Section Of Beach Research Articles

Hydrodynamic mechanisms of topographic evolution in straight sandy beach: a case study of Wanpingkou beach, China

Stricter controls on destructive human activities in recent years have improved the protection and management of sandy coasts in China. Marine-driven geomorphic changes have become the predominant process influencing future beach evolution. However, in the complex geomorphic conditions of mixed artificial and natural coastlines, the mechanisms and contributions of various marine-driven factors to beach changes remain unclear. Using methods of field observations and numerical simulations by FVCOM model, this study reveals the sedimentary dynamic mechanism of straight sandy beach in the southern Shandong Peninsula (Wanpingkou beach, WPK beach). From 2005 to 2016, the northern section of WPK Beach eroded at a rate of approximately 2-3 m/year, the middle section at about 0.5-1.5 m/year, and the southern section accrued at an average rate of about 1-2 m/year, demonstrating an overall pattern of “northern erosion and southern accretion.” During winter, the average grain size of beach sediments is about 0.5 mm with minimal variations, indicating an onshore transport trend; in summer, the average grain size is about 0.7 mm with larger variations, indicating an offshore transport trend. Offshore sediment transport correlates mainly with seasonal changes in wind direction, while alongshore sediment transport is influenced by tidal currents, wind-induced currents, and wave-induced currents. Wave-induced currents are the primary force in alongshore sediment transport with a velocity of 0.1-0.3 m/s toward southwest. Followed by tidal currents with a velocity of 0.05-0.1 m/s, and wind-induced currents with a velocity of 0-0.1 m/s, which have a relatively minor impact. Therefore, seasonal changes in beach morphology are primarily controlled by waves, while interannual variations is mainly influenced by a combination of wave-induced currents and tidal currents. With increasing efforts in beach maintenance and coastal ecological restoration in recent years, understanding the sedimentary dynamics of beaches remains of vital theoretical and practical value.

UAV REMOTE SENSING APPLICATIONS IN BEACH-CLIFF SYSTEM MONITORING OF MORPHODYNAMIC PROCESSES

This study aims to evaluate the morphodynamic changes in a beach-cliff system in northeastern Brazil using high resolution data collected by UAV-SfM techniques to understand the geomorphic changes of the coastal landscape. The study used the Geomorphic Change Detection (GCD) method applied to short-term monitoring. This method uses Digital Elevation Models (DEMs) to determine the morphological changes in terms of both erosion and deposition through DEMs of Difference (DoDs). The difference gridded models are acquired by drone-based remote sensing, which can accurately and efficiently provide ultra-high resolution imagery and digital surface model data to measure volumetric changes. The geomorphic changes are observed on high resolution maps. The multi-temporal analysis revealed significant volumes of erosion and deposition throughout the beach-cliff system over the study period. In the first interval (May/2021 - November/2021), the cliff recorded -8,715 m³ of erosion and 2,816 m³ of deposition, with the beach sector showing erosion in 86% of its area. In the second period (November/2021 - March/2022), more severe erosion rates were observed on the cliff, reaching -10,853 m³ with 51% of its area eroded, while the beach showed the opposite behavior to that previously analyzed, with 73% of the beach experiencing an accumulation of sand and a positive balance of 5,960 m³. The results of this study can be fruitful in identifying the different of geomorphology hazards, coastal impacts of cliff urbanization and in the use of remotely piloted aircraft in coastal monitoring. Furthermore, the results indicate that the management of the beach-cliff system must be integrated and never dissociated, as is generally done by coastal managers. Keywords: Geomorphometry; DEMs; Drone-Based Remote Sensing; Mass Movement; Elevation and Volumetric.

Spatial and Temporal Dynamics of the Canine Population and Contamination by Canine Feces on an Urban Beach

Objective: The objective of this study was to analyze the spatio-temporal distribution of dogs and feces using the visual census method. The research aimed to quantify the presence of dogs and the number of feces observed in these environments. Method: The visual census was conducted every fifteen days over the course of one year along the Mar Grosso beach shoreline, which was divided into areas and sectors. The data were subsequently tabulated, and statistical analysis was performed using the non-parametric Kruskal-Wallis test. Research Results and Discussions: The highest number of feces and stray dogs were found in the urban sector during the summer. Regarding the areas observed and feces, the area with the highest number of feces was A3 in the urban sector during the summer. As for the number of stray, domiciled, and off-leash dogs, they were more frequently observed in the summer, with stray dogs predominantly in A2 (beach sector), and domiciled and off-leash dogs in A3 and A2, respectively, in the urban sector. Research Implications: The results identify hotspots of feces and dogs along the study area, providing valuable information that can assist in decision-making and the implementation of public policies aimed at controlling animals on beaches and protecting the environment, thereby reducing the risk of disease transmission to the population frequenting these locations. Originality/Value: This study contributes to evidence-based policy implementation to promote environmental health, public health, and animal welfare in coastal areas.

No man’s land support the endemic Red Sea ghost crab (Ocypode saratan) in the Gulf of Eilat

Tourism pressure on the Red Sea ecosystem have posed significant threats to numerous endemic species, including the Ghost Crab Ocypode saratan, which is exclusively found along a small stretch of beach in the Eilat/Aqaba Red Sea Gulf. Due to the limited understanding of their ecology, we investigated how tourism impacts the behavior of this species. Employing a natural setup, we compared burrow dimensions, pyramid structures, and density across three distinct beach sections subjected to varying levels of human interference. Access to a secluded beach, referred to as “No Man’s Land,” provided a crucial control for our study. This facilitated a comparative analysis of ghost crab activity among beaches experiencing differing levels of human disturbances: (1) a tourist beach characterized by continual high disturbance, (2) a naval beach subject to moderate and sporadic disturbances, and (3) the isolated “no man’s land” beach devoid of human presence. Our observations revealed notable differences in ghost crab density among the three beaches. Furthermore, we observed that on the secluded beach, larger individuals tended to establish burrows farther from the waterline and construct taller sand pyramids. Given the significance of sexual selection processes, their conservation becomes imperative for the survival and potential expansion of the ghost crab population across the Gulf of Eilat/Aqaba. We propose a straight-forward and cost-effective strategy: the designation of short, secluded beach enclaves along this gulf. We believe that this approach will mitigate adverse impacts of tourisms while simultaneously benefiting various sandy beach species.

Shoreline evolution in adjacent to a coastal structure in Hiep Thanh commune, Duyen Hai district, Tra Vinh province

Coastal erosion is significant along the coastline in Hiep Thanh commune, Duyen Hai district, Tra Vinh province, Viet Nam. In order to address this severe coastal erosion, the local community has constructed a concrete embankment as an emergency solution to protect the coastline. However, this solution exacerbates the issue since the fundamental processes of coastal erosion remain inadequately explored and understood. Specifically, in beach sections without the concrete embankment, erosion still occurs. Therefore, this paper aims to investigate the shoreline changes adjacent to the embankment using an integrated approach with remote sensing and diffusion theory. The results show that beach erosion is occurring near the embankment at a rate of 44 meters per year, and the diffusion coefficient for longshore sand transport in the study area is 130 square meters per day. This study offers a practical approach to examining changes in the shoreline adjacent to a coastal structure, particularly valuable in situations where there is a scarcity of measured field data.

The Côte d’Argent, France: Quantification of Plastic Pollution in Beach Sediments

Pollution with anthropogenic waste, particularly persistent plastic, has now reached every remote corner of the world. The French Atlantic coast, given its extensive coastline, is particularly affected. To gain an overview of current plastic pollution, this study examined a stretch of 250 km along the Silver Coast of France. Sampling was conducted at a total of 14 beach sections, each with five sampling sites in a transect. At each collection site, a square of 0.25 m2 was marked. The top 5 cm of beach sediment was collected and sieved on-site using an analysis sieve (mesh size 1 mm), resulting in a total of approximately 0.8 m3 of sediment, corresponding to a total weight of 1300 kg of examined beach sediment. A total of 1972 plastic particles were extracted and analysed using infrared spectroscopy, corresponding to 1.5 particles kg−1 of beach sediment. Pellets (885 particles), polyethylene as the polymer type (1349 particles), and particles in the size range of microplastics (943 particles) were most frequently found. The significant pollution by pellets suggests that the spread of plastic waste is not primarily attributable to tourism (in February/March 2023). The substantial accumulation of meso- and macro-waste (with 863 and 166 particles) also indicates that research focusing on microplastics should be expanded to include these size categories, as microplastics can develop from them over time.

Zone-specific longshore sampling as a strategy to reduce uncertainties of SGD-driven solute fluxes from high-energy beaches

Submarine groundwater discharge (SGD) from intertidal beach systems forms a source of fresh and saline, often nutrient-enriched water to the near-shore across the world. The chemical composition of solute flux via SGD depends on several factors, including solid phase composition, organic matter supply, hydraulic gradients, as well as pore water residence time and origin, which are partly related to the beach topography. High-energy sandy beaches are especially prone to frequent sediment relocation and a variable topography, often characterized by a ridge and runnel structure. Topography may not only change on a temporal scale, but also in the longshore direction, which may alter SGD-driven solute fluxes. However, sampling high-energy beach sites is challenging and often does not allow for high resolution cross- and longshore sampling. We tested the approach of zone-specific pore water sampling, whereby samples were taken at the high water line, in the runnel, on top of the ridge, and close to the low water line of eight cross-shore transects. This was done in order to assess the longshore variability of pore water composition and flux over a 2.5 km wide beach section. In this study we relied on relatively few data points per transect and still found a characteristic cross-shore distribution of pore water parameters, related to redox conditions of each zone. Recharge zones (high water line and ridge) exhibited higher O2 and NOx concentrations and discharge zones (runnel and low water line) exhibited higher nutrient, DOC, Mn, and Fe concentrations. Furthermore, DOC concentrations in pore waters were lower than in coastal seawater, supporting previous assumptions of rapid organic matter turnover. Nevertheless, we observed large concentration ranges among samples assigned to the same zone, which could partly be related to longshore topography differences. The measured pore water concentrations and calculated SGD-driven solute fluxes indicated that sampling of single cross-shore transects may be representative for a beach section when assessing a redox-independent parameter like Si, while it is less representative for parameters affected by more complex biogeochemical processes like P, NH4, Mn, and Fe. For these, we suggest that longshore distributed data coverage combined with higher resolution sampling in discharge zones is a good strategy to reduce the uncertainty associated with estimating SGD-driven solute fluxes in a practicable way.

Factors regulating incubation temperature and thermal stress in hawksbills in St. Croix, USVI

The hawksbill sea turtle is listed as Critically Endangered under the IUCN Red List and has been slow to recover in the Caribbean due to historical exploitation and ongoing anthropogenic threats. In turtles, sex and reproductive success are determined by incubation temperatures, whereby lower temperatures produce male hatchlings and higher temperatures produce female hatchlings. As incubation temperatures increase due to climate change, nests are predicted to produce predominantly female hatchlings, threatening sex ratios, reproductive success, and species persistence. One of the largest remaining nesting hawksbill populations within the USA nests on Buck Island. This study aimed to (1) assess the factors driving incubation temperatures and (2) identify the relationship between hatch success and the proportion of time exposed to increasing incubation temperatures. Nest incubation temperatures, beach sector, habitat type, deposition month, percent soil composition, hatch success, and emergence success data were collected from 2019 to 2021. Differences in incubation temperatures across these factors confirmed that the absence of vegetative cover is increasing incubation temperatures on Buck Island, leading to reduced hatchling survival. Results from this study indicate that declines in hatch success may be driven by long-term exposure to temperatures that were previously considered in the literature to be non-lethal to embryos. These findings emphasize the continued need for conservation interventions to protect the future of hawksbills.

Statistically assessing vertical change on a sandy beach from permanent laser scanning time series

In the view of climate change, understanding and managing effects on coastal areas and adjacent cities is essential. Permanent Laser Scanning (PLS) is a successful technique to not only observe notably sandy coasts incidentally or once every year, but (nearly) continuously over extended periods of time. The collected point cloud observations form a 4D point cloud data set representing the evolution of the coast provide the opportunity to assess change processes at high level of detail. For an exemplary location in Noordwijk, The Netherlands, three years of hourly point clouds were acquired on a 1 km long section of a typical Dutch urban sandy beach. Often, the so-called level of detection is used to assess point cloud differences from two epochs. To explicitly incorporate the temporal dimension of the height estimates from the point cloud data set, we revisit statistical testing theory. We apply multiple hypothesis testing on elevation time series in order to identify different coastal processes, like aeolian sand transport or bulldozer works. We then estimate the minimal detectable bias for different alternative hypotheses, to quantify the minimal elevation change that can be estimated from the PLS observations over a certain period of time. Additionally, we analyse potential error sources and influences on the elevation estimations and provide orders of magnitudes and possible ways to deal with them. Finally we conclude that elevation time series from a long term PLS data set are a suitable input to identify aeolian sand transport with the help of multiple hypothesis testing. In our example case, slopes of 0.032 m/day and sudden changes of 0.031 m can be identified with statistical power of 80% and with 95% significance in 24-h time series on the upper beach. In the intertidal area the presented method allows to classify daily elevation time series over one month according to the dominating model (sudden change or linear trend) in either eroding or accreting behaviour.

Substantially excess uranium in the waters of an intertidal salt marsh: A case study of eastern Chongming Beach

Knowledge of the geochemical behavior of uranium is key to an accurate tracing of the decay chain of the uranium series nuclides for material transportation processes on different temporal scales. However, direct observations for understanding dissolved uranium input in tidal water are very limited. Therefore, dissolved uranium was measured in tidal creek water, overlying water, and pore water collected from the central cross section of eastern Chongming Beach, Changjiang Estuary, from November 2012 to October 2013, to observe the spatiotemporal distribution of uranium. The results indicated that the behavior of dissolved uranium is conservative in the tidal creek waters during the flooding process, and an excess of dissolved uranium is observed during the ebbing process; excess uranium phenomena are dominant in the overlying and pore waters throughout the year, particularly at the middle and high tidal flats. The element concentration profiles in pore water showed that uranium release follows Mn oxide reduction in the subsurface suboxic zone. Hence, the exchange process between tidal water and pore water, coupled with ebb tide, represents a potential path for uranium release into the estuary. The three-end-member (Changjiang River, seawater, and pore water) model estimates that 35% of the amount of uranium in ebbing water is derived from pore water. The exchange rate between tidal water and pore water is 196.4 nmol/(cm2·d), with an export flux of 2.34 × 104 mol/a. We suggest that the release of uranium from intertidal salt marshes is an important uranium source in estuarine and coastal regions.

Architecture of lacustrine deposits in response to early Carboniferous rifting and Gondwanan glaciation, Nova Scotia, south‐east Canada

AbstractUpper Palaeozoic lacustrine basin deposits not only record local tectonism but are also an archive to evaluate global palaeoclimate changes linked to the Late Palaeozoic Gondwanan ice age. The Tournaisian Horton Group of Nova Scotia, south‐east Canada, accumulated in rift basins following the final accretion of peri‐Gondwanan terranes to the Appalachians. Sedimentology, mineralogy and geochemistry of the well‐exposed sandstones and shales at the classic Blue Beach section (ca 353.5 to 352 Ma) reveal the interplay of local tectonism and global climatic controls on lacustrine sedimentation. The lacustrine depositional environment gradually transitioned from deep water offshore at the base of the section to wave‐dominated and fluvial‐dominated nearshore at the top. Multiple small transgressive–regressive sedimentation cycles have an average 21 ka duration, likely related to Milankovitch cyclicity. Unusually abundant soft‐sediment deformation structures and landslides are the sedimentary responses to frequent earthquakes during the most active phase of rift subsidence. The overall succession shows changes from a shallowing‐up balanced‐filled to an overfilled lacustrine basin. The chemical weathering intensity index and the Th/K ratio show a longer‐term trend from dry and cool conditions low in the section to humid and warm conditions near the top, with rapid change in the transition period. The section records the peak of the global mid‐Tournaisian carbon isotope excursion and the corresponding cooling event (354 Ma to approximately 351 Ma). The sedimentary succession is a response to long‐term and short‐term climatic cycles influencing lake level and sediment supply during the time of maximum rift basin subsidence recorded by the soft‐sediment deformation structures.

Forecast of the Dynamics of a Sandy Beach in Complexed Hydrodynamic Conditions

Changes in the coastal zone under the influence of currents of different nature and wind waves are being investigated. A sandy beach located in the water area of the “Park of the 300th Anniversary of St. Petersburg”, the Neva Bay of the Gulf of Finland of the Baltic Sea, is considered as an object. The beach is actively affected by wind waves and eventually washes away with the intensity of the retreat of the shore of about 4 m per year. For numerical modeling, a set of models is used: SWAN–wind-wave model and COASTOX-UN–a two-dimensional model of currents, sediment transport and bottom reformation. It was developed a model of the Neva Bay and the mouth of the Neva River from the Flood Prevention Facility Complex in the west to the river Neva near the Liteiny Bridge in the east. Based on the reanalysis of wind data, 36 strong storms were selected for a five-year period from 2014 to 2018, for the sequence of which numerical modeling of waves, currents and lithodynamic processes was carried out. It was obtained balances of alluvial and washouts after a ten-years simulated period for beach sectors. To verify the results, satellite images of the modeling area are used, it was found that the model adequately describes the main observed trends in the development of the beach.

Do costal erosion and urban development threat loggerhead sea turtle nesting? Implications for sandy beach management

Nest beach selection by sea turtles at a regional scale may depend on upper shore environmental cues. Thus, the variability of sandy beach conditions, including coastal erosion rates and urban development can affect their nesting ecology. Almost half of worldwide sandy beaches are suffering from erosion and most of them are located in highly developed areas. This can lead to shore stretches with coastal squeeze and loss of habitat for beach-dependent species such as sea turtles. Understanding whether an endangered species, such as the loggerhead sea turtle Caretta caretta (Linnaeus, 1758), selects certain beaches to nest is the first step in devising mitigation strategies for human activities and climate change impacts. We predicted that the occurrence of loggerhead nests along 62 km of sandy beaches in southeastern Brazil is negatively related to higher urbanization levels and extreme erosion. A total of 731 nests of the loggerhead sea turtle were recorded in the 2022-2023 nesting season. Only 6% of those nests were found on beach sectors with severe and extreme erosion. The probability of laying a nest was negatively related to erosion rate. Also, approximately 50% of nests were found on low-urbanized beaches; thus, the higher the urbanization, the lower the probability of a turtle laying a nest. Nature-based solutions to recover the beach-dune system are recommended in order to mitigate coastal erosion where loggerheads are avoiding nesting. This should be coupled with management planning of the protected areas where nests are laid and must include nest relocation and monitoring as priority actions.

Effect of touristic activities on seabirds’ habitat selection on sandy beaches

Seabirds are biological models for habitat selection studies at different spatial scales. In general, seabirds select areas with a higher availability of prey, but human disturbances can modify their spatial and temporal foraging patterns in urban coastal ecosystems. Here we tested the hypothesis that human activities prevent seabirds foraging on beach sectors that are impacted by urbanization and recreational activities. Seabirds were counted while foraging at the interface between the surf zone and foreshore in three sectors with different levels of urbanization in southeastern Brazil. Physical variables, prey abundance, and human stressors, such as the number of people and dogs, were also measured. The brown booby Sula leucogaster foraged mainly in the least impacted sector, despite the lower abundance of prey and harsher physical conditions. The number of individuals of this species was negatively related to the number of people, indicating a human-induced avoidance behaviour. In turn, the kelp gull Larus dominicanus, a synatropic species, was more abundant in the high impact sector. Our results have implications for the management and conservation of sandy beaches, especially regarding the zoning and selection of priority areas for environmental protection and nature-based ecotourism activities.

Fossil micrometeorites from Monte dei Corvi: Searching for dust from the Veritas asteroid family and the utility of micrometeorites as a palaeoclimate proxy

We searched late Miocene sedimentary rocks in an attempt to recover fossil micrometeorites derived from the Veritas asteroid family. This study was motivated by the previous identification of a pronounced 3He peak (4-5x above background) within marine sediments with ages between ∼8.5–6.9 Ma ago (Montanari et al., 2017. GSA Bulletin, 129:1357–1376). We processed 118.9 kg of sediment from the Monte dei Corvi beach section (Italy), the global type-section for the Tortonian epoch (11.6–7.2 Ma). Samples were collected both before and within the 3He peak. Although a small number of iron-rich (I-type) fossil micrometeorites were recovered from each horizon studied (Ntotal = 20), there is no clear difference between the pre- and intra- 3He peak samples. All micrometeorites are compositionally similar, and three out of five horizons yielded similar abundances and particle sizes. Micrometeorites extracted from sediments at the base of the 3He peak were exclusively small (ø <75 µm), while micrometeorites extracted from sediments near the highest 3He values were relatively large (ø <270 µm). The recovered fossil micrometeorites are interpreted as samples of the background dust flux derived from metal-bearing chondritic asteroids. The presence of a 3He signature combined with the absence of fossil micrometeorites or extraterrestrial spinels (Boschi et al., 2019, Spec. Pap. Geol. Soc. Am. 542:383–391) unambiguously related to the Veritas event suggests that the Veritas family is composed of highly friable materials that rarely survive on the sea floor to become preserved in the geological record. Our data supports the existing hypothesis that the Veritas asteroid family is an aqueously altered carbonaceous chondrite parent body, one that contains minimal native metal grains or refractory Cr-spinels. The low yield of fossil micrometeorites at Monte dei Corvi is attributed to loss of particles by dissolution whilst they resided on the sea floor but also due to high sedimentation rates leading to dilution of the extraterrestrial dust flux at this site. As with other fossil micrometeorite collections (e.g. Cretaceous chalk [Suttle and Genge, EPSL, 476:132–142]) the I-type spherules have been altered since deposition. In most particles, both magnetite and wüstite remain intact but have been affected by solid state geochemical exchange, characterised by partial leaching of Ni, Co and Cr and implantation of Mn, Mg, Si and Al. In some particles Mn concentrations reach up to 16.6 wt%. Conversely, in some micrometeorites wüstite has been partially dissolved, or even replaced by calcite or ankerite. Finally, we observe evidence for wüstite recrystallisation, forming a second generation of magnetite. This process is suggested to occur by oxidation during residence on the seafloor and has implications for the use of fossil I-type micrometeorites as a potential proxy for probing Earth’s upper atmospheric composition (oxidative capacity) in the geological past. However, solutions to the limitations of post-depositional recrystallisation are suggested. Fossil I-type spherules remain a potential tool for palaeo-climatic studies.

Coastal erosion in temperate barriers: an anthropized sandy beach in Buenos Aires, Argentina

Coastal erosion is a common issue in urbanized areas located on sandy barriers in Latin America, making them highly vulnerable to both natural and human induced disasters. This pose a significant threat to the long-term sustainability of these coastal systems. The main objective of this study was to evaluate the medium-term shoreline evolution of a highly-anthropized beach sector located within a coastal barrier system of Buenos Aires, Argentina. For this purpose, a geospatial analysis based on aerial imagery and high-resolution satellite data was conducted for the 1965–2021 period. Additionally, the study aimed to identify critical erosive sectors and to provide estimations for the near-future shoreline evolution of these beaches. The results showed contrasting patterns, with sectors presenting shoreline retreat rates up to 0.7 m/yr while others demonstrated accretion rates exceeding 0.6 m/yr. Despite these along-shore variations in erosion/accretion balances, more than 70% of the shoreline presented an erosional trend for the studied period. This led to the identification of an erosional hot spot covering 30% of the urbanized waterfront. Furthermore, the 2030 forecast suggests that a highly urbanized beach sector could suffer a shoreline retreat of about 20 m. These results could be directly linked to the historical land use/land cover changes, mainly related to dune stabilization processes and to the implantation of urban surfaces. At this point, erosive patterns could be mainly caused by local cross-shore imbalances due to these anthropogenic disturbances. It is expected that the results of the present study will serve as a basis for coastal management policies, and the proposed method will be a useful tool for assessing coastal erosion hazard.

Against All Odds

Against All Odds

Coastal erosion and accretion on the Caribbean coastline of Costa Rica long-term observations

Several studies show erosive processes on the Caribbean coastline of Costa Rica. These processes may be accelerated as a result of an increase in the sea level. This study covered the entire Caribbean coastline of Costa Rica between 1986 and 2019. This allowed reporting new sites with accelerated coastal accretion and erosion processes, as well as confirming other processes that have already been identified. The methodology was based on shoreline rising images obtained from Landsat and on their processing in a Geographical Information System supported with the “Digital Shoreline Analysis System” (DSAS) tool. The presence of important accretion areas related to the mouth of significant fluvial systems, such as Colorado, Parismina, Matina, Estrella, and Sixaola rivers is highlighted. Moreover, eight beach sectors showing erosion problems have been analyzed. The beach located to the south of Isla Portillos and beaches located on Cahuita Point stand out due to their intensity. Additionally, an intense beach erosion process has been detected at Soropta in Panamá. It should be highlighted that six of the eight sites showing erosion are located within protected zones. This confirms the little anthropic interference on these processes. It was not possible to find a difference between the north and the south of the Caribbean Coast in terms of the magnitude of coastal erosion. The contribution of the rivers is a key factor in the North Caribbean while the responses to the 1991 earthquake conditioned the behavior on the South coast. The results may serve as a basis for management plans or adaptation to climate change proposals.

Assessment of the Geomorphological and Sedimentological Changes in Mamaia Sector after the Implementation of the Coastal Protection Measures

"The paper analyses the changes in the beach sector of Mamaia resort from a geomorphological and sedimentological point of view in the context of coastal protection works carried out in 2014-2015 and 2021 (measures to reduce wave energy, beach protection with structures to stabilize the sand and beach nourishment). The Mamaia sector, with a length of about 12 km, is geomorphologically constituted mainly by sandy barrier of Lake Siutghiol representing a transition unit between the northern unit (deltaic and lagoon shore) and the southern unit (small pocket rocks-beaches in front, separated by small coastal sandbars). From an economic point of view, the sector is important for coastal tourism both in terms of the number of tourists and the existing of infrastructure generating significant revenues. Since the 1950s, the sector has been severely affected by the construction of the dikes of the Midia Port in the north, which have affected the longitudinal transport of sediments and accentuated the erosion of the submerged and backshore beach. To counteract the effects of erosion, a longitudinal and transversal coastal protection system was built between 1960 and 1990, which proved to be ineffective in the long term. The data collected in the field (topographic profiles of the backshore, shoreline, sediment samples) before and after the recent coastal protection works were processed using a dedicated software (ArcGIS 10.x and Gradistat v8) and represented in the form of maps and graphics. The spatial analysis highlighted the modification of the coastal system components, the trends of the beach evolution in longitudinal and transversal profile and the changes in the structure and distribution of sediments determined by the impact of the coastal protection works."

Pollution of Beach Sand from Selected Recreational Reservoirs by Microplastics

Abstract The presence of microplastics have been ubiquitously confirmed in aquatic environment possessing the potential risk to the health of ecosystem. Most studies concerning microplastics are focused on water bodies, but it is considered that sediments and sands from the beaches may to be a long-term sink for microplastics. High concentrations of microplastics have been found in sand beach in Europe and all over the world. In the present studies samples of beach sand originating from three beaches of recreational reservoirs in Southern Poland (Silesian Voivodship) were analysed. Preliminary screening tests were done to evaluate the degree of microplastics pollution of the selected sandy beaches. Samples were taken once from three places on the beaches of each reservoir. Beach sections parallel to the waterline were selected at each study at the swash zone – about 1 m above the waterline. Previously, no studies were done on the presence of microplastics in these beaches. The samples taken from the beach were homogenized and mixed with saturated NaCl solutions, after separation of microplastics the pollutants were counted under optical microscope (under magnification 40 -100 x). It was found that in all three places the microplastics occurred in the beach sand samples. The most contaminated samples originated from Lisiniec recreation park (Adriatyk) which contained 340 ± 222 particles per kg/d.m. The most abundant fractions in the examined samples were fibres and fragments, the less abundant ones were granules. It can be concluded that recreational reservoirs beaches can be significantly contaminated by microplastics particles, but simultaneously the concentrations of these micropollutants can vary a lot between the individual places.