Climate determines diversity but not abundance of nitrogen-cycling microorganisms in rivers across a latitudinal gradient

Abstract

A central goal in microecology is to understand the ecological factors shaping spatial patterns of microbial communities and the underlying mechanisms. However, the biogeographical patterns of microbial functional groups involved in nitrogen cycling (e.g., nitrifiers and denitrifiers) and their drivers at a large scale remain poorly understood. In this study, we evaluated the geographical distributions of nitrifiers and denitrifiers in riparian rhizosphere soils, riparian bulk soils, and channel sediments of 30 river regions along a latitudinal gradient from 21.8°N to 45.1°N across eastern China. We found that the diversity of nitrifiers and denitrifiers exhibited a gradual latitudinal gradient, in direct contrast to no significant changes observed for their abundance along the same latitudinal gradient. Statistical analyses suggested that climatic factors (mean annual temperature and mean annual precipitation) were the major drivers for the diversity of nitrifiers and denitrifiers, whereas soil properties were the key environmental factors shaping the abundance of nitrifiers and denitrifiers. Overall, these results provide new insights into the biogeographical distributions and ecological drivers for nitrogen-cycling microorganisms in river ecosystems at a large scale and can help us to improve the simulation models of the nitrogen cycle for accurately predicting the diversity of nitrogen-cycling microbes under ongoing climate changes.

Keywords:

• Abundance
• Biodiversity
• Denitrification
• Latitudinal gradient
• Nitrifiers

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Acknowledgments

We thank Gang He, Yongtai Pan, Wen Zhou, Bei Lu, Xiaoliang Jiang, Jian Ouyang, Xiaoyan Liu, and Lu Ouyang for their assistance with fieldwork and laboratory analyses. This work was supported by the National Natural Science Foundation of China (32301369) and the Youth Innovation Promotion Association of the Chinese Academy of Sciences (Y2021092).

Author Contributions

Bangjing Ding and Wenzhi Liu conceived the ideas and designed the methodology; Bangjing Ding, Jiaying Li, Shuo Wang, and Wenzhi Liu collected the data; Bangjing Ding, Wenzhi Liu, Ziqian Xiong, and Mingzhu Lu analyzed the data; Bangjing Ding, Ziqian Xiong, Mingzhu Lu, and Wenzhi Liu led the writing of the manuscript. All authors contributed critically to the drafts and gave final approval for publication.

Data availability statement

The data that support the findings of this study are available from Figshare at https://doi.org/10.6084/m9.figshare.23787387

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Conflict of interests

The authors declare no conflict of interests.