Stratified microbial communities in Australia’s only anchialine cave are taxonomically novel and drive chemotrophic energy production via coupled nitrogen-sulphur cycling

Microbiome

Research

Amaranta Focardi¹  Brodie Sutcliffe²  William Humphreys³  Timothy M. Ghaly⁴  Ian T. Paulsen⁵  Liam D. H. Elbourne⁵  Sasha G. Tetu⁵ 

[1] Climate Change Cluster (C3), University of Technology Sydney, Sydney, Australia;NSW Department of Primary Industries, Sydney, Australia;School of Biological Sciences, University of Western Australia, Perth, Australia;School of Natural Sciences, Macquarie University, Sydney, Australia;School of Natural Sciences, Macquarie University, Sydney, Australia;ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, Australia;

关键词: Chemolithotrophy;    Metabolic coupling;    Biogeochemical cycling;    Stratified water column;    Groundwater ecology;    Subterranean estuary;    Marine oxygen minimum zones;   

DOI  :  10.1186/s40168-023-01633-8

 received in 2022-12-20, accepted in 2023-07-27,  发布年份 2023

来源: Springer

【 摘 要 】

BackgroundAnchialine environments, in which oceanic water mixes with freshwater in coastal aquifers, are characterised by stratified water columns with complex physicochemical profiles. These environments, also known as subterranean estuaries, support an abundance of endemic macro and microorganisms. There is now growing interest in characterising the metabolisms of anchialine microbial communities, which is essential for understanding how complex ecosystems are supported in extreme environments, and assessing their vulnerability to environmental change. However, the diversity of metabolic strategies that are utilised in anchialine ecosystems remains poorly understood.ResultsHere, we employ shotgun metagenomics to elucidate the key microorganisms and their dominant metabolisms along a physicochemical profile in Bundera Sinkhole, the only known continental subterranean estuary in the Southern Hemisphere. Genome-resolved metagenomics suggests that the communities are largely represented by novel taxonomic lineages, with 75% of metagenome-assembled genomes assigned to entirely new or uncharacterised families. These diverse and novel taxa displayed depth-dependent metabolisms, reflecting distinct phases along dissolved oxygen and salinity gradients. In particular, the communities appear to drive nutrient feedback loops involving nitrification, nitrate ammonification, and sulphate cycling. Genomic analysis of the most highly abundant members in this system suggests that an important source of chemotrophic energy is generated via the metabolic coupling of nitrogen and sulphur cycling.ConclusionThese findings substantially contribute to our understanding of the novel and specialised microbial communities in anchialine ecosystems, and highlight key chemosynthetic pathways that appear to be important in these energy-limited environments. Such knowledge is essential for the conservation of anchialine ecosystems, and sheds light on adaptive processes in extreme environments.8p_44mfK8oMcThCGxAovzMVideo Abstract

【 授权许可】

CC BY   
© BioMed Central Ltd., part of Springer Nature 2023

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