Impact of resuspension of cohesive sediments at the Oyster Grounds (North Sea) on nutrient exchange across the sediment–water interface

Couceiro, Fay; Fones, Gary R.; Thompson, Charlotte; Statham, Peter J.; Sivyer, D. B.; Parker, Robert P.; Kelly-Gerreyn, B.A.; Amos, Carl L.

doi:10.1007/s10533-012-9710-7

Cited by 57 publications

(49 citation statements)

References 67 publications

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“…Bacterial recycling within the BML is rarely accounted for and could contribute to this unaccounted for oxygen depletion. In addition, recent work has begun focusing more on the importance of resuspension events in seasonal oxygen depletion (Van der Molen et al, 2012;Couceiro et al, 2013;Thompson et al, 2011;Greenwood et al, 2010).…”

Section: Potential Dissolved Oxygen Sinksmentioning

confidence: 99%

Drivers of summer oxygen depletion in the central North Sea

et al. 2016

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Abstract. In stratified shelf seas, oxygen depletion beneath the thermocline is a result of a greater rate of biological oxygen demand than the rate of supply of oxygenated water. Suitably equipped gliders are uniquely placed to observe both the supply through the thermocline and the consumption of oxygen in the bottom layers. A Seaglider was deployed in the shallow ( ≈ 100 m) stratified North Sea in a region of known low oxygen during August 2011 to investigate the processes regulating supply and consumption of dissolved oxygen below the pycnocline. The first deployment of such a device in this area, it provided extremely high-resolution observations, 316 profiles (every 16 min, vertical resolution of 1 m) of conductivity, temperature, and depth (CTD), dissolved oxygen concentrations, backscatter, and fluorescence during a 3-day deployment.The high temporal resolution observations revealed occasional small-scale events (< 200 m or 6 h) that supply oxygenated water to the bottom layer at a rate of 2 ± 1 µmol dm −3 day −1 . Benthic and pelagic oxygen sinks, quantified through glider observations and past studies, indicate more gradual background consumption rates of 2.5 ± 1 µmol dm −3 day −1 . This budget revealed that the balance of oxygen supply and demand is in agreement with previous studies of the North Sea. However, the glider data show a net oxygen consumption rate of 2.8 ± 0.3 µmol dm −3 day −1 , indicating a localized or shortlived (< 200 m or 6 h) increase in oxygen consumption rates. This high rate of oxygen consumption is indicative of an unidentified oxygen sink. We propose that this elevated oxygen consumption is linked to localized depocentres and rapid remineralization of resuspended organic matter.The glider proved to be an excellent tool for monitoring shelf sea processes despite challenges to glider flight posed by high tidal velocities, shallow bathymetry, and very strong density gradients. The direct observation of these processes allows more up to date rates to be used in the development of ecosystem models.

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Section: Potential Dissolved Oxygen Sinksmentioning

confidence: 99%

Drivers of summer oxygen depletion in the central North Sea

et al. 2016

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“…This exchange of nutrients across the sediment water interface (SWI) modifies both sediment nutrient pools (pore water, exchangeable/adsorbed, and strongly bound) and water column conditions [4,5]. Three key processes for the exchange of nutrients across the SWI are: the passive diffusion of solutes, biota-mediated transport (bioirrigation, bioturbation, and bioresuspension [6]), and the physical disturbance and resuspension of sediment [7,8]. Disturbance and resuspension events may occur under natural circumstances (e.g., tidal currents and wave induced; [9]), but also as a result of anthropogenic activities such as vessel movement (e.g., vessel wake and propeller wash) and mooring, and dredging practices [10,11].…”

Section: Introductionmentioning

confidence: 99%

Short-Term Nitrogen and Phosphorus Release during the Disturbance of Surface Sediments: A Case Study in an Urbanised Estuarine System (Gold Coast Broadwater, Australia)

Dunn

Waltham

Teasdale

et al. 2017

JMSE

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Understanding the effects of sediment disturbances on nutrient loadings is important for the management of estuarine settings. This study investigated the initial influence of sediment disturbance on water column nutrient concentrations in a shallow estuarine setting within the Gold Coast Broadwater, using a laboratory-based approach. Undisturbed sediment cores (200 mm Ø × 330 mm length, plexiglass) were incubated before and after being subjected to a disturbance event, to investigate the effect on the immediate and subsequent short-term water column nutrient concentrations. Sediment NH 4 + bio and PO 4 3− bio concentrations ranged from 150 to 478 and 1.50 to 8.56 nmol g −1 dry wt, respectively. Water column NH 4 + concentrations underwent the greatest increase (>1000% or approx. 14 times greater) immediately following disturbance, with mean effluxes increasing by >300%. Thereafter, water column NH 4 + concentrations and efflux rates declined to near initial pre-disturbance concentrations. Water column NH 4 + concentrations accounted for 0.58%-5.50% of the depth-integrated sediment NH 4 + bio concentration, indicating mobilization of the sediment bound exchangeable NH 4 + . The observed changes in PO 4 3− concentrations and fluxes were much lower in comparison to those observed for N-species. Following disturbance, increases in the water column PO 4 3− concentration accounted for 7.16%-8.22% depth-integrated sediment bioavailable PO 4 3− at +1 and +2 hours, and 5.65% at +7 hours, respectively. These results provide important insight into the potential implications of disturbance events, such as vessel activities and dredging operations, within the case study region, providing information for potential management options and relevant water quality concerns.

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“…The CMF was designed with nutrient sampling and nutrient flux measurements in mind (Couceiro et al 2013). Immediately after sediment core collection DET (diffusive equilibrium in thin films) probes (Davison et al 2000;Monbet et al 2008) were deployed for 24 hours around the outer edge of the core barrel to enable fine resolution pore water profiles of nitrate, nitrite, ammonium, phosphate, and dissolved silicon to be determined.…”

Section: Nutrient Samplingmentioning

confidence: 99%

Shipboard measurements of sediment stability using a small annular flume—Core Mini Flume (CMF)

Thompson

Couceiro

Fones

et al. 2013

Limnology & Ocean Methods

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Estimates of bed stability in coastal environments are essential to physical, biological, and chemical investigations of cohesive sediments. The Core Mini Flume (CMF), a 200 mm diameter annular flume has been designed to undertake sediment stability experiments on collected intact sediment box cores. Bed properties were assessed for replicate box cores at 3 contrasting sites in UK coastal waters (Tyne [in 2011 and 2012], Plymouth and Celtic Deep), each covering a maximum area of 80 m2. No significant horizontal spatial variations were found for grain size, bulk density, porosity, or oxygen penetration at the sites. Resuspension experiments performed on replicate cores yielded highly replicable results for each site, giving average erosion thresholds of 0.33 ± 0.02 (Tyne 2011), 0.215 ± 0.03 (Tyne 2012), 0.23 ± 0.01 (Plymouth), and 0.09 ± 0.006 (Celtic Deep) Pa and erosion depths of 10.7 ± 1.7, 6.63 ± 1.10, 3.65 ± 0.95, and 4.6 ± 0.5 mm. Using an already established methodology, the CMF allowed detailed replicate experiments to be performed on‐board ship rapidly after sediment collection, while minimizing the time spent at each station. The use of intact box cores minimized the disturbance to the bed often associated with recovering material to a laboratory or remoulding a bed. We have demonstrated that the convenience of laboratory‐based methodologies can be combined with the benefit of prompt investigations on undisturbed beds complete with overlying in situ water to produce robust measurements of sediment stability.

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Impact of resuspension of cohesive sediments at the Oyster Grounds (North Sea) on nutrient exchange across the sediment–water interface

Cited by 57 publications

References 67 publications

Drivers of summer oxygen depletion in the central North Sea

Drivers of summer oxygen depletion in the central North Sea

Short-Term Nitrogen and Phosphorus Release during the Disturbance of Surface Sediments: A Case Study in an Urbanised Estuarine System (Gold Coast Broadwater, Australia)

Shipboard measurements of sediment stability using a small annular flume—Core Mini Flume (CMF)

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