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Nitrification and Nitrifying Bacteria in a Coastal Microbial Mat.

Fan H, Bolhuis H, Stal LJ - Front Microbiol (2015)

Bottom Line: In all three mats AOB amoA genes were significantly more abundant than AOA amoA genes.The abundance of neither AOB nor AOA amoA genes correlated with the potential nitrification rates, but AOB amoA transcripts were positively correlated with the potential nitrification rate.We conclude that AOB are responsible for the bulk of the ammonium oxidation in these coastal microbial mats.

View Article: PubMed Central - PubMed

Affiliation: Department of Marine Microbiology, Royal Netherlands Institute for Sea Research Yerseke, Netherlands.

ABSTRACT
The first step of nitrification, the oxidation of ammonia to nitrite, can be performed by ammonia-oxidizing archaea (AOA) or ammonium-oxidizing bacteria (AOB). We investigated the presence of these two groups in three structurally different types of coastal microbial mats that develop along the tidal gradient on the North Sea beach of the Dutch barrier island Schiermonnikoog. The abundance and transcription of amoA, a gene encoding for the alpha subunit of ammonia monooxygenase that is present in both AOA and AOB, were assessed and the potential nitrification rates in these mats were measured. The potential nitrification rates in the three mat types were highest in autumn and lowest in summer. AOB and AOA amoA genes were present in all three mat types. The composition of the AOA and AOB communities in the mats of the tidal and intertidal stations, based on the diversity of amoA, were similar and clustered separately from the supratidal microbial mat. In all three mats AOB amoA genes were significantly more abundant than AOA amoA genes. The abundance of neither AOB nor AOA amoA genes correlated with the potential nitrification rates, but AOB amoA transcripts were positively correlated with the potential nitrification rate. The composition and abundance of amoA genes seemed to be partly driven by salinity, ammonium, temperature, and the nitrate/nitrite concentration. We conclude that AOB are responsible for the bulk of the ammonium oxidation in these coastal microbial mats.

No MeSH data available.


Mean (±standard error, n = 3) potential nitrification rate (PNR) and abundance of amoA (of β-AOB and AOA) and their transcripts at Station 1, Station 2, and Station 3 during the 2010–2011 sampling period (July, September, November, January, and April).
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Figure 4: Mean (±standard error, n = 3) potential nitrification rate (PNR) and abundance of amoA (of β-AOB and AOA) and their transcripts at Station 1, Station 2, and Station 3 during the 2010–2011 sampling period (July, September, November, January, and April).

Mentions: The potential nitrification rate was measured using the isotope (15N nitrate) dilution method (Kirkham and Bartholomew, 1954) and the measurements covered the four seasons during 2010 and 2011. The potential rate of nitrification varied between stations as well as between seasons and ranged from 34 to 537 μmol N m−2d−1 (Table 6). At all three stations the potential rate of nitrification showed a similar seasonal pattern with higher rates occurring in November and January and lowest rates occurring in July and September (Figure 4). The highest rate was measured at Station 3 (537 μmol N m−2d−1) while the lowest was detected at Station 2. The potential rate of nitrification was always lowest at Station 2, irrespective of the season.


Nitrification and Nitrifying Bacteria in a Coastal Microbial Mat.

Fan H, Bolhuis H, Stal LJ - Front Microbiol (2015)

Mean (±standard error, n = 3) potential nitrification rate (PNR) and abundance of amoA (of β-AOB and AOA) and their transcripts at Station 1, Station 2, and Station 3 during the 2010–2011 sampling period (July, September, November, January, and April).
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Related In: Results  -  Collection

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Figure 4: Mean (±standard error, n = 3) potential nitrification rate (PNR) and abundance of amoA (of β-AOB and AOA) and their transcripts at Station 1, Station 2, and Station 3 during the 2010–2011 sampling period (July, September, November, January, and April).
Mentions: The potential nitrification rate was measured using the isotope (15N nitrate) dilution method (Kirkham and Bartholomew, 1954) and the measurements covered the four seasons during 2010 and 2011. The potential rate of nitrification varied between stations as well as between seasons and ranged from 34 to 537 μmol N m−2d−1 (Table 6). At all three stations the potential rate of nitrification showed a similar seasonal pattern with higher rates occurring in November and January and lowest rates occurring in July and September (Figure 4). The highest rate was measured at Station 3 (537 μmol N m−2d−1) while the lowest was detected at Station 2. The potential rate of nitrification was always lowest at Station 2, irrespective of the season.

Bottom Line: In all three mats AOB amoA genes were significantly more abundant than AOA amoA genes.The abundance of neither AOB nor AOA amoA genes correlated with the potential nitrification rates, but AOB amoA transcripts were positively correlated with the potential nitrification rate.We conclude that AOB are responsible for the bulk of the ammonium oxidation in these coastal microbial mats.

View Article: PubMed Central - PubMed

Affiliation: Department of Marine Microbiology, Royal Netherlands Institute for Sea Research Yerseke, Netherlands.

ABSTRACT
The first step of nitrification, the oxidation of ammonia to nitrite, can be performed by ammonia-oxidizing archaea (AOA) or ammonium-oxidizing bacteria (AOB). We investigated the presence of these two groups in three structurally different types of coastal microbial mats that develop along the tidal gradient on the North Sea beach of the Dutch barrier island Schiermonnikoog. The abundance and transcription of amoA, a gene encoding for the alpha subunit of ammonia monooxygenase that is present in both AOA and AOB, were assessed and the potential nitrification rates in these mats were measured. The potential nitrification rates in the three mat types were highest in autumn and lowest in summer. AOB and AOA amoA genes were present in all three mat types. The composition of the AOA and AOB communities in the mats of the tidal and intertidal stations, based on the diversity of amoA, were similar and clustered separately from the supratidal microbial mat. In all three mats AOB amoA genes were significantly more abundant than AOA amoA genes. The abundance of neither AOB nor AOA amoA genes correlated with the potential nitrification rates, but AOB amoA transcripts were positively correlated with the potential nitrification rate. The composition and abundance of amoA genes seemed to be partly driven by salinity, ammonium, temperature, and the nitrate/nitrite concentration. We conclude that AOB are responsible for the bulk of the ammonium oxidation in these coastal microbial mats.

No MeSH data available.