AUTHOR=Siljanen Henri M., Saari Anne , Bodrossy Levente , Martikainen Pertti J.

TITLE=Effects of Nitrogen Load on the Function and Diversity of Methanotrophs in the Littoral Wetland of a Boreal Lake

JOURNAL=Frontiers in Microbiology

VOLUME=3

YEAR=2012

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2012.00039

DOI=10.3389/fmicb.2012.00039

ISSN=1664-302X

ABSTRACT=<p>Methane is the second most abundant greenhouse gas in the atmosphere. A major part of the total methane emissions from lake ecosystems is emitted from littoral wetlands. Methane emissions are significantly reduced by methanotrophs, as they use methane as their sole energy and carbon source. Methanotrophic activity can be either activated or inhibited by nitrogen. However, the effects of nitrogen on methanotrophs in littoral wetlands are unknown. Here we report how nitrogen loading <italic>in situ</italic> affected the function and diversity of methanotrophs in a boreal littoral wetland. Methanotrophic community composition and functional diversity were analyzed with a particulate methane monooxygenase (<italic>pmoA</italic>) gene targeted microarray. Nitrogen load had no effects on methane oxidation potential and methane fluxes. Nitrogen load activated <italic>pmoA</italic> gene transcription of type I (<italic>Methylobacter</italic>, <italic>Methylomonas</italic>, and LW21-freshwater phylotypes) methanotrophs, but decreased the relative abundance of type II (<italic>Methylocystis</italic>, <italic>Methylosinus trichosporium</italic>, and <italic>Methylosinus</italic> phylotypes) methanotrophs. Hence, the overall activity of a methanotroph community in littoral wetlands is not affected by nitrogen leached from the catchment area.</p>