Wave enhancement of solute exchange within empty burrows

Webster, Ian T.

doi:10.4319/lo.1992.37.3.0630

Cited by 22 publications

(13 citation statements)

References 17 publications

(18 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Other transport processes can also stimulate O 2 uptake by sediments. Currents over an uneven bottom or wave action at shallow sites can induce a significant advective transport, either through the interstitial pores in more permeable sediments such as sand, or through tubes and borrows created by fauna (Rutgers van der Loeff 1981, Savant et al 1987, Thibodeaux & Boyle 1987, Huettel & Gust 1992, Shum 1992, Webster 1992, Webster & Taylor 1992. This advection can be the dominant transport process in sediments, and enhances O 2 uptake manyfold relative to uptake by molecular diffusion (Malan & McLachlan 1991, Forster et al 1996, Lohse et al 1996.…”

Section: Introductionmentioning

confidence: 99%

Oxygen uptake by aquatic sediments measured with a novel non-invasive eddy-correlation technique

Berg¹,

Røy²,

Janßen³

et al. 2003

Mar. Ecol. Prog. Ser.

252

318

View full text Add to dashboard Cite

This paper presents a new non-invasive technique for measuring sediment O 2 uptake that, in its concept, differs fundamentally from other methods used to date. In almost all natural aquatic environments, the vertical transport of O 2 through the water column toward the sediment surface is facilitated by turbulent motion. The new technique relies on measuring 2 parameters simultaneously and at the same point in the water above the sediment: the fluctuating vertical velocity using an acoustic Doppler velocimeter and the fluctuating O 2 concentration using an O 2 microelectrode. From these 2 parameters, which typically are measured 10 to 50 cm above the sediment surface for a period of 10 to 20 min and at a frequency of 15 to 25 Hz, the vertical flux of O 2 toward the sediment surface is derived. Based on measurements performed under actual field conditions and comparisons with in situ flux-chamber measurements, we believe that this new technique is the optimal approach for determining O 2 uptake by sediments. The technique is superior to conventional methods as measurements are done under true in situ conditions, i.e. without any disturbance of the sediment and under the natural hydrodynamic conditions. Furthermore, this technique can be used for bio-irrigated or highly permeable sediments, such as sands, where traditional methods often fail. While this paper only focuses on O 2 uptake by sediments, the technique can also be applied to other solutes that can be measured at a sufficiently high temporal resolution. KEY WORDS: Oxygen uptake · Sediment · Eddy-correlation measurementsResale or republication not permitted without written consent of the publisher

show abstract

Section: Introductionmentioning

confidence: 99%

Oxygen uptake by aquatic sediments measured with a novel non-invasive eddy-correlation technique

Berg¹,

Røy²,

Janßen³

et al. 2003

Mar. Ecol. Prog. Ser.

252

318

View full text Add to dashboard Cite

show abstract

“…Flow in animal burrows has received increased attention by researchers in recent years (Webster, 1992;Ridd, 1996). The study of Allanson et al (1992) investigated flow through burrows of the thalassinidean prawn, Upogebia africana Ortmann.…”

Section: Introductionmentioning

confidence: 99%

The Use of Computational Fluid Dynamics in Predicting the Tidal Flushing of Animal Burrows

Heron

Ridd

2001

Estuarine, Coastal and Shelf Science

View full text Add to dashboard Cite

Numerical hydrodynamic modelling has been used extensively over the last few decades to simulate flow in the ocean, bays and estuaries; however, modelling of much smaller scale phenomena is less common. In this work a commercially available Computational Fluid Dynamics package (FIDAP), normally used for industrial applications, was used to simulate tidally-induced flow in multi-opening animal burrows. U-shaped burrows of varying complexities were modelled to determine the effect of different surface characteristics and burrow geometries on surface water velocities, burrow velocities and burrow flushing times. The turbulent 2D model showed the slope of the surface water was proportional to the square of both the surface and burrow velocities. The effect of placing a root in the surface flow was to reduce the surface water velocity; however, the burrow flow depended upon the root position. For the root location either upstream or downstream of the burrow, the burrow velocity was reduced by 50%. With the root located between the burrow openings the burrow velocity increased by 200%, due to the increase in pressure difference across the burrow openings. A buttress root placed in the flow immediately downstream of the upstream burrow, caused the burrow flushing rate to increase significantly with increasing buttress height. Flushing times for burrows of varying depth were determined computationally by use of a tracer for the burrow water. For a burrow of depth 1·2 m, the flushing times were 5 and 28 min for root location between the burrow openings and downstream of the burrow, respectively. Animal burrows often consist of multiply-connected loops. A second burrow was added to the primary burrow and flushing times were found to be 15 and 38 min, respectively. A burrow system of four connected burrows was modelled which had corresponding flushing times up to 24 and 47 min, respectively. The calculated times are consistent with the hypothesis that a significant flushing of animal burrows occurs within a single tidal event. This preliminary investigation indicates that CFD models may be very useful in studying small scale hydrodynamic phenomena such as flow in animal burrows. Academic Press

show abstract

“…The effect of bioturbation on nitrate flux would be the same during the whole period of submergence (Kristensen, 1988). On the other hand, the physical effect of tidal flooding on interstitial nitrate would be transient, since physical turbulence decreases with increasing water depth (Webster, 1992).…”

Section: Change In Pore Water Nitrate During Submergencementioning

confidence: 99%

“…These high fluxes can probably be attributed either to physical turbulence and/or bioturbation at the time of flooding (Rutgers van der Loeff et al, 1984;Kikuchi, 1986;Simon, 1989;Webster, 1992). Because of the purge of air and the ample supply of nitrate from the overlying water, (a) Observed at 30 minutes before tidal flooding on 2 November, and at 2 hours 40 minutes before the flooding on 15 December.…”

Section: (B))mentioning

confidence: 99%

Tidal effect on dynamics of pore water nitrate in intertidal sediment of a eutrophic Estuary

1998

View full text Add to dashboard Cite

To evaluate the effect of the tidal cycle on the pore water nitrate dynamics in intertidal sediment, concentrations of inorganic nitrogen in water and sediment were monitored during tidal cycles in the mud flat of Tama Estuary, Japan. During submergence, nitrate concentration was highest in the overlying water and decreased monotonically with increasing depth in the sediment, suggesting that the primary source of nitrate in the sediment was nitrate transported from the overlying water. Pore water nitrate decreased remarkably during the initial 3-4 hours after the onset of exposure. Thereafter, it was constant or slightly increased until tidal flooding. In situ accumulation of nitrate at the end of exposure, however, did not exceed the nitrate concentrations in the overlying water. The inhibition of nitrate reduction and the stimulation of nitrification would explain the change of nitrate concentration, both consistent with the input of oxygen into the sediment following a 10 mm drop of the water table. In Tama Estuary sediments, the effect of the tidal cycle on the removal of combined nitrogen is rather negative, because high nitrate concentrations in the overlying water canceled the positive effect of nitrate accumulation by nitrification during exposure, while tidal oxygen intrusion have an inhibitory effect on sedimentary denitrification.

show abstract

Wave enhancement of solute exchange within empty burrows

Cited by 22 publications

References 17 publications

Oxygen uptake by aquatic sediments measured with a novel non-invasive eddy-correlation technique

Oxygen uptake by aquatic sediments measured with a novel non-invasive eddy-correlation technique

The Use of Computational Fluid Dynamics in Predicting the Tidal Flushing of Animal Burrows

Tidal effect on dynamics of pore water nitrate in intertidal sediment of a eutrophic Estuary

Contact Info

Product

Resources

About