Suspended Particulate Matter drives the spatial segregation of
nitrogen turnover along the hyper-turbid Ems estuary

Schulz, Gesa; Sanders, Tina; Beusekom, Justus E. E. van; Voynova, Yoana G.; Schöl, Andreas; Dähnke, Kirstin

doi:10.5194/bg-2021-321

Cited by 3 publications

(8 citation statements)

References 83 publications

(105 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Using the delta values, we calculated the relationship between δ 18 O and δ 15 N (δ 18 O:δ 15 N) in the tidal river (Fig. 3b), which comes with 0.483 very close to the slope of 0.5 (Kendall et al, 2007;Schulz et al, 2022) and supports the relevance of denitrification.…”

Section: Along the Estuarysupporting

confidence: 57%

“…In a recent study, Schulz et al (2022) identified a dominance of denitrification with nitrification as an additional contributor in our focus area, the tidal river. They found δ 15 N values between 15 and 30 ‰ and suggested that these were caused by denitrification as the dominant process according to Kendall et al (2007), visualized in Fig.…”

Section: Along the Estuarymentioning

confidence: 92%

“…According to Kendall et al (2007), δ 15 N values between 15 and 30 ‰ suggest denitrification as the dominant pathway, which is an important sink for anthropogenic nitrate and the global nitrogen budget. In a recent study, Schulz et al (2022) identified three distinct biogeochemical zones along the Ems Estuary with different predominant nitrogen cycling pathways based on water column properties and stable isotopes. In our focus area, the tidal river, Schulz et al (2022) found a dominance of denitrification, with nitrification as an additional contributing pathway in the downstream part.…”

Section: Nitrate Respiration In the Tidal Rivermentioning

confidence: 99%

“…In a recent study, Schulz et al (2022) identified three distinct biogeochemical zones along the Ems Estuary with different predominant nitrogen cycling pathways based on water column properties and stable isotopes. In our focus area, the tidal river, Schulz et al (2022) found a dominance of denitrification, with nitrification as an additional contributing pathway in the downstream part. In addition to the assessment along the estuary, we investigated five vertical profiles at km 7.2 in the tidal river during ebb tide.…”

Section: Nitrate Respiration In the Tidal Rivermentioning

confidence: 99%

See 3 more Smart Citations

Alkalinity and nitrate dynamics reveal dominance of anammox in a hyper-turbid estuary

Norbisrath

Neumann²,

Dähnke³

et al. 2022

Preprint

View full text Add to dashboard Cite

Abstract. Total alkalinity (TA) regulates the oceanic storage capacity of atmospheric CO2. TA is produced along two general pathways, weathering reactions and anaerobic respiration of organic matter, e.g., by denitrification, the anaerobic reduction of nitrate (NO3-) to elemental nitrogen (N2). Anammox, is another anaerobic pathway, yields N2 as its terminal product via comproportionation of ammonium (NH4+) and nitrite (NO2-); this is, however, without release of alkalinity as a byproduct. In order to investigate these two nitrate / nitrite respiration pathways and their resulting impact on TA generation, we sampled the highly turbid estuary of the Ems River, discharging into the North Sea in June 2020. We sampled a transect from the Wadden Sea to the upper tidal estuary, five vertical profiles during ebb tide, and fluid mud for incubation experiments in the hyper-turbid tidal river. The data reveal a strong increase of TA and DIC in the tidal river, where stable nitrate isotopes indicate water column denitrification as the dominant pathway. In the fluid mud of the tidal river, the TA data imply only low denitrification rates, with the majority of the N2 being produced by anammox (> 90 %). The relative abundances of anammox and denitrification, respectively, thus exert a major control on the CO2 storage capacity of adjacent coastal waters.

show abstract

Section: Along the Estuarysupporting

confidence: 57%

Section: Along the Estuarymentioning

confidence: 92%

Section: Nitrate Respiration In the Tidal Rivermentioning

confidence: 99%

Section: Nitrate Respiration In the Tidal Rivermentioning

confidence: 99%

See 2 more Smart Citations

Alkalinity and nitrate dynamics reveal dominance of anammox in a hyper-turbid estuary

Norbisrath

Neumann²,

Dähnke³

et al. 2022

Preprint

View full text Add to dashboard Cite

show abstract

“…High variation in water column denitrification rates have been previously observed in suspended sediments of streambed origin across rivers of contrasting size (Reisinger et al, 2016). Recent work has emphasized the role of heterogeneous anoxic/hypoxic microsites on the activation of anaerobic microbial activity in suspended sediments (Zhu et al, 2018;Schulz et al, 2022). We contend that large variation in denitrification and Álvarez-Cobelas, 2006).…”

Section: Discussionmentioning

confidence: 65%

Stream nitrogen uptake associated with suspended sediments: A microcosm study

Bacmeister

Peck²,

Bernasconi³

et al. 2022

Front. Environ. Sci.

View full text Add to dashboard Cite

Despite significant advances in our understanding of nitrogen (N) removal pathways along river networks, the role of water column processes remains largely understudied. This knowledge gap not only limits our capacity to determine N transport and retention in mid-to-large rivers but also hampers our understanding of N removal processes in smaller streams during stormflow conditions, in which significant increases in suspended sediment concentrations (SSC) typically occur. High SSC in the water column can provide abundant substrate for microbial growth and water column N uptake. However, storms of different size mobilize different quantities of sediment of varying properties and sizes, which can ultimately modulate water column N uptake rates in the stream during stormflows. To assess water column N uptake associated with suspended sediment particles of different sources and sizes, we quantified assimilatory and dissimilatory N uptake rates in a set of microcosms representing a gradient of sediment properties (organic matter, N content, and microbial activity) and surface area (fine vs. coarse size) availability. Water column assimilatory uptake (Used) ranged from 12.7 to 187.8 µg N [g sediment]−1 d−1 across all sediment sources and size fractions, and was higher on average than denitrification rates (DNsed) in agricultural and stream bank sediments but not in streambed sediments (mean DNsed = 240.9 ± 99 µg·N [g sediment]−1·d−1). Sediment-bound C in suspended sediment varied among sediment sources and was directly related to Used rates, but not to DNsed rates, which were less predictable and more variable. Overall, our results showed a positive nonlinear relationship between water column N uptake and SSC, while indicating that water column N uptake may scale differently to SSC depending on sediment source, and to a lesser degree, particle size. Because low, moderate, and large storms can mobilize different quantities of sediment in the watershed of different sources and sizes, it is likely that storm size will ultimately modulate the contribution of water column uptake during storm events to whole-reach N retention.

show abstract

Nitrogen turnover in the Ems estuary 2020

Schulz,

Voynova,

Metzke

et al. 2022

View full text Add to dashboard Cite

Suspended Particulate Matter drives the spatial segregation of nitrogen turnover along the hyper-turbid Ems estuary

Cited by 3 publications

References 83 publications

Alkalinity and nitrate dynamics reveal dominance of anammox in a hyper-turbid estuary

Alkalinity and nitrate dynamics reveal dominance of anammox in a hyper-turbid estuary

Stream nitrogen uptake associated with suspended sediments: A microcosm study

Nitrogen turnover in the Ems estuary 2020

Contact Info

Product

Resources

About