Interaction and Assembly of Bacterial Communities in High-Latitude Coral Habitat Associated Seawater.

Yu Chen,Qingsong Yang,Yiyang Zou,Xiangcheng Yuan,Yuanjiao Lyu,Zhijian Jiang,Xiaoyu Tang,Si Zhang,Qiqi Li,Jie Li

doi:10.3390/microorganisms10030558

Abstract

Threatened by climate change and ocean warming, coral reef ecosystems have been shifting in geographic ranges toward a higher latitude area. The water-associated microbial communities and their potential role in primary production contribution are well studied in tropical coral reefs, but poorly defined in high-latitude coral habitats to date. In this study, amplicon sequencing of 16S rRNA and cbbL gene, co-occurrence network, and βNTI were used. The community structure of bacterial and carbon-fixation bacterial communities showed a significant difference between the center of coral, transitional, and non-coral area. Nitrite, DOC, pH, and coral coverage ratio significantly impacted the β-diversity of bacterial and carbon-fixation communities. The interaction of heterotrophs and autotrophic carbon-fixers was more complex in the bottom than in surface water. Carbon-fixers correlated with diverse heterotrophs in surface water but fewer lineages of heterotrophic taxa in the bottom. Bacterial community assembly showed an increase by deterministic process with decrease of coral coverage in bottom water, which may correlate with the gradient of nitrite and pH in the habitat. A deterministic process dominated the assembly of carbon-fixation bacterial community in surface water, while stochastic process dominated t the bottom. In conclusion, the structure and assembly of bacterial and carbon-fixer community were affected by multi-environmental variables in high-latitude coral habitat-associated seawater.

Highlights

Coral reefs are highly diverse and productive ecosystems [1,2]
Our results demonstrated that coral coverage ratio, nitrite, and nitrate significantly influence the bacterial and carbon-fixation bacterial community
We investigated the diversity of bacterial and carbon-fixation community in seawater of a high-latitude coral habitat in the northern South China Sea (SCS) and revealed that the compositions of both communities significantly changed between different areas in the habitat

Summary

Introduction

Coral reefs are highly diverse and productive ecosystems [1,2]. The gross primary production rates of coral reefs range from 256 to 1696 mmol C m−2 d−1 [3,4]. Benthos including coral symbiotic zooxanthellae, macroalgae, algal, turfs, and endolithic algae contribute a major fraction of the primary production in the ecosystem [5,6], while planktonic creatures contribute up to 13% of the primary production [4,5]. Environmental microbes may play a key role against reef degradation by altering its productivity and trophic dynamics [7]. Environmental microbes are crucial for productivity and maintenance of coral reefs. Benthos influences the reef water column environment at different scales [8], and bacterial communities have been found that are highly diverse and vary among reef water

Methods

Results

Discussion

Conclusion