Nitrosomonas Nm143-like ammonia oxidizers and Nitrospira marina-like nitrite oxidizers dominate the nitrifier community in a marine aquaculture biofilm

Declining marine fish stocks have induced a rapid growth in marine aquaculture, an industry that can have deleterious effects on local environments via uncontrolled discharge of nutrients and organic matter

Bärbel U. Foesel

2009

Scholarcy highlights

  • Declining marine fish stocks have induced a rapid growth in marine aquaculture, an industry that can have deleterious effects on local environments via uncontrolled discharge of nutrients and organic matter
  • Repeated rounds of the full-cycle rRNA approach were necessary to optimize DNA extraction and the probe set for FISH to obtain a reliable and comprehensive picture of the ammonia-oxidizing community
  • More than eight other nitrifying populations were detected, including Crenarchaeota closely related to the ammonia-oxidizer ‘Nitrosopumilus maritimus’, their collective abundance was below 1% of the total biofilm volume; their contribution to nitrification in the biofilter is likely to be negligible
  • As an environmentally friendly alternative, a zero-discharge marine aquaculture system has been developed with integrated microbial biofilters that couple nitrification with sludge digestion and denitrification
  • Analysis of ammonia monooxygenase gene largely confirmed the 16S rRNA gene-based ammonia-oxidizing bacteria community; in an amoA library constructed from DNA extraction method A, exclusively Nitrosomonas marina-like sequences were detected, while method B yielded both Nitrosomonas marina and Nitrosomonas sp
  • Nm143 in the first 16S rRNA and amoA gene libraries could be clearly traced to the DNA extraction method A, because both genes were detected when using the improved extraction method B
  • Even though one might speculate that the unnaturally high ammonium concentration in the MAR incubation may inhibit a low ammonia-adapted ammonia-oxidizing bacteria population, the combined results render a nitrifying metabolism of the ‘potential AOB’ very unlikely

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