scholarly journals Combined Gel Probe and Isotope Labeling Technique for Measuring Dissimilatory Nitrate Reduction to Ammonium in Sediments at Millimeter-Level Resolution

2010 ◽  
Vol 76 (18) ◽  
pp. 6239-6247 ◽  
Author(s):  
Peter Stief ◽  
Anna Behrendt ◽  
Gaute Lavik ◽  
Dirk De Beer
Keyword(s):  
Quartz Sand ◽  
Nitrate Reduction ◽  
Isotope Labeling ◽  
Sediment Cores ◽  
Isotopic Labeling ◽  
Physical Disturbance ◽  
Sediment Pore Water ◽  
Dissimilatory Nitrate Reduction ◽  
The Vertical Distribution

ABSTRACT Dissimilatory NO3 − reduction in sediments is often measured in bulk incubations that destroy in situ gradients of controlling factors such as sulfide and oxygen. Additionally, the use of unnaturally high NO3 − concentrations yields potential rather than actual activities of dissimilatory NO3 − reduction. We developed a technique to determine the vertical distribution of the net rates of dissimilatory nitrate reduction to ammonium (DNRA) with minimal physical disturbance in intact sediment cores at millimeter-level resolution. This allows DNRA activity to be directly linked to the microenvironmental conditions in the layer of NO3 − consumption. The water column of the sediment core is amended with 15NO3 − at the in situ 14NO3 − concentration. A gel probe is deployed in the sediment and is retrieved after complete diffusive equilibration between the gel and the sediment pore water. The gel is then sliced and the NH4 + dissolved in the gel slices is chemically converted by hypobromite to N2 in reaction vials. The isotopic composition of N2 is determined by mass spectrometry. We used the combined gel probe and isotopic labeling technique with freshwater and marine sediment cores and with sterile quartz sand with artificial gradients of 15NH4 +. The results were compared to the NH4 + microsensor profiles measured in freshwater sediment and quartz sand and to the N2O microsensor profiles measured in acetylene-amended sediments to trace denitrification.

scholarly journals Vertical activity distribution of dissimilatory nitrate reduction in coastal marine sediments

2013 ◽  
Vol 10 (11) ◽  
pp. 7509-7523 ◽  
Author(s):  
A. Behrendt ◽  
D. de Beer ◽  
P. Stief
Keyword(s):  
Nitrate Reduction ◽  
Sediment Cores ◽  
The Core ◽  
Dissimilatory Nitrate Reduction ◽  
Coastal Marine ◽  
Isotope Technique ◽  
Ammonium Production ◽  
High Concentrations ◽  
A Site ◽  
The Vertical Distribution

Abstract. The relative importance of two dissimilatory nitrate reduction pathways, denitrification (DEN) and dissimilatory nitrate reduction to ammonium (DNRA), was investigated in intact sediment cores from five different coastal marine field sites (Dorum, Aarhus Bight, Mississippi Delta, Limfjord and Janssand). The vertical distribution of DEN activity was examined using the acetylene inhibition technique combined with N2O microsensor measurements, whereas NH4+ production via DNRA was measured with a recently developed gel probe-stable isotope technique. At all field sites, dissimilatory nitrate reduction was clearly dominated by DEN (59–131% of the total NO3− reduced) rather than by DNRA, irrespective of the sedimentary inventories of electron donors such as organic carbon, sulfide, and iron. Highest ammonium production via DNRA, accounting for up to 8.9% of the total NO3− reduced, was found at a site with very high concentrations of total sulfide and NH4+ within and below the layer in which NO3− reduction occurred. Sediment from two field sites, one with low and one with high DNRA activity in the core incubations, was also used for slurry incubations. Now, in both sediments high DNRA activity was detected accounting for 37–77% of the total NO3− reduced. These contradictory results might be explained by enhanced NO3− availability for DNRA bacteria in the sediment slurries compared to the core-incubated sediments in which diffusion of NO3− from the water column may only reach DEN bacteria, but not DNRA bacteria. The true partitioning of dissimilatory nitrate reduction between DNRA and DEN may thus lie in between the values found in whole core (underestimation of DNRA) and slurry incubations (overestimation of DNRA).

scholarly journals Vertical activity distribution of dissimilatory nitrate reduction in coastal marine sediments

2013 ◽  
Vol 10 (5) ◽  
pp. 8065-8101 ◽  
Author(s):  
A. Behrendt ◽  
D. de Beer ◽  
P. Stief
Keyword(s):  
Nitrate Reduction ◽  
Sediment Cores ◽  
The Core ◽  
Dissimilatory Nitrate Reduction ◽  
Coastal Marine ◽  
Isotope Technique ◽  
Ammonium Production ◽  
High Concentrations ◽  
The Vertical Distribution ◽  
Stable Isotope Technique

Abstract. The relative importance of two dissimilatory nitrate reduction pathways, denitrification (DEN) and dissimilatory nitrate reduction to ammonium (DNRA), was investigated in intact sediment cores from five different coastal marine field sites. The vertical distribution of DEN activity was examined using the acetylene inhibition technique combined with N2O microsensor measurements, whereas NH4+ production via DNRA was measured with a recently developed gel probe-stable isotope technique. At all field sites, dissimilatory nitrate reduction was clearly dominated by DEN (> 59% of the total NO3− reduced) rather than by DNRA, irrespective of the sedimentary inventories of electron donors such as organic carbon, sulfide, and iron. Ammonium production via DNRA (8.9% of the total NO3− reduced) was exclusively found at one site with very high concentrations of total sulfide and NH4+ in the layer of NO3− reduction and below. Sediment from two field sites, one with and one without DNRA activity in the core incubations, was also used for slurry incubations. Now, in both sediments high DNRA activity was detected accounting for 37–77% of the total NO3− reduced. These contradictory results can be explained by enhanced NO3− availability for DNRA bacteria in the sediment slurries compared to the core-incubated sediments. It can be argued that the gel probe technique gives more realistic estimates of DNRA activity in diffusion-dominated sediments, while slurry incubations are more suitable for advection-dominated sediments.

In Situ Dissimilatory Nitrate Reduction to Ammonium in a Paddy Soil Fertilized with Liquid Cattle Waste

Pedosphere ◽  
2012 ◽  
Vol 22 (3) ◽  
pp. 314-321 ◽  
Author(s):  
Wei-Wei LU ◽  
S. RIYA ◽  
Sheng ZHOU ◽  
M. HOSOMI ◽  
Hai-Lin ZHANG ◽  
...  
Keyword(s):  
Paddy Soil ◽  
Nitrate Reduction ◽  
Dissimilatory Nitrate Reduction

scholarly journals Anammox, denitrification and fixed-nitrogen removal in sediments from the Lower St. Lawrence Estuary

2012 ◽  
Vol 9 (11) ◽  
pp. 4309-4321 ◽  
Author(s):  
S. A. Crowe ◽  
D. E. Canfield ◽  
A. Mucci ◽  
B. Sundby ◽  
R. Maranger
Keyword(s):  
Nitrate Reduction ◽  
Sediment Cores ◽  
Oxygen Demand ◽  
N Cycling ◽  
Fixed Nitrogen ◽  
Lawrence Estuary ◽  
Hypoxic Conditions ◽  
Nitrate And Nitrite ◽  
St Lawrence Estuary

Abstract. Incubations of intact sediment cores and sediment slurries reveal that anammox is an important sink for fixed nitrogen in sediments from the Lower St. Lawrence Estuary (LSLE), where it occurs at a rate of 5.5 ± 1.7 µmol N m−2 h−1. Canonical denitrification occurs at a rate of 11.3 ± 1.1 µmol N m−2 h−1, and anammox is thus responsible for up to 33% of the total N2 production. Both anammox and denitrification are mostly (> 95%) fueled by nitrate and nitrite produced in situ through benthic nitrification. Nitrification accounts for > 15% of the benthic oxygen demand and may, therefore, contribute significantly to the development and maintenance of hypoxic conditions in the LSLE. The rate of dissimilatory nitrate reduction to ammonium is three orders of magnitude lower than denitrification and anammox, and it is insignificant to N-cycling. NH4+ oxidation by sedimentary Fe(III) and Mn(III/IV) in slurry incubations with N isotope labels did not occur at measurable rates; moreover, we found no evidence for NH4+ oxidation by added Mn(III)-pyrophosphate.

scholarly journals Environment Gradient related Dissimilatory Nitrate Reduction to Ammonium in Huangmao Sea Estuary: Rates and Community Diversity

2019 ◽  
Author(s):  
Ran Jiang ◽  
Shu-Xin Zhang ◽  
Gou Wei ◽  
Rui He ◽  
Li-Ling Yang ◽  
...  
Keyword(s):  
Nitrate Reduction ◽  
River Estuary ◽  
Pearl River Estuary ◽  
Community Diversity ◽  
Pearl River ◽  
Bacterial Populations ◽  
Dissimilatory Nitrate Reduction ◽  
The Pearl River ◽  
One Year

Abstract. The potential rates of dissimilatory nitrate reduction to ammonium (DNRA) in the sediments collected from Huangmao Sea Estuary (HSE), one of Pearl River Estuaries in China, were investigated. The research covers a one-year period at 20 sites of HSE based on the 15N isotope and molecular biology analysis. The results showed that the environment gradients of nitrogen pollutants decreased from the estuary to the sea, and the characteristics of terrestrial pollutant export were obvious. 15NH4+ was detected in all sites in continuous-flow systems, which showed that DNRA existed in HSE potentially. In which the maximum 15NH4+ was 1948.5 μg/L, accordingly in situ rate of DNRA was 6.3 μg/L.h in 72 h. The high transcripts of nrfA gene were found at the same site, with values of 1 159 715 copics/(g wet sediment). Correspondingly, a very low transcripts of nrfA were found at other sites. Principal components analysis (PCA) based on community composition at genus level showed the distribution pattern of the nrfA gene sequences. Nine samples formed three distinct clusters, corresponding to their geographical locations, which suggested that salinity was likely to affect the selection of the nrfA bacterial populations. This study provide a better understanding of DNRA in the Pearl River Estuary.

scholarly journals Anammox, denitrification and fixed-nitrogen removal in sediments of the Lower St. Lawrence Estuary

2011 ◽  
Vol 8 (5) ◽  
pp. 9503-9534 ◽  
Author(s):  
S. A. Crowe ◽  
D. E. Canfield ◽  
A. Mucci ◽  
B. Sundby ◽  
R. Maranger
Keyword(s):  
Nitrate Reduction ◽  
Sediment Cores ◽  
Oxygen Demand ◽  
N Cycling ◽  
Fixed Nitrogen ◽  
Lawrence Estuary ◽  
Hypoxic Conditions ◽  
Nitrate And Nitrite ◽  
St Lawrence Estuary

Abstract. Incubations of intact sediment cores and sediment slurries reveal that anammox is an important sink for fixed nitrogen in the Lower St. Lawrence Estuary (LSLE), where it occurs at a rate of 5.5 ± 1.7 μmol N m−2 h−1 in the sediment. Anammox is responsible for up to 33% of the total N2 production, and both anammox and denitrification are mostly (>95%) fueled by nitrate and nitrite produced in situ through benthic nitrification. Nitrification accounts for >15% of the benthic oxygen demand and contributes significantly to the development and maintenance of hypoxic conditions in the LSLE. The rate of dissimilatory nitrate reduction to ammonium is three orders of magnitude lower than denitrification and anammox and is therefore insignificant to N-cycling. Tests for NH4+ oxidation by sedimentary Fe(III) and Mn(III/IV), using slurry incubations with N isotope labels, revealed that it does not occur at measurable rates, and we found no evidence for NH4+ oxidation by added Mn(III)-pyrophosphate.

scholarly journals Phosphorous Supply to a Eutrophic Artificial Lake: Sedimentary versus Groundwater Sources

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 563
Author(s):  
Wiebe Förster ◽  
Jan C. Scholten ◽  
Michael Schubert ◽  
Kay Knoeller ◽  
Nikolaus Classen ◽  
...  
Keyword(s):  
Water Quality ◽  
Stable Isotope ◽  
Pore Water ◽  
Lake Water ◽  
Sediment Cores ◽  
Eutrophic Lake ◽  
Stable Water Isotopes ◽  
Artificial Lake ◽  
Sediment Pore Water ◽  
Mass Balance Models

The eutrophic Lake Eichbaumsee, a ~1 km long and 280 m wide (maximum water depth 16 m) dredging lake southeast of Hamburg (Germany), has been treated for water quality improvements using various techniques (i.e., aeration plants, removal of dissolved phosphorous by aluminum phosphorous precipitation, and by Bentophos® (Phoslock Environmental Technologies, Sydney, Australia), adsorption) during the past ~15 years. Despite these treatments, no long-term improvement of the water quality has been observed and the lake water phosphorous content has continued to increase by e.g., ~670 kg phosphorous between autumn 2014 and autumn 2019. As no creeks or rivers drain into the lake and hydrological groundwater models do not suggest any major groundwater discharge into the lake, sources of phosphorous (and other nutrients) are unknown. We investigated the phosphorous fluxes from sediment pore water and from groundwater in the water body of the lake. Sediment pore water was extracted from sediment cores recovered by divers in August 2018 and February 2019. Diffusive phosphorous fluxes from pore water were calculated based on phosphorus gradients. Stable water isotopes (δ2H, δ18O) were measured in the lake water, in interstitial waters in the banks surrounding the lake, in the Elbe River, and in three groundwater wells close to the lake. Stable isotope (δ2H, δ18O) water mass balance models were used to compute water inflow/outflow to/from the lake. Our results revealed pore-water borne phosphorous fluxes between 0.2 mg/m2/d and 1.9 mg/m2/d. Assuming that the measured phosphorous fluxes are temporarily and spatially representative for the whole lake, about 11 kg/a to 110 kg/a of phosphorous is released from sediments. This amount is lower than the observed lake water phosphorous increase of ~344 kg between April 2018 and November 2018. Water stable isotope (δ2H, δ18O) compositions indicate a water exchange between an aquifer and the lake water. Based on stable isotope mass balances we estimated an inflow of phosphorous from the aquifer to the lake of between ~150 kg/a and ~390 kg/a. This result suggests that groundwater-borne phosphorous is a significant phosphorous source for the Eichbaumsee and highlights the importance of groundwater for lake water phosphorous balances.

Variations of dissimilatory nitrate reduction processes along reclamation chronosequences in Chongming Island, China

2021 ◽  
Vol 206 ◽  
pp. 104815
Author(s):  
Yinghui Jiang ◽  
Guoyu Yin ◽  
Lijun Hou ◽  
Min Liu ◽  
Dengzhou Gao ◽  
...  
Keyword(s):  
Nitrate Reduction ◽  
Chongming Island ◽  
Reduction Processes ◽  
Dissimilatory Nitrate Reduction
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