Search Results (21)

Posidonia oceanica seagrass, endemic to the Mediterranean Sea, provides ecological goods and ecosystem services of paramount importance. In shallow and sheltered bays, P. oceanica meadows can reach the sea surface, with leaf tips slightly emerging, forming fringing and barrier reefs. During the 20th century, P. oceanica declined conspicuously in the vicinity of large ports and urbanized areas, particularly in the north-western Mediterranean. The main causes of decline are land reclamation, anchoring, bottom trawling, turbidity and pollution. Artificial sand nourishment of beaches has also been called into question, with sand flowing into the sea, burying and destroying neighbouring meadows. A fringing reef of P. oceanica, located at Saint-Mandrier-sur-Mer, near the port of Toulon (Provence, France), is severely degraded. Analysis of aerial photos shows that, since the beginning of the 2000s, it has remained stable in some parts or continued to decline in others. This contrasts with the trend towards recovery, observed in France, thanks to e.g., the legally protected status of P. oceanica, and the reduction of pollution and coastal developments. The sand nourishment of the study beach, renewed every year, with the sand being washed or blown very quickly (within a few months) from the beach into the sea, burying the P. oceanica meadow, seems the most likely explanation. Other factors, such as pollution, trampling by beachgoers and overgrazing, may also play a role in the decline. Full article

Palytoxins (PLTXs) and ovatoxins (OVTXs) are a group of highly potent marine toxins that pose significant health risks through seafood contamination and environmental exposure. OVTX-producing algae have been linked to dermatitis and respiratory distress in Mediterranean beachgoers, while serious public health concerns are related to PLTX accumulation in seafood. In 2009, the European Food Safety Authority highlighted the need for analytical detection methods of the PLTX group of toxins and for the preparation of reference materials. This study investigates the stability of the palytoxin signal using liquid chromatography tandem mass spectrometry (LC-MRM-MS) and UV-Vis spectrophotometry under different experimental conditions: three concentrations (10, 1, and 0.5 µg/mL), three methanol–water mixtures (10%, 50%, and 90%), and two temperatures (6 °C and 25 °C). The results showed that the PLTX signal response is significantly influenced by the experimental conditions used. LC-MRM-MS analysis revealed the optimal response of PLTX in 50% and 90% MeOH at 25 °C, with minimal signal loss occurring over 16 h (9% and 6%). UV-Vis data indicated reduced absorbance in 10% MeOH, but a stable spectral intensity over 21 h in all the tested solvent mixtures. These results underscore the necessity of carefully controlled experimental conditions to ensure accurate and reproducible PLTX detection in environmental and food safety monitoring. Full article

Rip currents are fast-moving, narrow channels of water that flow seaward from the shoreline, typically forming within the surf zone and extending beyond the wave-breaking region. These currents pose significant hazards to swimmers, contributing to numerous drowning incidents, especially with the increasing popularity of ocean recreation. Despite their prevalence, rip currents remain difficult to detect visually, and no universally reliable method exists for their identification by beachgoers. To address this challenge, this study presents a novel approach for detecting rip currents in optical images using wavelet-based edge detection and image convolution techniques. Five identification criteria were established based on previous literature and expert observations. The proposed program incorporates image augmentation, averaging, and frame aggregation to enhance generalization and accuracy. Experimental analysis involving four iterations and four wavelet bases demonstrated that using two iterations with the Daubechies wavelet yielded the highest interpretation accuracy (88.3%). Performance evaluation using a confusion matrix further confirmed an accuracy rate of 83.0%. The results indicate that the proposed method identifies rip currents in images, offering a valuable tool for researchers studying rip current patterns. This approach lays the groundwork for future advancements in rip current detection and related research. Full article

This study is based on a 10-day survey carried out at seven beaches in March 2023 in El Puerto de Santa María municipality (SW Spain). An amount of 5592 items were collected, with a combined weight of 26 kg. Fresh litter, which refers to litter transported to the shore by marine/coastal processes, accounted for 4634 items weighing 23 kg. The remaining 958 items, weighing 3 kg, were identified as litter deposited by beach visitors. The average total litter recorded during the sampling was 0.40 ± 0.07 items m⁻¹ with a density of 1.85 ± 0.69 g m⁻¹. Litter materials were relatively consistent regardless of whether they were stranded by marine processes or discharged by beachgoers. Plastic dominates fresh and deposited litter followed by metal and glass, with minimal contributions of chemicals, organic matter, clothing, rubber, wood, and paper. They were identified 115 items’ categories from the 184 listed in the EU Joint List: 107 for fresh and 75 for deposited litter. Food consumption-related items made up a significant portion of the total debris followed by personal hygiene and care-related and smoking-related litter. The obtained information is very useful to propose sound management actions that have to be especially devoted to raise beach users’ responsibility. Last, in order to have a year-round view of litter characteristics and behavior, further investigations should be carried out during winter, when the number of visitors is very low and waves’ energy is high, and summer, when opposite conditions are recorded. Full article

Coastlines are suffering from the effects of erosive processes, the decrease in sediment supply, the rise in mean sea level, and the construction of coastal infrastructure and drainage works, which are further exacerbated by global climate change. The area of the Parque Natural do Litoral Norte (North Coast Natural Park) reveals worsening erosion rates and the transformations directly affect the natural resources that support tourism activities, particularly beach and nature tourism. As part of the CLICTOUR project, we have selected the coastline from Restinga de Ofir to Bonança Beach as a case study. The ESRI ArcGIS software and the Digital Shoreline Analysis System (DSAS) were used to quantify coastline migration and identify the impacts on beach morphology between 2010 and 2023. Based on this information, we calculated changes in carrying capacity and scenarios for visitor usage availability to ensure the protection of fauna and flora, as well as the safety of beachgoers. The results of the linear regression rate confirm the coastline has retreated during the period analyzed (2010–2023). The outcome of these dynamics is noticeable in the beach area, promoting its reduction in area and leisure quality. Considering climate change, this study shows the importance of developing resilience strategies for coastal territories that serve as traditional summer destinations. Full article

The rise of sun and beach tourism has led to concerns about the environmental impact of sunscreens on marine ecosystems. Although the contaminants included in sunscreens are being studied from various perspectives, there are still gaps in the understanding of beachgoers’ habits and sunscreen use, and their awareness of the problems these products can cause. But do we even know how much sunscreen ends up in the ocean when beachgoers apply it? To estimate the amount of sunscreen entering coastal waters during a summer season, a survey (n = 429) was conducted at two urban beaches in southern Spain (La Caleta and La Bajadilla). It was estimated that 76.3 to 109.3 mL of sunscreen per beachgoer enters the water during the season. For this estimation, it was crucial that we the analyze beachgoers’ behavior statistically. Additionally, our study calculated their willingness to pay (WTP) for eco-labeled sunscreen alternatives. The results showed significant differences between the two sites, with La Bajadilla reporting higher sunscreen usage (11.9 mL vs. 7.9 mL per application) and a greater WTP for eco-labeled sunscreen (€14.2 vs. €11.5). These findings highlight the need for more field studies to better understand the input of sunscreen into coastal waters, which is closely linked to beach use and its social factors. This approach, which considers specific sunscreen input and characterizes beachgoers’ habits, behaviors, and preferences for alternatives, provides valuable insights for decision-makers and may guide future research on the potential impact of sunscreens on marine ecosystems using behavioral data as well as alternative approaches to solving the problem. Full article

Escherichia coli is commonly found in the gastrointestinal tract of warm-blooded animals and is routinely used as an indicator of fecal contamination in recreational waters. While most E. coli are commensal, some can harbor pathogenic potential, posing a major public health risk. This study investigated the sources of fecal contamination in recreational waters through the characterization of E. coli isolates. Presumptive E. coli detection was performed using selective and differential media, confirmed by PCR, and followed by characterization. E. coli were detected in all studied aquatic environments, with most isolates belonging to phylogenetic groups D1 (24%, non-human mammals) and B1 (20%, birds), suggesting animals as primary contaminants sources. Among E. coli isolates, 35% were identified as diarrheagenic E. coli (DEC), with enterotoxigenic (34%) and enterohemorrhagic (26%) being the most prevalent pathotypes. Furthermore, 85% of all isolates and 86.5% of DEC isolates exhibited multi-drug resistance, with highest rates displayed in phylogenetic subgroups A1 (human and non-human mammals) and B1. This study highlights the importance of the One Health approach encompassing a human, animal, and environmental holistic health perspective to effectively manage public health strategies and ensure the safety of beachgoers. Full article

High counts of bacteria are present in beach sand, and human health threats attributable to contact with sand have been reported. In this study, we investigated fecal indicator bacteria in the top surface sand of coastal beaches. Monitoring investigations were performed during a monsoon when rainfall occurs randomly, and the composition of the coliforms was analyzed. The coliform count in the top surface sand (depth < 1 cm) increased by approximately 100 fold (26–2.23 × 10³ CFU/100 g) with increasing water content because of precipitation. The composition of the coliforms in the top surface sand changed within 24 h of rainfall, with Enterobacter comprising more than 40% of the coliforms. Estimation of factors that changed the bacterial counts and composition revealed that coliform counts tended to increase with increasing water content in the top surface sand. However, the abundance of Enterobacter was independent of the sand surface temperature and water content. Coliform counts in the top surface sand rapidly increased and the composition showed remarkable variations because of the supply of water to the beach following rainfall. Among them, some bacteria with suspected pathogenicity were present. Controlling bacteria in coastal beaches is important for improving public health for beachgoers. Full article

Among many coastal hazards, rip currents have gradually become one of the most noticeable hazards. Studies have demonstrated that most drowning accidents at beaches around the world are related to rip currents. In this study, online and field questionnaires were combined for the first time to reveal beachgoers’ awareness of rip currents in China from four aspects: demographic characteristics, swimming ability, information about visiting beaches, and knowledge about rip currents. One educational strategy was introduced to the field survey. The results suggest that (i) the proportion of online and field respondents who have heard of “rip currents” and seen warning signs of rip currents is extremely small. This reflects that beachgoers lack awareness of rip current hazards. Thus, China needs to strengthen the safety education of rip current knowledge. (ii) The level of awareness of rip currents can significantly affect the community’s ability to identify the location of rip currents and their choice of escape direction. (iii) In the field survey, we implemented an educational strategy as an intervention for respondents, and the accuracy of identifying rip currents and choosing the correct escape route improved by 34% and 46.7%, respectively. This implies that the intervention of educational strategy can significantly deepen beachgoers’ awareness of rip currents. It is recommended that more educational strategies about rip current knowledge be implemented on Chinese beaches in the future. Full article

This study aimed to quantify marine litter before and during the COVID pandemic found on urban touristic beaches closed to beachgoer access in northeastern Brazil. Litter identification and quantification was conducted during April, June, and August 2019, when 3583 items were sampled, and replicated during the same months in 2020, when access to the beaches studied was prohibited and a significant reduction in the amount of litter was found, 1812 items (49% decrease). Transects were used to monitor and classify litter according to its source, namely: autochthonous (litter that was locally discarded) and allochthonous (litter from other sites and sources). All beaches were classified as “very clean” and presented a smaller amount of litter during the beach closure period. The highest total marine litter reduction between the periods studied was 83%, while autochthonous litter in particular showed the most significant reduction, 88%. The comparison between the quantity and type of litter found in both periods showed greater specific anthropic pressure from beach users. Full article

The dinoflagellate Ostreopsis cf. ovata produces several families of toxic polyketides. Despite only a few field measurements of these phycotoxins in seawater and aerosols, they are believed to be responsible for dermatitis and the toxic inhalations reported during blooms of this species. Therefore, the stability of these compounds in seawater is essential to understanding the causes of these symptoms, however, this has never been assessed. In the current study, the optimization of a solid phase extraction (SPE) procedure was first performed to ensure the most efficient extraction of all phycotoxins known to be produced by this strain, including the recently described liguriatoxins. The SPE cartridge SDBL^® under non acidified conditions offered the best option. The stability of the ovatoxins and the liguriatoxins under biotic and abiotic stress was assessed by exposing the spent medium of a culture of Ostreopsis cf. ovata to its bacterial consortium and natural sunlight. A rapid biotic transformation was detected for both families of compounds. When exposed to bacteria, the half-lives of the ovatoxins were reached before 10 h and at 36 h, 97% of these toxins had been transformed. The half-lives of the liguriatoxins were 10 h under these conditions. Photolysis (abiotic degradation) of the ovatoxins (T_1/2 < 36 h) was faster than for the liguriatoxins (T_1/2 > 62 h). Although none of the catabolites of these phycotoxins were thoroughly identified, an untargeted metabolomics approach combined with molecular networking highlighted the presence of several compounds exhibiting structural similarities with the ovatoxins. Additional work should confirm the preliminary findings on these potential ovatoxins’ catabolites and their biological properties. The rapid transformation of O. cf. ovata’s phycotoxins introduces questions concerning their presence in seawater and their dispersion in the sea spray aerosols. The compounds involved in the toxic inhalations and dermatitis often experienced by beachgoers may stem from the catabolites of these toxins or even unrelated and as yet unidentified compounds. Full article

Large Woody Debris (LWD) accumulation serves essential ecological functions and benefits society’s coastal ecosystems (e.g., beaches). Thus far, the ecosystem services perspective has paid little attention to LWD. Therefore, we aim to contrast social perceptions on LWD and its ecological significance in Puerto Velero beach, Caribbean, Colombia. In consequence, the contribution of LWD to the conformation and creation of Puerto Velero beach was analyzed, as well as how beachgoers perceive the importance of LWD and if they were willing to pay to remove LWD in this beach. To achieve this, a quantitative convergent approach was then proposed using GIS analysis and remote sensing to understand the contributions of LWD to the Puerto Velero beach ecosystem; and in addition, a survey was performed to determine how beachgoers perceived LWD and how they valued the phenomenon. Results indicate that LWD contributed to beach maintenance; nevertheless, most people neglected LWD values because of its lack of visual attractiveness. As such, ecosystem services targets become conflicted because people positively perceived ecosystem services provided by beaches, but they did not assign importance to the beach dynamics they deemed unattractive, regardless of their vast importance. Full article

In addition to its ecological and recreational relevance, beach cleanliness is also one of the five most important aspects (i.e., the “Big Five”) for beach visitors around the world. Nonetheless, few efforts have been carried out to guide the sound management of this rising issue. This paper presents a quantitative and qualitative method to assess the level of beach cleanliness, in order to allow managers to focus their attention on the environmental management of the most frequent and relevant types of litter in tropical areas. In a first step, a survey on users’ perception was applied to 361 beachgoers in eight beaches in Colombia to identify the most relevant types of beach litter and the weighting factors to obtain quantitative calculations. In a second step, the thirteen categories of litter identified were analyzed in relation to beach cleanliness, origin of litter, and environmental impact, to define its individual weighting importance. Some categories were also selected according to particularities of tropical countries, such as the presence of abundant natural vegetation debris and gross polystyrene items, largely transported by rivers in great quantities. In a third step, the method was then tested at eight beaches in the Caribbean coast of Colombia through a period of four months, during which 192 transect samplings were carried out. The qualitative module of the proposed technique, named Beach Litter Assessment Technique—Qualitative and Quantitative (BLAT-QQ), identified the main types of beach litter and the quantitative module gave an overview on the state of beach cleanliness. The method is demonstrated to be quick and effective in diagnosing beach cleanliness, providing a simple instrument to carry out sound environmental management actions in coastal destinations. Full article

Coastal sites offer a range of services that contribute to human wellbeing. While some of the services are entirely human-made (e.g., parasol and sunbed rental), others are produced thanks to the contribution of marine ecosystems (e.g., water clarity). The purpose of this paper is to investigate the preferences of a sample of beachgoers for these two categories of services that policymakers have to balance when designing management strategies for coastal sites. We consider a marine site in the north of Italy that partially falls within the boundaries of a protected area but that is characterized by a medium-to-high level of anthropization. The results of a discrete choice experiment show that in the current state of things, the ecosystem services proposed for the sample have, on average, a higher marginal utility, suggesting that actions increasing those services have a larger effect on well-being. Full article

Considering the rapid growth of tourism in recent years and the acknowledgement that exposure to solar UV radiation may cause skin cancer, sunscreens have been widely used by beachgoers in recent decades. UV filters contained in sunscreens, however, were recently identified as emerging pollutants in coastal waters since they accumulate in the marine environment with different adverse effects. In fact, exposure to these components was proven to be toxic to most invertebrate and vertebrate marine species. Some UV filters are linked to the production of significant amounts of reactive oxygen species (ROS), such as hydrogen peroxide, and the release of inorganic micronutrients that may alter the status of coastal habitats. Bioaccumulation and biomagnification have not yet been fully addressed. This review highlights recent progress in research and provides a comprehensive overview of the toxicological and ecotoxicological effects of the most used UV filters both on the abiotic and biotic compartments in different types of coastal areas, to gain a better understanding of the impacts on coastal biodiversity. Full article