Spatial and temporal variation in denitrification and in the denitrifier community in a boreal lake
Rissanen, A., Tiirola, M., & Ojala, A. (2011). Spatial and temporal variation in denitrification and in the denitrifier community in a boreal lake. Aquatic Microbial Ecology, 64 (1), 27-40. doi:10.3354/ame01506
Published inAquatic Microbial Ecology
© Inter-Research 2011. This is an open access article distributed under the Creative Commons license.
We investigated the spatial and temporal variation in denitrification rates (isotopepairing technique, IPT) and in the denitrifier community (examination of gene nirK by denaturinggradient gel electrophoresis [DGGE] of microbial DNA) in the sediments of a boreal, clear-water, eutrophic lake using samples collected from shallow littoral, deep littoral and shallow profundal sediments during early summer, mid-summer, autumn and winter. The measured denitrification rates (44 to 613 μmol N m−2 d−1) are among the lowest ever reported from lacustrine sediments. Denitri fi - cation rates varied both spatially and temporally, being highest in the profundal zone during midsummer and in the littoral zones during winter. Correlation analyses indicated that these variations were due to variations in the concentrations of nitrate and oxygen in the water overlying the sediment. The structure of the denitrifier community was temporally extremely stable and differed only slightly between the sites. Distance-based linear model (DISTLM) analysis indicated that the observed variation was probably due mainly to variations in the content of organic matter, and in the porosity, of the sediment. The structure of the denitrifier community and the denitrifying activities were uncoupled. ...