Sediment bacterial communities associated with environmental factors in Intermittently Closed and Open Lakes and Lagoons (ICOLLs)

Giulia Filippini*, Ana B. Bugnot, Emma L. Johnston, Jason Ruszczyk, Jaimie Potts, Peter Scanes, Angus Ferguson, Martin Ostrowski, Deepa Varkey, Katherine A. Dafforn

*Corresponding author for this work

Research output: Contribution to journalArticle

Abstract

Intermittently Closed and Open Lakes and Lagoons (ICOLLS) are important coastal systems that are periodically separated from the ocean by a sand barrier or a berm. In urban ICOLLs, continuous inputs of organic material and nutrients into coastal lagoons are contributing to eutrophic conditions that, together with natural environmental factors have implications for the resident sediment bacterial communities. We used molecular tools to investigate the ecological communities of four ICOLLs; Narrabeen, Dee Why, Curl Curl and Manly in Sydney, Australia, which have been subjected to increasing pressure from anthropogenic activities over the last century. We used targeted gene sequencing of the prokaryotic 16S ribosomal RNA gene to describe the bacterial diversity and community structure and discuss differences with respect to environmental factors at the ICOLL scale (e.g. size, shape, normalised N loading) and site scale (e.g. water and sediment quality) within each lagoon. Due to differences in hydrological patterns, we expected that sediment bacterial communities would be more heterogenous in displacement-dominated lagoons (Curl Curl and Manly) than the mixing-dominated lagoons (Narrabeen and Dee Why). Interestingly, we did not find strong relationships between the main bacterial groups and distance from the lagoon entrance (used as a proxy for salinity and silt) in the displacement-dominated lagoons. Moreover, we found that α diversity was highest in Narrabeen and Manly lagoons despite differences in lagoon size and shape. Furthermore, while bacterial community structure was similar in Curl Curl and Dee Why, communities in Manly and Narrabeen differed along temperature/TOC and salinity/silt gradients respectively. In Manly lagoon, we found relatively more anaerobic bacteria such as Epsilonbactereota which is involved in the oxidation and reduction of sulfur compounds. Moreover, we identified several bacterial taxa (including sulfur metabolising Chlorobiaceae) related to increasing TOC that could be investigated further as potential indicators of excess enrichment.

Original languageEnglish
Article number133462
Pages (from-to)1-12
Number of pages12
JournalScience of the Total Environment
Volume693
DOIs
Publication statusPublished - 25 Nov 2019

Keywords

  • biochemical cycles
  • organic material
  • eutrophication
  • bacteria
  • reducing sediment
  • biodiversity

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