Environmental conditions for gravelly and pebbly dunes and sorted bedforms on a moderate-energy inner shelf (Marettimo Island, Italy, western Mediterranean)

Iacono, Claudio Lo; Guillén, Jorge

doi:10.1016/j.csr.2007.08.005

Cited by 20 publications

(15 citation statements)

References 49 publications

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“…2c). These features have been identified as rippled scour depressions, or sorted bedforms as observed elsewhere (Cacchione et al, 1984;Thieler et al, 1995;Ferrini and Flood, 2005;Diesing et al, 2006;Lo Iacono and Guillén, 2008). As commented upon above, these bedforms are present as slightly depressed, elongate features, consisting of gravelly and sandy gravel sediments; these form, usually, ripples and dunes lying adjacent to medium to fine sand bodies (Fig.…”

Section: Seascapes On the Continental Shelfmentioning

confidence: 87%

Morphological characteristics of the Basque continental shelf (Bay of Biscay, northern Spain); their implications for Integrated Coastal Zone Management

et al. 2010

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Section: Seascapes On the Continental Shelfmentioning

confidence: 87%

Morphological characteristics of the Basque continental shelf (Bay of Biscay, northern Spain); their implications for Integrated Coastal Zone Management

et al. 2010

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“…The height of flow-transverse bedforms ranges from less than one meter to tens of meters and their wavelengths from tens to hundreds of meters (Ashley, 1990). The main forcing mechanism for the generation and evolution of marine subaqueous dunes is often related to tidal currents (Hulscher, 1996;van Landeghem et al, 2009, among others), although the development of dunefields has also been observed in microtidal and even tideless continental shelves associated with wind-induced currents (Kubicki, 2008), storm events (Li and King, 2007;Lo Iacono and Guillén, 2008), geostrophic currents (Flemming, 1978;Green, 2009) and strong currents favored by topographic constrictions (Grochowski et al, 1993;Le Bot and Trentesaux, 2004;Daniell and Hughes, 2007;Lo Iacono et al, 2010). The shape of subaqueous dunes is symmetric when they are dominated by bidirectional flows and asymmetric when a preferential migration associated with unidirectional currents occurs.…”

Section: Introductionmentioning

confidence: 98%

Sediment dynamics over sand ridges on a tideless mid-outer continental shelf

et al. 2015

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“…The bedforms then help to maintain the RSD by disrupting the laminar flow of water and creating a localized turbulence which resuspends fine sediment (Murray & Thieler 2004). While RSDs have been described from many parts of the world and are abundant on the inner continental shelf, the majority of research has focused on the physical character and geomorphic dynamics of these habitat features (Garnaud et al 2005, Gutierrez et al 2005, Lo Iacono & Guillen 2008, Bellec et al 2010. As a result, little is known about the biological communities associated with or the ecological importance of RSDs.…”

Section: Resale or Republication Not Permitted Without Written Consenmentioning

confidence: 99%

“…1) have been identified and physically described in small-scale studies on many of the world's continental shelves (Garnaud et al 2005, Gutierrez et al 2005, Lo Iacono & Guillen 2008, Bellec et al 2010. These elongate shallow depressions (0.3 to 1 m in depth), oriented normal to isobathic contours, are characterized by long crested bedforms (0.5 to 1 m wavelength), coarse sediment (0.3 to 1 mm), and abundant shell hash.…”

Section: Introductionmentioning

confidence: 99%

Rippled scour depressions add ecologically significant heterogeneity to soft-bottom habitats on the continental shelf

Hallenbeck¹,

Kvitek²,

Lindholm³

2012

Mar. Ecol. Prog. Ser.

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Comprehensive mapping of California's state waters has revealed rippled scour depressions (RSDs) to be abundant and widespread on the inner continental shelf. Ranging from 100s to 1000s of m 2 in areal extent, RSDs are 30 to 50 cm deep depressions of coarser sediments and longer period bedforms than found on the surrounding seabed. Although RSDs have been physically described on many continental margins, previous studies have not addressed the ecological influence and associated biological communities of RSDs. Here, we test the hypothesis that there are ecologically important differences in the distribution and abundance of benthic fish and invertebrate groups inside and outside RSDs. A small ROV was used to survey 20 RSDs in 3 depth zones (<15 m, 15 to 30 m, and > 30 m) within Monterey Bay, California. Density and richness of benthic communities were determined from the recorded video imagery. Sediment grab samples confirmed significantly larger mean grain sizes inside (0.71 mm) than outside (0.22 mm) the RSDs. Overall mean faunal density (fish and invertebrates) was lower inside RSDs in the shallow, intermediate, and deep zones (0.32, 1.61, and 2.17 ind. 10 m −2 respectively) than outside (0.38, 3.06, and 4.48 ind. 10 m ). Surprisingly, RSDs did contain significantly more young-of-the-year rockfishes and small flatfishes than adjacent fine sediments, suggesting a possible nursery function for these otherwise depauperate coarsegrained habitats. These results indicate that RSDs can add a significant and previously undescribed level of ecological patchiness to soft sediment communities on the continental shelf. KEY WORDS: Rippled scour depressions · Continental shelf · Marine spatial planning · ROV · Soft sediment · Benthic ecology · Sorted bedforms · Sebastes Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 468: [119][120][121][122][123][124][125][126][127][128][129][130][131][132][133] 2012 1978, Auster et al. 1991, Zajac et al. 1998, Auster et al. 2003b, Diaz et al. 2003, Lindholm et al. 2007, Stoner et al. 2007.Rippled scour depressions (RSDs; Fig. 1) have been identified and physically described in small-scale studies on many of the world's continental shelves (Garnaud et al. 2005, Gutierrez et al. 2005, Lo Iacono & Guillen 2008, Bellec et al. 2010. These elongate shallow depressions (0.3 to 1 m in depth), oriented normal to isobathic contours, are characterized by long crested bedforms (0.5 to 1 m wavelength), coarse sediment (0.3 to 1 mm), and abundant shell hash. RSDs have been found in water depths of 15 to 160 m with reported dimensions of 30 to 250 m wide and 100 to 3000 m long (Cacchione et al. 1984, Bellec et al. 2010. The sediments surrounding RSDs are typically characterized by finer grain size (0.05 to 0.3 mm), shorter period bedforms, and a sharp edge delineating the coarser-grained RSDs (Green et al. 2004, Goff et al. 2005, Diesing et al. 2006. Further, RSDs can be persistent, with their spatial extent and boundaries remaining stable fo...

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Environmental conditions for gravelly and pebbly dunes and sorted bedforms on a moderate-energy inner shelf (Marettimo Island, Italy, western Mediterranean)

Cited by 20 publications

References 49 publications

Morphological characteristics of the Basque continental shelf (Bay of Biscay, northern Spain); their implications for Integrated Coastal Zone Management

Morphological characteristics of the Basque continental shelf (Bay of Biscay, northern Spain); their implications for Integrated Coastal Zone Management

Sediment dynamics over sand ridges on a tideless mid-outer continental shelf

Rippled scour depressions add ecologically significant heterogeneity to soft-bottom habitats on the continental shelf

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