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Abstract Extreme ecosystem modification by humans has caused drastic reductions in populations and ranges of top mammalian predators, while simultaneously allowing synanthropic mesopredator species to expand. These conditions often result in inflated local densities of highly adaptable mesopredators that disrupt trophic dynamics and place unsustainable predation pressure on native prey populations. Colonization of a dominant predator may lead to top-down control of mesopredators and restore trophic balance. Coyotes are a novel colonizer of some coastal barrier islands of eastern North America, offering an opportunity to test how the addition of an apex predator impacts an established guild of mesopredators. To assess their trophic impact, we conducted 75,576 camera trapping hours over an 18-month study period, capturing > 1.5 million images across 108 coastal camera sites. Using two-species occupancy and habitat use models, we found sizeable effects of coyote habitat use on that of red foxes and free-ranging domestic cats, suggesting that coyotes function as apex predators in barrier island ecosystems. In fact, the only factor that determined the spatial pattern of highly ubiquitous red foxes was the sympatric habitat use of the largest carnivore in the food web—coyotes. That ‘novel’ apex predators can become established in coastal food webs illustrates the highly dynamic nature of conservation challenges for habitats and species at the edge of the sea.

We present here a first comprehensive database on the diversity of proseriate flatworms (Platyhelminthes: Rhabditophora: Proseriata) on Western Mediterranean microtidal, wave dominated beaches. We sampled 116 stations in two years, through Spain (22 beaches, including Balearic Islands), France (25 beaches, including Corsica), Italy (63 beaches, including Sardinia, Sicily, and Lampedusa), and Tunisia (6 beaches). In each beach, we sampled at three depths, corresponding to the swash, shoal, and subtidal zones. For each sample, we obtained environmental data. The research yielded a total of 152 species, of which 93 were new to science. For each of the species found, we coded and described 16 functional traits. We discuss the functional meaning of the selected traits, as well as on diversity patterns and emerging biogeographic signals across the investigated regions. We particularly focused on the most widespread and dominant species in our dataset, concentrating on their putative adaptations to high energy environments; as well as the high number (58) of the species only found once. Finally, we discussed the coverage of our sampling by estimating the diversity at each investigated region and comparing it to the actual diversity. All information provided is available through the Global Biodiversity Information Facility (GBIF) and the Open Science Framework (OSF) following the Darwin Core Standard.

This study focuses on quantifying the susceptibility of sandy beaches to storm-induced erosion by analyzing 14 key morphometric indicators. We used a 24-year morphological and metocean dataset, enabling the identification of 347 storms and their beach responses. Four beach profile patterns were identified according to the presence and characteristics of sandbars. Subsequently, four XGBoost models were individually trained for each profile pattern to discern the complex morphodynamics during storm conditions. SHAP analysis was then employed to identify the most influential morphometrics, revealing variations in the morphometrics contributing to beach susceptibility based on the beach profile type. Storm cases were divided into three groups based on storm power to validate the beach erosion susceptibility number (BESN). Evaluation of BESN for each profile pattern and storm group showed that unbarred profiles under average storm conditions exhibited the highest correlation, with a Pearson correlation coefficient (r) of 0.75. There was at least a 0.40 correlation coefficient between observed beach erosion and BESN in eight of the 12 scenarios studied. These findings highlight the effectiveness of BESN in quantifying the susceptibility of different beach profile patterns to erosion. BESN provides valuable insights regarding the vulnerability of sandy beaches by considering key morphometrics. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) contamination is a well-established impact in oceans, but integrated approaches combining simultaneous analyzes of biotic and abiotic components are scarce. This study addresses this gap, demonstrating Atherinella brasiliensis (fish species) ingestion of MPs and comparing with the contaminant presence in water and sediment. Three Ubatuba beaches (exposed, calm and sheltered estuary) were surveyed for fish, water, and sediment components in summer and winter. Environmental data evidenced spatial and seasonal differences (PCA/ANOVA). Presence of synthetic particles (SPs) in fish was high (~38%). Maximum concentrations occurred in the estuary, for water (490 SPs/m³), and in the exposed beach, for sediment (62 SPs/50g). Fibers format predominated in all components. Fish preference for blue color seems to occur. Significant statistical relationships were determined for fish length and SPs size and between SPs concentrations in water and fish. The chemical identities (µ-FTIR spectra) polypropylene, polyethylene, polyamide, polyester, and cardboard/cellulose predominated. Influences of local hydrodynamics (e.g., SPs sizes) and reduction in tourism during Covid-19 epidemic (e.g., less SPs in summer) are discussed. This study confirms environmental contamination by SPs (mostly MPs) in Ubatuba beaches, affecting fish through direct water column ingestion. Urgent actions from authorities and changes in local user's habits are crucial. [ABSTRACT FROM AUTHOR]

Olivancillaria carcellesi occurs in shallow sandy shores from north Patagonia, in intertidal and subtidal sandy bottoms. Females of O. carcellesi exhibited a remarkable specificity for spawning on the shells of living males and females, indiscriminately, of the buccinanopsid Buccinastrum deforme, measuring 26.9 ± 4.7 mm in shell length. The egg capsule was semispherical and attached to B. deforme shells by a small elliptical and wide base. The capsule was translucid when spawned, with a thick and semirigid wall and a hatching aperture of 1.8 ± 0.1 mm (n = 111) in diameter. Each egg capsule contained a single egg that measured 1367 ± 34 μm (n = 5) in diameter before cleavage. The embryo developed a small bilobed velum and an operculum, which were both lost before hatching as a crawling juvenile of 1762 ± 47 μm (n = 28) in shell length. As in other species in the genus, the eggs of O. carcellesi are among the largest in the caenogastropods with direct development. The time from oviposition to hatching is estimated to be approximately 6 months. [ABSTRACT FROM AUTHOR]

The once plentiful population of the tufted ghost crab, Ocypode cursor, a legally protected species, suffered a steep decline along the densely populated Mediterranean coast of Israel.Here we assessed the effects of recreational disturbance on crab populations in three sandy shore nature reserves and adjacent bathing beaches with differing accessibility during the summers of 2020–2021, employing burrow counts and burrow opening diameter as proxies for population abundance and population size structure.A total 6270 burrows were identified, counted and their opening diameter measured during the study period. The number of burrows was greatest close by the waterline and diminished landwards; this landwards decline was notable in the smallest burrows (<20 mm), representing the youngest population fraction. Comparison of population abundance between the surveyed nature reserves and adjacent bathing beaches revealed greater numbers in the former. However, a pronounced postweekend reduction in the number of burrows was apparent in nature reserves during both survey years, across sites and months and clearly indicates elevated recreational activity. The number of burrows in the nature reserve nearest to main population centres and abutting a popular bathing beach was smaller compared with the peripheral nature reserves.We observed no postsunrise activity of adult crabs, though in strictly access‐restricted beaches, crabs were active diurnally. We thus suggest that the crabs shifted their diel activity patterns as avoidance response to chronic anthropogenic disturbance, enduring a forced curfew and a temporal habitat loss.If the sandy nature reserves are to function as true refugia for the tufted ghost crab, restorative management is to include significant conservation and mitigation intervention measurements/actions. [ABSTRACT FROM AUTHOR]

The Brazilian coastal zone comprises several types of environments, including lagoons and beaches, chosen for this study, which evaluate benthic meiofauna spatial distribution patterns in three areas, suffering different disturbance levels, throughout the Brazilian Amazon coast. Sediments from three areas (São Marcos Beach – Low level of disturbance; Calhau Beach – Medium level of disturbance; and Jansen Lagoon – High level of disturbance), in São Luís city (Maranhão, Brazil), were sampled for meiofauna assessments, granulometry and organic matter analyses. A total of 7,254 meiofaunal organisms were identified, 4,371 at São Marcos Beach, 1,856 at Jansen Lagoon, and 1,027 at Calhau Beach. The findings indicate that richness, density, and community structures differed significantly among the sampled areas. Nematoda and Copepoda were the most abundant groups. Copepoda stood out in São Marcos Beach compared to other taxa. Nematoda dominated in Jansen Lagoon. Calhau Beach presented the lowest density and richness values, with Tardigrada as the predominant meiofaunal group. Additionally, the composition of meiofauna was influenced by environmental variables, such as salinity, OM, sediment grain size and nitrate concentration, as well as anthropogenic activities taking place in the sampled areas. Considering the lack of studies in the region with this focus, it is expected that the results presented will contribute to public policies development aimed to conservation of the coastal zone in São Luís. [ABSTRACT FROM AUTHOR]

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Knowing patterns and processes that govern macroinvertebrate distribution in sandy beaches becomes necessary in the framework of increasing human activities. Spatial patterns in sandy beaches are affected by daily changes in physical environmental conditions and species-specific features. Here, we assess the effect of daily changes on the spatial distribution along transects perpendicular to the waterline and habitat dispersion using Callichirus corruptus as a study model. Eleven sectors (urbanized and non-urbanized) were sampled on 6 beaches in southeastern Brazil, where ecological and biological information on this species was obtained. The spatial distribution of C. corruptus differed between the sampled sectors. However, higher density of burrows was observed in the intermediate portion, indicating aggregation in this zone. The burrow spatial dispersion index presented significant positive linear relationship with the size of saturated zones and the mean size of individuals. The spatial distribution of burrows was influenced by the sampling method, adequately represented by the gradient from low to the high tide mark in the intertidal zone. There was a strong clustering when burrows were counted along perpendicular transects to the shoreline, whereas a uniform distribution when burrows were counted in parallel transects. Aggregated patterns in the distribution of C. corruptus were observed in most of sampled beaches, highlighting the preference of the species for inhabiting the intermediate portion of the intertidal zone. Furthermore, other conditions that might additionally explain the spatial dispersion of macroinvertebrates in soft sediments and the effect of human activities on natural populations of sandy beaches remain to be explored. [ABSTRACT FROM AUTHOR]

Coastlines globally are sensitive to the effects of sea-level rise, increased coastal storminess and changes in coastal sediment supply and sediment dynamics in the Anthropocene. Coastlines are also influenced by land use change, urbanization and development of built infrastructure. These changes can affect the dynamics of coastal landforms, weaken coastal resilience and make coasts more sensitive to climate hazards. This study critically examines the properties of coastlines that contribute to coastal biophysical resilience in South Africa, highlighting their relativerates of change and dynamic behaviour in response to physical and human forcing factors. Coastal landforms can be considered as 'green infrastructure' that can buffer the effects of climate change as well as providing ecosystem and environmental services in their own right. Viewing coastal landforms as green infrastructure provides a 'nature-based solution' to mitigate against climate change impacts that can work with – not against – the natural geomorphic, sedimentary and ecological processes of coastlines. Coastal landforms can also contribute to socioecological resilience, where they provide environmental and ecosystem services. The green infrastructure approach to coastal resilience has not been well developed in South Africa but is more effective in supporting coastal sustainable development. [ABSTRACT FROM AUTHOR]

Abstract Microplastics (MPs) contamination is a well-established impact in oceans, but integrated approaches combining simultaneous analyzes of biotic and abiotic components are scarce. This study addresses this gap, demonstrating Atherinella brasiliensis (fish species) ingestion of MPs and comparing with the contaminant presence in water and sediment. Three Ubatuba beaches (exposed, calm and sheltered estuary) were surveyed for fish, water, and sediment components in summer and winter. Environmental data evidenced spatial and seasonal differences (PCA/ANOVA). Presence of synthetic particles (SPs) in fish was high (~38%). Maximum concentrations occurred in the estuary, for water (490 SPs/m³), and in the exposed beach, for sediment (62 SPs/50g). Fibers format predominated in all components. Fish preference for blue color seems to occur. Significant statistical relationships were determined for fish length and SPs size and between SPs concentrations in water and fish. The chemical identities (μ-FTIR spectra) polypropylene, polyethylene, polyamide, polyester, and cardboard/cellulose predominated. Influences of local hydrodynamics (e.g., SPs sizes) and reduction in tourism during Covid-19 epidemic (e.g.,less SPs in summer) are discussed. This study confirms environmental contamination by SPs (mostly MPs) in Ubatuba beaches, affecting fish through direct water column ingestion. Urgent actions from authorities and changes in local user’s habits are crucial.

Beach erosion is a complex process influenced by multiple factors operating at different spatial scales. Local (e.g., waves, tides, grain size, beach width and coastal development) and regional (e.g., sea level rise and mean sea level pressure) factors both shape erosion processes. A comprehensive understanding of how these drivers collectively impact sandy beach erosion is needed. To address this on a global-scale we assembled a database with in-situ information on key physical variables from 315 sandy beaches covering a wide morphodynamic range and complemented by satellite data on regional variables. Our results revealed the combined influence of local and regional factors on beach erosion rates. Primary drivers were regional anomalies in mean sea level pressure and variations in mean sea level, and local factors such as tide range, beach slope and width, and Dean’s parameter. By analyzing morphodynamic characteristics, we identified five distinct clusters of sandy beaches ranging from wave-dominated microtidal reflective beaches to tide-modified ultradissipative beaches. This energy dissipation gradient emerged as a critical factor, with erosion rates increasing with beach width and dissipativeness. Our study also highlighted the tangible impact of climate change on beach erosion patterns. Hotspots were identified, where intensification of regional anomalies in mean sea level pressure, increasing onshore winds and warming rates, and rising sea levels synergistically accelerated erosion rates. However, local variables were found to either amplify the effects of regional factors on erosion or enhance a beach’s resistance, mitigating erosive trends initiated by regional drivers. Our analysis showed that more than one-fifth of the analyzed beaches are experiencing intense, extreme, or severe erosion rates, and highlighted the significant role of human activities in explaining erosion trends, particularly in microtidal reflective and intermediate beaches. This underscores the long-term threat of coastal squeeze faced by sandy beaches worldwide and emphasizes the need to consider both local and regional drivers in order to understand erosion processes. Integrating localized measurements with broader satellite observations is required for a comprehensive understanding of the main drivers behind coastal evolution, which in turn is needed to manage and preserve these fragile ecosystems that are at risk.

Many shorebirds rely on sandy beaches to breed. However, these ecosystems are rare and unstable on the Guianas coast because of sediment dynamics. Nonetheless, they host 2 shorebirds that breed in the Nearctic and the Neotropic: Wilson's Plover (Charadrius wilsonia) and Black-necked Stilt (Himantopus mexicanus). We studied their breeding biology in the Amana Nature Reserve, a Ramsar Site in French Guiana, on sandy beaches bordered by brackish lagoons during 1 breeding season. From early June to late August 2008, we located and monitored 19 Wilson's Plover and 15 Black-necked Stilt nests. Most nests were associated with bare ground. While stilts preferred to build their nests with twigs closer to lagoons, plovers did not show any preference in nest location and composition. For plovers and stilts, clutch sizes were 2–3 eggs or 3–4 eggs per nest, respectively, and the mean egg volumes were 12.1 ± 0.4 cm3and 20.6 ± 0.6 cm3, respectively. The apparent hatching success for both species was low, 11% for Wilson's Plover and 13% for Black-necked Stilt, whereas daily nest survival was high for both species. Clutch sizes, egg dimensions, and egg colorations were comparable to those described elsewhere, but the breeding season started later than at other localities for the Wilson's Plover. In French Guiana, the apparent nest success values for both species were much lower than those reported in the United States and the West Indies but seemed slightly higher than in Brazil. Human activity impacts were limited in our study area and did not explain the low nest success values found. Beach flooding at high tide was the main cause of clutch failure, followed by predation. Ironically, flooding allows the maintenance of this low, open, and debris-covered habitat used by beach-nesting shorebirds. Beaucoup de limicoles dépendent des plages sableuses pour se reproduire. En raison de la dynamique sédimentaire, ces plages sont rares et instables sur la côte des Guyanes. Néanmoins, elles abritent deux espèces de limicoles nichant dans le néarctique et le néotropique: le Pluvier de Wilson (Charadrius wilsonia) et l'Echasse d'Amérique (Himantopus mexicanus). Nous avons étudié la biologie de leur reproduction dans la réserve naturelle de l'Amana, un site Ramsar en Guyane Française, sur des plages sableuses bordées de lagunes saumâtres pendant une saison de reproduction. De début juin à fin août 2008, nous avons localisé et suivi 19 nids de Pluvier de Wilson et 15 nids d'Echasse d'Amérique. La plupart des nids étaient associés à des sols nus. Le pluvier de Wilson n'a montré aucune préférence quant à l'emplacement et à la composition des nids. Tandis que l'Echasse d'Amérique préférait construire son nid avec des brindilles plus près des lagunes. La taille des couvées était respectivement de 2–3 œufs et de 3–4 œufs par nid, et le volume moyen des œufs était de 12.1 ± 0.4 cm3 et 20.6 ± 0.6 cm3. Le succès apparent d'éclosion était faible pour les 2 espèces, avec 11% pour le pluvier et 13% pour l'échasse, alors que la survie journalière des nids était haute. La taille des pontes, la dimension et la coloration des œufs étaient comparables à celles décrites ailleurs, mais la période de reproduction était plus tardive chez le Pluvier de Wilson. En Guyane française, les succès apparents des nids des deux espèces étaient beaucoup plus faibles que ceux observés aux États-Unis et aux Antilles, mais ils semblaient légèrement plus élevés qu'au Brésil. Les activités humaines étaient limitées sur le site d'étude et n'ont pas expliqué ce faible succès. La submersion des plages lors des grandes marées était la principale cause de l'échec des pontes, suivie par la prédation. Mais ces submersions ont paradoxalement participées au maintien de cet habitat bas, ouvert et couvert de débris utilisé par les limicoles nichant sur les plages. [ABSTRACT FROM AUTHOR]

The wave-impacted waters off exposed sandy beaches support marine megafauna, including dolphins, whales, sharks, rays and turtles. To characterise variation in megafaunal assemblages in this challenging habitat, we used drone-based remote sensing to survey marine megafauna off 23 beaches along 1050 km of the New South Wales (NSW, Australia) coast from 2017 to 2020. The surveys occurred from September to May and included 17,085 drone flights, with megafaunal abundances standardised by flight hours. In total, we identified 3838 individual animals from 16 taxa, although no megafauna was observed off 5 of the 23 beaches surveyed. Bottlenose dolphins were the most commonly sighted taxa and accounted for 82.3% of total megafaunal abundance. Cownose (6.7%) and eagle (3.4%) rays were the next most abundant taxa, with potentially dangerous sharks being rarely sighted (<1% of total megafauna). The megafaunal assemblages off wave-exposed beaches in northern NSW significantly differed from those in the central region, whereas the assemblages off the central region and southern NSW did not differ significantly. Wave exposure and water temperature were the best predictors of megafaunal assemblage structure. The richness of marine megafauna off ocean beaches was significantly greater in northern than southern NSW, and turtles were only observed off beaches in the northern region. However, variation in megafaunal richness, as well as the abundances of total megafauna, dolphins, rays, sharks and turtles were not significantly explained by water temperature, wave height, distance to estuary, or proximity to the nearest reef. Overall, drone-based surveys determined that megafaunal assemblages off wave-exposed beaches are characterised by sparse individuals or small groups of sharks, turtles and rays, punctuated by occasional large aggregations of dolphins, cownose rays and schooling sharks. The exception to this pattern was bottlenose dolphins, which routinely patrolled some beaches in northern NSW. [ABSTRACT FROM AUTHOR]

Coastal urbanization, plastic pollution and climate change are increasingly affecting marine turtles' nesting habitats. In addition to facing risks of mortality due to saltwater inundation or predation, their eggs and hatchlings' might also be affected by plastic debris accumulation on beaches, but no studies to date have analysed such impact. To analyse whether plastic pollution on nests' surfaces affects the embryos' and hatchlings' survival odds, we designed a field experiment in a turtle hatchery on a nesting beach of the loggerhead turtle (Caretta caretta) in Boa Vista Island (Cabo Verde). We applied three treatments with distinct plastic levels (18 nests per treatment): control (no added plastics), low density (64 plastic fragments with 24.5 g of plastic weight per nest) and high density (128 plastic fragments with 49.0 g of plastic weight per nest). Then, we tested 16 variables related to the incubation period, emergence period and hatchlings' fitness. Our results suggest that nests with high plastic density have a significantly lower probability of successful emergence. Moreover, plastics also affected the synchronized emergence of hatchlings, with more scattered and smaller emergent groups, which might increase the predation risk. Considering that turtle nesting habitats are becoming increasingly threatened, this additional threat might compromise the survival of turtle hatchlings on beaches. [ABSTRACT FROM AUTHOR]

As problematic as global warming, ocean acidification is a widespread problem, but the consequences of the interstitial fauna are still underrated. The biodiversity within sandy beaches is out of measurement, and its loss will be significantly felt. Estimations of the number of species are still vague. Acting as a key role in the trophic net, the interstitial organisms are threatened by pH value changes. Changing the pH values is already linked with less species richness and weakness of the sea community. The sediments may not be a sufficient buffer. Beyond this, there is another environmental problem aggravating the scenario. The decreasing complexity in the sand structure generated by the destruction of biological-generated sediments will impact the local biodiversity. Other environmental situations such as lack of sufficient O2 levels may be an aggravating combination. Here, I propose a protocol to observe if occur offshore extinctions, the veiled extinctions of interstitial fauna. [ABSTRACT FROM AUTHOR]

Free living marine nematodes were sampled from two sandy beaches in Dalian City, in December of 2015, and April, July, and October of 2016. The spatial and seasonal variations of marine nematode species diversity (based on species abundance dataset) and functional diversity (based on functional traits dataset: feeding types and life history strategies) were investigated to understand the environmental drivers and how they respond to specific environmental variations. Sediment granularity was revealed to be the main environmental factor causing spatial differences in nematode diversity indices between the two beaches. Species diversity indices, namely species number, Margalef index, Shannon-Wiener diversity index (H′), were higher in fine-grained sediments, while the functional diversity indices, including functional evenness, functional dispersion, and Rao's quadratic entropy index (RaoQ), were higher in coarse-grained sediments. Nematode species diversity indices also fluctuated with seasonal variations of temperature, dissolved oxygen, pH, salinity, and sediment chlorophyll-a within the study beaches. However, functional diversity indices did not show significant seasonal variations and exhibited weak correlation with the studied environmental variables. Overall, the functional diversity indices were negatively correlated with the species diversity indices, suggesting an inconsistent response to environmental changes. A decrease in nematode species diversity in coarse sands, accompanied by an increase in functional diversity, can be regarded as an early warning signal of environment disturbance. If more biological traits are involved in calculating functional diversity indices, it will be helpful for the future study of the internal connections of species diversity and functional diversity. [ABSTRACT FROM AUTHOR]

Urban expansion in Brazilian coastal zones has caused various anthropic impacts on coastal marine ecosystems that have resulted from unorganized use and the lack of infrastructure projects. The inadequate disposal of domestic and industrial effluents in coastal waterbodies is notable, which can cause severe environmental problems. For sandy beaches, the relationships between the contamination of groundwater with domestic sewage and the possible effects on spatial and temporal variations in the density and composition of benthic infauna are still poorly understood. This work aimed to relate variations in benthic infaunal associations with the concentrations of groundwater nutrients in summer and winter on Enseada Beach. The greater concentrations of nutrients in water percolating through the sediment in the summer, increasing of domestic effluents, and periods of intense precipitation increased the contamination of the surface and groundwater. This contributes to an increase in the population density of Thoracophelia furcifera, demonstrating its use as an indicator of eutrophication of the groundwater, allowing monitoring and contribution to actions aimed at improving the environmental quality of sandy beaches. [ABSTRACT FROM AUTHOR]

Since the 1970s, dredging sands have been poured onto the embayed beaches of La Magdalena in the western mouth of the estuarine Bay of Santander (N Spain) in order to increase beach width. Up until the year 2000, the sands were systematically fed by a trailing suction dredge, which was later replaced by truck sand transfers from the surplus sands of the western beach to the eastern ones and by mechanical redistribution to create artificial berms. A recent project aimed to solve sand losses after each storm by building two perpendicular breakwaters about 620 m apart. The eastern breakwater was built in the early summer of 2018, and wave storms in November 2018, February 2019, October 2020 and the last days of 2021 progressively dismantled the reconstructed upper beach areas and eroded other segments. The western breakwater, however, designed to retain the E–W sandy beach drift, was never built. Four photogrammetric restitutions from 2005, 2010, 2014 and 2017 and an aerial LiDAR in 2012 were obtained to better understand the previous topographic distribution of the back and foreshore. Numerous field observations were made, and six field surveys have been performed since 2018 using laser TLS and GNSS, which occurred in November 2018, March 2019, October 2019, March 2020, October 2020 and April 2021. The definitive results of the evolution of the sand loss are presented, a hypothesis is proposed to explain the dynamo-sedimentary trend, in which longitudinal transport dominates promoting the formation in the progress of a new sand beach, and some sustainable solutions are proposed. The results show that the constructive solution has failed to stabilize the beach and that the predictive models that justified it have not coincided with the real dynamic and sedimentary evolution. [ABSTRACT FROM AUTHOR]

Introduction: Pollution by microplastics is a global problem in marine environments, which impacts microorganisms and ecosystems at several spatial levels. Sandy beaches are depositional environments where microplastics tend to accumulate in large quantities. The co-occurrence of interstitial meiofauna and microplastics in sand grains raises the question on whether the accumulation of microplastics in the sediments affects the abundance and composition of the meiofaunal communities. Objective: To test the hypothesis that microplastics affect the meiofauna of urban sandy beaches. Methods: We studied the three main urban sandy beaches of Santa Marta, Colombia: El Rodadero, Santa Marta Bay, and Taganga. All are similar in morphology and external pressures, and differ from other beaches in the region. In April 2019 we collected 81 sand samples, equally distributed in the intertidal zone (upper, mid, and lower intertidal levels). We applied generalized linear models to abundance, and multivariate permutational tests to community composition. Results: We identified 17 taxonomic groups of meiofauna, and microplastic particles (mainly 45-500 micron fibres) evenly distributed across beaches and intertidal levels. There was more meiofauna at the mid intertidal level, and in fine and medium grain sediment. At the lower intertidal level, sites with more microplastics had less meiofauna. Abundance of microplastics explained 39 % of the variation in meiofaunal community composition at lower intertidal levels. Conclusions: The accumulation of microplastics might have a negative impact on these meiofaunal interstitial communities. This is not surprising: if microplastics occupy the same physical space as these animals, they might presumably modify the structure of sediments and the composition of interstitial water. [ABSTRACT FROM AUTHOR]

A preliminary sediment budget for the sandy shores flanking the entrance to Western Port, a large bay in Australia, was formulated using a comparison between two Digital Surface Models (DSMs) with a 30-year interval and auxiliary shoreline data. The 1977 DSM was generated from ten aerial photographs using Structure-from-Motion (SfM) photogrammetry. Assessment of its accuracy obtained an RMSE of 0.48 m with most of the independent points overpredicting or underpredicting elevations by less than 0.5 m following manual point cloud cleaning. This technique created a 7.5 km2 surface with a Ground Sampling Distance of 34.3 cm between two coastal towns separated by a narrow channel. Comparison of the 1977 DSM to a second, light detection and ranging (LiDAR)-derived DSM from 2007 showed that a volume of ~200,000 m3 of sediment (above Mean Sea Level) was deposited at Newhaven Beach on Phillip Island, while, during the same period, ~40,000 m3 of sediment was lost from the mainland beaches of San Remo, on the eastern side of the channel. Shoreline positions extracted from aerial photographs taken in 1960 and a nautical chart published one century earlier indicate that the progradation experienced at Newhaven Beach has been possible due to provision of sediment via destabilisation of the vegetation covering the updrift Woolamai isthmus on the southeast coast of Phillip Island, whereas the retreat observed at San Remo Beach since 1960 can be attributed to the natural dynamics of the entrance, which appears to favour flood-dominance on the western side and ebb-dominance on the eastern side. While a more comprehensive balance of volumes entering and exiting the area would specifically benefit from volumetric assessments of the subaqueous part of the entrance, the general usefulness of quantifying coastal change using SfM and historical photographs is demonstrated. [ABSTRACT FROM AUTHOR]

The wave-impacted waters off exposed sandy beaches support marine megafauna, including dolphins, whales, sharks, rays and turtles. To characterise variation in megafaunal assemblages in this challenging habitat, we used drone-based remote sensing to survey marine megafauna off 23 beaches along 1050 km of the New South Wales (NSW, Australia) coast from 2017 to 2020. The surveys occurred from September to May and included 17,085 drone flights, with megafaunal abundances standardised by flight hours. In total, we identified 3838 individual animals from 16 taxa, although no megafauna was observed off 5 of the 23 beaches surveyed. Bottlenose dolphins were the most commonly sighted taxa and accounted for 82.3% of total megafaunal abundance. Cownose (6.7%) and eagle (3.4%) rays were the next most abundant taxa, with potentially dangerous sharks being rarely sighted (

Ghost Crabs, Ocypode cursor (Linnaeus, 1758), are used as a bioindicator species to evaluate the ecological condition of sandy beaches. Studies using Ghost Crabs as bio-indicator have often focused on the influence of human disturbance and beach geomorphology, separately. However, the relative importance of these variables should be assessed to maintain community structure. Here, I used an indirect burrow examination technique to understand whether Ghost Crabs respond to human disturbance stronger than to geomorphological properties of the sites. I analysed sand compaction rate, sand grain size, beach width, and beach slope as geomorphological features and urbanization index as a measure of human disturbance on each site. I further examined Ghost Crab burrows by counting and measuring the openings. Ghost Crabs showed lower population density and individual body sizes as a response to human disturbance, and the level of this response was partly related to the geomorphological features of the sites. However, human disturbance explained approximately 72% of the variation in the Ghost Crab burrow density and about 70% of the variation in the burrow size, alone. The findings of this study corroborate the use of Ghost Crabs as an efficient bioindicator species of human disturbance on sandy shores to achieve efficient beach management, yet suggest that managers and scientists should combine the influences of geomorphological features of the beaches and the degree of human disturbances in their ecological assessments. [ABSTRACT FROM AUTHOR]

The swash zone is a critical area of the nearshore hydrodynamics contributing significantly to beach evolution. The role of infiltration of water during swash events has been investigated, but an enhanced data collection methodology will improve prediction and analyses of swash processes. A new and simple technique was proposed to determine the rate of swash infiltration on sandy beaches. Direct, in situ measurements of swash infiltration rates were conducted on the sandy beach of Las Cuevas Bay located on the north coast of Trinidad. The method incorporated the use of a double ring infiltrometer paired with a Bluetooth water level logger, where infiltration rates were inferred from the changes in water level recorded within the double ring infiltrometer. Observed infiltration rates were variable and showed a dependency on sediment characteristics and location of measurement. The study also sought to ascertain any correlation between the measured infiltration rates and sediment properties. While correlation was generally low, the use of the maximum recorded infiltration rate yielded the best correlation across most cases observed. In addition, the highest correlation occurred with the D10 grain size for the upper beach, and the D90 grain size for the lower beach which is closer to the Still Water Line. The sediment sorting ratio of D84/D16 and D90/D10 showed the best correlation for the upper and lower beach locations respectively. While the field method was practical, the results of the study demonstrate a need to capture additional bed features that contribute to the rate of infiltration. [ABSTRACT FROM AUTHOR]

Anthropogenic marine debris (AMD) is an environmental pollution that affects marine life, human health, wellbeing, and the economy. This marine litter can deposit in the coastlines, particularly on tidal zones and beaches. To pursue future mitigation strategies to reduce AMD is important to monitor the amount, type and frequency of litter being dumped on shores. This study presents the composition, temporal distribution, abundance and size of AMD on three sandy beaches from Guayas province, Ecuador. The field data was recollected from December 2018 to February 2020. A total of 12,362 items of AMD were collected with an abundance of 1.95 macro-litter items/m2. The composition of AMD was marked by the predominance of plastic items (91.8%), followed by wood and cloth (1.9%), while cigarettes were only present in village beaches. Our results suggest that sites with more AMD abundance are beaches nearby small coastal villages and fishing communities. Also, the AMD abundance is slightly higher at the beginning of the dry season than in the rainy season. Our findings indicate that it is necessary to implement concerted solid waste management measures and proactive environmental education programs to empower the local population, as well as investigate the anthropogenic sources and other variables influencing the AMD abundance coming onto sandy shores.

Light pollution is becoming prevalent among other coastal stressors, particularly along intertidal habitats, arguably the most exposed to anthropogenic light sources. As the number of light pollution studies on sandy beaches, rocky shores and other intertidal habitats raises, commonalities, research gaps and venues can be identified. Hence, the influence of light pollution on the behavior and ecology of a variety of intertidal macro-invertebrates and vertebrates are outlined by examining 54 published studies. To date, a large majority of the reported effects of light pollution are negative, as expected from the analysis of many species with circadian rhythms or nocturnal habits, although the severity of those effects ranges widely. Experimental approaches are well represented throughout but methodological limitations in measurement units and standardization continue to limit the proposal of general conclusions across species and habitats. In addition, studies targeting community variables and the explicit influence of skyglow are heavily underrepresented. Likewise, studies addressing the interaction between light pollution and other natural and anthropogenic stressors are critically needed and represent a key venue of research. The nature of those interactions (synergistic, additive, antagonistic) will likely dictate the impact and management of light pollution in the decades ahead.

Shoreline variations, triggered by climate change, eustatism, and tectonic, drive the coastal landscape evolution over multiple spatial and temporal scales. Among the many different existing coast types, sandy coasts are the most sensitive to coastal erosion and accretion processes and, at the same time, often host valuable anthropogenic assets. The rapid and ongoing evolution of these coastal environments poses challenges for their management, necessitating cost-effective and highly reliable methods for measuring these changes. Many remotely sensed shoreline extraction methods have been proposed in the literature, providing valuable tools for improving coastal management. Even if these methodologies allow the demarcation of the shoreline, its pixelated shape usually requires refinement through subsequent smoothing or vector generalization processes. It is important to note that the position of the thus extracted coastline is not a direct result of a measured physical quantity but rather a product of these refinement techniques. To address this problem, we developed a sub-pixel resolution method for extracting shorelines from remotely sensed images of sandy beaches, leveraging the radiometric signature of the shoreline. Validated through precise Global Navigation Satellite System field surveys for positioning the beach foreshore, this method was successfully applied to three beaches in Sicily, in the central Mediterranean, all exhibiting similar microtidal conditions. Its robust design allows for application across various satellite images, employing a straightforward radiometric interpolation method adaptable to different spatial resolutions. This method would be a valuable tool for coastal managers in detecting and mitigating coastal erosion and developing and maintaining anthropogenic coastal assets. • Shoreline monitoring is often limited by time series length and spatial resolution. • A new subpixel shoreline isoradiometric extraction method was proposed. • Shorelines were extracted from various spectral bands. • Extracted shorelines were validated at different resolutions. • The beach grain size and slope impact on the shoreline extraction was quantified. [ABSTRACT FROM AUTHOR]

Despite a recent ambitious plan to improve waste management in Thailand, few studies have monitored the impact of these policies on beached marine litter. Here, we assessed weekly the amounts and composition of stranded macro-litter (≥2.5 cm) on five beaches from an uninhabited island in Thailand during one year. A total of 24,407 items (391.86 kg) yielded a mean abundance of 3.18 ± 11.39 items m−2 (52.75 ± 204.68 g m−2), with plastic being the most abundant marine litter (48% of the total number). The overall Clean Coast Index (30.1) classified the beaches as ' extremely dirty ', with a Plastic Abundance Index of 9.8 (' very high abundance ' of plastics). When assessing the seasonal rates of accumulation, we found a higher flux pre-monsoon (0.05 items m−2 d−1; 0.66 g m−2 d−1) than post-monsoon (0.01 items m−2 d−1; 0.35 g m−2 d−1). Using modeling of the local hydrodynamic conditions, we explored the potential sources of the pollution, and surprisingly found that the closest river appeared not to be the source. Our results denote that the distribution and typology of marine litter were representatives of household and fishing activities, which in turn highlights the need for better regional litter management measures. [Display omitted] • ●Site location and season influenced macro-litter distribution over 7 months. • Plastic was the dominant debris, with a prevalent contribution of single-use items. • Marine litter were representatives of household and fishing activities. • Modeling of currents suggests that litter did not originate from the closest river. • Despite a recent management plan, Thailand is still challenged by marine pollution. [ABSTRACT FROM AUTHOR]

Ecological connectivity can influence the distributions of diversity and productivity among ecosystems, but relationships among multiple marine ecosystems remain relatively uncharacterized. Sandy beaches are recipient ecosystems that support coastal food webs through deposits of drift macrophytes (wrack), and serve as test cases for exploring within-seascape connectivity. We present results from the first comprehensive survey of geographic and temporal patterns of wrack cover and composition on beaches along the North Central Coast of California and test the role of local donor ecosystems and physical factors in predicting wrack distribution. We surveyed wrack at 17 beaches in August 2010, and monthly at a subset of 10 beaches for 13 months. We estimated explanatory variables of (1) local donor ecosystem cover (kelp forests, rocky intertidal, and bays and estuaries), (2) biomass transport, and (3) beach morphology. Regression analyses were used to evaluate relationships among the cover of six key wrack categories and the explanatory variables above, for two time periods. We found persistent geographic variation in wrack composition and detected significant relationships between wrack cover and cover of local donor ecosystems for five of the six wrack categories (Nereocystis, Zostera, Postelsia, mixed red algae, and mixed brown algae). Transport mechanisms (wind exposure, swell exposure) or attributes of the recipient ecosystem (beach width, beach slope) explained additional spatial variation for three of the six wrack categories (Zostera, Phyllospadix, and mixed red algae). Our results support the concept of considering ecological connectivity (particularly the role of donor ecosystems upon which recipient ecosystems rely) in the design and management of protected areas.

Morphological and molecular evidence suggests that the ghost shrimp population in Brazil that had been assigned to Callichirus major (Say, 1818) represents a distinct species. A neotype of C. major is designated in the interest of nomenclature, because the holotype is no longer extant. Based on material from Brazil, a new species, Callichirus corruptus, is described. Differentiating characters between the new species and C. major are discussed and an identification key to species of Callichirus is provided. [ABSTRACT FROM AUTHOR]

Wrack supply represents the main organic input in sandy beaches ecosystems and is a common feature of beaches around the world. The chemical composition of the wrack is important in determining the extent and rate of the decay; in particular, phenolic compounds may affect consumption rates by wrack‐associated macrofauna and, consequently, modify the nutrient processing and recycling in sandy beaches. The aim of this research was to investigate the possible links between phenolic content of wrack supplies and the macrofaunal community inhabiting them. To achieve this, patches of wrack in three beaches of the NW coast of Spain were analysed and the phenolic contents and macrofaunal distribution, both at spatial and temporal scales, were assessed. Wrack and macrofaunal samples were collected along two shore‐parallel transects, coinciding with the wrack lines of previous tidal deposition. The results showed a general spatial distribution in the phenolic content of the beach‐cast according to their tidal position on the beach. Thus, two distinct zones were identified: the "spring‐tide deposited" zone located in the upper beach close to the base of the dunes and composed by wrack material with the lowest phenolic concentrations; and a "freshly deposited" zone with wrack deposits containing the highest concentrations of deterrent compounds. Nevertheless, only supratidal grazers, mostly linked to fresh deposits, have shown a slightly negative association between their abundance and the increasing phenolic contents of the stranded macroalgae. The lack of a consistent pattern in macrofaunal occupation of fresh and decayed drift lines detected suggests the species could be selecting habitats for reasons other than phenolic content. [ABSTRACT FROM AUTHOR]

Since the 1970s, dredging sands have been poured onto the embayed beaches of La Magdalena in the western mouth of the estuarine Bay of Santander (N Spain) in order to increase beach width. Up until the year 2000, the sands were systematically fed by a trailing suction dredge, which was later replaced by truck sand transfers from the surplus sands of the western beach to the eastern ones and by mechanical redistribution to create artificial berms. A recent project aimed to solve sand losses after each storm by building two perpendicular breakwaters about 620 m apart. The eastern breakwater was built in the early summer of 2018, and wave storms in November 2018, February 2019, October 2020 and the last days of 2021 progressively dismantled the reconstructed upper beach areas and eroded other segments. The western breakwater, however, designed to retain the E–W sandy beach drift, was never built. Four photogrammetric restitutions from 2005, 2010, 2014 and 2017 and an aerial LiDAR in 2012 were obtained to better understand the previous topographic distribution of the back and foreshore. Numerous field observations were made, and six field surveys have been performed since 2018 using laser TLS and GNSS, which occurred in November 2018, March 2019, October 2019, March 2020, October 2020 and April 2021. The definitive results of the evolution of the sand loss are presented, a hypothesis is proposed to explain the dynamo-sedimentary trend, in which longitudinal transport dominates promoting the formation in the progress of a new sand beach, and some sustainable solutions are proposed. The results show that the constructive solution has failed to stabilize the beach and that the predictive models that justified it have not coincided with the real dynamic and sedimentary evolution.

Acanthocephalan parasites, specifically from the genus Profilicollis, are known to infect decapod crustaceans, including mole crabs like Emerita brasiliensis, which serve as intermediate hosts in their complex life cycles. This study reports the first occurrence of the acanthocephalan parasite Profilicollis altmani infecting the mole crab Emerita brasiliensis on a sandy beach in southeastern Brazil, thereby expanding the known geographic range of this parasite. Additionally, the study provides novel molecular data that enhance our understanding of the parasite's taxonomy and distribution, including the first evidence of genetic variation within populations of the intermediate host E. brasiliensis. Phylogenetic analysis based on mitochondrial COX1 gene sequences confirmed the identification of the parasite and underlined small genetic differences among P. altmani populations. These findings suggest a weak genetic population structure of the parasite and underscore the need for further studies to understand gene flow among these populations. This work contributes to the knowledge of parasite-host interactions in sandy beach ecosystems. It highlights the importance of monitoring parasitic infections in species like E. brasiliensis, which play a crucial ecological role in these environments., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The interstitial environment of sandy bottoms is an enigmatic habitat that forms unique ecosystems containing significant numbers of biodiversity. One of the lesser known marine invertebrate that inhabit this environment are sea cucumbers. The relative scarcity and lack of attention paid on these species have been the main obstacles to research and hence, knowledge of their taxonomy, biology, and ecology is limited. Thus, this review attempts to summarize the up-to-date overview of available knowledge on the diversity, distribution and the biology of interstitial sea cucumbers. [ABSTRACT FROM AUTHOR]

The accurate knowledge of the location and movement of the sand bars is important for the coastal manager to establish correctly the coastal defence elements. This work applies a numerical model of finite elements based on Galerkin's formulation for predicting the location of the start, crest and end of the outer bar. The model that shows the best results is the one that combines the variables wave height, period and median sediment size. The mean errors are less than 10 m in the distance to the shoreline and 17 cm in the depth, while in the formulations proposed by other authors the errors are more than 100 m in the distance to the shoreline and 2 m in the depth. Thus, the proposed model significantly improves the calculation of the sand bars position. This will allow a better location of the coastal defence elements, and therefore an improvement in their effectiveness and optimisation of the materials to be used in their construction, the key to sustainable coastal management. Furthermore, although the model was developed for the area of Valencia (Spain), the model can be used in any area with similar characteristics (open sandy beach), and the methodology (variables and process) could be applied worldwide. [ABSTRACT FROM AUTHOR]

Technological advances have reinvigorated the aerial photogrammetric technique using both historical and contemporary imagery, and fostered new perspectives in geomorphology studies. On sandy beaches, however, the dynamic processes, the lack of tonal contrast and reduced texture, make the application of photogrammetry extremely more difficult than in most other landscapes. This study quantifies decadal volumetric changes along the beaches of the Great Ocean Road, Australia, using improved digital surface models (DSMs) derived from structure‐from‐motion (SfM) photogrammetry applied to historical archives and a contemporary unmanned aerial vehicle survey. Alongside surficial sediment analysis, this approach demonstrates the potential to relate present‐day to historical morphological changes at sandy beaches worldwide. The discussion highlights the influence of photographic scale, lens distortions, ground control points in segmented blocks, and the use of shoreline as a proxy of volumetric change. DSMs were derived using datasets obtained in 1946, 1966, 1971, 1977, 1986 and 2019, and compared to a 2007 light detection and ranging (LiDAR)‐derived DSM. The emerging approach produced suitable DSMs for volumetric analysis, except for the 1946 dataset, which had the smallest scale and was significantly vertically offset. Volumetric losses of up to 60 m3/m of beach length were calculated for parts of Mounts Bay between 1977 and 2007, and up to 21 m3/m in recent years. At Apollo Bay, the construction of the port in the early 1950s significantly impacted the natural longshore drift to the beach. The adjacent stretch of coastline accreted at a rate of ~35 m3/m between 1966 and 2007, as a function of dredge disposal and changes in sediment transport, whereas a maximum volumetric loss of ~47 m3/m was detected further north between 1977 and 2007. A volume of ~71,330 ± 15,200 m3 was lost from the system from 2007 to 2019, despite the continued deposition along the northern section of the beach. [ABSTRACT FROM AUTHOR]

Assessing the susceptibility of sandy beaches to flooding during major storms is an important topic, given the implications that these events can have for beach-dependent coastal systems. A flood susceptibility index based on wave run-up, storm surge and beach morphology is applied to three sectors of the northwest coast of Portugal. An extended ERA5 wave dataset is used (1950–2022) to characterize the most frequent storm events, and topographic data from aerial UAV surveys are examined to obtain specific morphological parameters of the sandy beaches – mean face slope and height of the beach. The flood susceptibility index results show that 54 % of the analyzed coast is classified with extreme or very high susceptibility. The most critical sector is the coastal stretch between Cortegaça and Torrão do Lameiro beaches, where mostly natural systems are present, while the urban front of Furadouro is frequently flooded during storm events. Between Miramar beach (south) and Paramos beach, with a susceptibility index classified between medium and extreme, the presence of some urban fronts points to high-risk exposure situations. The sector between São Jacinto and Poço da Cruz beaches presented lower susceptibility levels for the three urban areas. The problem does not end with the threat to urban fronts, which already have several defense structures, but it is also extends to dune systems and sand dykes. [ABSTRACT FROM AUTHOR]