Distribution and Diversity of Anaerobic Ammonium Oxidation (Anammox) Bacteria in the Sediment of a Eutrophic Freshwater Lake, Lake Kitaura, Japan

Abstract

Although the emission of N2 via anaerobic ammonium oxidation (anammox) is a key process in the elimination of nitrogenous compounds from aquatic environments, little information is available regarding its significance and the relevant microorganisms (anammox bacteria) in eutrophic freshwater lakes. In the present study, the anammox bacteria in the sediment of a eutrophic lake in Japan, Lake Kitaura, were examined using a 15 N-tracer technique to measure their potential anammox activity. Potential anammox activity was localized to the northern region of the lake where a stable supply of both NH4 + and NO3− existed in the sediment. These results suggest the contribution of anammox bacteria to the total emission of N2 from sediment in this eutrophic lake to not be negligible. Moreover, selective PCR successfully amplified anammox bacteria-related (Brocadiales-related) 16S rRNA genes from sediment samples in which potential anammox activity was observed. The clone libraries consisted of diverse phylotypes except the genus "Scalindua"-lineages, and the lineages of genus "Brocadia" were dominantly recovered, followed by the genus "Kuenenia"-lineages. Most of them, however, were novel and phylogenetically distinguishable from known Brocadiales species. A unique population of anammox bacteria inhabits and potentially contributes to the emission of N2 from Lake Kitaura.

The phenological stage of rice growth determines anaerobic ammonium oxidation activity in rhizosphere soil

“…The five predominant genera of anammox bacteria identified in this study (see above) have been observed in many habitats, including soils (Humbert et al, 2010;Wang et al, 2012b;Hu et al, 2013;Wang and Gu, 2013) and sediments (Zhang et al, 2007;Yoshinaga et al, 2011). Similar to previous reports, Candidatus Brocadia dominated in this paddy soils fields (Bai et al, 2015;Yang et al, 2015).…”

Nitrogen cycling in Sandusky Bay, Lake Erie: oscillations between strong and weak export and implications for harmful algal blooms

“…High variability was also observed in a study of potential anammox rates in the water column of Sandusky Bay and Lake Erie (Lu et al, 2018). Marked variability may be characteristic of anammox activity in freshwater environments, even across small spatial and temporal scales (Yoshinaga et al, 2011;Zhu et al, 2013Zhu et al, , 2015. Anammox made up an average of 14 % of sediment N removal across the sampling period, indicating that anammox activity in Sandusky Bay may be typical of shallow estuarine and freshwater systems (Thamdrup and Dalsgaard, 2002;Dalsgaard et al, 2005;Schubert et al, 2006;Dong et al, 2009;Hsu and Kao, 2013;McCarthy et al, 2016).…”

“…Dissimilatory microbial processes may also consume DIN in sediments, representing pathways of permanent N removal whereby N leaves the system as N 2 . Denitrification is expected to be the dominant microbial N removal pathway in freshwaters (Seitzinger et al, 2006), although anammox, a competing pathway, has not been extensively studied in freshwater systems (Yoshinaga et al, 2011;Zhu et al, 2013). Nitrous oxide (N 2 O), a potent greenhouse gas, is a byproduct of denitrification and nitrification (Wrage et al, 2001) and is a detrimental consequence of microbial N removal.…”

The nitrogen pendulum in Sandusky Bay, Lake Erie: Oscillations between strong and weak export and implications for harmful algal blooms

“…Marked variability may be characteristic of anammox activity in freshwater environments, even across small spatial and temporal scales (Yoshinaga et al, 2011;Zhu et al, 2013;. typical of shallow estuarine and freshwater systems (Thamdrup and Dalsgaard, 2002;Dalsgaard et al, 2005;Schubert et al, 2006;McCarthy et al, 2016).…”

“…Denitrification is expected to be the dominant microbial N removal pathway in freshwaters (Seitzinger et al, 2006), although anammox, a competing pathway, has not been extensively studied in freshwater systems (Yoshinaga et al, 2011;Zhu et al, 2013). Nitrous oxide (N2O), a potent greenhouse gas, is a byproduct of denitrification and nitrification (Wrage et al, 2001) and is a detrimental consequence of microbial N removal.…”