Open AccessAmmonia transformations and abundance of ammonia oxidizers in a clay soil underlying a manure pond
Author(s) -
Sher Yonatan,
Baram Shahar,
Dahan Ofer,
Ronen Zeev,
Nejidat Ali
Publication year - 2012
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1111/j.1574-6941.2012.01347.x
Subject(s) - nitrate , manure , environmental chemistry , anammox , nitrification , denitrification , ammonia , groundwater , environmental science , agronomy , nitrogen , ecology , biology , chemistry , denitrifying bacteria , geology , geotechnical engineering , organic chemistry , biochemistry
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 (10 7 amoA copies per g soil ). 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.