Shoreline Features Research Articles

Behavioral hotspots of bottlenose dolphins in industrialized ship channels

Anthropogenic activity in coastal areas can damage marine habitats and alter marine mammal behavior and habitat use. Understanding behavioral associations with diverse habitat features in industrialized coastal areas is crucial for marine mammal conservation management. A shore-based digital theodolite was used to assess the behavioral states and habitat use of common bottlenose dolphins (Tursiops truncatus) off Port Aransas, Texas across seasons. The relationship between behavioral states and environmental and geographical variables were analyzed. Behavioral hotspots were identified. Dolphins frequently foraged (46%), indicating the area is an important feeding ground. Dolphins also traveled (25%) and milled (22%), with less frequent occurrences of socializing (6%) and resting (1% of observations). Season, time of day, and distance to shoreline were significant predictors of foraging and traveling behavioral states. Dolphins engaged in all behavioral states closer to seawall shorelines than to mangroves and natural seagrass beds, suggesting that hard shoreline features may influence daily activity patterns. Despite daily anthropogenic operations, bottlenose dolphins use features of the industrialized area (i.e., deeply dredged channels, human-engineered seawalls) to engage in a variety of behaviors. Monitoring of dolphin behavioral states and habitat use in active ship channels are needed to assess changes from baseline data from increasing coastal development and vessel activities.

Disentangling late quaternary fluvial and climatic drivers of palaeohydrological change in the Najaf Sea basin, Western Iraq

AbstractThe water resource provided by lake basins in the western desert of Iraq is important for human occupation of areas outside the Tigris‐Euphrates floodplain, both in the past and into the future. This paper presents the first geomorphological and geochronological study of the date of formation of the Najaf Sea and the only such study of any lake basin to the west of Mesopotamia. Geomorphological shoreline features and a palaeochannel linking to the Euphrates were studied and dated using optically stimulated luminescence (OSL) and radiocarbon dating. Provenance was determined using heavy mineral analysis. Past environments in the Najaf Sea were reconstructed by molluscan analysis. The earliest OSL ages date from c. 30 000 and 22 000 years ago and seem to predate lake formation. Younger OSL ages date the highest lake level at c. 19 m asl to between 1620–1760 AD (base) to 1906–1974 AD (near surface). The radiocarbon ages are affected by a freshwater reservoir effect, but the maximum ages recorded for either of the c. 15 m and c. 17 m asl shorelines are c. 800 cal. BC. This predates the first archaeological sites in the Najaf basin and is similar to maximum ages of c. 850 and c. 1100 cal. BC from the associated palaeochannel. This timing does not seem to be linked to a humid climate event. We therefore conclude that the establishment of the Najaf Sea in the Najaf basin occurred as a result of an avulsion event within the Euphrates system that diverted flow to the basin. The trigger for this avulsion event likely related to rapid sediment accumulation and may have been either autogenic or driven by human activity. This study therefore suggests that Najaf Sea formation facilitated human expansion beyond the Tigris‐ Euphrates floodplain and occurred due to avulsion of the Euphrates.

Late history of glacial Lake Agassiz in northwestern Ontario, Canada: a case study in the Sandy Lake basin

The Sandy Lake basin in northwestern Ontario is a potentially important area for insights into the late history of glacial Lake Agassiz because of its extensive glaciolacustrine deposits and well-preserved shoreline features of this geological episode. However, little information is available on its deglaciation history. Recent mapping shows the withdrawal of the ice from the basin center and subsequent deposition of extensive varved clay in the lake with an optically stimulated luminescence-dated maximum age at 11.4 ± 0.9 ka. With its further recession, the ice constructed the Opasquia moraine on the northern rim of the basin sometime before the development on the moraine of the first major shoreline of the lake (the The Pas, inferred at 10.1 ka). Lowering of the lake level formed many strandlines on the moraine and elsewhere in the basin, which can be correlated with those in the main Agassiz basin based on projected water planes (the The Pas to Ponton). Radiocarbon dating on basal wood remains of surface peat in a former strait defined by the Ponton shoreline and a nearby site on the former lake floor indicates the abandonment of this shoreline and hence the withdrawal of Lake Agassiz from the Sandy Lake basin by 8.3 ± 0.1 cal ka (UOC-7883). The date, although a minimum-limiting age, provides the hitherto best possible age constraint for the Ponton–Kinojévis shorelines, which many hypothesize represent one of the major lake levels during the final drainage of Lake Agassiz into Hudson Bay but have never been adequately dated before.

Late Holocene tectonics inferred from emerged shoreline features in Higashi-Izu monogenetic volcano field, Central Japan

Emerged shoreline features such as morphology, stratigraphy, and fossil assemblages are useful to reconstruct the history of vertical crustal movement in coastal areas. In particular, resolving the history of individual tectonic events can help understand regional seismo- and volcano-tectonic processes. In the eastern coast of the Izu Peninsula, central Japan, multiple levels of emerged shoreline features formed as a result of repeated uplift caused by the activity of Higashi-Izu monogenetic volcano field or related seismo-tectonic processes during the Late Holocene. To clarify the history of uplift events and the mechanism of regional tectonics, we surveyed these features with a focus on fossil sessile assemblages. Based on an analysis of their height and age, three zones associated with intermittent emergence events, denoted Zone 1 (1.05-m uplift in 595–715 CE), Zone 2 (1.33-m uplift in 1356–1666 CE), and Zone 3 (0.82-m uplift after 1830 CE), were identified. The interval between events was 400–800 years. Zone 3 can be regarded to have emerged via a stepwise but gradual uplift that lasted 130 years. This movement was caused by geodetically observed volcanic crustal deformation with earthquake swarms. We infer that zones 1 and 2 were uplifted by similar intervals of volcanic deformation, but cannot discard coseismic contributions from offshore faults as a possible explanation. The timing of these emergence events coincides with periods of both increased volcanic and seismic activities in the vicinity, suggesting that they are interrelated. Based on the height and age of the additional older assemblage denoted Zone 0 overlying Zone 1 and those of the post-glacial transgressive deposits in the adjacent areas, we suggest that the crustal uplift of the Izu Peninsula was initiated around 3000 years ago, which coincides with the largest eruption of Kawagodaira volcano. Therefore, volcanic activity is an important factor governing coastal uplift in this region.

River Delta Morphotypes Emerge From Multiscale Characterization of Shorelines

AbstractDelta shoreline structure has long been hypothesized to encode information on the relative influence of fluvial, wave, and tidal processes on delta formation and evolution. We introduce here a novel multiscale characterization of shorelines by defining three process‐informed morphological metrics. We show that this characterization yields self‐emerging classes of morphologically similar deltas, that is, delta morphotypes, and also predicts the dominant forcing of each morphotype. Then we show that the dominant forcings inferred from shoreline structure generally align with those estimated via relative sediment fluxes, while positing that misalignments arise from spatiotemporal heterogeneity in deltaic sediment fluxes not captured in their estimates. The proposed framework for shoreline characterization advances our quantitative understanding of how shoreline features reflect delta forcings, and may aid in deciphering paleoclimate from images of ancient deposits and projecting delta morphologic response to changes in sediment fluxes.

Limnology and diatom ecology of shallow lakes in a rapidly thawing discontinuous permafrost peatland

ABSTRACT Lakes in discontinuous permafrost peatlands are on the front lines of climate change, sensitive to even modest increases in air temperature. The aim of this study was to provide the first limnological characterization of shallow (∼1–2 m depth) lakes in the Scotty Creek basin (Northwest Territories, Canada), a field site of circumpolar significance due to the existence of long-term ecohydrological monitoring going back decades. We use this previous work as a foundation to advance our process-based understanding of the potential drivers of lake ecosystem change. Our results showed that dissolved organic carbon (DOC) and lake color were not correlated, a pattern that seems to be an important driver of diatom (siliceous single-celled algae) assemblages in these lakes. Diatoms in the study lakes tended to fall into 1 of 2 assemblage clusters. One cluster, composed of small benthic Fragilariaceae and small Navicula species (sensu lato), was found associated with higher lake color; the second cluster, composed of Encyonopsis and large Navicula species, was found associated with high DOC, lower color, and the presence of a benthic moss mat. From this finding, we suggest that DOC quality is a primary control on lake ecology in this region for its role in controlling light penetration to the lake bottom. Our hypothesis that the prevalence of nearshore fens and collapse scar wetlands would be important drivers of DOC was not supported in the 9 study lakes with available data to map shoreline features.

Assessment of Shoreline Change Along The Sandy Beach of Ellembelle District of Ghana

Sandy beaches are most popular tourists and fish landing sites, and serve as habitat for several endangered species. However, sandy beaches more vulnerable to coastal erosion, particularly those along open oceans. Assessment of shoreline change using reliable dataset aid in understanding the morphology of coastal landforms, the processes associated with their occurrence and support decision making. This paper analysed available multi-temporal spatial dataset and field observations using GNSS techniques to assess the shoreline change along the study area. The shoreline features were extracted from 1974 topographic map and 2005 orthophotographs using the High Water Line (HWL) in conjunction with 2020 spatial data. Shoreline change statistics were computed using DSAS. A geodatabase was created, transects were cast and the shoreline change rates computed using EPR, LRR and WLR methods. Both accretion and erosion were recorded with mean erosion rate of 0.97 m/year. It was observed that sections of the shoreline nourished by Ankobra and Amunzuri rivers were experiencing some accretion, particularly the mouth of the Amuzuri river. The estuary of Amunzuri river was found to be drifting eastwards at a rate of 5.4m/year possibly due to tides, waves and currents. The study concludes that in spite of the littoral drift eastwards, fluvial sediment supplied by coastal rivers accounts for the relative stability of shoreline in the area. Policy formulation regarding possible damming of coastal rivers by government under the ‘one district one dam’ agenda must be carefully considered to avert high levels of erosion along the western coast of Ghana.

Comparison of Spectral Wave Dissipation by Two Living Shoreline Features in a Sheltered Tidal Bay

Comparison of Spectral Wave Dissipation by Two Living Shoreline Features in a Sheltered Tidal Bay

Antecedent geological control on transgressive delta and shoreline preservation: Examples from the SE African shelf

Using a suite of ultra-high resolution geophysical tools, remote operated vehicle dives, legacy cores, and isolated grab samples, we demonstrate at a regional shelf scale, the influence of antecedent geology (basement topography, shelf gradient and submerged shoreline features) on the evolving transgressive shelf stratigraphy of a subaqueous delta. The unconsolidated uppermost delta occurs as isolated remnants scattered across the low-gradient shelf. Seismic data reveal across-shelf heterogeneity in bedrock elevation, with prominent bedrock highs and depressions and several well-preserved aeolianite palaeo-shoreline complexes at water depths of −100, −60 and − 40 m. Analysis of bathymetric and seismic data demonstrates that these pre-existing shoreline complexes exert an overarching control on the distribution patterns of i) deltaic sediments, where they abut the landward flank of the shoreline form, acting as a barrier to seaward dispersal, and ii) shoreface sediments which remain sequestered on the mid-shelf on the seaward flank of the shoreline complex, hampering the landward translation of the shoreface in step with rising sea levels. Moreover, sediment distribution/accumulation is further constrained where elevated portions of the basement topography provide little to no accommodation, and act as zones of sediment bypass, and adjacent basement depressions accommodate sediment to seaward. The gentle antecedent slope, coupled with the gentle shoreline trajectory mediated transgressive erosion directly to landward. This is reinforced where local inflections in the wave ravinement profile form due to the presence of palaeo-shoreline complexes, aiding in the ultimate preservation of these submerged delta facets in the palaeo-shoreline lee. This study shows that low antecedent gradients, and palaeo-shoreline features, lead to development of transgressive coastal profiles that are predisposed to delta overstepping. The pre-existing basement topography and palaeo-shorelines constrain the positioning and morphology of the delta. We suggest that antecedent conditioning has partitioned accommodation for delta accumulation and moderated wave ravinement associated with transgression since the Last Glacial Maximum (LGM). The geological framework has acted as a recurring primary control on the geomorphic evolution of the submarine delta and shelf.

Cyber-resilience for marine navigation by information fusion and change detection

Cyber-resilience is an increasing concern for autonomous navigation of marine vessels. This paper scrutinizes cyber-resilience properties of marine navigation through a prism with three edges: multiple sensor information fusion, diagnosis of not-normal behaviours, and change detection. It proposes a two-stage estimator for diagnosis and mitigation of sensor signals used for coastal navigation. Developing a Likelihood Field approach, the first stage extracts shoreline features from radar and matches them to the electronic navigation chart. The second stage associates buoy and beacon features from the radar with chart information. Using real data logged at sea tests combined with simulated spoofing, the paper verifies the ability to timely diagnose and isolate an attempt to compromise position measurements. A new approach is suggested for high level processing of received data to evaluate their consistency, which is agnostic to the underlying technology of the individual sensory input. A combined generalized likelihood ratio test using both parametric Gaussian modelling and Kernel Density Estimation is suggested and compared with a detector using only either of two. The paper shows how the detection of deviations from nominal behaviour is possible when the navigation sensor is under attack or defects occur.

10Be exposure age dating of Late Quaternary relative sea level changes and deglaciation of W Jura and NE Islay, Scottish Inner Hebrides

ABSTRACTNew 10Be exposure age dating and geomorphological mapping of emerged shoreline features in W Jura and NE Islay throw new light on the regional pattern of ice sheet deglaciation and late-glacial relative sea level change. We conclude that the oldest and highest emerged shorelines in this area were produced ~15.7–16.3 ka, shortly after ice sheet deglaciation ~16.5 ka. It is envisaged that the first incursion of marine waters into coastal areas took place close to a former ice sheet margin that oscillated in position across this part of the Scottish Inner Hebrides. The first evidence of late-glacial marine sedimentation following deglaciation consists of emerged marine terrace fragments and unvegetated gravel beach ridges, the former represented by a prominent glacio-isostatically tilted shoreline that declines in altitude NE to SW, from ~40 m above ordnance datum (OD) in NW Jura to ~19 m OD in central Islay. In W Jura, north of Loch Tarbert, spectacular staircases of up to 55 unvegetated gravel beach ridges were formed shortly after regional deglaciation, possibly within 1 ka. A preliminary estimate of the average rate of relative sea level lowering across W Jura between deglaciation and the Younger Dryas is in the order of ~7 mmyr−1. Geomorphological evidence from Shian Bay, W Jura, indicates a truncation of the late-glacial beach ridge staircases by a large 480-m-long beach ridge (the Colonsay Ridge) at ~14.9 ka, when former relative sea level was at ~18 m OD. This ridge may represent the product of either a stillstand in the progressive lowering of relative sea level during the late-glacial or a reversal. This raises the intriguing possibility of an association between ridge formation and the timing of the well-established global meltwater pulse 1A between ~14.65 and ~14.8 ka.

OSL Dating of Paleo-Shorelines at Dagze Co, Central Tibetan Plateau

Well-preserved paleo-shoreline systems suggest lake shrinkage occurred in a vast region of the Tibetan Plateau, indicating dramatic paleo-environmental changes that linked closely to variations in Asian monsoon precipitation, glacial meltwater, and evaporation. The elevation and chronology of these shoreline features can be used to reconstruct lake level fluctuation history and regional paleo-climate. Here, we report optically stimulated luminescence (OSL) dating of 14 sediment samples from three of seven paleo-shorelines at south of Dagze Co, central Tibetan Plateau, using coarse-grained quartz and K-feldspar. Two fine grain silt samples were also measured. The results suggest the following: 1) The highest paleo-shoreline for Dagze Co has an elevation around 4,525 m (+55 m above modern lake). Its age is estimated to be 9.1 ± 0.5 to 9.6 ± 0.6 ka, suggesting a relative humid condition in the early Holocene. 2) After that, the lake level dropped ∼20 m and remained relatively stable (+35 m) from ∼8 to 5 ka, implying a dry condition with reduced runoff. Lake level further declined for ∼40 m since about 5 ka. 3) The general trend of shrinkage for Dagze Co broadly matches studies from adjacent lakes, suggesting a common pattern of lake’s evolution on the south/central plateau in the late Quaternary. The long-term decreasing trend of Asian monsoon precipitation should be the main reason.

Multispectral satellite imagery and machine learning for the extraction of shoreline indicators

Analysis of shoreline change is fundamental to a broad range of investigations undertaken by coastal scientists, coastal engineers, and coastal managers. Multispectral Satellite Imagery (MSI) provides high resolution datasets that allow coastlines to be monitored more frequently and on a global scale. The Landsat and Sentinel-2 MSI datasets are free for public use, which has increased the frequency of studies focusing on coastal change using satellite imagery. However, despite access to global and free satellite imagery, a method has yet to be developed to monitor different shoreline types and indicators globally, as not all shorelines are sandy beaches, and the waterline cannot be representative of all shoreline changes. The review paper introduces different techniques used currently to extract shoreline features, including water indexing, Machine Learning (ML) and segmentation methods. We presented here a comprehensive review of range of the methods available for shoreline extraction from MSI and discuss why some shoreline features have been identified using multispectral satellite imagery and others not. This approach helps to signal where the gaps are on the current methods for shoreline extraction and provides a roadmap of the key challenges that prevents MSI to be used for understanding shoreline changes at a global scale. • Assessing shoreline indicators and their extraction through the use of Multispectral Satellite Imagery (MSI). • There is a no “one size fits all” technique to monitor different shoreline types and indicators globally. • Machine Learning can reduce the number of options for shoreline extraction for all temporal and spatial scales.

Evolution of Glacial Lake Cochrane During the Last Glacial Termination, Central Chilean Patagonia (∼47°S)

Large ice-dammed lakes developed along the eastern margin of the Patagonian Ice Sheet (PIS) during the Last Glacial Termination (T1). Their spatial/temporal evolution, however, remains poorly constrained despite their importance for deciphering fluctuations of the shrinking PIS, isostatic adjustments, and climate forcing. Here we examine the distribution and age of shoreline features deposited or sculpted by Glacial Lake Cochrane (GLC) in the Lago Cochrane/Pueyrredón (LCP) basin, Central Patagonia, following recession of the LCP glacier lobe from its final Last Glacial Maximum (LGM) moraines. GLC drained initially toward the Atlantic Ocean and continuing ice shrinking opened new drainage routes allowing the discharge toward the Pacific Ocean. We identify five clusters of lake terraces, shorelines, and deltas between elevations ∼600–500 (N5), ∼470–400 (N4), ∼360–300 (N3), ∼230–220 (N2), and ∼180–170 masl (N1) throughout the LCP basin. The distribution of these clusters and associated glaciolacustrine deposits provide constraints for the evolving position of the damming glacier bodies. Elevation gradients within the landform clusters reveal glacio-isostatic adjustments that enable us to quantify the magnitude of deglacial rebound and construct isostatically corrected surfaces for the different phases in the evolution of GLC. Our chronology, based principally on radiocarbon dates from lake sediment cores and new OSL dating, suggests that these phases developed between ∼20.7–19.3 ka (N5), ∼19.3–14.8 ka (N4), ∼14.8–11.3 ka (N3), and shortly thereafter (N2 and N1). The N3 landforms are the most ubiquitous, well-preserved, and voluminous, attributes that resulted from a ∼3,500-year long period of glacial stability, enhanced sediment supply by peak precipitation regime, and profuse snow and ice melting during the most recent half of T1. This scenario differs from the cold and dry conditions that prevailed during the brief N5 phase and the moderate amount of precipitation during the N4 phase. We interpret the limited development of the N2 and N1 landforms as ephemeral stabilization events following the final and irreversible disappearance of GLC after N3. This event commenced shortly after the onset of an early Holocene westerly minimum at pan-Patagonian scale at ∼11.7 ka, contemporaneous with peak atmospheric and oceanic temperatures in the middle and high latitudes of the Southern Hemisphere.

Towards understanding desert shorelines - coastal landforms and dynamics around ephemeral Lake Eyre North, South Australia

ABSTRACT While shorelines around playa lakes have traditionally played a key role for reconstructing late Quaternary megalakes in drylands, little attention has been given to recent shorelines associated with episodic filling events of modern ephemeral playa lakes such as Kati Thanda-Lake Eyre in central Australia. We here present results from geomorphic mapping around the playa margin of Lake Eyre North and interpret these data regarding timescales and drivers of shoreline processes. The diversity and distribution of landforms point to lithology and variations in wave energies as major controls on large-scale shoreline geomorphology. Our results suggest that the presence or absence of shoreline features is an incomplete and inaccurate indicator of past lake levels. Instead, wave-built landforms in ephemeral playa lake settings need to be considered threshold-related phenomena, with differences in frequency, magnitude and rate of water level change leading to vertically differing potential for wave-driven geomorphic activity and thus topographic differences between landforms. While mainland barriers probably best represent rare peak lake levels, barrier spits or islands dominantly form at lower and intermediate levels through lower energy longshore drift, thus providing a more complete record of playa flood events. Additionally, the lowest magnitude events offer potential for frequent wetting and drying along playa margins that effectively drives salt-related production and aeolian sediment deflation. Therefore, in contrast to marine or perennial lake shorelines, the complete range of wind-driven sedimentary processes needs to be coupled with an accurate understanding of lake-specific flooding frequency and magnitude towards a comprehensive model of shoreline evolution around playa lakes.

Analyses of Short- and Long-Term Shoreline Trends of the Southwest Benin Coast

Balle, G.R.A.; Ahouansou, D.M.M.; Sintondji, L.C.O., and Agbossou, E.K., 2021. Analyses of short- and long-term shoreline trends of the southwest Benin coast. Journal of Coastal Research, 37(2), 316–325. Coconut Creek (Florida), ISSN 0749-0208.Coastal zones are the economic heart of coastal countries and are therefore densely populated. In recent times, coastal zones are found to be globally eroding at variable spatiotemporal scales, leading to loss of business activities, ecosystems, economic lands, and infrastructures. Similar to elsewhere in the world, in West Africa and particularly the Benin Republic, the problem of the eroding shoreline is on the increase. Currently, the Grand-Popo section (the western part of the Benin coast) is experiencing serious shoreline change, which is causing the destruction of physical infrastructure and ecosystems. This study aims to determine the shoreline change trends in the study area over approximately a 10-year period from 1988 to 2018. To attend this objective, the SPOT and Sentinel-2 remotely sensed data of 10-m resolution were used, and the shoreline feature was extracted using the high-water line as an indicator. The shoreline feature dynamics were analysed using the Digital Shoreline Analysis System extension in ArcGIS, where the shoreline change statistics were computed and analysed. The results indicate that from 1988 to 2001, a high net shoreline accretion occurred, representing 80.39% of the entire study area at an average rate of 3.46 m/y. From 2001 to 2012, the Grand-Popo shoreline was affected by erosion representing approximately 85.17% of the study area at an average erosion rate of –4.54 m/y. Net shoreline accretion corresponding to 76.08% of the entire study coast at an average rate of 7.98 m/y also occurred between 2001 and 2012. Considering the entire study period (1988 to 2018), 68.51% of the shoreline accreted at an average rate of 0.79 m/y whereas 31.49% of the entire coast eroded at an average rate of –0.75 m/y. Major erosion was observed near the mouth of the Bouche du Roy estuary.

Response of a wave-dominated coastline and delta to antecedent conditioning and fluctuating rates of postglacial sea-level rise

In the context of rising sea levels, wave-dominated coasts and deltas are among the most threatened of coastal landforms. The study of submerged deltas, in tandem with other drowned wave-dominated shoreline sequences, can shed light on the long-term coastal behaviour of these threatened shorelines when subject to high-end scenarios of relative sea-level rise. Using ultra high-resolution seismic reflection data and gravity core samples, this paper investigates the post-glacial stratigraphic development and architecture of the shelf off southern Mozambique. We document several well-preserved beachrock/aeolianite palaeo-shoreline complexes from water depths of −100, −75 and −60 m, interpreted as representing the positions of former sea-level slowstands or stillstands. These overlie the regional subaerial unconformity associated with the last glacial maximum and are linked to two phases of deltaic deposition. Pro-deltaic deposits on the outer shelf were linked with the period of sea-level stability attributed to the −100 m shoreline, while proximal delta front deposits on the inner- to mid-shelf are linked to a slowstand evident in the local sea level record at −40 m. Well-developed lower delta plain facies overlie both shoreline and delta front facies and show evidence of strong channelisation during normal regression of the delta. These are overlain across the shelf by isolated and stranded pieces of the now relict shoreface, trapped to seaward by the shoreline complexes. The more proximal parts of the shelf are in turn overlain by fluvial-derived muddy facies of the current prodeltas of the area.The preservation of shoreline and delta deposits was enhanced by intervening rapid increments in sea-level rise associated with meltwater pulses 1A (−100 m) and 1B,(−60 m) though the preservation of the −75 shoreline feature, in spite of modest rates of Older Dryas base-level change, points toward other factors such as rapid cementation as dominant in this instance. The region's high sediment supply exerted a primary control on shelf preservation by dampening the erosive extent of wave-ravinement. Variations in antecedent gradient are responsible for much of the documented along-shelf and down-dip depositional variability: low-gradient settings promoted the development of broad coastal plains and strongly wave-dominated deltaic facies, while steeper areas of the shelf favoured the development of coastal landforms in relatively narrow complexes fronted by deep-water deltaic deposits. Steeper areas of the shelf also tend be characterised by an embayed along-coast profile that locally mitigates wave-energy, reinforcing the influence of inherited gradient.Once preserved, drowned coastal barriers introduced an additional geological control as post-glacial sediment became trapped between these features on the outer shelf. The dispersal of modern sediments is strongly influenced by the hydrodynamic regime Delagoa Bight, under which fluvial muds are transported northeastward along the shelf by a persistent inner-mid shelf counter-current. A considerable proportion of the modern sediment budget is lost off-shelf where the shelf narrows.This study shows that low antecedent gradients foster gentle coastal profiles predisposed to delta overstepping. Though local topographic knickpoints can aid in preserving the delta during submergence, they do not buffer the delta from the general effects of inundation which include drowning of the delta top. Once overstepped, the former delta can be overlain by distal deltaic sediments associated with the higher sea level and associated fluvial and oceanographic forcing quite different from earlier phases of delta construction.

Operationalizing resilience: co-creating a framework to monitor hard, natural, and nature-based shoreline features in New York State.

Wijsman, K., D. S. N. Auyeung, P. Brashear, B. F. Branco, K. Graziano, P. M. Groffman, H. Cheng, and D. Corbett. 2021. Operationalizing resilience: co-creating a framework to monitor hard, natural, and nature-based shoreline features in New York State. Ecology and Society 26(3):10. https://doi.org/10.5751/ES-12182-260310

Oil spill trajectory modelling and environmental vulnerability mapping using GNOME model and GIS.

This study develops an oil spill environmental vulnerability model for predicting and mapping the oil slick trajectory pattern in Kota Tinggi, Malaysia. The impact of seasonal variations on the vulnerability of the coastal resources to oil spill was modelled by estimating the quantity of coastal resources affected across three climatic seasons (northeast monsoon, southwest monsoon and pre-monsoon). Twelve 100m3 (10,000 splots) medium oil spill scenarios were simulated using General National Oceanic and Atmospheric Administration Operational Oil Modeling Environment (GNOME) model. The output was integrated with coastal resources, comprising biological, socio-economic and physical shoreline features. Results revealed that the speed of an oil slick (40.8m per minute) is higher during the pre-monsoon period in a southwestern direction and lower during the northeast monsoon (36.9m per minute). Evaporation, floating and spreading are the major weathering processes identified in this study, with approximately 70% of the slick reaching the shoreline or remaining in the water column during the first 24h (h) of the spill. Oil spill impacts were most severe during the southwest monsoon, and physical shoreline resources are the most vulnerable to oil spill in the study area. The study concluded that variation in climatic seasons significantly influence the vulnerability of coastal resources to marine oil spill.

Small Port Detection Based on Combination of Shoreline Feature Points in Polarimetric SAR Images

Du, Y. and Yang, N., 2020. Small port detection based on combination of shoreline feature points in polarimetric SAR Images. In: Bai, X. and Zhou, H. (eds.), Advances in Water Resources, Environmental Protection, and Sustainable Development. Journal of Coastal Research, Special Issue No. 115, pp. 102-105. Coconut Creek (Florida), ISSN 0749-0208.SAR (Synthetic Aperture Radar) is a coherent imaging radar mechanism working in microwave band. SAR image classification is the main component of remote sensing image classification. It has certain penetrability to the surface vegetation and is increasingly becoming one of the most representative earth observation methods today. This paper presents a method of merging shoreline feature points suitable for small port inspection. Firstly, the polarimetric SAR image level set segmentation algorithm is used to realize the accurate segmentation of land and sea, then it is fused with the classical edge detector based on statistical characteristics, and the rough detection of small ports is realized through the characteristics of less edge and good overall connectivity in the sea surface area. On this basis, the classification is completed iteratively by using complex Wishart statistical features. The algorithm can better improve the edge smoothness and regional consistency, and improve the classification quality of polarimetric SAR images. The experimental results show that the method proposed in this paper can realize high-precision detection of bridges.