Anaerobic Ammonium Oxidation in Acidic Red Soils

Abstract

Anaerobic ammonium oxidation (anammox) has been proven to be an important nitrogen removal process in terrestrial ecosystems, particularly paddy soils. However, the contribution of anammox in acidic red soils to nitrogen loss has not been well-documented to date. Here, we investigated the activity, abundance, and distribution of anammox bacteria in red soils collected from nine provinces of Southern China. High-throughput sequencing analysis showed that Candidatus Brocadia dominates the anammox bacterial community (93.03% of sequence reads). Quantification of the hydrazine synthase gene (hzsB) and anammox 16S rRNA gene indicated that the abundance of anammox bacteria ranged from 6.20 × 106 to 1.81 × 109 and 4.81 × 106 to 4.54 × 108 copies per gram of dry weight, respectively. Contributions to nitrogen removal by anammox were measured by a 15N isotope-pairing assay. Anammox rates in red soil ranged from 0.01 to 0.59 nmol N g−1 h−1, contributing 16.67–53.27% to N2 production in the studied area, and the total amount of removed nitrogen by anammox was estimated at 2.33 Tg N per year in the natural red soils of southern China. Pearson correlation analyses revealed that the distribution of anammox bacteria significantly correlated with the concentration of nitrate and pH, whereas the abundance and activity of anammox bacteria were significantly influenced by the nitrate and total nitrogen concentrations. Our findings demonstrate that Candidatus Brocadia dominates anammox bacterial communities in acidic red soils and plays an important role in nitrogen loss of the red soil in Southern China.

Biotic and Abiotic Controls on Dinitrogen Production in Coastal Sediments

“…We investigated N 2 production rates and processes across ∼2,500 km continental shelf sediment transect along coastline in eastern China (Figure 1) and found that denitrification process dominated N 2 production with the average relative contribution of 90% and ranged from 0.03 to 9.73 nmol N 2 g −1 h −1 (Figure 1 and Figure S3 in Supporting Information S1). Our measured N 2 production rates by denitrification were comparable to previous studies in marine and estuarine sediments (Gao et al., 2016; Lin et al., 2017) and in terrestrial ecosystems (Gu et al., 2017; Tang et al., 2018; Wu et al., 2018; Xi et al., 2016). Additionally, sediment denitrification rates in the studied regions are higher than the rates from sea water columns in some coastal regions (Dalsgaard et al., 2013; Seitzinger, 1988), confirming the estimate from models that sedimentary denitrification rate may be higher than suboxic zones (DeVries et al., 2013).…”

Diversity and Distribution of Anaerobic Ammonium Oxidation Bacteria in Hot Springs of Conghua, China

“…Anammox diversity in the terrestrial systems was higher in soil than in freshwater environments; for example, in wetland and dryland soils, three different genera of anammox bacteria were detected, including “ Candidatus Kuenenia,” “ Candidatus Brocadia,” and “ Candidatus Jettenia” ( Zhao et al, 2018 ). In acidic red soils, anammox bacteria were related to “ Candidatus Brocadia,” “ Candidatus Scalindua,” “ Candidatus Kuenenia,” and “ Candidatus Anammoxoglobus” ( Wu et al, 2018 ). The above discussions indicated that in natural ecosystems, the highest diversity of anammox bacteria occurred in terrestrial systems, followed by freshwater systems and marine systems, which was in accordance with our finding that anammox bacteria had a higher diversity in hot springs.…”

Wide distribution of anaerobic ammonium‐oxidizing bacteria in the water column of the South China Sea: Implications for their survival strategies

“…High‐throughput sequencing was performed using Mothur software V1.40.5 according to the standard protocol, as described previously by Schloss et al (2009) and Wu et al. (2018). In short, the tags and primers were removed from quality‐controlled sequences.…”

“…The pre.cluster , chimera.uchime and remove.seqs commands were used to reduce errors and remove chimeras. To conduct further diversity analyses, representative sequences were gathered into operational taxonomic units (OTUs) as defined by 97% sequence identity through the dist.seqs , cluster , make.shared , and classify.otu commands (Wu et al., 2018; Zhao et al., 2013). Rarefaction curves and Principal Coordinates analyses (PCoA) were conducted by the rarefaction.single and pcoa commands, respectively.…”

“…Anammoxoglobus (Kartal et al, 2007); these genera are affiliated with the phylum Planctomycetes . The existence of anammox processes has been proven in various ecosystems, including paddy soils (Yang et al., 2015), acidic red soils (Wu et al, 2018), marine sediments and water columns (Qian et al, 2018; Han & Gu, 2013; Hong, Yin, & Zheng, 2011; Kuypers et al., 2003; Song, Buckner, Hembury, Mills, & Palmer, 2014; Ward, 2003), lakes (Yang et al., 2016), land‐freshwater interfaces (Zhu et al, 2015), mangroves (Wang, Li, & Gu, 2014; Xiao et al., 2018), wetlands and freshwater rivers (Sun et al., 2014).…”