Evidence of sediment resuspension by nonlinear internal waves on the western Portuguese mid-shelf

Quaresma, L.; Vitorino, J.; Oliveira, Anabela; Silva, José António Pereira da

doi:10.1016/j.margeo.2007.04.019

Cited by 143 publications

(143 citation statements)

References 27 publications

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“…It funnels organic matter to depth via a variety of mechanisms including tidal currents, internal waves and turbidity flows (Duineveld et al, 2001;Quaresma et al, 2007). The greater hydrodynamic activity in the canyon leads to an increase in organic matter input and increased food quality within the canyon in comparison to less active areas on the open continental slope.…”

Section: Discussionmentioning

confidence: 99%

“…Current velocities increase when flow comes into contact with steep topography (Genin et al, 1986(Genin et al, , 1989. In a canyon this can be coupled with the creation of higher intensity internal waves than the surrounding slopes (Quaresma et al, 2007). This can result in increased turbulence and sediment resuspension, leading to the creation of nepheloid layers and turbidity flows within the canyon (de Stigter et al, 2007;Arzola et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

“…This can result in increased turbulence and sediment resuspension, leading to the creation of nepheloid layers and turbidity flows within the canyon (de Stigter et al, 2007;Arzola et al, 2008). The combination of these phenomena make canyons significant for shelf-slope particulate exchange (Oliveria et al, 2002;Quaresma et al, 2007;Arzola et al, 2008;Garcia et al, 2008). Consequently, canyons are highly heterogeneous environments leading to the creation of a wide variety of niches for biological communities.…”

Section: Introductionmentioning

confidence: 99%

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Distribution of cold-water corals in the Whittard Canyon, NE Atlantic Ocean

Morris

Tyler

Masson

et al. 2013

Deep Sea Research Part II: Topical Studies in Oceanography

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a b s t r a c tThe deep-sea floor occupies about 60% of the surface of the planet and is covered mainly by fine sediments. Most studies of deep-sea benthic fauna therefore have concentrated on soft sediments with little sampling of hard substrata, such as rocky outcrops in submarine canyons. Here we assess the distribution and abundance of cold-water corals within the Whittard Canyon (NE Atlantic) using video footage from the ROV Isis. Abundances per 100 m of video transect were calculated and mapped using ArcGIS. The data were separated into five substratum types, 'Sediment', 'Mixed Sediment and Rock', 'Sediment Slope', 'Lophelia reef' and 'Lophelia and rock'. Abundance and community structure were compared. A maximum abundance of 855 coral colonies per 100 m of ROV transect were observed with 31 coral types identified. Highest taxon richness was observed along a 'Lophelia reef' area, although a larger richness of Octocorallia was observed away from the 'Lophelia reef' areas. 'Lophelia reef' and 'Lophelia and rock' areas were found to have a different coral community structure from the other substratum types. We suggest this is the result of Lophelia outcompeting other coral types because there is increased coral taxon richness in areas without Lophelia. We also hypothesise that the hydrodynamic regime within the Whittard Canyon results in differences in organic matter input including higher quality food, in comparison with other deep-water environments, leading to changes in the coral communities.Crown

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Distribution of cold-water corals in the Whittard Canyon, NE Atlantic Ocean

Morris

Tyler

Masson

et al. 2013

Deep Sea Research Part II: Topical Studies in Oceanography

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“…In the upper and middle canyon there are moderately strong tidal currents (max. currents speeds up to 35 cm s −1 ) (de Stigter et al, 2007), which can cause sediment resuspension and consequently, transport and redistribution of particulate matter (Quaresma et al, 2007). …”

Section: Study Areamentioning

confidence: 99%

The trophic biology of the holothurian <i>Molpadia musculus</i>: implications for organic matter cycling and ecosystem functioning in a deep submarine canyon

et al. 2010

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Abstract. Megafaunal organisms play a key role in ecosystem functioning in the deep-sea through bioturbation, bioirrigation and organic matter cycling. At 3500 m water depth in the Nazaré Canyon, NE Atlantic, very high abundances of the infaunal holothurian Molpadia musculus were observed. To quantify the role of M. musculus in sediment cycling, sediment samples and holothurians were collected using an ROV and in situ experiments were conducted with incubation chambers. The biochemical composition of the sediment (in terms of proteins, carbohydrates and lipids), the holothurians' gut contents and holothurians' faecal material were analysed. In the sediments, proteins were the dominant organic compound, followed by carbohydrates and lipids. In the holothurian's gut contents, protein concentrations were higher than the other compounds, decreasing significantly as the material passed through the digestive tract. Approximately 33 ± 1% of the proteins were digested by the time sediment reached the mid gut, with a total digestion rate equal to 67 ± 1%. Carbohydrates and lipids were ingested in smaller amounts and digested with lower efficiencies (23 ± 11% and 50 ± 11%, respectively). As a result, the biopolymeric C digestion rate was on average 62 ± 3%. We estimated that the population of M. musculus could remove approximately 0.49 ± 0.13 g biopolymeric C and 0.13 ± 0.03 g N m −2 d −1 from the sediments. These results suggest that M. musculus plays a key role in the benthic tropho-dynamics and biogeochemical processes in the Nazaré Canyon.

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“…Hennings et al [13] showed that in a stratified two water layer system, simultaneous reductions in the near-surface water temperature and beam transmittance have been recorded, whereas fluorescence data are increased above sand waves. Quaresma et al [14] published their results concerning that the passage of each nonlinear internal wave is pumping near bottom suspended sediment to levels above the bottom nepheloid layer, therefore contributing to the measured short-period echo intensity increase in the vertical region. A good linear relationship between water depth and total suspended sediment (TSM) data derived from Moderate Resolution Imaging Spectroradiometer (MODIS) measurements above sand ridges in the southern Yellow Sea was found [15].…”

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confidence: 99%

Observed Suspended Sediment Dynamics during a Tidal Cycle above Submerged Asymmetric Compound Sand Waves

Hennings¹,

Herbers²

2016

JESE

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Abstract:The data from Acoustic Doppler Current Profiler (ADCP) of the three-dimensional current-field, echo intensity, modulation of Suspended Sediment Concentration (SSC), and related water levels and wind velocities have been analyzed as a function of water depth above submerged asymmetric compound sand waves during a tidal cycle in the Lister Tief of the German Bight in the North Sea. Signatures of vertical current component, echo intensities and calculated SSC modulations in the water column depend strongly on wind and current velocity. Bursts of vertical current component and echo intensity are triggered by sand waves itself as well as by superimposed megaripples due to current wave interaction at high current  1.0 ms -1 and wind speeds  10.0 ms -1 , preferably of opposite directions, measured at high spatial resolution. The magnitude of currents and SSC modulations during ebb and flood tidal current phases are only weakly time dependent, whereas the local magnitudes of these parameters are variable in space above the sand waves. Some hydrodynamic parameters are further investigated and analyzed, showing a consistence of ADCP measurements in the applied theory.

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Evidence of sediment resuspension by nonlinear internal waves on the western Portuguese mid-shelf

Cited by 143 publications

References 27 publications

Distribution of cold-water corals in the Whittard Canyon, NE Atlantic Ocean

Distribution of cold-water corals in the Whittard Canyon, NE Atlantic Ocean

The trophic biology of the holothurian <i>Molpadia musculus</i>: implications for organic matter cycling and ecosystem functioning in a deep submarine canyon

Observed Suspended Sediment Dynamics during a Tidal Cycle above Submerged Asymmetric Compound Sand Waves

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Evidence of sediment resuspension by nonlinear internal waves on the western Portuguese mid-shelf

Cited by 143 publications

References 27 publications

Distribution of cold-water corals in the Whittard Canyon, NE Atlantic Ocean

Distribution of cold-water corals in the Whittard Canyon, NE Atlantic Ocean

The trophic biology of the holothurian &lt;i&gt;Molpadia musculus&lt;/i&gt;: implications for organic matter cycling and ecosystem functioning in a deep submarine canyon

Observed Suspended Sediment Dynamics during a Tidal Cycle above Submerged Asymmetric Compound Sand Waves

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The trophic biology of the holothurian <i>Molpadia musculus</i>: implications for organic matter cycling and ecosystem functioning in a deep submarine canyon