity) rather than by biotic factors. Our findings in the Gwangyang Bay waters may provide information on underlying (biotic or abiotic) factors of the assembly process in microbial communities in the estuarine–coastal zone.

Highlights

Gwangyang Bay (GB), a semi-enclosed estuary, forms the estuarine–coastal zone at the southern tip of the Korean Peninsula and is a suitable area to monitor the spatiotemporal variability of environmental heterogeneity
In GB waters, diversity and community composition of prokaryotes and microeukaryotes was surveyed at the spatiotemporal scale using the 16S and 18S rRNA gene metabarcoding approach
The biogeographic patterns of microbial communities represent the environmental heterogeneity at the spatiotemporal scale in the estuarine–coastal zone

Summary

Introduction

Gwangyang Bay (GB), a semi-enclosed estuary, forms the estuarine–coastal zone at the southern tip of the Korean Peninsula and is a suitable area to monitor the spatiotemporal variability of environmental heterogeneity. A recent metabarcoding survey of GB revealed that water mass mixing shapes bacterial communities in the estuarine–coastal zone and provided valuable insights into bacterial contributions to phytoplankton-derived organic matter under seasonal variation and phylogenetic bacterial diversity at euphotic depths[16]. The previous GB survey by Han et al.[16] improved our understanding of the phylogenetic structuring (phylogenetic over-dispersion or clustering) of bacterial communities in the estuarine–coastal zone, the ecological significance of eukaryotic communities and its comparison with that of prokaryotic communities remains unknown. Considering the preliminary findings of Han et al.[16], GB may provide fundamental information regarding the phylogenetic responses of microbial (prokaryotic and eukaryotic) communities to the seasonal climate change in the estuarine–coastal zone. The present study primarily aimed to estimate the phylogenetic diversity of prokaryotic and eukaryotic communities and their ecological significance at the spatiotemporal scale in the estuarine–coastal zone. The phylogenetic diversity was estimated using ecological statistics with metabarcoding sequences

Methods

Results

Conclusion