Unveiling unique microbial nitrogen cycling and nitrification driver in coastal Antarctica

Abstract Largely removed from anthropogenic delivery of nitrogen (N), Antarctica has notably low levels of nitrogen. Though our understanding of biological sources of ammonia have been elucidated, the microbial drivers of nitrate (NO3 −) cycling in coastal Antarctica remains poorly understood. Here,...

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Bibliographic Details
Published in:Nature Communications
Main Authors: Ping Han, Xiufeng Tang, Hanna Koch, Xiyang Dong, Lijun Hou, Danhe Wang, Qian Zhao, Zhe Li, Min Liu, Sebastian Lücker, Guitao Shi
Format: Article in Journal/Newspaper
Language:English
Published: Nature Portfolio 2024
Subjects:
Science
Q
Antarc*
Antarctic
Antarctica
Online Access:https://doi.org/10.1038/s41467-024-47392-4
https://doaj.org/article/53f118298a864f8ab961ce252d7af5a0
Description
Summary:Abstract Largely removed from anthropogenic delivery of nitrogen (N), Antarctica has notably low levels of nitrogen. Though our understanding of biological sources of ammonia have been elucidated, the microbial drivers of nitrate (NO3 −) cycling in coastal Antarctica remains poorly understood. Here, we explore microbial N cycling in coastal Antarctica, unraveling the biological origin of NO3 − via oxygen isotopes in soil and lake sediment, and through the reconstruction of 1968 metagenome-assembled genomes from 29 microbial phyla. Our analysis reveals the metabolic potential for microbial N2 fixation, nitrification, and denitrification, but not for anaerobic ammonium oxidation, signifying a unique microbial N-cycling dynamic. We identify the predominance of complete ammonia oxidizing (comammox) Nitrospira, capable of performing the entire nitrification process. Their adaptive strategies to the Antarctic environment likely include synthesis of trehalose for cold stress, high substrate affinity for resource utilization, and alternate metabolic pathways for nutrient-scarce conditions. We confirm the significant role of comammox Nitrospira in the autotrophic, nitrification process via 13C-DNA-based stable isotope probing. This research highlights the crucial contribution of nitrification to the N budget in coastal Antarctica, identifying comammox Nitrospira clade B as a nitrification driver.

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