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1.
Water Res ; 252: 121186, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38340453

RESUMO

Short-term fecal pollution events are a major challenge for managing microbial safety at recreational waters. Long turn-over times of current laboratory methods for analyzing fecal indicator bacteria (FIB) delay water quality assessments. Data-driven models have been shown to be valuable approaches to enable fast water quality assessments. However, a major barrier towards the wider use of such models is the prevalent data scarcity at existing bathing waters, which questions the representativeness and thus usefulness of such datasets for model training. The present study explores the ability of five data-driven modelling approaches to predict short-term fecal pollution episodes at recreational bathing locations under data scarce situations and imbalanced datasets. The study explicitly focuses on the potential benefits of adopting an innovative modeling and risk-based assessment approach, based on state/cluster-based Bayesian updating of FIB distributions in relation to different hydrological states. The models are benchmarked against commonly applied supervised learning approaches, particularly linear regression, and random forests, as well as to a zero-model which closely resembles the current way of classifying bathing water quality in the European Union. For model-based clustering we apply a non-parametric Bayesian approach based on a Dirichlet Process Mixture Model. The study tests and demonstrates the proposed approaches at three river bathing locations in Germany, known to be influenced by short-term pollution events. At each river two modelling experiments ("longest dry period", "sequential model training") are performed to explore how the different modelling approaches react and adapt to scarce and uninformative training data, i.e., datasets that do not include event pollution information in terms of elevated FIB concentrations. We demonstrate that it is especially the proposed Bayesian approaches that are able to raise correct warnings in such situations (> 90 % true positive rate). The zero-model and random forest are shown to be unable to predict contamination episodes if pollution episodes are not present in the training data. Our research shows that the investigated Bayesian approaches reduce the risk of missed pollution events, thereby improving bathing water safety management. Additionally, the approaches provide a transparent solution for setting minimum data quality requirements under various conditions. The proposed approaches open the way for developing data-driven models for bathing water quality prediction against the reality that data scarcity is common problem at existing and prospective bathing waters.


Assuntos
Rios , Qualidade da Água , Rios/microbiologia , Teorema de Bayes , Monitoramento Ambiental/métodos , Estudos Prospectivos , Bactérias , Microbiologia da Água , Fezes/microbiologia , Praias , Poluição da Água
2.
Environ Monit Assess ; 196(3): 329, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38424357

RESUMO

Poor waste management and unsustainable institutional and individual behaviors, have led to the accumulation of plastic litter in many habitats worldwide. Assessment of plastic pollution in Kenyan marine environment was conducted focusing on the impact of banning the single-use plastic carrier bags in Kenya. The quantification, composition, and distribution of plastics were determined at nine (9) beaches along Kenyan coastline using standing stock method. A total of 750 plastic items were collected and categorized with only 47 pieces being single-use plastic carrier bags. A great number of plastics (n = 383), were identified by their original use, with packaging plastics being the most common (n = 155). Macroplastics were the overall dominant plastics at 76%, mesoplastics, 21% and microplastics, 3%, which were altogether dominated by low-density polyethylene (LDPE) at (46%), followed by polypropylene (PP), 30%; polyethylene tetraphthalate (PET), 9%; polyvinyl chloride (PVC), 8%; and polystyrene (PS), 7%. The absence of identifiable single-use plastic carrier bags in 6 out of 9 beaches signified the effectiveness of the ban in Kenya. Monitoring of trends and sources of plastic debris is encouraged to help enhance the science-policy linkage aimed at reducing marine plastic pollution.


Assuntos
Microplásticos , Plásticos , Quênia , Monitoramento Ambiental/métodos , Polipropilenos , Polietileno , Resíduos/análise , Praias
3.
Epidemiol Infect ; 152: e38, 2024 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-38403890

RESUMO

Understanding historical environmental determinants associated with the risk of elevated marine water contamination could enhance monitoring marine beaches in a Canadian setting, which can also inform predictive marine water quality models and ongoing climate change preparedness efforts. This study aimed to assess the combination of environmental factors that best predicts Escherichia coli (E. coli) concentration at public beaches in Metro Vancouver, British Columbia, by combining the region's microbial water quality data and publicly available environmental data from 2013 to 2021. We developed a Bayesian log-normal mixed-effects regression model to evaluate predictors of geometric E. coli concentrations at 15 beaches in the Metro Vancouver Region. We identified that higher levels of geometric mean E. coli levels were predicted by higher previous sample day E. coli concentrations, higher rainfall in the preceding 48 h, and higher 24-h average air temperature at the median or higher levels of the 24-h mean ultraviolet (UV) index. In contrast, higher levels of mean salinity were predicted to result in lower levels of E. coli. Finally, we determined that the average effects of the predictors varied highly by beach. Our findings could form the basis for building real-time predictive marine water quality models to enable more timely beach management decision-making.


Assuntos
Praias , Escherichia coli , Teorema de Bayes , Qualidade da Água , Colúmbia Britânica , Monitoramento Ambiental , Microbiologia da Água , Fezes
4.
Mar Pollut Bull ; 200: 116164, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38364645

RESUMO

The study presents the results of the survey of beached litter on the two opposite shores of the Fields Peninsula (King George Island) conducted during the austral summer seasons of 2022 and 2023, as part of the 67th and 68th Russian Antarctic expeditions. Beaches situated on the coast of the Drake Passage were much more polluted compared to the beaches on the Maxwell Bay side. Plastic accounted for 86 % of all found items on the shores of the Drake Passage, with the majority of items related to fisheries or shipping. On the Maxwell Bay beaches, only 36 % of litter was plastic, with other categories like wood and metal dominating the total number. The average density of marine litter is 0.32 items/m (0.017 items/m2), comparable to other similar surveys conducted on Antarctic islands; however, this is at least 15-20 times lower than beach litter densities in the Arctic.


Assuntos
Monitoramento Ambiental , Resíduos , Resíduos/análise , Regiões Antárticas , Monitoramento Ambiental/métodos , Plásticos , Madeira/química , Praias
5.
Environ Pollut ; 344: 123338, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38218543

RESUMO

Santa Luzia, an uninhabited island in the archipelago of Cabo Verde, serves as a natural laboratory and important nesting site for loggerhead turtles Carettacaretta. The island constitutes an Integral Natural Reserve and a Marine Protected Area. We assessed marine litter accumulation on sandy beaches of the island and analysed their spatial patterns using two sampling methods: at a fine scale, sand samples from 1 × 1 m squares were collected, identifying debris larger than 1 mm; at a coarse scale, drone surveys were conducted to identify visible marine debris (>25 mm) in aerial images. We sampled six points on three beaches of the island: Achados (three points), Francisca (two points) and Palmo Tostão (one point). Then, we modelled the abundance of marine debris using topographical variables as explanatory factors, derived from digital surface models (DSM). Our findings reveal that the island is a significant repository for marine litter (>84% composed of plastics), with up to 917 plastic items per m2 in the sand samples and a maximum of 38 macro-debris items per m2 in the drone surveys. Plastic fragments dominate, followed by plastic pellets (at the fine-scale approach) and fishing materials (at the coarse-scale approach). We observed that north-facing, higher-elevation beaches accumulate more large marine litter, while slope and elevation affect their spatial distribution within the beach. Achados Beach faces severe marine debris pollution challenges, and the upcoming climate changes could exacerbate this problem.


Assuntos
Areia , Resíduos , Resíduos/análise , Cabo Verde , Plásticos/análise , Praias , Monitoramento Ambiental/métodos
6.
Sci Total Environ ; 918: 170442, 2024 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-38278231

RESUMO

We investigated whether higher quantities of faecal indicator bacteria (FIB) are in the areas with red algae-dominated wrack compared to areas without it and if the birds are the primary source of faecal pollution on sandy beaches of the Baltic Sea. Water, sand and wrack samples were collected during the recreational season, and abundances of FIB, HF183 (human faecal pollution) and GFD (bird faecal pollution) markers, as well as the presence of Salmonella and Campylobacter, were assessed. Significantly higher levels of Enterococcus spp. were found in the wrack accumulation areas in water and sand than in the areas without wrack when there was a faecal pollution event, which could be explained by entrapment and changed physico-chemical water conditions. Both faecal pollution markers were identified, however, with no apparent pattern. Campylobacter bacteria were identified in the wrack-affected water, sand, and beach wrack. While this research provides valuable insights into beach wrack serving as a reservoir for FIB, further investigations, including multi-day samplings, are necessary to gain a deeper understanding of the long-term dynamics of microbiota within red algae-dominated wrack.


Assuntos
Monitoramento Ambiental , Areia , Humanos , Enterococcus , Bactérias , Poluição da Água , Água , Praias , Fezes/microbiologia , Microbiologia da Água
7.
Mar Pollut Bull ; 200: 116036, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38237260

RESUMO

This study evaluated the distribution and abundance of marine litter on 30 beaches around Okinawa Island, Japan. Beach quality indices and multivariate statistical analyses were used to assess the quality of the beaches and their pollution patterns. A total of 11,626 items weighing 513.49 kg with an average density of 0.13 ± 0.10 items/m2 were collected. Litter was dominated by plastics (81.72 %), broken glass (8.38 %), and cigarette butts (7.44 %), and 74.05 % of total litter was from land-based sources. Single-use plastics (SUPs) were present in all surveyed beaches and made up 30.54 % of the total litter. The clean coast index (CCI), plastic abundance index (PAI), and hazardous index (HI) were between 0.1 and 7.6, 0.1-4.0 and 0.01-1.42, respectively, indicating low to moderate levels of pollution of Okinawan beaches. This study should aid in the formation of strategies to deal with marine litter in Okinawa, other areas of Japan and the Asia-Pacific region.


Assuntos
Monitoramento Ambiental , Resíduos , Japão , Resíduos/análise , Praias , Plásticos/análise
8.
Environ Pollut ; 341: 122885, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-37951525

RESUMO

The abundance of fecal-indicating bacteria in water bodies are said to be influenced by environmental conditions. The effect of environmental parameters on the changing microbial population plays an important role in coastal water quality assessment. It's crucial to comprehend these patterns in order to support management initiatives for pollution control. There are studies on faecal bacteria contamination of surface water and how environmental conditions affect it, however majority of them are based on large river basins and temperate regions of developed countries. In this paper, we study the different physicochemical and physical factors of the five recreational beaches in Mumbai, India and examine how these environmental factors affect the levels of faecal indicating bacteria, namely, coliforms in the region. A relatively high number of coliform was identified from the water and sediment samples of Marve Beach (>1600 MP N/100 ml or g), followed by Erangal Beach and Danapani Beach (∼150-350 MP N/100 ml or g), exceeding the normal standard limits of <100 MP N/100 ml set by the Central Pollution Control Board (CPCB) of India. Of the physiochemical parameters examined, BOD showed to have a strong positive correlation with the coliform bacteria. The nutrients and heavy metal concentrations did not show any major effect on the microbial population. The MIKE CMAP predicted tide, MIKE3 Flow Model FM simulated coastal current, ERA5 hourly wind, as well as SWAN model simulated nearshore wave together considerably exhibit alliance of microbial behavior in the beaches with ambient physical processes. This study reveals that Mumbai's coastal water contain significant concentrations of faecal bacteria, which, if not monitored regularly could have future consequences on the recreational activities of the region, thereby on public health. This assessment might help in simulation of water quality prediction, and for optimizing the coastal zone management and development across recreational beaches.


Assuntos
Praias , Microbiologia da Água , Bactérias , Qualidade da Água , Bactérias Gram-Negativas , Fezes/microbiologia , Índia , Monitoramento Ambiental
9.
Mar Pollut Bull ; 199: 115976, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38154174

RESUMO

This paper examines the environmental effects of fashion waste on the central Caribbean coast of Colombia, highlighting significant ecological issues in coastal areas. A survey of 27 beaches found 503 items of fashion waste, mainly shoes and sandals, with an average density of 0.93 items/m2. The distribution of this type of waste varies notably across different beach types, with exposed, rural, and remote beaches showing higher accumulation, indicating a relationship between beach characteristics and waste concentration. Primary sources of this waste include riverine transport, coastal tourism, and poorly managed sewage systems, impacting urban, rural, and village beaches differently. The study reveals that longshore currents and oceanic movements, significantly influence the transport and fate of this waste, with exposed beaches accumulating more fashion waste than sheltered ones. The presence of driftwood also plays a vital role in trapping fashion waste along coastlines. The findings highlight the need for effective management strategies to mitigate the impact of fashion waste, providing crucial insights for local and national coastal managers and implications for managing fashion waste in the Southern Caribbean and similar regions worldwide.


Assuntos
Monitoramento Ambiental , Plásticos , Colômbia , Praias , Região do Caribe , Resíduos/análise
10.
Artigo em Inglês | MEDLINE | ID: mdl-38063564

RESUMO

BACKGROUND: The goal of this study was to monitor the microbial biodiversity in beach sand that is heavily visited by tourists during the summer, and to determinate whether the high presence of bathers (around 5000 per day) can modify sand microbial composition. METHODS: Between 2016 and 2020, 150 sand samples were collected from nine different points at La Pelosa beach in Sardinia, Italy. Non-culturing methods were used; DNA extraction and meta-barcode sequencing were performed. All samples were analyzed with sequencing methods for 16S and ITS sequences. RESULTS: Fungal genera differ on the three beaches and in the winter/summer zones. The ITS sequence showed the most common presence of Candida during summer and Paradendryphiella in the winter. The greatest diversity was found in the dune during winter, while in other parts of the beach, there are differences between bacteria and fungi, particularly in the wash zone during the winter, with high diversity for 16S sequences but low diversity for ITS sequences. CONCLUSIONS: It appears reasonable that the sands, even on non-urban beaches, should be included in health monitoring programs in addition to the waters, and that access to them should be regulated by limiting the number of bathers with the aim of reducing the presence of pathogenic fungal species.


Assuntos
Areia , Microbiologia da Água , Estações do Ano , Bactérias/genética , Fungos/genética , Praias , Monitoramento Ambiental/métodos
11.
Mar Pollut Bull ; 197: 115716, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37918139

RESUMO

Recreational activities are important source of disturbance on sandy beaches and have a negative effect on benthic communities as they alter species abundance, diversity, and/or distribution. Here, we report for the first time the effects of the recreational activities on the distribution pattern of macrobenthic communities of Amazonian sandy beaches. Sampling was performed during three consecutive months with different beach use intensity in 2017 (before, during vacation, and one month after the vacation period) on two contrasting beaches regarding disturbance (Urban: Atalaia; and Protected: Corvinas) in the intertidal zone along two equidistant transects at seven equidistant sampling stations: from the high-tide water mark to the swash zone. At each sampling station, four biological and sediment samples were randomly collected. Also, in each station, the sediment compaction was determined using a manual penetrometer. Physical sediment variables remained constant over time in both beaches, whereas differences were found in sediment compaction over the periods. Sediment compaction was considered the most important factor for the differences observed in macrobenthic community structure in the study beaches, and it was related to intensity of recreational activities. Variations in density and changes in richness between periods and sampling stations were observed in Atalaia beach. On the other hand, Corvinas beach remained the same throughout the study. Overall, three faunal zones were distinguished: upper intertidal, intermediate intertidal, and low-intertidal, whereas in the vacation period, only two faunal zones were distinguished: upper-intertidal and intermediate-low intertidal.


Assuntos
Ecossistema , Recreação , Estações do Ano , Praias
12.
Sci Rep ; 13(1): 17621, 2023 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-37848615

RESUMO

Organised bathing areas located within leisure facilities, in addition to the function typical of their purpose, allow in most cases the use of their own barbecue facilities. This type of cooking of food before consumption is very popular during leisure time at the waterfront. However, cooking food on a barbecue produces fumes emitted from both the fuel being burned and the food being grilled. In addition, the fat from the grilled food falls on the hearth, contributing to the release of further toxic compounds and, in many cases, together with other exhaust fumes, causing considerable smoke and the summer smog effect. Such cumulative gases emitted by irregularly dispersed barbecues repeatedly irritate the respiratory tract of beachgoers in the area of these devices, and the residue of unburned barbecue fuel contaminates the resting area. Small pieces of charcoal of various textures tend to sink into the sand when exposed to the elements and can pose a risk to young children playing on the beach by causing choking and minor injuries. The study revealed an assumed range of exposure to dust and gases emitted from barbecuing that extended up to 40 m from the hearth. Additionally, it was demonstrated that the thermal processing of food using barbecue fuels could lead to increased contamination of beach sands from the fuel itself and food storage materials. Therefore, taking into account the studies carried out showing the adverse effects of active barbecues on beach sands and, above all, the atmospheric air and directly on beachgoers, administrators of recreational facilities should strive to concentrate these devices at a distance (up to several tens of metres) from beaches and bathing areas.


Assuntos
Alimentos , Areia , Criança , Humanos , Pré-Escolar , Gases , Praias , Recreação
13.
Mar Pollut Bull ; 196: 115481, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37857060

RESUMO

Anthropogenic Marine Litter (AML) accumulating on beaches causes damage to coastal ecosystems and high costs to local communities. Volunteers sampled AML on 130 beaches along the central and southern East Pacific coasts, with AML densities ranging from 0.46 to 2.26 items m-2 in the different countries. AML composition was dominated by plastics and cigarette butts, the latter especially in Mexico and Chile. The accumulation of AML in the upper zones of the beaches and substantial proportions of cigarette butts, glass and metal pointed mainly to local sources. Statistical modelling of litter sources on continental beaches revealed that tourism, access and related infrastructure (e.g. parking lots) best explained AML densities, while plastic densities were also influenced by the distance from river mouths and national Gross Domestic Product. Large-scale monitoring can be a useful tool to evaluate the effectiveness of public policies that should primarily focus on land sources.


Assuntos
Leucemia Mieloide Aguda , Resíduos , Humanos , Resíduos/análise , Monitoramento Ambiental , Ecossistema , Praias , Plásticos
14.
Mar Pollut Bull ; 196: 115625, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37813062

RESUMO

Over the years, the Black Sea has been impacted by the issue of marine litter, which poses ecological and health threats. A mid-term monitoring program initiated in 2018 assessed the abundance, density, and composition of beach litter (BL) on 40 frequently visited beaches. From 2018 to 2022, there was a significant increase in average abundance, rising by 261 %. Artificial polymer materials accounted for the majority (84 %) of the litter. Land-based sources dominated 77 % of the litter. The Clean Coast Index (CCI) categorized the beaches as "moderate" with an average value of 8.9 for the period between 2018 and 2022. However, the years 2021 and 2022, during the COVID-19 epidemic, were identified as the "dirtiest period" with 11 beaches classified as "extremely dirty" due to high domestic tourist pressure. The study demonstrates a successful combination of standard in situ visual assessment supported by unmanned aerial systems for beach litter surveys.


Assuntos
Praias , Plásticos , Mar Negro , Resíduos/análise , Monitoramento Ambiental , Bulgária
15.
Mar Pollut Bull ; 196: 115615, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37804669

RESUMO

In this study, we conducted the first assessment of the litter abundance, diversity and predictors in Mozambique, by collecting approximately 2 tons of litter along six beaches across the country. We tested whether population, touristic industry, fishing, and recreation activities predict the quantity of macro litter for each of the 11 types and 141 subtypes of litter. Overall, we found that plastics made up 60.1 % of the items across all sampled beaches. Following plastics, clothing objects accounted for the second most weight (20.4 %) while foam objects were the second most abundant (15.7 %). More importantly, our results show that the tourism industry is a strong predictor for lower levels of litter across most types of litter while population density and fishing activity were strong predictors for higher levels. Our findings suggest that the tourism industry plays a crucial role in the country by maintaining the beaches clean.


Assuntos
Monitoramento Ambiental , Turismo , Moçambique , Resíduos/análise , Praias , Plásticos
16.
Mar Pollut Bull ; 195: 115579, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37742516

RESUMO

This study aimed to assess the occurrence of marine litter on selected beaches in Mabini Protected Landscape and Seascape, Davao de Oro, Philippines, where records have not been published yet. Beach litter was collected during low tide from four beaches in June 2023. Results revealed that plastics were the most abundant type of litter at 82.22 %. Most plastic materials sampled were plastic fragments and packaging at 37.72 % and 18.24 %, respectively. An independent t-test showed that rocky beaches had significantly higher litter density at 1.38 items m-2 than sandy beaches at 0.45 items m-2, t(10) = 4.281, p = 0.001. The present results indicated that the actual cleanliness of the Mabini coast is low, suggesting that clean-up strategies from various stakeholders are needed.


Assuntos
Monitoramento Ambiental , Resíduos , Filipinas , Resíduos/análise , Monitoramento Ambiental/métodos , Praias , Plásticos
17.
Mar Pollut Bull ; 195: 115474, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37672921

RESUMO

Even in pristine and remote environments of the Mediterranean, marine litter is building up threatening habitats and species and inhibiting sustainable development. The present study reports the findings of beach litter surveys carried out by 250 local community members in nine sites along the coastline of the Asterousia Biosphere Reserve, situated in the southernmost end of Europe. The average recorded litter density along these sites amounted to 125 items per 100 meters of coastline (range: 22-510) and to 0.05 items per square meter of beach (range: 0.01-0.13). Only two of the nine surveyed beaches were found to be in good environmental status, in compliance with the European threshold value for beach litter. The other seven studied beaches surpassed the European threshold value. The primary sources of the litter identified in the study can be attributed to unsustainable practices and inadequate waste management by individuals, communities and municipalities using the coastal and marine environment. Additionally, unsustainable waste management practices within the agricultural sector were also found to be a significant contributor to marine litter pollution.


Assuntos
Monitoramento Ambiental , Resíduos , Humanos , Resíduos/análise , Plásticos , Praias , Poluição Ambiental
18.
Mar Pollut Bull ; 195: 115469, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37703630

RESUMO

Increasing amount of anthropogenic litter in the marine environment has provided an enormous number of substrates for a wide range of marine organisms, thus serving as a potential vector for the transport of fouling organisms. Here, we examined the fouling organisms on different types of stranded litter (plastic, glass, rubber, foam sponge, cloth, metal and wood) on eight beaches along the southeast coast of India. In total, 17 encrusting species belonging to seven phyla (Arthropoda, Bryozoa, Mollusca, Annelida, Cnidaria, Chlorophyta and Foraminifera) were identified on 367 items, with one invasive species, the mussel Mytella strigata, detected. The most common species associated with marine litter were the cosmopolitan bryozoans Jellyella tuberculata (%O = 31.64 %) and J. eburnea (28.61 %), the barnacle species Lepas anserifera (29.97 %), Amphibalanus amphitrite (22.34 %) and Amphibalanus sp. (14.16 %), and the oyster species Saccostrea cucullata (13.62 %) and Magallana bilineata (5.44 %). We also reported the first records on stranded litter of four species: the gastropod species Pirenella cingulata and Umbonium vestiarium, the foraminiferan Ammonia beccarii, and the oyster M. bilineata. This study is thus the first documentation of marine litter as a vector for species dispersal in India, where the production and consumption of plastic rank among the highest in the world. We also highlight the increasing risk of invasions by non-indigenous organisms attached to debris along the southeast coast of India. Comprehensive monitoring efforts are thus needed to elucidate the type of vectors responsible for the arrival of invasive species in this region. Raising awareness and promoting education are vital components in fostering sustainable solutions to combat plastic pollution in the country and globally.


Assuntos
Briozoários , Ostreidae , Animais , Monitoramento Ambiental , Plásticos/química , Madeira/química , Têxteis , Espécies Introduzidas , Resíduos/análise , Praias
19.
Mar Environ Res ; 190: 106107, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37540961

RESUMO

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


Assuntos
Braquiúros , Humanos , Animais , Densidade Demográfica , Praias , Ecossistema , Biodiversidade
20.
Environ Monit Assess ; 195(9): 1028, 2023 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-37558890

RESUMO

This study marks the first-ever assessment of radiological hazards linked to the sands and rocks of Patuartek Sea Beach, situated along one of the world's longest sea beaches in Cox' Bazar of Bangladesh. Through the utilization of an HPGe detector, a comprehensive analysis of the activity concentrations of 226Ra, 232Th, and 40 K was conducted, and their activity ranged from 7 to 23 Bq/kg, 9-58 Bq/kg, and 172-340 Bq/kg, respectively, in soils, and 19-24 Bq/kg, 27-39 Bq/kg, and 340-410 Bq/kg, respectively, in rocks. Some sand samples exhibited elevated levels of 232Th, while the rock samples displayed higher levels of 40 K compared to the global average. The radiological hazard parameters were assessed, and no values surpassed the recommended limits set by several international organizations. Hence, the sands and rocks of Patuartek sea beach pose no significant radiological risk to the residents or tourists. The findings of this study provide crucial insights for the development of a radiological baseline map in the country, which is important due to the commissioning of the country's first nuclear power plant Rooppur Nuclear Power Plant. The data may also stimulate interest in the rare-earth minerals present in the area, which is important for the electronics industry, thorium-based nuclear fuel cycles.


Assuntos
Monitoramento de Radiação , Radioatividade , Rádio (Elemento) , Poluentes Radioativos do Solo , Radioisótopos de Potássio/análise , Dióxido de Silício/análise , Solo , Areia , Bangladesh , Poluentes Radioativos do Solo/análise , Praias , Tório/análise , Rádio (Elemento)/análise
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