Vertical activity distribution of dissimilatory nitrate reduction in coastal marine sediments

Behrendt, Anna; Beer, Dirk de; Stief, Peter

doi:10.5194/bg-10-7509-2013

Cited by 46 publications

(28 citation statements)

References 82 publications

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“…These rates are in the same range as areal denitrification rates reported for Wadden Sea and other intertidal sediments (8-48 [47], 1-55 [58], 10-280 [59], and 230-470 µmol N 2 –N m -2 h -1 [60]). Very recently, the areal denitrification rate in the intertidal flat near Dorum-Neufeld was measured to be 88 µmol N 2 –N m -2 h -1 [61], which is also within the estimated range of areal nitrate ammonification rates of diatoms. Additionally, diatoms with intact ICNO 3 stores, possibly filled in the water column, may also decay and be mineralized in the sediment.…”

Section: Discussionmentioning

confidence: 58%

Role of Diatoms in the Spatial-Temporal Distribution of Intracellular Nitrate in Intertidal Sediment

2013

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Intracellular nitrate storage allows microorganisms to survive fluctuating nutrient availability and anoxic conditions in aquatic ecosystems. Here we show that diatoms, ubiquitous and highly abundant microalgae, represent major cellular reservoirs of nitrate in an intertidal flat of the German Wadden Sea and are potentially involved in anaerobic nitrate respiration. Intracellular nitrate (ICNO3) was present year-round in the sediment and was spatially and temporally correlated with fucoxanthin, the marker photopigment of diatoms. Pyrosequencing of SSU rRNA genes of all domains of life confirmed that ICNO3 storage was most likely due to diatoms rather than other known nitrate-storing microorganisms (i.e., large sulfur bacteria and the eukaryotic foraminifers and gromiids). Sedimentary ICNO3 concentrations reached up to 22.3 µmol dm-3 at the sediment surface and decreased with sediment depth to negligible concentrations below 5 cm. Similarly, the ICNO3/fucoxanthin ratio and porewater nitrate (PWNO3) concentrations decreased with sediment depth, suggesting that ICNO3 of diatoms is in equilibrium with PWNO3, but is enriched relative to PWNO3 by 2-3 orders of magnitude. Cell-volume-specific ICNO3 concentrations in a diatom mat covering the sediment surface during spring were estimated at 9.3-46.7 mmol L-1. Retrieval of 18S rRNA gene sequences related to known nitrate-storing and nitrate-ammonifying diatom species suggested that diatoms in dark and anoxic sediment layers might be involved in anaerobic nitrate respiration. Due to the widespread dominance of diatoms in microphytobenthos, the total nitrate pool in coastal marine sediments may generally be at least two times larger than derived from porewater measurements and partially be recycled to ammonium.

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Section: Discussionmentioning

confidence: 58%

Role of Diatoms in the Spatial-Temporal Distribution of Intracellular Nitrate in Intertidal Sediment

2013

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“…Despite this, DNRA is still an important nitrate transformation process in the study area, accounting for around 10–30% of total nitrate reduction based on the data from this study and our previous studies [ Deng et al ., ; Cheng et al ., ]. The rates of DNRA in the Yangtze Estuary are comparable to the data available from other estuarine and coastal environments, but the percentage of DNRA in total nitrate loss varies greatly among these ecosystems [ Christensen et al ., ; An and Gardner , ; Gardner et al ., ; Laverman et al ., ; Dong et al ., ; Gardner and McCarthy , ; Koop‐Jakobsen and Giblin , ; Dong et al ., ; Sgouridis et al ., ; Hou et al ., ; Jäntti and Hietanen , ; Behrendt et al ., ; Dunn et al ., ; Song et al ., ; Yin et al ., ; Bernard et al ., ; Robertson et al ., ]. Interestingly, by integrating the percentages from these estuarine and coastal systems, temperature was found to be correlated significantly positively with the contributions of DNRA to total nitrate reduction ( r = 0.65, p = 0.009; Figure ), despite that no significant correlation between temperature and DNRA rates was observed in this study.…”

Section: Discussionmentioning

confidence: 98%

“…Figure 6. Relationship between temperature and the contributions of DNRA to total nitrate reduction of the Yangtze Estuary and other estuarine and coastal environments [Christensen et al, 2000;An and Gardner, 2002;Gardner et al, 2006;Laverman et al, 2007;Dong et al, 2009;Gardner and McCarthy, 2009;Koop-Jakobsen and Giblin, 2010;Dong et al, 2011;Sgouridis et al, 2011;Hou et al, 2012;Jäntti and Hietanen, 2012;Behrendt et al, 2013;Dunn et al, 2013;Song et al, 2013;Yin et al, 2014b;Bernard et al, 2015;Robertson et al, 2016]. Figures 2 and 3 and Table S2.…”

Section: Discussionmentioning

confidence: 99%

DNRA in intertidal sediments of the Yangtze Estuary

et al. 2017

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Dissimilatory nitrate reduction to ammonium (DNRA) plays an important role in regulating the fate of reactive nitrogen in estuarine and coastal ecosystems. In this work, intertidal sediments of the Yangtze Estuary were collected in January and August 2015. Potential rates of DNRA and associated functional gene were investigated with nitrogen isotope‐tracing and molecular techniques. The measured DNRA rates ranged from 0.14 to 5.57 μmol 15N kg−1 h−1 in the intertidal sediments. DNRA rates were tightly related to abundance of nrfA gene (p < 0.001), demonstrating that fermentation reaction may be the dominant pathway of DNRA in the study area. Redundancy analysis (RDA) showed a relationship between DNRA and organic matter and NO2−, suggesting that these substrates stimulated the metabolism of DNRA microorganisms. On the other hand, the correlation between abundances of nrfA gene and Fe2+ and sulfide in the RDA analysis implied that oxidation of both Fe2+ and sulfide can enhance fermentative DNRA by providing extra free energy. DNRA converted approximately 2.29 × 105 t of nitrate to ammonia annually in the sampling area of the Yangtze Estuary, and most of the converted ammonium was retained in the estuarine ecosystem. DNRA may further contribute to eutrophication in the Yangtze Estuary and also in the other hypereutrophic estuaries.

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“…Generally, sulfide serves as a potential electron donor and increases the DNRA rates via inhibiting denitrification in sediments [Myers, 1972;Bonin, 1996;Brunet and Garcia-Gil, 1996;Sher et al, 2008;Lu et al, 2013]. Furthermore, DNRA may be coupled to Fe (II) oxidation by the following expected stoichiometric equation [Behrendt et al, 2013;Roberts et al, 2014]:…”

Section: Discussionmentioning

confidence: 99%

Dissimilatory nitrate reduction processes and associated contribution to nitrogen removal in sediments of the Yangtze Estuary

et al. 2015

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Dissimilatory nitrate reduction processes, including denitrification, anaerobic ammonium oxidation (ANAMMOX), and dissimilatory nitrate reduction to ammonium (DNRA), play an important role in controlling the nitrate dynamics and fate in estuarine and coastal environments. We investigated potential rates of denitrification, ANAMMOX, and DNRA in the sediments of the Yangtze Estuary via slurry incubation experiments combined with isotope-tracing techniques to reveal their respective contributions to total nitrate reduction in this hypereutrophic estuarine ecosystem. Measured rates of denitrification, ANAMMOX, and DNRA ranged from 0.06 to 4.51 μmol N kg À1 h À1, 0.01 to 0.52 μmol N kg À1 h À1, and 0.03 to 0.89 μmol N kg À1 h À1, respectively. These potential dissimilatory nitrate reduction process rates correlated significantly with salinity, sulfide, organic carbon, and nitrogen. Denitrification contributed 38-96% total nitrate reduction in the Yangtze Estuary, as compared to 3-45% for DNRA and 1-36% for ANAMMOX. In total, the denitrification and ANAMMOX processes removed approximately 25% of the external inorganic nitrogen transported annually into the estuary. In contrast, most external inorganic nitrogen was retained in the estuary and contributes substantially to the severe eutrophication of the Yangtze Estuary.

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Vertical activity distribution of dissimilatory nitrate reduction in coastal marine sediments

Cited by 46 publications

References 82 publications

Role of Diatoms in the Spatial-Temporal Distribution of Intracellular Nitrate in Intertidal Sediment

Role of Diatoms in the Spatial-Temporal Distribution of Intracellular Nitrate in Intertidal Sediment

DNRA in intertidal sediments of the Yangtze Estuary

Dissimilatory nitrate reduction processes and associated contribution to nitrogen removal in sediments of the Yangtze Estuary

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