Coastal Beaches Research Articles

TWEED SAND BYPASSING TRANSITION PROJECT

The Tweed River is located in New South Wales, Australia, just south of the state border with Queensland. The Tweed River Entrance Sand Bypass Project, aka Tweed Sand Bypassing (TSB), was formulated to overcome problems caused by the extension of the Tweed River entrance training walls in the 1960s (Dyson et al., 2001). These issues were primarily: the interception of natural longshore movement of sand, resulting in loss of sand supply to the southern Gold Coast beaches; and sand movement into the river entrance with consequential impacts on vessel navigation. TSB is a joint initiative of the New South Wales and Queensland State Governments. The TSB is similar to the nearby Gold Coast Seaway Sand Bypass (GCSSB) that was commissioned in 1986 to stabiles the Nerang River entrance (Clausner, 1989). Together, these two facilities have come to represent best practice outcomes in sustainable coastal management. A Transition Project was established by TSB to identify the most appropriate operational system / model post-expiry of the CA and to ensure ongoing effective coastal management that meets the legislated objectives. The Transition Project has provided a unique opportunity to improve how TSB functions through the exploration of available options and analysis of historical operational performance.

INVESTIGATING DREDGE PLACEMENT OPTIMISATION TO BENEFIT SURF AMENITY

Dredge material removed from the Tweed River Entrance is deposited offshore from Gold Coast beaches to assist in mitigating erosion. Research was undertaken by the Queensland Government Hydraulics Laboratory (QGHL), in collaboration with Tweed Sand Bypassing (TSB), to investigate the potential of targeting dredge depositions to also improve surf amenity. A time-domain numerical wave model (SWASH) was developed as a design tool and calibrated using physical model data. Overall, SWASH reproduced wave heights over and in the lee of the mound with reasonable accuracy. However, tuning of the breaking parameters (α and β) is necessary to accurately simulate the onset and persistence of the breaking process. The results of both physical and numerical modelling highlight the importance of sand mound shape in disrupting the wave field, resulting in breakpoint variability in the mound's lee, which could potentially create more favorable surfing conditions.

The During Nearshore Event Experiment (DUNEX): A collaborative coastal community experiment to address coastal resilience

The During Nearshore Event Experiment (DUNEX) was a large-scale coastal field effort focused on improving understanding of during-storm nearshore processes to ultimately develop predictive technologies, engineering solutions, and actions to enhance coastal resilience. The experiments were conducted on the North Carolina coast by a multidisciplinary group of over 30 research scientists from 18 academic and federal institutions supporting over 30 graduate students and deploying over 300 instruments from 2019 to 2021. The overarching goal of DUNEX was to gather information collaboratively to improve understanding of the interactions of coastal water levels, waves, currents, beach and dune evolution, soil behavior, vegetation, and groundwater during major coastal storms that affect infrastructure, habitats, and communities. In the short term, these high-quality field measurements will lead to better understanding of during-storm processes and impacts and will enhance U.S. academic coastal research programs by providing opportunities for students to learn about field data collection and to potentially analyze data as part of their studies. Longer-term, DUNEX data and outcomes will improve the ability to predict extreme event physical processes and impacts, validate coastal processes numerical models, and improve coastal resilience strategies and communication methods for coastal communities impacted by storms. The purpose of this paper is to describe the motivation for and science goals of the experiment, how stakeholder needs led to these goals, collaborations amongst researchers, and the knowledge gained that will lead to tools to improve coastal resilience. Herein, we first describe how researchers worked with stakeholders to structure their community-driven needs into science-based requirements. Next, we summarize how federal, academic, and stakeholder researchers worked together to design and execute a multi-organizational experiment aligned with those requirements. Finally, we articulate early findings and lessons learned from the experiment. This paper does not summarize all the research findings from DUNEX, as analyses are still ongoing. An American Geophysical Union (AGU) Special Collection on Coastal Storm Research will be published in 2025 including outcomes from DUNEX research.

Ecological risk assessment of selected contaminants in seawater, sediment and some fish species from Alexandria beaches, South-Eastern Mediterranean Sea, Egypt

The present study aims to investigate the hydrographical characteristics, nutrient salts, and heavy metals (HM) to estimate the contamination status of selected coastal beaches along the Alexandria coastal area in the southeast Mediterranean Sea. Water and sediment samples were collected from 8 beaches along the cost of Alexandria, while 122 fish samples representing 10 species were collected from 2 beaches representing two ports at Alexandria city. All samples were subjected to specific analyses to assessment of ecological risks at study area. The study indicated that the seawater quality of the investigated beaches varied between medium to good based on the Water Quality Index (WQI = 0.233–0.713). Moreover, the highest average concentration in water was observed for Fe (33.624 μgl−1) and the lowest was detected for Cd (0.050 μgl−1). HM in sediment have the same trend of these HM in water. The most of beaches’ sediments were classified as non-contaminated (PI < 1) with all examined HM. Hazard Quotient and Hazard Index (HQ &HI < 1) this indicated that the lack of non-carcinogenic impacts for children and adults due to dermal contact with sediments of all beaches. The most abundance HM in fish were Fe and Zn. Bioaccumulation factors (BAF) in fish muscles was evaluated. MPI (Metal Pollution Index) of HM in the investigated species ranged from (0.381–2.216) in Pomatomus saltatrix and Scomberomorus commerson species respectively. HQ, HI, EDI (Estimated Daily Intake), and TR (Target Risk) values showed that the examined species are still safe for human consumption.

The Sector Analysis as a Coastal Management Tool for Sustainable Tourism Development on the Mediterranean Coast of Morocco

Beaches are ecologically valuable ecosystems and sites that attract many tourists from all over the world, therefore, knowledge of their environmental conditions to establish sound management strategies is of extreme relevance. This study aims to assess and classify 50 beaches through an innovative coastal management approach called “Sector Analysis”, which integrates Litter grading, the coastal scenic quality and beach typology in order to classify sites into one of three sectors: Green (high value sites), Red (low value sites) and Yellow (sites with contradictory values). Litter Grade makes it possible to classify a site according to the quantity of litter using four grades from “A” (low) to “D” (high amount). The Coastal Scenic Evaluation System (CSES) allows to classify sites into five classes, ranging from extremely attractive natural sites (Class I) to unattractive degraded and urbanized sites (Class V). This innovative methodology for sustainable coastal area management can be easily applied to any beach in the world. The results on Litter Grade and CSES considered in this paper were obtained from previous studies and used to obtain the Sector Analysis that showed only 8 sites (16%) are in the Green sector, 18 sites (36%) in the Red sector and 24 sites (48%) in the Yellow sector. The significant percentage of sites in the Red sector (one third of the sites studied) clearly indicates the degradation that the Moroccan Mediterranean coast has undergone due to considerable anthropogenic activities and the lack of adequate coastal management programs. In this study, various management interventions were proposed to conserve and improve the aesthetic quality of beaches and reduce the impact and presence of litter in the coastal areas.

Profile Distribution of Iron and Zinc in Soils formed from Three Different Parent Materials in Akwa Ibom State, Nigeria

The distribution of total and available levels of iron (Fe) and zinc (Zn) was studied in three major soil types derived from different parent materials in Akwa Ibom State. The parent materials were: Sandstone (SS), Coastal Plain Sands (CPS) and Beach Ridge Sands (BRS), respectively. Six representative soil profiles, two each for SS, CPS and BRS were dug. The soils from the different parent materials were sampled at different depths of 0 – 20, 20 – 40, 40- 60, 60 – 80, 80 – 100 and 100 – 120 cm. The soil samples were air dried, crushed and sieved using a 2mm sieve and stored in labeled bags for analysis. Laboratory analysis was conducted. The soils were strongly weathered, coarse in texture, acidic and generally low in fertility. Total Fe contents ranged from 365-1576mg/kg with sandstone soils having the highest mean of 1400mg/kg, followed by those of the coastal plain sand with a mean value of 883mg/kg and 485mg/kg for beach ridge sands. The total content of Zn followed the same trend ranging from 43 to 335mg/kg with a mean value of 246, 114 and 79mg/kg for the sandstone soils, coastal plain sands and beach ridge sand soils, respectively. Available Fe contents in the entire profiles ranged from 9.8 to 33.3mg/kg with sandstone having the highest mean value of 28.2mg/kg, followed by those of coastal plain sands with a mean of 14.7mg/kg and beach ridge sands with a mean of 12.2mg/kg. The available Zinc content followed the same trend. Available Zn content ranged from 4.2-20.0mg/kg with a mean value of 12.2, 9.3 and 6.5 mg/kg for the sandstone, coastal plain sands and the beach ridge sands, respectively. The distribution of the micronutrients in the soil profile was generally irregular, but in some profiles, it decreased with depth. The micronutrients were weakly correlated with organic carbon, clay and silt in the three parent materials. The available levels of the micronutrients in the soils were relatively high, having values above the critical levels of 4.5mg/kg for available Fe and 1mg/kg for available Zn. The result showed that the content of the two micronutrients were highest in sandstone soils, followed by that of coastal plain sands and least in the beach ridge sand. The high content of the available iron and zinc indicate possible toxicity effect to plant grown on these soils.

Fusarium spp. an emerging fungal threat to leatherback (Dermochelys coriacea) eggs and neonates

IntroductionFungal diseases are a rising health problem globally, in humans, nonhuman animals, and plants. Emerging fungal diseases have been associated with mass mortality events. A recent example of fungal disease pathogenicity is sea turtle egg fusariosis (STEF). The pathogenicity of STEF has been linked to fungi within the Fusarium solani species complex (FSSC). This complex is composed of over 45 phylogenetically identifiable species commonly found in the environment. Species within the FSSC lineage have been isolated from the nests of multiple sea turtle species and are linked to decreased hatching success in all 7 of the extant sea turtle species. Fungi within this lineage are also known to cause cutaneous and subcutaneous infections. These fungi are not only a threat to sea turtles but also to other animals, including humans, that use coastal waters and beaches inhabited by Fusarium spp. The presence of Fusarium spp., in the context of sea turtle health, has not been investigated on southeastern Florida beaches which are fundamentally important for at least three sea turtle species that nest there in large numbers.MethodsWe performed a retrospective assessment of necropsy reports from dead captive leatherback neonates from 2010 to 2022 to assess the most common microscopic diagnoses and the presence of skin lesions associated with mycotic dermatitis. Additionally, live captive leatherbacks and dead-in-nest samples from the 2022 hatching season were used to assess the presence and effect of mycotic dermatitis in Juno Beach and Boca Raton, Florida, USA. This was accomplished by observing gross lesions, fungal cultures, and blood values.ResultsThe retrospective analysis of dead captive neonates revealed that the diagnosis of mycotic dermatitis on histopathology has significantly increased since 2010. The assessment of gross skin lesions associated with mycotic dermatitis in dead and live captive leatherback neonates also revealed a similar increase. Investigations in live captive leatherbacks revealed fungal cultures positive for Fusarium spp. and significant differences in blood values at emergence between healthy turtles and those that later developed mycotic dermatitis.DiscussionPositive dead-in-nest culture results suggest that Fusarium spp. are likely present in leatherback sea turtle nests in Boca Raton and Juno Beach, Florida, USA. Additionally, the occurrence of mycotic dermatitis in dead and live captive leatherback neonates suggests that the presence of Fusarium spp. in the nest likely affects leatherback neonates even after emergence.

Impact of Sea Rice Planting on Enzymatic Activity and Microbial Community of Coastal Soils: Focus on Proteinase

Soil proteinase and proteinase-producing microbial community are closely associated with soil fertility and soil health. Sea rice has been planted in the coastal beach of Jiaozhou Bay, China, in an effort to transform saline-alkali soil into arable land. However, the knowledge regarding the bacterial degradation of organic nitrogen in sea rice soils is limited. This study aims to investigate the physicochemical characteristics and enzymatic activities of the sea rice soils, as well as the microbial communities by both the Illumina sequencing-based culture-independent technology and culture-dependent methods. Sea rice soils exhibited a lower salinity and higher organic matter content and proteinase activity, as well as an increase in both the richness and diversity of the proteinase-producing bacterial community, compared to the adjacent non-rice soils. The Proteobacteria phylum and the Gammaproteobacteria class were dominant in sea rice soils, showing higher abundance than in the reference soils. The Planococcus genus and Bacillus-like bacterial communities were abundant in the cultivable proteinase-producing bacteria isolated from sea rice soils. Furthermore, a significant proportion of the extracellular proteinase produced by the isolated soil bacteria consisted of serine proteinases and metalloproteinases. These findings provided new insights into the degradation of soil organic nitrogen in coastal agricultural regions.

Enrichment of soil nutrients and salt ions with different salinities under Tamarix chinensis shrubs in the Yellow River Delta

In this study, we investigated the characteristics of soil salt ions and soil nutrients at different locations around Tamarix chinensis and with different salinity levels on a coastal beach of the Yellow River Delta. The findings help clarify the effects of T. chinensis growth on the enrichment rates of soil nutrients and salt ions. T. chinensis shrublands with low salinity (0.25 %), moderate salinity (0.51 %), and high salinity (1.03 %) on the coastal beach of the Yellow River Delta were studied. The available nitrogen (AN), available phosphorus (AP), available potassium (AK), total organic carbon (SOC), and levels of eight major salt ions were measured and analyzed at different locations around the T. chinensis plants. The results showed that soil salinity significantly affected the contents of soil nutrients and salt ions. Soil salinity, soil location, and their interaction had significant effects on the following contents of soil: AN, AP, SOC, K+, Na+, Cl−, and SO42− (P < 0.01). The soil nutrient contents differed significantly at different locations around a T. chinensis plant (P < 0.05), and the highest nutrient content was found under the center of the canopy, followed by that at the roots. The soil nutrient enrichment rates under different salinity levels were all greater than 1, and T. chinensis shrubs had the strongest enrichment capacity for SOC. The enrichment rates of AN, AK, and SOC under the center and edge of the canopy of T. chinensis were higher under moderate salinity than under low or high salinity; thus, T. chinensis produced a stronger “fertile island” effect under moderate salinity. Soil salinity and location had a significant impact on the enrichment of salt ions. Under low and moderate salinity, the enrichment rates of soil K+, Ca2+, and Mg2+ were all greater than 1, forming “salt islands,” whereas under high salinity, “salt basin” formed. In soil at different locations and with different salinity levels, T. chinensis produced a “salt basin” effect on Na+ and Cl− but a “salt island” effect on soil SO42− and HCO3–. The Na+ enrichment rates under low and moderate salinity were significantly lower than those under high salinity. In summary, T. chinensis shrubs under different salinity levels in the coastal beaches all exhibited the fertile island effect, which was most significant under moderate salinity. In the saline–alkali land on coastal beaches mainly containing Na+ and Cl−, T. chinensis had a salt basin effect on both ions; thus, T. chinensis shrubs significantly reduced the overall soil salinity.

Beach morphodynamics modulate the effects of multidirectional habitat loss on population density and size structure of the Atlantic ghost crab Ocypode quadrata

Sandy beaches are land-sea transitional habitats experiencing ‘multidirectional’ habitat loss due to coastal developments (e.g. armoring and/or conversion of natural vegetation into manmade structures) and beach erosion. This ‘coastal squeeze’ is a chronic and progressive process; however, its impacts on beach biodiversity across morphodynamic gradients are still to be unveiled. We hypothesized that the effects of multidirectional habitat loss would be more severe on dissipative than on reflective beaches, due to the higher elevation, amount of built up sediment, and width of the backshore compartment of the latter. We, thus, examined the effects of coastal developments and erosion on density and size structure of the Atlantic ghost crab, Ocypode quadrata, on beaches with different morphodynamics. Given that the living area of ghost crabs spans all cross-shore compartments and the whole dissipative-to-reflective morphodynamic gradient, they are appropriate organisms to access the synergic effects of coastal developments and beach erosion under different morphodynamic regimes. On dissipative beaches, density and mean crab size increased with moderate erosion, attributed to the effects of space loss, which might increase territorial competition, favoring the remaining larger individuals. However, mean size and density decreased with high erosion given the more intense reduction in the abundance of large-sized crabs living in up-shore habitats. Mean crab size also decreased in the presence of coastal development while crab density did not vary with loss of backshore habitats occupied by larger individuals. On reflective beaches, both density and crab size decreased with coastal development; the crab size decrease recorded under moderate erosion was more evident in the presence of coastal development. Under high erosion, mean crab sizes declined, reflecting those under low erosion conditions. Overall, populations on reflective beaches appeared more resilient to extreme erosion. Notwithstanding, coastal developments affected population structure across all beach types, and especially in areas subjected to high erosion, exhibiting a synergic effect. We predict that, in combination, these stressors may lead to functionally extinct populations where conditions necessary for individuals to reach sexual maturity (i.e. occurrence of only small-sized and immature individuals) are not met. Thus, the connectivity between water, beach compartments and dunes/coastal plain, on both local and regional scales, may be essential to maintain viable and connected populations of ghost crabs. Further, our results strongly suggest that both size and density (complemented with crab abundance) must be considered equally important and in combination in future efforts to assess anthropogenic stressors on ghost crab populations and when guiding conservation strategies and policies to prevent their local and regional extinctions.

Evidence of increasing juvenile white sharks' (Carcharodon carcharias) habitat use at the Northern Channel Islands.

Juvenile white sharks (Carcharodon carcharias) typically aggregate along coastal beaches; however, high levels of recruitment and shifting oceanographic conditions may be causing habitat use expansions. Telemetry data indicate increased habitat use at the Northern Channel Islands (California, USA) by juvenile white shark that may be in response to increased population density at aggregation locations, or anomalous oceanographic events that impact habitat use or expand available habitat. Findings illustrate the need for long-term movement monitoring and understanding drivers of habitat use shifts and expansion to improve ecosystem management.

Ecological Risk Assessment and Impact Factor Analysis of Ecological Spatial Patterns in Coastal Counties: Taking Dalian Pulandian District as an Example

A scientific foundation for the sustainable development of ecosystems and the improvement of the ecological spatial security pattern in the area is provided by carrying out a scientific assessment of ecological risk levels in coastal counties. An ecological risk assessment model was established in Pulandian district, Dalian, based on four periods of land use data from 1990 to 2020 combined with the PSR model. The spatial and temporal evolution of ecological risk in Pulandian was analyzed on this basis, and an exploratory regression analysis and a geographically weighted regression model were then used to explore the driving role of natural and social factors on comprehensive ecological risk in coastal counties. The findings demonstrate that there is an obvious ecological landscape type of conversion, with the majority of arable land being converted to forest land in northcentral and southwest areas, reflecting an improvement in the ecological environment and air quality, and the majority of coastal beach land being converted to construction land among the volumes transferred out and in. The area of high risk increased by 73.17% during the course of 30 years, with the majority of it concentrated in the research areas southern Fengrong, Tiexi, and Taiping regions in 1990 before expanding to the northeast, southeast, and central regions. The status index and response index both show a decline followed by an increase in change, while the pressure index shows a rising tendency with socioeconomic progress. The comprehensive ecological risk in the study area is significantly influenced by the urbanization rate, the ratio of environmental protection investment to GDP, the ecosystem service index, and the ecological space–land use ratio, with the urbanization rate displaying more overt negative correlation-driving characteristics, the ratio of environmental protection investment to GDP displaying significant spatial division characteristics, and the ecological space–land use ratio being an important factor. The findings serve as a foundation for decisions on ecological risk avoidance, control, and construction in Pulandian.

The unexplored role of surfers in drowning prevention: Aotearoa, New Zealand as a case study

ABSTRACT Every year people drown while visiting coastal beaches. Increasingly, studies indicate that bystanders play a critical role in rescuing people from drowning. However, very limited research has explored the contribution surfers make to reducing fatal drowning. This research examined aquatic bystander rescues conducted by surfers in Aotearoa, New Zealand. It analysed their characteristics and the conditions under which they took place. The study draws upon an online survey disseminated through several social media platforms which gathered 418 complete responses. The findings indicate that male and female surfers conducted an average of three rescues across their surfing career. Surfers typically perform rescues at their local surfing spot. Three quarters of the rescues were completed either at unpatrolled beaches or outside patrolled hours, thus filling a critical gap. In 46% of the rescues, surfers felt they had saved the person’s life. Overall, the research emphasises the significant, yet under-estimated, role of surfers in coastal drowning prevention and water safety. It concludes that organisations involved in drowning prevention should work closely with surfing communities on ways to reduce fatalities at coastal beaches.

Modern sand provenance and transport across the western Gulf of Mexico margin

Petrographic and detrital zircon U-Pb analysis of modern beach sands and river sands from major catchments in northeastern Mexico draining to the Gulf of Mexico provides evidence for a minimum of 650 km of littoral sand transport southward from the mouth of the Rio Grande at the Mexico-U.S. border to the central part of the state of Veracruz, Mexico. Principal tracers of Rio Grande sand include: (1) quartzose composition that contrasts with lithic compositions of sand in eastern Mexico rivers and (2) detrital zircon ages with Mesoproterozoic modes at 1.8−1.5 Ga and 1.4 Ga, age groups that are typical of basement and derivative sediment of the SW United States but are uncommon to rare in Mexican river catchments. In contrast, abundant Miocene and younger grains in beach sands of Veracruz indicate primary sediment derivation from active and recently active volcanoes in the Trans-Mexican volcanic belt in central Mexico. A proportional decrease in sand of Rocky Mountain provenance with distance southward along the coast from the mouth of the Rio Grande and absence of Miocene and younger zircon grains in beaches north of rivers draining the Trans-Mexican volcanic belt indicate net littoral sand transport southward along the eastern coast of Mexico, demonstrating that wintertime shoreline-parallel surface currents rather than north-directed summertime currents dominate sediment transfer. Sand samples of Tamaulipas beaches in northeastern Mexico commonly have equal or higher proportions of U.S.-derived Mesoproterozoic zircon grains than are present in river bar sand of the lower Rio Grande and the Rio Grande delta, and thus require that littoral processes rework and incorporate coastal dune and beach sands of northeastern Mexico that are enriched in predam Rio Grande sediment. Implied coastal erosion may be related to Holocene transgression or interruption of sediment supply to the coastal sediment transport system by dams in the Rio Grande drainage basin. Such coastal erosion is impacting long-term shoreline stability and viability of the littoral environment.

Status of intertidal populations of Pismo clams (Tivela stultorum) across their range in California

Long-term monitoring programs are critical to understanding a species’ population dynamics through time and to inform policy decisions. Pismo clams, Tivela stultorum (Mawe, 1823), are an iconic species in California and once supported commercial, recreational, and subsistence harvest for many decades. Despite their economic and cultural importance, little is known about their current population status and monitoring efforts in California are spatially and temporally limited. This project aimed to: (1) collect standardized baseline data on Pismo clam abundance across their range in California; (2) identify factors associated with Pismo clam presence to inform future monitoring efforts and to begin developing testable hypotheses about population drivers; and (3) synthesize historical surveys of Pismo clam populations in California. We conducted intertidal field surveys for Pismo clams at 38 sites in California during 2018 and 2019. We observed no legal sized clams (4.5 in/114 mm) and only 2% of individuals were half of legal size across all survey locations. Clam populations are in lower abundance and comprise smaller sizes than historical accounts. We detected small individuals at most sites, suggesting that successful recruitment has occurred on the majority of beaches where clams were present; however, population recovery may require many years. Finally, we found that median sediment grain size is an important predictor for clam presence on open coast beaches in California. Future research will need to examine a number of factors and their interactions across spatial scales to disentangle Pismo clam population drivers.

Holes on surfaces of the weathered plastic fragments from coastal beaches

The surface morphology of weathered plastics undergoes a variety of changes. In this study, 3950 plastic fragments from 26 beaches around the world, were assessed to identify holes. Holes were identified on 123 fragments on 20 beaches, with the highest frequency (10.3 %) being identified at Qesm AL Gomrok Beach in Egypt. The distribution of holes could be divided into even, single-sided, and random types. The external and internal holes were similar in size (37 ± 15 μm) of even type fragments. The external holes were larger than the internal holes in single-sided (516 ± 259 μm and 383 ± 161 μm) and random (588 ± 262 μm and 454 ± 210 μm) fragment types. The external hole sizes were positively correlated with the internal hole sizes for each type. This study reports a novel deformation phenomenon on the surface of weathered plastics and highlights their potential effects on plastics.

Shoreline Analysis and Extraction Tool (SAET): A New Tool for the Automatic Extraction of Satellite-Derived Shorelines with Subpixel Accuracy

SAET (Shoreline Analysis and Extraction Tool) is a novel open-source tool to enable the completely automatic detection of shoreline position changes using the optical imagery acquired by the Sentinel-2 and Landsat 8 and 9 satellites. SAET has been developed within the ECFAS (European Coastal Flood Awareness System) project, which is intended to be the first European service for coastal flood forecasting, management, and recovery analysis. The tool is developed to characterise the shoreline response associated with punctual events such as coastal storms as well as any other phenomenon. For a given beach segment, SAET facilitates the selection of the satellite images closest in time to the analysed events that offer an adequate cloud coverage level for analysing the shoreline change. Subsequently, the tool automatically downloads the images from their official repositories, pre-processes them and extracts the shoreline position with sub-pixel accuracy. In order to do so, an initial approximate definition of the shoreline is carried out at the pixel level using a water index thresholding, followed by an accurate extraction operating on the shortwave infrared bands to produce a sub-pixel line in vector formats (points and lines). The tool offers different settings to be adapted to the different coastal environments and beach typologies. Its main advantages refer to its autonomy, its efficiency in extracting complete satellite scenes, its flexibility in adapting to different environments and conditions, and its high subpixel accuracy. This work presents an accuracy assessment on a long Mediterranean sandy beach of SDSs extracted from L8 and S2 imagery against coincident alongshore reference lines, showing an accuracy of about 3 m RMSE. At the same time, the work shows an example of the usage of SAET for characterising the response to Storm Gloria (January 2020) on the beaches of Valencia (E Spain). SAET provides an efficient and completely automatic workflow that leads to accurate SDSs while only relying on publicly available information. The tool appears to be a useful extraction tool for beach monitoring, both for public administrations and individual users.

BeachLog: A multiple uses and interactive beach picture

There are some tools in place that classifies and/or rank beaches according to a series of parameters. It is possible to identify a gap in the development of tools that map and describe beaches without putting the results into a classification status of good or bad. Since beaches are important from different points of views such as ecology, tourism, economy, pollution or invasive species studies and management, fisheries, estate development, protected areas, among others it is relevant to describe and understand parameters in detail. This work offers a multi-purpose and interactive beach descriptor called BeachLog. It can be used by beachgoers to keep their own records in the same way a diver uses a Diver's LogBook, managers can use the tool to support coastal management projects, long-term monitoring, and beach description baseline. Also, BeachLog can be a didactic tool to aiming to bring environmental sciences closer to technology through the use of spreadsheets and dashboards. BeachLog is based on the more frequent parameters in the literature, selected, organized, accounted for, and altered/added according to expert opinion. We created a list of 28 parameters, all of which were described in details of what is expected to be observed by the user. They were divided into 5 groups (Environmental characteristics, Services & Infrastructure, Information & Security, Planning & Management, and Descriptive). Here, we describe 14 Brazilian beaches using the BeachLog by inputting the results as parameters presence or absence (0/1) and descriptives in a table that can be transformed into an interactive dashboard for better/easier visualization. Planning & Management was absent on all 14 beaches studied, pointing out the relevance and gaps in this group. In the other groups it was possible to observe variation in the parameter occurrence, indicating that each beach is different and it is important to observe parameters individually. Beach Litter and Invasive Species parameters from the Environmental characteristics group were present in all beaches. BeachLog showed as an easy way to describe a beach and can be a tool to support diagnosis and understanding of the beach's status.

The physical processes of sandy beach evolution under storm and non-storm wave conditions simulated in wave flume

Large waves and high water levels generated by coastal storms are predominant drivers for coastal beach erosion. This experimental study is undertaken to investigate the physical processes of beach profile evolution under storm waves by simulating step varying storm waves and variable water levels in a wave flume of 30 m long, 0.6 m wide and 1 m high and mild beach slope tanθ=1/10. The storm waves were simulated by following a conceptual storm hydrograph of three stages: at the first stage of 60 min both wave height and water level were gradually increased to peak storm wave height and water level, at the second stage of 60 min both maximum wave height and water level were kept for constant, and at the last stage of 60 min storm wave heights were gradually decreased to non-storm waves and water levels. Non-intrusive high-resolution cameras were used to record time-series of free surface water elevation, wave breaking point position, sandbar migration and location, and beach elevation profile in a spatial resolution of 1.4 mm and a temporal resolution of 0.1 s. In analyzing the collected experimental data, the physical processes of beach evolution under both non-storm and storm waves were found significantly different: under non-storm waves, the movement of sandbar always was found to be in the seaward direction, and the beach profile was eroded and accreted before and after the sandbar, respectively, but under storm waves, the sandbar location was found to migrate in either the landward or seaward direction, the beach profile was slowly accreted before the sandbar and eroded after the sandbar when the storm waves were gradually decreased to the non-storm waves. The surf zone is the main change area in beach morphology modification, and the sandbar is the important indicator for distinguishing the cross-shore sediment exchange. Under both non-storm and storm waves, large waves, high water levels, and especially great gradient of wave energy flux due to changes in wave height, period and water depth are the main factors controlling the formation and migration of sandbar, and resulting in beach erosion and accretion before and after the wave breaking point, respectively.

Hydrographical Studies in the Nearshore Seawater of the Red Sea Coast of AlHodeida City, Yemen

Hydrographic studies of nearshore seawater are important because they are sensitive to both natural and human influences. The hydrographic study is very important for nearshore waters because it is very sensitive to natural and human influences. In this research, an attempt was made to study the hydrographic properties of the nearshore water of the Red Sea coast of Hodeida city, Yemen. During the period from December 2021 to June 2022, to represent the two seasons of winter and summer. The water temperatures ranged from 30 to 34.5 °C, salinity fluctuated from 39.3 to 42.4 psu, pH varied from 7.9 to 8.2 and dissolved oxygen ranged from 4.88 to 8.54 mg/l. The higher values of temperature and salinity were recorded during summer. In contrast, an increase in pH and dissolved oxygen were observed during winter. The present study confirmed that salinity has a negative correlation with pH and dissolved oxygen although it was not significant and also it showed significant positive correlation between pH and dissolved oxygen (0.828). Hydrographic parameters showed different patterns of spatial and temporal distributions. These current baseline data are useful for further environmental monitoring, assessment and management along Yemeni coastal beaches.