Impact of streambed morphology on the abundance and activity of ammonia-oxidizing bacteria

Keren Yanuka-Golub, Shai Arnon, Ali Nejidat

Research output: Contribution to journalArticlepeer-review


Ammonia oxidizers catalyze the first step of nitrification. Combined microbial nitrification-denitrification activities are essential for the removal of excess nitrogen from water bodies. In sandy streambeds, bed form structures are created by water flow and lead to the creation of heterogeneous microenvironments. The objective of this study, therefore, was to investigate the effect of bed form morphology on the abundance and activity of ammonia-oxidizing bacteria (AOB) within a benthic biofilm. An 8-month-old benthic biofilm was established in a recirculating laboratory flume under controlled flow conditions and frequent amendment with ammonium. The sand bed was arranged into bed form structures. The highest concentrations of chlorophyll a (indicative of algae) were measured on the upstream side of the bed forms. The biofilm was dominated by Nitrosospira species, and amoA gene abundance was higher on the downstream sides of the bed forms with no significant difference in oxygen consumption between the upstream and downstream sections of the bed form. In contrast, potential ammonium oxidation rates were higher on the upstream sides of the bed forms. The results suggest that bed form morphology can affect the spatial distribution and activity of AOB, possibly through the creation of distinct microhabitats. These results contribute to our understanding of nitrogen transformations and removal from streams.

Original languageEnglish
Pages (from-to)175-183
Number of pages9
JournalFEMS Microbiology Ecology
Issue number1
StatePublished - 1 Oct 2014
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2014 Federation of European Microbiological Societies.


  • Ammonium uptake
  • Bed form morphology
  • Benthic biofilm
  • Microenvironments

ASJC Scopus subject areas

  • Microbiology
  • Ecology
  • Applied Microbiology and Biotechnology


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