Journal of Marine Science and Engineering

Research

17 pages, 8244 KiB

Open AccessArticle

High-Resolution Interannual Evolution of the Dune Toe at a Mesotidal Barrier (Camposoto Beach, SW Spain)

by Cristina Montes, Javier Benavente, María Puig, Juan Montes, Lara Talavera and Theocharis A. Plomaritis

J. Mar. Sci. Eng. 2024, 12(5), 718; https://doi.org/10.3390/jmse12050718 - 26 Apr 2024

Cited by 1 | Viewed by 1320

Abstract

Over recent years, processes related to marine storms, sediment shortages and human intervention have caused the global retreat of many coastal systems and the degradation of their dunes. In this context, changes in the dune toe are commonly used as a proxy to [...] Read more.

Over recent years, processes related to marine storms, sediment shortages and human intervention have caused the global retreat of many coastal systems and the degradation of their dunes. In this context, changes in the dune toe are commonly used as a proxy to study the interannual shoreline evolution, and it is usually analyzed using orthophotography, while high temporal- and spatial-scale resolution studies of dune toe evolution are not frequent. In this work, a quasi-monthly study of dune toe data was carried out between 2008 and 2018. These data, taken from the RTK-DGPS and UAS systems, were subjected to shoreline analysis, and they showed an average regression rate of −2.30 m/year, a higher value than the one registered until 2008 (1 m/year). This suggests an acceleration in the erosion suffered within the system, which was revealed to be more intense in the northern sector of the study area. Dune toe variability increased over the years, probably due to the presence of washover fans breaking the foredune that were reactivated and expanded during storm events. The ephemeral progradation of the dune toe was also noted, which could be explained with reference to wind events and/or beach nourishment that had been carried out over the studied period. From the analysis of the dune toe elevation, a decrease in this variable was obtained, especially in the areas affected due to washover fans. This finding is supported by the significant correlation of the dune toe elevation and erosion trend, suggesting that the areas where the dune toe was lower are prone to suffering a greater retreat. This correlation provides insight into the future evolution of the barrier, suggesting a state of degradation and a transition to a lower-resilience state. Full article

(This article belongs to the Special Issue Learning from Geomorphological Adaptation of Coasts at Different Time Scales)

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26 pages, 13635 KiB

Open AccessArticle

Mesoscale Shoreline Evolution on a Carbonate Sand Island: Anegada, British Virgin Islands

by Anna Lisa Cescon, J. Andrew G. Cooper, Derek W. T. Jackson, Antoine Collin and Shannon Gore

J. Mar. Sci. Eng. 2023, 11(9), 1725; https://doi.org/10.3390/jmse11091725 - 1 Sep 2023

Cited by 1 | Viewed by 1806

Abstract

Anegada, the easternmost island of the Virgin Islands group (Caribbean Sea), is a low Pleistocene carbonate platform surrounded by Horseshoe Reef, the world’s third-largest fringing reef. The western part of the island consists of an extensive beachridge plain (>40 ridges). The sandy carbonate [...] Read more.

Anegada, the easternmost island of the Virgin Islands group (Caribbean Sea), is a low Pleistocene carbonate platform surrounded by Horseshoe Reef, the world’s third-largest fringing reef. The western part of the island consists of an extensive beachridge plain (>40 ridges). The sandy carbonate shoreline exists in three morphodynamic domains that exhibit distinctive behaviour over the 59-year study period (1953 to 2012). The northern shore is dominated by westerly longshore drift under fair-weather conditions and cross-shore sediment transport during high-energy events. Storm wave run-up and high nearshore sediment availability contribute to the construction of shore-parallel beachridges. The western end of the island is affected by refracted waves that drive strong erosion and sediment transport. This is reflected in a succession of alternating rapid shoreline recession and progradation phases over the study period. The south–central shoreline is exposed to low wave energy and is stable and colonised by mangroves. The fringing reef plays a dominant role in mesoscale shoreline morphodynamics, both as a sediment source and in wave energy dissipation. Quasi-stable points and embayments suggest a strong influence of the reef framework in controlling the shoreline’s morphology and position. Sediment transfer from the reef to the shoreline appears to take place via shore-oblique, linear sediment transport pathways that develop across the lagoon in response to the modification of incoming waves. Cannibalisation of the shoreline sediment over the past 50 years is leading to straightening of the shoreline planform. This is counter to the long-term (Holocene) development of beachridges and suggests a change from a strongly positive to negative sediment budget. Full article

(This article belongs to the Special Issue Learning from Geomorphological Adaptation of Coasts at Different Time Scales)

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22 pages, 5534 KiB

Open AccessArticle

Hydrodynamics and Sediment-Transport Pathways along a Mixed-Energy Spit-Inlet System: A Modeling Study at Chincoteague Inlet (Virginia, USA)

by Ioannis Y. Georgiou, Francesca Messina, Md Mohiuddin Sakib, Shan Zou, Madeline Foster-Martinez, Martijn Bregman, Christopher J. Hein, Michael S. Fenster, Justin L. Shawler, Kaitlyn McPherran and Arthur C. Trembanis

J. Mar. Sci. Eng. 2023, 11(5), 1075; https://doi.org/10.3390/jmse11051075 - 18 May 2023

Cited by 3 | Viewed by 2866

Abstract

Tidal-inlet systems are dynamic features that respond to short-term (e.g., storms) and longer-term processes (e.g., sea-level rise, changes in tidal prism). The Chincoteague Inlet system, located along the northern Eastern Shore of Virginia (USA), is a dynamic coastal complex that experiences rapid change [...] Read more.

Tidal-inlet systems are dynamic features that respond to short-term (e.g., storms) and longer-term processes (e.g., sea-level rise, changes in tidal prism). The Chincoteague Inlet system, located along the northern Eastern Shore of Virginia (USA), is a dynamic coastal complex that experiences rapid change associated with sediment redistribution and a shifting inlet throat due to the southern elongation of adjacent Assateague Island. In this study, a numerical model based on Delft3D with coupled flow–waves, multiclass sediment transport, and morphologic feedback was developed to quantify the hydrodynamic and geomorphic controls within this rapidly evolving inlet–spit system and to develop a more comprehensive understanding of regional to local controls on sediment-transport pathways. Model results show that most of the sand transport along southern Assateague Island is sequestered nearshore and proximally in deeper sinks within Fishing Point, and, of that, only finer sand sizes are transported around the spit, confirming previous analysis and hypothesis. The model also showed that sand transport toward the south increases along Wallops Island and quantified spatially explicit transport trends for selected sediment classes, revealing that coarser sediment bypassing is a punctuated process that is proportional to storms. Full article

(This article belongs to the Special Issue Learning from Geomorphological Adaptation of Coasts at Different Time Scales)

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22 pages, 3459 KiB

Open AccessFeature PaperArticle

Evolutionary Trajectories of Coastal Sand Barriers along the West Portuguese Coast during the Holocene

by Susana Costas

J. Mar. Sci. Eng. 2022, 10(12), 1894; https://doi.org/10.3390/jmse10121894 - 5 Dec 2022

Cited by 4 | Viewed by 2118

Abstract

Coastal sand barriers are dynamic features with complex depositional sequences holding critical information regarding system response to disturbances at secular to millennial time scales. Here, the evolutionary trajectories of three barriers located along the Portuguese coast are reconstructed over the Middle to Late [...] Read more.

Coastal sand barriers are dynamic features with complex depositional sequences holding critical information regarding system response to disturbances at secular to millennial time scales. Here, the evolutionary trajectories of three barriers located along the Portuguese coast are reconstructed over the Middle to Late Holocene using geophysical subsurface images, modern morphology and dating of dune and beach deposits. The integration of new and available information from the documents of the selected site contrasts histories with modern barriers displaying ages ranging from hundreds to thousands of years and non-linear trajectories defined by shifts between morphological states. Younger barriers appear to represent the latest progradational state within a history of landward barrier migration, where progradational states alternated with transgressive states. Conversely, the oldest barrier shows a single phase of barrier growth, despite some minor hiatus in progradation. Barrier state shifts appear to have simultaneously occurred across systems, suggesting external drivers of regional scale linked to Holocene climate variability, namely, periods of storminess activity, while the different trajectories displayed by the three sites appear related to site-specific variables controlling exposure to waves and winds. Exposed sites showed a lower ability to absorb disturbances and a greater range of system responses, varying between transgressive and progradational states. Full article

(This article belongs to the Special Issue Learning from Geomorphological Adaptation of Coasts at Different Time Scales)

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26 pages, 19553 KiB

Open AccessArticle

Geologic Framework, Anthropogenic Impacts, and Hydrodynamics Contribute to Variable Sediment Availability and Shoreface Morphology at the Rockaway Peninsula, NY

by Emily Wei and Jennifer Miselis

J. Mar. Sci. Eng. 2022, 10(7), 989; https://doi.org/10.3390/jmse10070989 - 20 Jul 2022

Cited by 3 | Viewed by 2501

Abstract

Recent field and modeling studies have shown that barrier island resiliency is sensitive to sediment fluxes from the shoreface, making it important to evaluate how shoreface sediment availability varies in coastal systems. To do this, we assessed shoreface geology and morphology along the [...] Read more.

Recent field and modeling studies have shown that barrier island resiliency is sensitive to sediment fluxes from the shoreface, making it important to evaluate how shoreface sediment availability varies in coastal systems. To do this, we assessed shoreface geology and morphology along the Rockaway Peninsula, NY, USA. We find that spatial variability in shoreface volume is influenced by sediment accommodation above the Holocene-Pleistocene (H-P) contact, historical barrier island evolution, and natural and engineered morphologic features, suggesting that simply identifying the H-P boundary may not be adequate for defining the shoreface reservoir. Further, sediment flux from the lower shoreface to the beach may be reduced by geologically limited cross-shore sediment distribution and shoreface steepening mediated by human modifications to the shoreline. Finally, the geologic limit of the shoreface is often shallower than a wave-based estimate of shoreface extent, implying that the geologic shoreface extent at our study site can be mobilized over short time scales (years-decades) and that the wave-based shoreface extent may be inaccurate when estimating shoreline response to sea-level rise. Our results demonstrate that the combination of hydrodynamics, humans, and geology on shoreface sediment fluxes impact how barrier islands respond to future changes in sediment supply and climate. Full article

(This article belongs to the Special Issue Learning from Geomorphological Adaptation of Coasts at Different Time Scales)

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32 pages, 13436 KiB

Open AccessArticle

Late Quaternary Evolution of a Submerged Karst Basin Influenced by Active Tectonics (Koločep Bay, Croatia)

by Dragana Šolaja, Slobodan Miko, Dea Brunović, Nikolina Ilijanić, Ozren Hasan, George Papatheodorou, Maria Geraga, Tatjana Durn, Dimitris Christodoulou and Ivan Razum

J. Mar. Sci. Eng. 2022, 10(7), 881; https://doi.org/10.3390/jmse10070881 - 27 Jun 2022

Cited by 7 | Viewed by 2813

Abstract

Koločep bay is a 30 km elongated karst basin located between the Elafiti Islands and the mainland with a NW–SE general direction. The bay lies within the seismically active southern Dalmatia zone. Irregular grid sub-bottom profiles and two legacy reflection seismic profiles have [...] Read more.

Koločep bay is a 30 km elongated karst basin located between the Elafiti Islands and the mainland with a NW–SE general direction. The bay lies within the seismically active southern Dalmatia zone. Irregular grid sub-bottom profiles and two legacy reflection seismic profiles have been used to determine the overall morphology of the bay and to establish the seismic stratigraphy of its sedimentary infill. Three major seismic–stratigraphic units have been identified in the upper ~50 m of the ~120-meter-thick sedimentary sequence that lies above the karstified limestone bedrock. The karst polje basin was flooded due to sea-level rise before 12.1 kyr BP. The morphology of the bay implies complex influences of Late Glacial meltwater discharges, aeolian sand deposition, the existence of paleo–ponor/karst spring zones and buried Pleistocene river channels. The Pleistocene seismotectonic units are deformed in the NW and SE parts of the basin. The central part of the basin has no signatures of intensive tectonic activity during the Holocene. A major erosion event was identified that led to the formation of a basin within the older sedimentary infill. In the southern part of the basin, we have evidence of Holocene tectonic activity with the formation of erosional scarps on the seafloor of the bay. Full article

(This article belongs to the Special Issue Learning from Geomorphological Adaptation of Coasts at Different Time Scales)

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19 pages, 13292 KiB

Open AccessFeature PaperArticle

Following the Sand Grains

by Duncan M. FitzGerald, Zoe J. Hughes, Alice Staro, Christopher J. Hein, Md Mohiuddin Sakib, Ioannis Y. Georgiou and Alyssa Novak

J. Mar. Sci. Eng. 2022, 10(5), 631; https://doi.org/10.3390/jmse10050631 - 5 May 2022

Cited by 3 | Viewed by 3641

Abstract

When longshore transport systems encounter tidal inlets, complex mechanisms are involved in bypassing sand to downdrift barriers. Here, this process is examined at Plum Island Sound and Essex Inlets, Massachusetts, USA. One major finding from this study is that sand is transferred along [...] Read more.

When longshore transport systems encounter tidal inlets, complex mechanisms are involved in bypassing sand to downdrift barriers. Here, this process is examined at Plum Island Sound and Essex Inlets, Massachusetts, USA. One major finding from this study is that sand is transferred along the coast—especially at tidal inlets—by parcels, in discrete steps, and over decadal-scale periods. The southerly orientation of the main-ebb channel at Plum Island Sound, coupled with the landward migration of bars from the ebb delta to the central portion of the downdrift Castle Neck barrier island, have formed a beach protuberance. During the constructional phase, sand is sequestered at the protuberance and the spit-end of the barrier becomes sediment starved, leading to shoreline retreat and a broadening of the spit platform at the mouth to Essex Bay (downdrift side of Castle Neck). Storm-induced sand transport from erosion of the spit and across the spit platform is washed into Essex Bay, filling channels and enlarging flood deltas. This study illustrates the pathways and processes of sand transfer along the shoreline of a barrier-island/tidal-inlet system and provides an important example of the processes that future hydrodynamic and sediment-transport modeling should strive to replicate. Full article

(This article belongs to the Special Issue Learning from Geomorphological Adaptation of Coasts at Different Time Scales)

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24 pages, 4484 KiB

Open AccessArticle

Measuring Organization of Large Surficial Clasts in Heterogeneous Gravel Beach Sediments

by Dennis C. Lees, Christopher J. Hein and Duncan M. FitzGerald

J. Mar. Sci. Eng. 2022, 10(4), 525; https://doi.org/10.3390/jmse10040525 - 11 Apr 2022

Cited by 2 | Viewed by 2992

Abstract

The natural stratification and interlocking “organization” of armored sediments in heterogeneous, coarse-grained, beaches provides protection and enhances habitat for borrowing sedentary megafauna and macrofauna such as hard-shelled clams. Here, we develop a novel metric for quantifying sediment organization of large surficial beach clasts [...] Read more.

The natural stratification and interlocking “organization” of armored sediments in heterogeneous, coarse-grained, beaches provides protection and enhances habitat for borrowing sedentary megafauna and macrofauna such as hard-shelled clams. Here, we develop a novel metric for quantifying sediment organization of large surficial beach clasts through sedimentologic and photogrammetric analyses of 37 lower intertidal heterogeneous gravel beaches in western Prince William Sound, Alaska (USA). Grain size, photogrammetric, and Wolman Pebble Count clast-size data from 64, ~1-m² study plots are combined into a clast-size-independent “Organization Metric” to quantify the degree of organization in the meshed arrangement of larger surficial sediments. This metric was validated through field manipulation experiments and comparisons of adjacent plots characterized by different clast sizes. Application of this metric to subsets of Prince William Sound beaches that underwent differential treatment following the Exxon Valdez oil spill reveals persistent physical effects of artificial beach disturbance even 21 years after the cleanup. This has important implications for beach management (e.g., cleaning or dredging) and for the diverse and productive sedentary megafaunal assemblages that live within these sediments. Overall, this study provides a new approach for quantifying organization of heterogenous coarse sediments in diverse natural settings; in particular, heterogenous gravel beaches. Full article

(This article belongs to the Special Issue Learning from Geomorphological Adaptation of Coasts at Different Time Scales)

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