Ammonia transformations and abundance of ammonia oxidizers in a clay soil underlying a manure pond

Yonatan Sher, Shahar Baram, Ofer Dahan, Zeev Ronen, Ali Nejidat

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

Unlined manure ponds are constructed on clay soil worldwide to manage farm waste. Seepage of ammonia-rich liquor into underlying soil layers contributes to groundwater contamination by nitrate. To identify the possible processes that lead to the production of nitrate from ammonia in this oxygen-limited environment, we studied the diversity and abundance of ammonia-transforming microorganisms under an unlined manure pond. The numbers of ammonia-oxidizing bacteria and anammox bacteria were most abundant in the top of the soil profile and decreased significantly with depth (0.5 m), correlating with soil pore-water ammonia concentrations and soil ammonia concentrations, respectively. On the other hand, the numbers of ammonia-oxidizing archaea were relatively constant throughout the soil profile (107 amoA copies per gsoil). Nitrite-oxidizing bacteria were detected mainly in the top 0.2 m. The results suggest that nitrate accumulation in the vadose zone under the manure pond could be the result of complete aerobic nitrification (ammonia oxidation to nitrate) and could exist as a byproduct of anammox activity. While the majority of the nitrogen was removed within the 0.5-m soil section, possibly by combined anammox and heterotrophic denitrification, a fraction of the produced nitrate leached into the groundwater.

Original languageEnglish
Pages (from-to)145-155
Number of pages11
JournalFEMS Microbiology Ecology
Volume81
Issue number1
DOIs
StatePublished - 1 Jul 2012

Keywords

  • Ammonia-oxidizing archaea
  • Ammonia-oxidizing bacteria
  • Anammox bacteria
  • Manure ponds

ASJC Scopus subject areas

  • Microbiology
  • Ecology
  • Applied Microbiology and Biotechnology

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