Taxonomic and metabolic shifts in the Coorong bacterial metagenome driven by salinity and external inputs

Kelly Newton, Thomas Jeffries, Renee Smith, Laurent Seuront, James Mitchell

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

The Coorong estuary lies at the terminus of Australia’s largest river system, the Murray-Darling; both are strongly influenced by human activities; including farming and extensive flow modification. Metagenomic approaches were used to determine the planktonic bacterial community composition and potential metabolic function at two extremes in the Coorong, the river mouth which exhibits marine-like salinity, and the hypersaline upper-reaches of the estuary. Significant shifts in taxa and metabolic function were seen between the two sites. The river mouth exhibited an increase in abundance of Rhodobacteriaceae and Alteromonadaceae; families readily able to adapt to change in nutrient conditions; and the potentially pathogenic families Brucellaceae, Enterobacteriaceae and Vibrionaceae. Metabolisms over-represented include motility and chemotaxis, RNA metabolism and membrane transport, all of which are involved in actively searching for and obtaining nutrients. Also over-represented were metabolisms involved in population succession and stress response. An over-representation of taxa and metabolisms indicative of environmental change is reflective of anthropogenically affected riverine input. In the hypersaline upper reaches of the estuary, the halophilic family Ectothiorhodospiraceae was over-represented, as were the families Flavobacteriaceae, Cytophagaceae and Nocardioidaceae, members of which are able to survive over a wide salinity range. Metabolisms over-represented here were reflective of increased bacterial growth, characteristic of hypersaline environments, and included DNA metabolism, nucleotide and nucleoside synthesis and cell cycle. Coorong metagenomes clustered taxonomically and metabolically with other planktonic metagenomes, but remained an outlier of this group with only 71% and 84% similarity, respectively. This indicates that the Coorong exhibits a unique planktonic bacterial community that is influenced by riverine input at the river mouth and salinity in the upper-reaches.[Figure not available: see fulltext.].

Original languageEnglish
Pages (from-to)2033-2049
Number of pages17
JournalJournal of Oceanology and Limnology
Volume36
Issue number6
DOIs
Publication statusPublished - 1 Nov 2018

Keywords

  • bacteria
  • estuary
  • hypersaline
  • metabolic potential
  • taxonomy

Fingerprint Dive into the research topics of 'Taxonomic and metabolic shifts in the Coorong bacterial metagenome driven by salinity and external inputs'. Together they form a unique fingerprint.

Cite this