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1.
Harm Jan Pierik Jelle I. M. Moree Karianne M. van der Werf Lonneke Roelofs Marcio Boechat Albernaz Antoine Wilbers Bert van der Valk Marieke van Dinter Wim Z. Hoek Tjalling de Haas Maarten G. Kleinhans 《Sedimentology》2023,70(1):179-213
In the transformation from tidal systems to freshwater coastal landscapes, plants act as eco-engineering species that reduce hydrodynamics and trap sediment, but nature and timing of the mechanisms of land creation along estuaries remains unclear. This article focuses on the Old Rhine estuary (The Netherlands) to show the importance of vegetation in coastal landscape evolution, predominantly regarding tidal basin filling and overbank morphology. This estuary hosted the main outflow channel of the river Rhine between ca 6500 to 2000 cal bp , and was constrained by peat during most of its existence. This study reconstructs its geological evolution, by correlating newly integrated geological data and new field records to varying conditions. Numerical modelling was performed to test the inferred mechanisms. It was found that floodbasin vegetation and resulting organic accumulation strongly accelerated back-barrier infill, by minimizing tidal influence. After tidal and wave transport had already sufficiently filled the back-barrier basin, reed rapidly expanded from its edges under brackish conditions, as shown by diatom analysis and datings. Reed growth provided a positive infilling feedback by reducing tidal flow and tidal prism, accelerating basin infilling. New radiocarbon dates show that large-scale crevassing along the Old Rhine River – driven by tidal backwater effect – only started as nutrient-rich river water transformed the floodbasin into an Alder carr in a next phase of estuary evolution. Such less dense vegetation promotes crevassing as sediments are more easily transported into the floodbasin. As river discharge increased and estuary mouth infilling progressed, crevasse activity diminished around 3800 to 3000 cal bp , likely due to a reduced tidal backwater effect. The insights from this data-rich Holocene study showcase the dominant role that vegetation may have in the long-term evolution of coastal wetlands. It provides clues for effective use of vegetation in vulnerable wetland landscapes to steer sedimentation patterns to strategically adapt to rising water levels. 相似文献
2.
Multiplatform observation of the surface circulation in the Gulf of Naples (Southern Tyrrhenian Sea) 总被引：1，自引：1，他引：0
Marco Uttieri Daniela Cianelli Bruno Buongiorno Nardelli Berardino Buonocore Pierpaolo Falco Simone Colella Enrico Zambianchi 《Ocean Dynamics》2011,61(6):779-796
The Gulf of Naples (Southern Tyrrhenian Sea) is a highly urbanised area, where human activities and natural factors (e.g.
river runoff, exchanges with adjacent basins) can strongly affect the water quality. In this work we show how surface transport
can influence the distribution of passively drifting surface matter, and more in general if and how the circulation in the
basin can promote the renovation of the surface layer. To this aim, we carried out a multiplatform analysis by putting together
HF radar current fields, satellite images and modelling tools. Surface current fields and satellite images of turbidity patterns
were used to initialise and run model simulations of particle transport and diffusion. Model results were then examined in
relation to the corresponding satellite distributions. This integrated approach permits to investigate the concurrent effects
of surface dynamics and wind forcing in determining the distribution of passive tracers over the basin of interest, identifying
key mechanisms supporting or preventing the renewal of surface waters as well as possible areas of aggregation and retention. 相似文献
3.
Simone Simeone Emanuela Molinaroli Alessandro Conforti Giovanni De Falco 《Climatic change》2018,150(3-4):227-242
The production of sediments by carbonate-producing ecosystems is an important input for beach sediment budgets in coastal areas where no terrigenous input occurs. Calcifying organisms are a major source of bioclastic carbonate sediment for coastal systems. Increased levels of CO2 in the atmosphere are leading to an increase in the partial pressure of CO2 on ocean seawater, causing ocean acidification (OA), with direct consequences for the pH of ocean waters. Most studies of OA focus on its impact on marine ecosystems. The impact of OA on carbonate-producing ecosystems could be to reduce the amount of sediments supplied to temperate coastal systems. The aim of this study was to quantify the effect of the predicted OA on the long-term sediment budget of a temperate Mediterranean mixed carbonate beach and dune system. Based on projections of OA we estimated a fall of about 31% in the present bioclastic carbonate sediment deposition rate, with the biggest decreases seen in the dunes (? 46%). OA is also expected to affect the carbonate sediment reservoirs, increasing the dissolution of CaCO3and causing net sediment loss from the system (~ 50,000 t century?1). In the long-term, OA could also play a primary role in the response of these systems to sea-level rise. Indeed, the reduction in the quantity of carbonate sediments provided to the system may affect the speed with which the system is able to adapt to sea-level rise, by increasing wave run-up, and may promote erosion of dunes and subaerial beaches. 相似文献
4.
Matteo Vacchi Giovanni De Falco Simone Simeone Monica Montefalcone Carla Morri Marco Ferrari Carlo Nike Bianchi 《地球表面变化过程与地形》2017,42(1):42-54
Here we review the multiple interactions between the endemic Mediterranean seagrass, Posidonia oceanica, and coastal geomorphologic processes as an outstanding example of biogeomorphology, taking into account recent advances in the field. Seagrass meadows are among the most important elements for the functioning of marine coastal ecosystems, and represent a major focus for research and conservation. Being considered a priority habitat, P. oceanica meadows are protected by several European Union directives and national laws. In this paper we examine: the role of sedimentary features in controlling the development of the meadows; the interplay between P. oceanica leaf litter (i.e. beached necromass) cast ashore and erosional‐depositional processes on the beaches; the interactions between meadows and nearshore hydrodynamics, and; possible linkages between geomorphological features of the seafloor and the architecture of meadows. Finally, we provide perspectives for future research on P. oceanica and other Mediterranean seagrass meadows in a biogeomorphological context with specific reference to climate change. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
5.
Emanuela Molinaroli Giovanni De Falco Sandro Rabitti Rosana Asunta Portaro 《Sedimentary Geology》2000,130(3-4):269-281
Surface and deep-sea core sediments and two sets of standards were measured by three different techniques — Galai Cis-1 laser system, Coulter Counter TA II, and Micromeritics SediGraph 5000D — in order to compare the Galai results with the other two. The differences between the three types of measuring device turned out to be greater in sediments than in standards, and were attributed to the physical properties, shape, density and composition of the particles (complexity of the matrix). Comparison of moment statistics showed that the Galai determines coarser grain sizes than the Coulter and finer than the SediGraph, particularly as regards analysis of surface sediments. The relationships between Galai and SediGraph were estimated using analysis of variation/residuals within individual intervals. The analysis showed a higher variability of residuals for the coarser fractions (8–16 μm and 16–32 μm) with respect to the finer (2–4 μm and 4–8 μm) fractions. The <2 μm SediGraph fraction, with a cut-off at 0.49 μm, showed good correspondence with the <2.5 μm Galai analysis. 相似文献
6.
Francesca Budillon Alessandro Conforti Renato Tonielli Giovanni De Falco Gabriella Di Martino Sara Innangi Ennio Marsella 《Marine Geophysical Researches》2011,32(1-2):83-97
The Bulgheria canyon-fan system in the eastern Tyrrhenian Sea displays well-developed, small-scale, fluvial-like features and has formed alongside the northern slope of the Sapri peri-Tyrrhenian basin. This study reveals, for the first time, the morphology and course of the present-day system as well as the buried elements based on a Digital Terrain Model and high-resolution seismic profiles interpretation. Two adjacent canyons (Infreschi and Luna) originate in the Cilento outer shelf at a short distance from each other and feed an intraslope basin fan through two main sub-parallel channels that run about 12 and 8 km, respectively. Channel and levee development seems to be controlled primarily by the local slope gradient and by Coriolis forces that induce a faster vertical growth of the right-side features, as is often observed in the Northern Hemisphere. Centrifugal forces, on the other hand, have induced episodic flow-stripping at the meander loops and bends, causing local destruction of the main channel levees rather than new levee growth at the outer bends. Overbank deposits are associated with overspill turbidite deposition in the mid fan where a topographic constraint occurs, whereas large-sediment, low-angle wave fields are mainly developed on the outer fan. Buried features and relict morphologies suggest that the Infreschi channel experienced at least two phases of re-incision since the final stages of the middle Pleistocene. Local re-adjustment of outer lobe growth due to channel avulsion and meander abandonment is possibly a consequence of relative base-level fluctuations. The sedimentary record of the mid and outer fan includes outrun mass wasting deposits from extensive failures of the Sapri slope. Indeed, a marked scar is present on the eastern side of the modern outer lobe that indicates the persistency of mass flow passages up to recent times. In addition to the environmental factors that are currently considered to cause canyon formation on the shelf margin, this study proposes the possibility that the head canyon branch close to the mainland was incised by massive and persistent underground freshwater flow from the adjacent aquifer when the sea-level was lower than at present. 相似文献
7.
Giovanni De Falco Sandro De Muro Tiziana Batzella Andrea Cucco 《Estuarine, Coastal and Shelf Science》2011
The sedimentary features of the inner-middle shelf of the strait of Bonifacio (western Mediterranean) were analyzed to evaluate the relationship between the production and transport of biogenic carbonate sediments and the basin morphology and hydrodynamics. A three-dimensional hydrodynamic modeling was performed in order to simulate the influence of waves and currents at seabed level. Superficial sediments were collected at depths ranging from 5 to 80 m and were analyzed for grain size, mineralogical composition and skeletal carbonate composition. Posidonia oceanica seagrass meadows border the coasts in a narrow strip on both sides of the strait down to a depth of 40 m. At greater depths, the seabed is characterized by the presence of plateaus and ridges which are controlled by outcropping bedrock morphology. 相似文献
8.
Coronato Tanea Carril Andrea F. Zaninelli Pablo G. Giles Julián Ruscica Romina Falco Magdalena Sörensson Anna A. Fita Lluis Li Laurent Z. X. Menéndez Claudio G. 《Climate Dynamics》2020,55(9-10):2543-2556
Based on a series of experiments conducted by two regional climate models (RCA4 and LMDZ) with and without soil moisture-atmosphere coupling, we investigate the role of soil moisture on the occurrence of surface air temperature extremes and its persistence in Southeastern South America. Our analysis reveals that both factors, soil moisture-atmosphere coupling and relatively drier soil conditions, enhance the temperature extremes. In addition, the existence of soil-atmosphere coupling and the associated soil moisture variability is crucial for the development of the extremes in SESA. The key role of soil-atmosphere coupling is also reflected in the intrinsic persistence of hot days, which is greater in simulations with interactive soil moisture than in those with prescribed soil conditions. In the absence of soil-atmosphere coupling, the imprint of the anomalous dry (and also wet) soil conditions on the intensity and persistence of hot days is weaker.
相似文献9.
10.
Volume estimate of flow-type landslides along carbonatic and volcanic slopes in Campania (Southern Italy) 总被引：1，自引：0，他引：1
Recent studies on flow-type landslides in pyroclastic deposits have been performed to identify potential source areas and
the main depositional mechanisms. Interesting methods for mapping landslide susceptibility have also been proposed. Since
the potential volume of flow-type landslides is a measure of event magnitude, hence of considerable use in hazard assessment,
we propose a method to estimate the potential volume for the morphometric analysis of 213 flow-like landslides occurred in
Campania in recent centuries. First, our data show that the height, H, of the detachment and erosion-transport zones (i.e. the difference in height between the top of source area and a point,
the first break at the foot of the slope, where the deposition stars to take place and the landslide loses velocity) and the
area, A
f, of the same zones are linked by a mathematical function. Secondly, only part of the entire thickness of the pyroclastic
material on the slope is involved. To define the potential volumes of the flow-type landslides, we analysed slopes, both in
volcanic and carbonatic contexts, considering both channelled and unchannelled flow-type landslides. The most susceptible
areas are identified by using a landslide-triggering susceptibility map, and then in each case the height H was estimated. This height is the difference in level between the point on the slope with highest susceptibility and the
first break at the foot of the slope. Using the statistical correlation between H and A
f, both calculated for historical landslides, we evaluate the area of a potential landslide on a slope. Finally, potential
volumes are calculated by using A
f and a constant thickness of the pyroclastic cover for the whole slope. This method could represent a useful tool to detect
the main areas where risk mitigation works are required. 相似文献