scholarly journals Long-term morphological evolution of funnel-shape tide-dominated estuaries

2008 ◽  
Vol 113 (C5) ◽  
Author(s):  
Ilaria Todeschini ◽  
Marco Toffolon ◽  
Marco Tubino
Keyword(s):  
Morphological Evolution

scholarly journals On the Relation between Beach-Dune Dynamics and Shoal Attachment Processes: A Case Study in Terschelling (NL)

2020 ◽  
Vol 8 (7) ◽  
pp. 541
Author(s):  
Filipe Galiforni-Silva ◽  
Kathelijne M. Wijnberg ◽  
Suzanne J. M. H. Hulscher
Keyword(s):  
Morphological Evolution ◽  
Coastal Dunes ◽  
Annual Data ◽  
Aeolian Transport ◽  
Cellular Automata Model ◽  
Beach Width ◽  
Ebb Tidal Delta ◽  
Dune Dynamics

Inlet-driven processes are capable of modifying the adjacent shoreline. However, few studies have attempted to understand how these changes affect coastal dunes. The present study aims to understand how shoreline changes induced by shoal attachment affect coastal dunes. A barrier island in the Netherlands is used as a case study. Both bathymetric and topographic annual data were analysed, together with the application of a cellular automata model for dune development. The objective of the model is to explore idealised scenarios of inlet-driven shoreline movements. With the model, ten different scenarios were examined regarding beach width increase and rate of alongshore spreading of the shoal. Field data showed that, for the case study, dune volume and shoal attachments could not be directly linked. Instead, rates of dune volume change differed significantly only due to long-term ebb-tidal delta evolution. Such morphological evolution oriented the beach towards the main wind direction, increasing overall aeolian transport potential. Modelling results showed that shoals significantly increased dune volumes only on three out of ten scenarios. This suggests that beach width increase, and rate of alongshore sediment spreading, determine whether the shoal will influence dune growth. Therefore, within the studied time-scale, local rates of dune growth are only increased if shoals are capable of increasing the beach width significantly and persistently.

Empirical modelling of beach evolution: implementation of coupled cross-shore and longshore approaches

2020 ◽  
Author(s):  
Teddy Chataigner ◽  
Marissa Yates ◽  
Nicolas Le Dantec
Keyword(s):  
Morphological Evolution ◽  
Computational Cost ◽  
Sandy Beaches ◽  
Sediment Flux ◽  
Beach Profile ◽  
Change Models ◽  
Empirical Modelling ◽  
Spatial And Temporal Scales ◽  
Shoreline Evolution

<p>Understanding shoreline evolution, and in particular, the consequences of shoreline erosion is a<br>major societal concern that threatens to become even more important in the future with the impacts<br>of climate change. Thus, it is necessary to improve both knowledge of the dominant physical processes<br>controlling medium to long-term shoreline evolution and the capabilities of morphological evolution<br>models to simulate beach changes at these spatial and temporal scales.<br>Empirical models may be an ideal choice for modelling complex and dynamic environments such as<br>sandy beaches at large spatial (beach) and long temporal (years to decades) scales. They reproduce<br>the effects of the main morphodynamical processes with low computational cost and relatively high<br>accuracy, in particular when high quality, long-term data are available for calibration.<br>Here, to broaden its range of application, a cross-shore equilibrium model, which has demon-<br>strated its accuracy and efficiency in reproducing shoreline and intertidal beach profile changes at<br>several micro and macrotidal beaches, is extended to couple it with a longshore beach evolution<br>modelling approach. The selection of a particular longshore model (based on a one-line approach),<br>and its implementation and validation with benchmark test cases of shoreline evolution caused by<br>the effects of diffusion, high angle wave instabilities, and coastal structures are presented.<br>The new hybrid model is applied at Narrabeen beach to reproduce the long-term evolution of<br>beach contours near the shoreline. The model is calibrated and tested using the 40-year timeseries of<br>monthly subaerial beach profile surveys conducted along 5 cross-shore profiles along the 3.6km-long<br>Narrabeen-Collaroy embayment. The novelty of the current work is to focus on reproducing changes<br>at different altitudes, with the objective of assessing the cross-shore variability of the longshore<br>sediment flux, which is assumed constant in most one-line longshore transport models. The coupled<br>model performance is discussed, and the results are compared to existing studies that have simulated<br>shoreline evolution at Narrabeen using other morphological change models.</p>

scholarly journals Long-term molecular evolutionary rate determines intraspecific genetic diversity

2019 ◽  
Author(s):  
Jiaqi Wu ◽  
Takahiro Yonezawa ◽  
Hirohisa Kishino
Keyword(s):  
Genetic Diversity ◽  
De Novo ◽  
Early Stage ◽  
Morphological Evolution ◽  
Biological Traits ◽  
Gene Trees ◽  
Intraspecific Genetic Diversity ◽  
Molecular Evolutionary Rates ◽  
Species Specific

AbstractWhat determines genetic diversity and how it connects to the various biological traits is unknown. In this work, we offer answers to these questions. By comparing genetic variation of 14,671 mammalian gene trees with thousands of individual genomes of human, chimpanzee, gorilla, mouse and dog/wolf, we found that intraspecific genetic diversity is determined by long-term molecular evolutionary rates, rather than de novo mutation rates. This relationship was established during the early stage of mammalian evolution. Expanding this new finding, we developed a method to detect fluctuations of species-specific selection on genes as the deviations of intra-species genetic diversity predicted from long-term rates. We show that the evolution of epithelial cells, rather than of connective tissue, mainly contributes to morphological evolution of different species. For humans, evolution of the immune system and selective sweeps subjected by infectious diseases are most representative of adaptive evolution.

scholarly journals LONG TERM MORPHOLOGICAL EVOLUTION OF THE GOLD COAST SEAWAY: HISTORICAL AND NUMERICAL ANALYSIS

2012 ◽  
Vol 1 (33) ◽  
pp. 28 ◽  
Author(s):  
Mahnaz Sedigh ◽  
Rodger Tomlinson ◽  
Aliasghar Golshani ◽  
Nick Cartwright
Keyword(s):  
East Coast ◽  
Morphological Evolution ◽  
Gold Coast ◽  
Shoreline Erosion ◽  
Tidal Inlets ◽  
The North ◽  
Beach Width ◽  
The Pacific ◽  
The Pacific Ocean

The Gold Coast Seaway is one of two main tidal inlets located on the Australian East coast at a longitude of 27°56’10S and a latitude of 153°25’60E linking an intra-coastal waterway known as The Broadwater with the Pacific Ocean.. The reasons for construction of the Gold Coast Seaway and the associated sand by-passing system in the 1980s were stabilising the entrance, maintaining a safe navigable channel, preventing shoreline erosion to the north and maintaining an adequate beach width to the south.

scholarly journals Long-term morphological evolution of urban pocket beaches in Montevideo (Uruguay): impacts of coastal interventions and links to climate forcing

2015 ◽  
Vol 15 (4) ◽  
pp. 467-484 ◽  
Author(s):  
Ofelia Gutiérrez ◽  
Daniel Panario ◽  
Gustavo J. Nagy ◽  
Gustavo Piñeiro ◽  
Carlos Montes
Keyword(s):  
Morphological Evolution ◽  
Climate Forcing

THE EFFECT OF STOCHASTICALLY SIMULATED STORM-INDUCED BREACHES ON THE LONG-TERM MORPHOLOGICAL EVOLUTION OF BARRIER COASTS

2019 ◽  
Author(s):  
K.R.G. REEF ◽  
P.C. ROOS ◽  
T.E. ANDRINGA ◽  
A. DASTGHEIB ◽  
S.J.M.H. HULSCHER
Keyword(s):  
Morphological Evolution

An unusual pattern of divergence between two fossil gastropods: ecophenotypy, dimorphism, or hybridization?

Paleobiology ◽  
1992 ◽  
Vol 18 (1) ◽  
pp. 93-109 ◽  
Author(s):  
Dana H. Geary
Keyword(s):  
Genetic Basis ◽  
Pannonian Basin ◽  
Morphological Changes ◽  
Morphological Evolution ◽  
Single Species ◽  
Morphological Divergence ◽  
Temporal Dimension ◽  
Species Formation ◽  
Fossil Gastropods

The temporal dimension of fossil sequences provides a critical component to the study of intraspecific dynamics and species formation. Here I report on the branching and subsequent morphological evolution of two gastropods (Melanopsis fossilis and M. vindobonensis) from the Late Miocene of the Pannonian basin in eastern and central Europe. Although morphological divergence between species is rapid, intermediates between the two species co-occur with typical individuals for approximately 1 m.y. and then disappear. The long-term persistence of intermediates followed by their ultimate disappearance is a pattern that, to my knowledge, has not been previously observed.Distinguishing genetic from ecophenotypic influences on shell form in freshwater prosobranchs is difficult. Nevertheless, consideration of the temporal, geographic, lithologic, and paleoecologic patterns of this sequence suggests that the morphologic differences between M. fossilis and M. vindobonensis had some genetic basis. Whether these forms were initially morphs of a single species or two species with some hybridization between them is impossible to determine. In either case, the morphological changes that resulted in M. vindobonensis were rapid, but the attainment of complete isolation between M. fossilis and M. vindobonensis apparently did not occur until approximately 1 m.y. later.

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