Sulphide addition favours respiratory ammonification (DNRA) over complete denitrification and alters the active microbial community in salt marsh sediments

Murphy, Anna E.; Bulseco, Ashley; Ackerman, Ross; Vineis, Joseph H.; Bowen, Jennifer L.

doi:10.1111/1462-2920.14969

Cited by 77 publications

(48 citation statements)

References 103 publications

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“…In the H 2 S-treated slurries, there was a steady increase in 15 N 2 , suggesting that denitrifying microbes were still reducing NO 3 − , although at rates lower than the controls and almost equal proportions of NO 3 − were reduced to N 2 and NH 4 + . This was expected, since stimulation of DNRA under elevated H 2 S concentrations has been previously demonstrated in several studies (Høgslund et al 2009;Schutte et al 2018;An and Gardner 2002;McCarthy et al 2008;Jäntti and Hietanen 2012;Bernard et al 2015;Murphy et al 2020), as well as in our core incubations, where the highest DNRA to denitrification ratio was observed when the bottom water contained H 2 S in October 2016. However, the NO 3 − concentrations remained higher in the H 2 S-treated samples than in the control and H 2 S + Fe 2+ -treated samples, suggesting that H 2 S overall inhibits NO 3 − reduction, particularly immediately after it becomes present.…”

Section: No 3 − Reduction Rates In the Sediment Slurry Samplessupporting

confidence: 87%

Effects of Ferrous Iron and Hydrogen Sulfide on Nitrate Reduction in the Sediments of an Estuary Experiencing Hypoxia

Jäntti

Aalto

Paerl

2020

Estuaries and Coasts

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Hypoxia is common feature of eutrophic estuaries and semi-enclosed seas globally. One of the key factors driving hypoxia is nitrogen pollution. To gain more insight into the effects of hypoxia on estuarine nitrogen cycling, we measured potential nitrate reduction rates at different salinities and levels of hypoxia in a eutrophic temperate microtidal estuary, the Neuse River Estuary, North Carolina, USA. We also tested the effect of hydrogen sulfide and ferrous iron additions on the nitrate reduction pathways. Overall, DNRA dominated over denitrification in this periodically hypoxic estuary and there was no correlation between the potential nitrate reduction rates, salinity, or dissolved oxygen. However, when hypoxia lasted several months, denitrification capacity was almost completely lost, and nearly all nitrate added to the sediment was reduced via DNRA. Additions of hydrogen sulfide stimulated DNRA over denitrification. Additions of ferrous iron stimulated nitrate consumption; however, the end product of nitrate consumption was not clear. Interestingly, substantial nitrous oxide formation occurred in sediments that had experienced prolonged hypoxia and were amended with nitrate. Given expanding hypoxia predicted with climate change scenarios and the increasing nitrate loads to coastal systems, coastal sediments may lose their capability to mitigate nitrogen pollution due to DNRA dominating over denitrification during extended hypoxic periods.

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Section: No 3 − Reduction Rates In the Sediment Slurry Samplessupporting

confidence: 87%

Effects of Ferrous Iron and Hydrogen Sulfide on Nitrate Reduction in the Sediments of an Estuary Experiencing Hypoxia

Jäntti

Aalto

Paerl

2020

Estuaries and Coasts

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“…The controlling factors that determine whether DNRA or denitrification is dominant in a habitat are a subject of debate. In the past studies have focussed on the impact of kinetics (King and Nedwell, 1985; Tiedje, 1988; Behrendt et al ., 2014; Kraft et al ., 2014; McTigue et al ., 2016; Murphy et al ., 2020), inhibition and/or thermodynamics (Dong et al ., 2011; Kraft et al ., 2014; Bonaglia et al ., 2017; Dolfing and Hubert, 2017). The dominance of DNRA in the benthos may be explained by selection for a particular NO 3 − reducing community based on other adaptation strategies beyond the NO 3 − reduction pathway.…”

Section: Resultsmentioning

confidence: 99%

Nitrate respiration and diel migration patterns of diatoms are linked in sediments underneath a microbial mat

Merz

Dick

Beer

et al. 2020

Environmental Microbiology

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Diatoms are among the few eukaryotes known to store nitrate (NO 3 −) and to use it as an electron acceptor for respiration in the absence of light and O 2. Using microscopy and 15 N stable isotope incubations, we studied the relationship between dissimilatory nitrate/nitrite reduction to ammonium (DNRA) and diel vertical migration of diatoms in phototrophic microbial mats and the underlying sediment of a sinkhole in Lake Huron (USA). We found that the diatoms rapidly accumulated NO 3 − at the mat-water interface in the afternoon and 40% of the population migrated deep into the sediment, where they were exposed to dark and anoxic conditions for 75% of the day. The vertical distribution of DNRA rates and diatom abundance maxima coincided, suggesting that DNRA was the main energy generating metabolism of the diatom population. We conclude that the illuminated redox-dynamic ecosystem selects for migratory diatoms that can store nitrate for respiration in the absence of light. A major implication of this study is that the dominance of DNRA over denitrification is not explained by kinetics or thermodynamics. Rather, the dynamic conditions select for migratory diatoms that perform DNRA and can outcompete sessile denitrifiers.

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“…In other ecosystems, concentrated organic matter loading below aquaculture operations has been shown to increase DNRA rates seven-fold (Christensen et al 2000). This introduction of organic matter is particularly important because under conditions of low NO 3 - and high labile C, DNRA is favored over complete denitrification, the dominant loss pathway for reactive N in most lake ecosystems (Nizzoli et al 2010; Murphy et al 2020). Given the large inputs of C that are likely associated with the industrial Tilapia operation in the deepest basin of the lake (nearest stations R, P and Q) these conditions are likely present in the pelagic hypolimnion of Lake Yojoa.…”

Section: Discussionmentioning

confidence: 99%

The interaction of physical structure and nutrient loading drives ecosystem change in a large tropical lake over 40 years

Fadum

Hall

2020

Preprint

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Lakes across the world are experiencing novel trophic states, declining water quality, and altered biogeochemical cycling due to the synergistic impacts of global change and local anthropogenic stressors. In the tropics these changes can be difficult to assess due to a lack of continuous monitoring or documented legacy conditions to serve as a reference for the contemporary lake. Over the last forty years, Lake Yojoa, located in west central Honduras, has shifted from an oligotrophic to mesotrophic ecosystem as evidenced by a loss of water clarity. To assess the changes that have occurred in Lake Yojoa as well as putative drivers for those changes, we compared secchi depth, dissolved inorganic nitrogen, and total phosphorus concentrations between 1979-1983 and today (2018-2020). While we found little change in total phosphorus between legacy and contemporary data, we found concurrent changes to seasonal trends in secchi depth and dissolved inorganic nitrogen (DIN). Seasonal peaks in DIN coincident with mixus suggest that accumulation of ammonium in the hypolimnion during stratification, and release to the epilimnion with mixus maintains algal productivity in what was previously a nutrient-limited, clear water phase, driving a change in the overall trophic state of Lake Yojoa. This impact of seasonal dynamics on the trophic state of the lake illustrates a key distinction in how physical structure and nutrients interact differently in tropical and temperate lake ecosystems and highlights the importance of warm anoxic hypolimnions to the biogeochemistry that governs the trophic state of tropical lake ecosystems.

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Sulphide addition favours respiratory ammonification (DNRA) over complete denitrification and alters the active microbial community in salt marsh sediments

Cited by 77 publications

References 103 publications

Effects of Ferrous Iron and Hydrogen Sulfide on Nitrate Reduction in the Sediments of an Estuary Experiencing Hypoxia

Effects of Ferrous Iron and Hydrogen Sulfide on Nitrate Reduction in the Sediments of an Estuary Experiencing Hypoxia

Nitrate respiration and diel migration patterns of diatoms are linked in sediments underneath a microbial mat

The interaction of physical structure and nutrient loading drives ecosystem change in a large tropical lake over 40 years

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