Seasonal fluxes across the sediment—water interface, and processes within sediments

Nedwell, David B.; Parkes, Ronald John; Upton, A. C.; Assinder, David

doi:10.1007/978-94-011-1236-9_11

Cited by 24 publications

(20 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…No published NO 3 -efflux values are available for the Thames, but our measured rates were not significantly different from those measured at the OSP or further north by Nedwell et al (1993). Very few data exist for Si efflux.…”

Section: Comparative Biogeochemical Measurements In the Southern Nortcontrasting

confidence: 56%

Impact of long-term benthic trawl disturbance on sediment sorting and biogeochemistry in the southern North Sea

Trimmer¹,

Petersen²,

Sivyer³

et al. 2005

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

Section: Comparative Biogeochemical Measurements In the Southern Nortcontrasting

confidence: 56%

Impact of long-term benthic trawl disturbance on sediment sorting and biogeochemistry in the southern North Sea

Trimmer¹,

Petersen²,

Sivyer³

et al. 2005

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

“…At Site 2 the thixotropic nature of the sediment, and deeper 0, penetration (Table l), suggested possible sub-surface irrigation of the sediment. The measured exchange fluxes of solutes across the sediment-water interface showed that, with the exception of Site 2, the sediments were similar to other estuarine sediments in being sinks for NO3- (Billen et al 1985, J~r g e n s e n & Ssrensen 1985, 1988, Binnerup et al 1992, Watson et al 1993) and sources of NH4+ (Nedwell 1982, Blackburn & Henriksen 1983, Hopkinson 1987, Nedwell et al 1993a, Watson et al 1993. The NO3-concentrations in the pore water at Site 2 were similar to those at the other sites although there were much lower concentrations of pore water NH,+, suggesting that nitrification may have been active in this more oxic sediment.…”

Section: Discussionmentioning

confidence: 83%

Nitrogen fluxes through the upper estuary of the Great Ouse, England:the role of the bottom sediments

Db¹,

Trimmer²

1996

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

ABSTRACT. The fate of nitrogen (N) in the bottom sediments of the upper Great Ouse estuary, England, was examined over the course of a year. The sedirnents were consistent sinks for NO3-from the overlying river water, and were weak sources of NH,'. Simultaneous measurements of oxygen uptake, nutrient exchange and sulphate reduction, when combined with the measured C:N ratios of the sediment organic matter, permitted calculation of the amount of N released within the sediment by organic matter mineralisation. With the exception of a site w~t h thixotropic sediment, at all other sites the amount of inorganic N entering the sedlment by transport from the overlying water and by internal ammonification of organic matter was not matched by measured exports of N from the sedirnents. We calculate that >90% of the flux of N through the sediment was lost as gases, and that 50'L of the N ammonified from organic matter must have been converted to gases by coupled nitrification-denitrification within the sediments. When compared to the total flux of N through the entire estuary, any N loss by denitrification in the sediments of the upper estuary was minor (-1 X ) because of the small surface area of sediment to freshwater flow

show abstract

“…These estimates are comparable to the model analysis of Krumins et al (2013), who estimated that sulfate reduction is the main respiratory pathway on continental shelves, accounting for 77-85 % of the organic matter mineralization, followed by aerobic respiration (16 %), denitrification (2-4 %) and iron reduction (0.3-0.7 %). Similarly, Nedwell et al (1993) estimated that sulfate reduction accounted for 10-53 % of the total organic matter mineralization in the SNS, while a coupled benthic-pelagic model for the North Sea suggests that up to 30 % of the organic matter is mineralized using sulfate as the electron acceptor (Luff and Moll, 2004). The TOU rate predicted by the model (10.4 mmol O 2 m −2 d −1 ) agrees well with the mean TOU observed in the SNS in September 2011 (10.3 mmol O 2 m −2 d −1 ), but the predicted respiratory coefficient (RQ = 1.25) is higher than the observed one (RQ = 0.95).…”

Section: Input Parameter Expressionmentioning

confidence: 98%

The impact of sedimentary alkalinity release on the water column CO<sub>2</sub> system in the North Sea

et al. 2016

View full text Add to dashboard Cite

Abstract. It has been previously proposed that alkalinity release from sediments can play an important role in the carbonate dynamics on continental shelves, lowering the pCO 2 of seawater and hence increasing the CO 2 uptake from the atmosphere. To test this hypothesis, sedimentary alkalinity generation was quantified within cohesive and permeable sediments across the North Sea during two cruises in September 2011 (basin-wide) and June 2012 (Dutch coastal zone). Benthic fluxes of oxygen (O 2 ), alkalinity (A T ) and dissolved inorganic carbon (DIC) were determined using shipboard closed sediment incubations. Our results show that sediments can form an important source of alkalinity for the overlying water, particularly in the shallow southern North Sea, where high A T and DIC fluxes were recorded in nearshore sediments of the Belgian, Dutch and German coastal zone. In contrast, fluxes of A T and DIC are substantially lower in the deeper, seasonally stratified, northern part of the North Sea. Based on the data collected, we performed a model analysis to constrain the main pathways of alkalinity generation in the sediment, and to quantify how sedimentary alkalinity drives atmospheric CO 2 uptake in the southern North Sea. Overall, our results show that sedimentary alkalinity generation should be regarded as a key component in the CO 2 dynamics of shallow coastal systems.

show abstract

Seasonal fluxes across the sediment—water interface, and processes within sediments

Cited by 24 publications

References 21 publications

Impact of long-term benthic trawl disturbance on sediment sorting and biogeochemistry in the southern North Sea

Impact of long-term benthic trawl disturbance on sediment sorting and biogeochemistry in the southern North Sea

Nitrogen fluxes through the upper estuary of the Great Ouse, England:the role of the bottom sediments

The impact of sedimentary alkalinity release on the water column CO<sub>2</sub> system in the North Sea

Contact Info

Product

Resources

About

Seasonal fluxes across the sediment—water interface, and processes within sediments

Cited by 24 publications

References 21 publications

Impact of long-term benthic trawl disturbance on sediment sorting and biogeochemistry in the southern North Sea

Impact of long-term benthic trawl disturbance on sediment sorting and biogeochemistry in the southern North Sea

Nitrogen fluxes through the upper estuary of the Great Ouse, England:the role of the bottom sediments

The impact of sedimentary alkalinity release on the water column CO&lt;sub&gt;2&lt;/sub&gt; system in the North Sea

Contact Info

Product

Resources

About

The impact of sedimentary alkalinity release on the water column CO<sub>2</sub> system in the North Sea