The Experts below are selected from a list of 1935 Experts worldwide ranked by ideXlab platform

Andrew J Plater - One of the best experts on this subject based on the ideXlab platform.

  • wave driven sediment resuspension and salt marsh frontal erosion alter the export of sediments from macro tidal estuaries
    Geomorphology, 2019
    Co-Authors: Nicoletta Leonardi, Andrew J Plater
    Abstract:

    Abstract The impact of wind waves and salt marsh erosion on sediment transport dynamics of macro-tidal estuarine systems has been examined using a numerical model. Morphological changes associated with salt marsh erosion facilitate the propagation of waves to the marsh edges, and increase the resuspension and export of sediments from the estuary. Results also highlight the impact of tidally-modulated changes in wave action upon sediment transport dynamics throughout a tidal cycle and from neap to spring tide. In particular, wave action at the landward margin of the estuary is limited by the shallow water depth, and tidally induced increments in water depth only cause a modest increase in wave shear stresses. At the Seaward Side of the domain, the impact of waves is limited by the deeper water, and tidally induced water level variations have a more significant control on wave shear stresses. The outcomes contribute new insights that are important for the sediment budget of macro-tidal estuaries facing climate change and have implications for the long-term morphological evolution of estuarine wetlands.

  • Wave-driven sediment resuspension and salt marsh frontal erosion alter the export of sediments from macro-tidal estuaries
    'Elsevier BV', 2019
    Co-Authors: Li X, Leonardi N, Andrew J Plater
    Abstract:

    © 2018 The Authors The impact of wind waves and salt marsh erosion on sediment transport dynamics of macro-tidal estuarine systems has been examined using a numerical model. Morphological changes associated with salt marsh erosion facilitate the propagation of waves to the marsh edges, and increase the resuspension and export of sediments from the estuary. Results also highlight the impact of tidally-modulated changes in wave action upon sediment transport dynamics throughout a tidal cycle and from neap to spring tide. In particular, wave action at the landward margin of the estuary is limited by the shallow water depth, and tidally induced increments in water depth only cause a modest increase in wave shear stresses. At the Seaward Side of the domain, the impact of waves is limited by the deeper water, and tidally induced water level variations have a more significant control on wave shear stresses. The outcomes contribute new insights that are important for the sediment budget of macro-tidal estuaries facing climate change and have implications for the long-term morphological evolution of estuarine wetlands

Nicoletta Leonardi - One of the best experts on this subject based on the ideXlab platform.

  • wave driven sediment resuspension and salt marsh frontal erosion alter the export of sediments from macro tidal estuaries
    Geomorphology, 2019
    Co-Authors: Nicoletta Leonardi, Andrew J Plater
    Abstract:

    Abstract The impact of wind waves and salt marsh erosion on sediment transport dynamics of macro-tidal estuarine systems has been examined using a numerical model. Morphological changes associated with salt marsh erosion facilitate the propagation of waves to the marsh edges, and increase the resuspension and export of sediments from the estuary. Results also highlight the impact of tidally-modulated changes in wave action upon sediment transport dynamics throughout a tidal cycle and from neap to spring tide. In particular, wave action at the landward margin of the estuary is limited by the shallow water depth, and tidally induced increments in water depth only cause a modest increase in wave shear stresses. At the Seaward Side of the domain, the impact of waves is limited by the deeper water, and tidally induced water level variations have a more significant control on wave shear stresses. The outcomes contribute new insights that are important for the sediment budget of macro-tidal estuaries facing climate change and have implications for the long-term morphological evolution of estuarine wetlands.

Cyril Marchand - One of the best experts on this subject based on the ideXlab platform.

  • Mangrove sediment carbon stocks along an elevation gradient : influence of the late Holocene marine regression (New Caledonia)
    Marine Geology, 2018
    Co-Authors: Adrien Jacotot, Cyril Marchand, Brad Rosenheim, Eugene Domack, Michel Allenbach
    Abstract:

    Among blue carbon ecosystems, mangroves are very efficient in storing carbon in their sediments over decadal to millennial time scales. However, this ability varies with numerous parameters, including climate and sea-level variations. In New Caledonia, mangrove ecosystems develop in semi-arid conditions with a typical zonation: Rhizophora spp. colonize the Seaward Side of the intertidal area, while Avicennia marina develops at higher elevations, just below the salt-flat. Within this context, we determined both the quantity (organic carbon content and carbon stocks) and the characteristics (carbon over nitrogen ratios (C/N), stable carbon and nitrogen isotopes, radiocarbon age) of the organic matter stored beneath each mangrove stands. Carbon stocks were determined down to different limits with depth: approximate extension of the root systems, one-meter depth, and the hard substrate. Within the extension of the root systems, the sediment carbon stock was lower than 100 MgC ha−1 regardless of the mangrove species. This low value resulted directly from the dry climate that limits mangrove productivity. At depth beneath every zone, a buried layer enriched in mangrove-derived organic matter, with C/N values around 40 and δ13C values around −26‰ was observed. This layer likely resulted from a sea-level high stand during the late Holocene that allowed a long period of stability of the mangrove, slowly accumulating organic matter within the sediment. In this buried layer, the carbon stock was higher than in the upper sediment and reached up to 665, 255 and 300 MgC ha−1 in the salt-flat zone, the A. marina stand and the R. spp. stand, respectively. The highest stock, determined beneath the salt-flat, was suggested to be related to a period of sea-level stability that lasted ~3000 years, whereas beneath the other zones, which are at lower elevations, mangrove colonization was more recent and the sea-level was continuously decreasing till recently. Sea-level variations, and, specifically current sea-level rise, may strongly influence mangrove development due to their migration along the tidal elevation gradient to maintain the biotic conditions needed for their development.

  • Soil carbon stocks and burial rates along a mangrove forest chronosequence (French Guiana)
    Forest Ecology and Management, 2017
    Co-Authors: Cyril Marchand
    Abstract:

    Abstract Mangroves provide a range of important ecosystem services, notably being efficient blue carbon sinks. In addition to their CO 2 fixing ability, these coastal tropical forests can store large amount of carbon in their soils due to waterlogging inducing slow rates of organic matter (OM) decomposition. The French Guiana coastline is a highly dynamic environment, characterized by a series of migrating mudbanks. Within this specific sedimentological context, only A. germinans propagules can develop at the highest elevation of mudbanks that are stabilized only for a few decades before being eroded. As a result, a clear zonation pattern, with mangrove stands of different ages paralleling the shoreline, allows the study at the same time of A. germinans forests from pioneer to mature and senescent stands. The unique characteristic of this system is the isolation of the older mangroves from the sea, being situated more than 2 km from the shoreline, which limits sedimentation and allochthonous inputs. Within the studied chronosequence, soil carbon stocks and carbon burial rates of each mangrove stand were determined. The thickness of the pedogenetic layer, enriched in autochthonous OM, reached an asymptote (∼45 cm) for the mixed mature and senescent forests (>40 years old), probably as a result of the asymptote reached by the net primary productivity (NPP) and low sedimentation rates. The organic carbon stock in the pedogenetic layers increased linearly with forest age, from 4 to 107 Mg OC ha −1 in pioneer and senescent stages, respectively. Consequently, conSidering only the pedogenetic layers, enriched with the OM derived from the current forest, soil organic carbon (SOC) stocks are limited. It is suggested that tidal export of the NPP may balance low mineralization rates induced by waterlogging, at least for the stand the closest to the sea. The mean carbon burial rate for this system was 2.3 Mg OC ha −1  yr −1 , with values ranging from 0.72 to 4.86 Mg OC ha −1  yr −1 depending on forest age and position of the stand in the tidal zone. The latter, either promoting tidal flushing and tidal pumping on the Seaward Side of the mangrove, or the development of associated mangrove species on the landward Side due to freshwater proximity and low sedimentation rates, influenced organic accumulation in soils.

Michel Allenbach - One of the best experts on this subject based on the ideXlab platform.

  • Mangrove sediment carbon stocks along an elevation gradient : influence of the late Holocene marine regression (New Caledonia)
    Marine Geology, 2018
    Co-Authors: Adrien Jacotot, Cyril Marchand, Brad Rosenheim, Eugene Domack, Michel Allenbach
    Abstract:

    Among blue carbon ecosystems, mangroves are very efficient in storing carbon in their sediments over decadal to millennial time scales. However, this ability varies with numerous parameters, including climate and sea-level variations. In New Caledonia, mangrove ecosystems develop in semi-arid conditions with a typical zonation: Rhizophora spp. colonize the Seaward Side of the intertidal area, while Avicennia marina develops at higher elevations, just below the salt-flat. Within this context, we determined both the quantity (organic carbon content and carbon stocks) and the characteristics (carbon over nitrogen ratios (C/N), stable carbon and nitrogen isotopes, radiocarbon age) of the organic matter stored beneath each mangrove stands. Carbon stocks were determined down to different limits with depth: approximate extension of the root systems, one-meter depth, and the hard substrate. Within the extension of the root systems, the sediment carbon stock was lower than 100 MgC ha−1 regardless of the mangrove species. This low value resulted directly from the dry climate that limits mangrove productivity. At depth beneath every zone, a buried layer enriched in mangrove-derived organic matter, with C/N values around 40 and δ13C values around −26‰ was observed. This layer likely resulted from a sea-level high stand during the late Holocene that allowed a long period of stability of the mangrove, slowly accumulating organic matter within the sediment. In this buried layer, the carbon stock was higher than in the upper sediment and reached up to 665, 255 and 300 MgC ha−1 in the salt-flat zone, the A. marina stand and the R. spp. stand, respectively. The highest stock, determined beneath the salt-flat, was suggested to be related to a period of sea-level stability that lasted ~3000 years, whereas beneath the other zones, which are at lower elevations, mangrove colonization was more recent and the sea-level was continuously decreasing till recently. Sea-level variations, and, specifically current sea-level rise, may strongly influence mangrove development due to their migration along the tidal elevation gradient to maintain the biotic conditions needed for their development.

Adrien Jacotot - One of the best experts on this subject based on the ideXlab platform.

  • Mangrove sediment carbon stocks along an elevation gradient : influence of the late Holocene marine regression (New Caledonia)
    Marine Geology, 2018
    Co-Authors: Adrien Jacotot, Cyril Marchand, Brad Rosenheim, Eugene Domack, Michel Allenbach
    Abstract:

    Among blue carbon ecosystems, mangroves are very efficient in storing carbon in their sediments over decadal to millennial time scales. However, this ability varies with numerous parameters, including climate and sea-level variations. In New Caledonia, mangrove ecosystems develop in semi-arid conditions with a typical zonation: Rhizophora spp. colonize the Seaward Side of the intertidal area, while Avicennia marina develops at higher elevations, just below the salt-flat. Within this context, we determined both the quantity (organic carbon content and carbon stocks) and the characteristics (carbon over nitrogen ratios (C/N), stable carbon and nitrogen isotopes, radiocarbon age) of the organic matter stored beneath each mangrove stands. Carbon stocks were determined down to different limits with depth: approximate extension of the root systems, one-meter depth, and the hard substrate. Within the extension of the root systems, the sediment carbon stock was lower than 100 MgC ha−1 regardless of the mangrove species. This low value resulted directly from the dry climate that limits mangrove productivity. At depth beneath every zone, a buried layer enriched in mangrove-derived organic matter, with C/N values around 40 and δ13C values around −26‰ was observed. This layer likely resulted from a sea-level high stand during the late Holocene that allowed a long period of stability of the mangrove, slowly accumulating organic matter within the sediment. In this buried layer, the carbon stock was higher than in the upper sediment and reached up to 665, 255 and 300 MgC ha−1 in the salt-flat zone, the A. marina stand and the R. spp. stand, respectively. The highest stock, determined beneath the salt-flat, was suggested to be related to a period of sea-level stability that lasted ~3000 years, whereas beneath the other zones, which are at lower elevations, mangrove colonization was more recent and the sea-level was continuously decreasing till recently. Sea-level variations, and, specifically current sea-level rise, may strongly influence mangrove development due to their migration along the tidal elevation gradient to maintain the biotic conditions needed for their development.