Predicting microbial nitrate reduction pathways in coastal sediments

Algar, Christopher K.; Vallino, Joseph J.

doi:10.3354/ame01678

Cited by 87 publications

(62 citation statements)

References 60 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…When all three reaction rates are collapsed into a single Nitrogen Retention Index (NIRI = DNRA/(denitrification + anammox)) the data support the proposition that OC availability is an important determinant of N retention versus loss by influencing the proportion of denitrification, anammox, and DNRA processing of DIN as described by Algar and Vallino []. The NRE data also indicate that there may be further, and equally important, controls exerted by sulfide and OC source type.…”

Section: Discussionmentioning

confidence: 99%

Nitrogen reduction pathways in estuarine sediments: Influences of organic carbon and sulfide

2015

View full text Add to dashboard Cite

Potential rates of sediment denitrification, anaerobic ammonium oxidation (anammox), and dissimilatory nitrate reduction to ammonium (DNRA) were mapped across the entire Niantic River Estuary, CT, USA, at 100–200 m scale resolution consisting of 60 stations. On the estuary scale, denitrification accounted for ~ 90% of the nitrogen reduction, followed by DNRA and anammox. However, the relative importance of these reactions to each other was not evenly distributed through the estuary. A Nitrogen Retention Index (NIRI) was calculated from the rate data (DNRA/(denitrification + anammox)) as a metric to assess the relative amounts of reactive nitrogen being recycled versus retained in the sediments following reduction. The distribution of rates and accompanying sediment geochemical analytes suggested variable controls on specific reactions, and on the NIRI, depending on position in the estuary and that these controls were linked to organic carbon abundance, organic carbon source, and pore water sulfide concentration. The relationship between NIRI and organic carbon abundance was dependent on organic carbon source. Sulfide proved the single best predictor of NIRI, accounting for 44% of its observed variance throughout the whole estuary. We suggest that as a single metric, sulfide may have utility as a proxy for gauging the distribution of denitrification, anammox, and DNRA.

show abstract

Section: Discussionmentioning

confidence: 99%

Nitrogen reduction pathways in estuarine sediments: Influences of organic carbon and sulfide

2015

View full text Add to dashboard Cite

show abstract

“…This material favors denitrification over anammox, with the latter tending to dominate under high C/N conditions (7). Nonetheless, some studies illustrated that dissimilatory nitrate reduction to ammonia (DNRA) is the dominant pathway when levels of organic carbon input are high and nitrate levels are low (51,52). Organisms using DNRA can outcompete denitrification at low NO 3 Ϫ due to their greater affinity for NO 3 Ϫ ; thus, they can derive more energy from NO 3 Ϫ reduction than denitrifiers (53).…”

Section: Figmentioning

confidence: 99%

Potential Contribution of Anammox to Nitrogen Loss from Paddy Soils in Southern China

Yang

Nie

et al. 2015

Appl Environ Microbiol

127

View full text Add to dashboard Cite

eThe anaerobic oxidation of ammonium (anammox) process has been observed in diverse terrestrial ecosystems, while the contribution of anammox to N 2 production in paddy soils is not well documented. In this study, the anammox activity and the abundance and diversity of anammox bacteria were investigated to assess the anammox potential of 12 typical paddy soils collected in southern China. Anammox bacteria related to "Candidatus Brocadia" and "Candidatus Kuenenia" and two novel unidentified clusters were detected, with "Candidatus Brocadia" comprising 50% of the anammox population. The prevalence of the anammox was confirmed by the quantitative PCR results based on hydrazine synthase (hzsB) genes, which showed that the abundance ranged from 1.16 ؋ 10 4 to 9.65 ؋ 10 4 copies per gram of dry weight. The anammox rates measured by the isotope-pairing technique ranged from 0.27 to 5.25 nmol N per gram of soil per hour in these paddy soils, which contributed 0.6 to 15% to soil N 2 production. It is estimated that a total loss of 2.50 ؋ 10 6 Mg N per year is linked to anammox in the paddy fields in southern China, which implied that ca. 10% of the applied ammonia fertilizers is lost via the anammox process. Anammox activity was significantly correlated with the abundance of hzsB genes, soil nitrate concentration, and C/N ratio. Additionally, ammonia concentration and pH were found to be significantly correlated with the anammox bacterial structure.

show abstract

“…Carbon limitation has been shown to limit denitrification in coastal sediments both in mesocosms (Babbin and Ward, 2013) and in biogeochemical models (Algar and Vallino, 2014), and is likely to be the ultimate factor limiting complete denitrification in this system. Regardless of whether it is carbon or NO − 3 limitation, the limitation was ultimately observed at the genetic level.…”

Section: Discussionmentioning

confidence: 99%

Connecting the dots: linking nitrogen cycle gene expression to nitrogen fluxes in marine sediment mesocosms

et al. 2014

View full text Add to dashboard Cite

Connecting molecular information directly to microbial transformation rates remains a challenge, despite the availability of molecular methods to investigate microbial biogeochemistry. By combining information on gene abundance and expression for key genes with quantitative modeling of nitrogen fluxes, we can begin to understand the scales on which genetic signals vary and how they relate to key functions. We used quantitative PCR of DNA and cDNA, along with biogeochemical modeling to assess how the abundance and expression of microbes responsible for two steps in the nitrogen cycle changed over time in estuarine sediment mesocosms. Sediments and water were collected from coastal Massachusetts and maintained in replicated 20 L mesocosms for 45 days. Concentrations of all major inorganic nitrogen species were measured daily and used to derive rates of nitrification and denitrification from a Monte Carlo-based non-negative least-squares analysis of finite difference equations. The mesocosms followed a classic regeneration sequence in which ammonium released from the decomposition of organic matter was subsequently oxidized to nitrite and then further to nitrate, some portion of which was ultimately denitrified. Normalized abundances of ammonia oxidizing archaeal ammonia monoxoygenase (amoA) transcripts closely tracked rates of ammonia oxidation throughout the experiment. No such relationship, however, was evident between denitrification rates and the normalized abundance of nitrite reductase (nirS and nirK) transcripts. These findings underscore the complexity of directly linking the structure of the microbial community to rates of biogeochemical processes.

show abstract

Predicting microbial nitrate reduction pathways in coastal sediments

Cited by 87 publications

References 60 publications

Nitrogen reduction pathways in estuarine sediments: Influences of organic carbon and sulfide

Nitrogen reduction pathways in estuarine sediments: Influences of organic carbon and sulfide

Potential Contribution of Anammox to Nitrogen Loss from Paddy Soils in Southern China

Connecting the dots: linking nitrogen cycle gene expression to nitrogen fluxes in marine sediment mesocosms

Contact Info

Product

Resources

About