Spatiotemporal variations in marine macro-litter pollution along the shoreline of Koh Mun Nai, an uninhabited island in the Gulf of Thailand

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.

Biological and functional responses of the benthic surf zone community to different beach types

In this study, we analyzed the biological descriptors and functional traits of the benthic community inhabiting the water/bottom layer in the surf zones of three sandy beaches: a tide-dominated flat, and two intermediate beaches, from tide-modified to wave-dominated. Samples were collected seasonally in the inner surf zone by hand-towing a benthic sledge equipped with two nets, one above the other, across transects parallel to the shore, capturing the benthic community in two levels, close to the seafloor. A total of 116 species were collected, with a total of 327,678 specimens. Arthropods were 99.63% of all individuals caught across the three beaches, mainly represented by peracarid crustaceans. An important species turnover was detected along the shore, with a significant change in community composition. The biological descriptors and some functional traits vary among beaches: the total density, the density of individuals of small (5-10 mm length) and very small sizes (<5 mm length), the density of larval forms, and the presence of colonial species were higher in the tide-dominated flat (sometimes also in the tide-modified beach). More arthropods and more mobile individuals were found in those beaches, while mollusks and sedentary individuals were found in high number in the wave-dominated beach. Stratification was present across the three studied beaches, with higher densities in the near-bottom layer. In the tide-dominated beach, there was also a higher richness in this layer, with a nested community between levels. In the wave-dominated beach, similar richness was registered between levels, with a different community composition (and some differences in functional traits), indicating that some species can maintain their position close to the bottom despite the turbulent conditions experienced on this beach. Differences in wave conditions among beach types could be an important factor driving the biological descriptors and functional traits of the benthic community in surf zone ecosystems. Therefore, acknowledging their role is crucial in deciphering global patterns in surf zone biodiversity.

Microplastic in clams: An extensive spatial assessment in south Brazil

Microplastic pollution is becoming a continuously growing environmental concern, while bivalve mollusks are particularly vulnerable due to their sessile habits and feeding through water filtration processes. Microplastic incidence in soft tissues of the clam Amarilladesma mactroides was assessed along unconsolidated substrates distributed in extensive coastal regions of southern Brazil. Influence of urbanization levels, distance to rivers and local hydrodynamics on microplastic accumulation by the clam was tested. The average concentration of microplastics was high (3.09 ± 2.11 particles.g-1), considering 16 sampled sites. Particles were mainly composed by polyamide, polyethylene and polyethylene terephthalate, while were mainly smaller, fibrous and colorless. High urbanization and closer proximity to rivers insured higher contamination, which is a trend observed globally. No influence of coastal hydrodynamics was seen. Considering obtained findings, A. mactroides presents good potential to be used as a valuable tool to assess microplastic contamination in unconsolidated substrates of beach areas.

Lost and found: Patterns of marine litter accumulation on the remote Island of Santa Luzia, Cabo Verde

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.

Plastic pellets make Excirolana armata more aggressive: Intraspecific interactions and isopod mortality differences between populations

Plastic pellets represent a significant component of microplastic (< 5 mm) pollution. Impacts caused by plastic pellets involve physical harm and toxicity related to ingestion and non-ingestion (such as the release of chemicals in leachates). The latter is the main route of exposure for invertebrate macrobenthic populations. This study aimed to compare the toxicity of plastic pellets in distinct marine macrobenthic populations, considering the influence of sediment characteristics (organic matter and grain size) and quality (contamination by hydrophobic chemicals) on ecotoxicological effects, as well as the influence of color on the toxicity of beach-stranded plastic pellets. We performed three experiments on plastic pellet exposure using Excirolana armata from beaches with high and low pellet density. When exposed to pellets, populations that inhabit beaches without pellets demonstrate higher mortality than those inhabiting beaches with high pellet densities. The mortality of E. armata to pellets was higher when the exposure occurred in sediment with high organic matter (OM), suggesting that chemicals were transferred from pellets to OM. Yellowish beach-stranded pellets induced higher mortality of E. armata than the white tones did. We also observed lethargic (near-dead) and dead individuals being preyed upon by healthy individuals, a cannibalistic behavior that raises an ecological concern regarding the negative effects of this exposure on intraspecific interactions in marine macrobenthic populations.

Meso- and microplastic composition, distribution patterns and drivers: A snapshot of plastic pollution on Brazilian beaches

Pollution by plastics is a worldwide problem on par with climatic change and biological invasions. In coastal sediments, plastic particles tend to accumulate and persist over the long term. We assessed the plastic pollution using a standardized surface sediment sampling protocol on 22 sandy beaches along >4600 km of the Brazilian coast. The abundance, size, color, type, and polymeric composition of all meso- and microplastic items found in the surveys were processed to disclose spatial patterns of distribution and pollution associated drivers. A General Linear Model (GLM) was run to investigate how the predictor variables influenced overall beach plastic amounts and by plastic type and size class. Overall, 3114 plastic items were found, with microplastics comprising just over half of all items (54 %). Most items were either white (60 %) or blue (13 %), while polystyrene foam (45 %) and fragments (39 %) comprised the most abundant plastic types. The principal polymers were Polyethylene (40 %) and Polypropylene (32 %). The analyses indicated that the distribution of plastic litter along beaches is determined by three predictive variables: the distance to the nearest estuary (-), tourism (+), and the number of inhabitants in the nearest urban center (+). Tourist (highly-visited) beaches and those near estuarine runoffs or urban centers presented the highest plastic pollution rates. The unveiling of plastic pollution patterns through a large-scale systematic survey is essential for future management guidance and science-based decisions for mitigating and solving the plastic pollution crisis.

Toxigenic Escherichia coli with high antibiotic resistance index recovered from sands of recreational beaches of Mumbai, India

Mumbai, India's seven-island city, is known for its sandy beaches as a major tourist attraction, but urbanization and industrialization have weakened the environment. Unregulated sewage disposal and untreated effluents off the coast have made the beach environment vulnerable. Therefore, monitoring water and sand quality at beaches should be mandatory. This study was thus designed to determine the microbiological status of selected sandy beaches, viz. Versova, Juhu, and Girgaon. The study found fecal coliforms in the sand, with stx1 and stx2 genes specific for Shiga toxin-producing E. coli pathotypes in 5.5 % of isolates, whereas the presence of eaeA gene specific for enteropathogenic E. coli pathotype was detected in 12.2 % of isolates, and the presence of the LT and ST genes specific for enterotoxigenic E. coli pathotype was detected in 6.6 % of isolates. Multiple antibiotic-resistant indices indicated high-risk contamination sources. The study suggests routine monitoring of pollution levels at coastal cities' beaches.

Plastisphere assemblages differ from the surrounding bacterial communities in transitional coastal environments

Marine plastic contamination is currently considered ubiquitous in aquatic environments. These particles present a resistant and hydrophobic substrate known to promote microbial colonisation and biofilm formation in aquatic ecosystems, the so-called "Plastisphere", raising concerns about its potential ecological risks. The novelty of this topic translates into a relatively low number of studies, including for transitional coastal ecosystems, such as sandy beaches or estuarine habitats. Therefore, a sampling campaign was conducted in two transitional coastal ecosystems - the Mondego estuary (Portugal) - and adjacent sandy beaches (winter 2020). After visual sorting and filtering of suspected particles under sterile conditions DNA extraction and 16S rRNA amplicon high throughput sequencing was used to profile the bacterial communities on the surface of plastic particles and from those found on the water and sediments from the sampled transitional coastal ecosystems. All particles were characterised according to type, colour and size, and the chemical nature of the particles was determined by FTIR-ATR or μ-FTIR spectroscopy after DNA extraction. All samples contained plastics in several sizes (micro and mesoplastics), shapes (higher abundances of fragments on beaches and fibres in the estuarine waters), colours and polymers. Although no significant differences were detected in the α-diversity indexes of the bacterial communities between plastics and their surrounding environments, data showed the occurrence of unique key bacterial groups on plastics from both environments, such as pathogens (e.g., Lactococcus, Staphylococcus and Streptococcus) and groups commonly associated with wastewater treatment plants (e.g., members of the phylum Firmicutes). This highlights the concerns for plastics to act as vectors of transmission and spread of these bacterial groups in transitional coastal ecosystems. Furthermore, it raises the possibility that (micro)plastics entering the estuary from the sea play a substantial contribution to overall dynamics of (micro)plastics and their microbial assemblages in the estuarine system.

Sedimentological features of asbestos cement fragments in coastal environments (Taranto, southern Italy)

Asbestos cement materials (ACMs) are widespread in coastal environments as result of illegal dumping activities. This study focuses on the Taranto area (Italy) in the Mar Grande basin within the northern sector of the Ionian Sea. The complex history of dumping building materials containing high amounts of ACM into the coastal zone, and the erosion, transport and deposition in Marechiaro Bay is a serious environmental hazard. An interdisciplinary research methodology defines the temporal dumping succession, and the erosional processes and phases, the diffusion of ACM, the mineralogical characteristics, and existing physical status of the ACM. A multiscale investigation was conducted. Results show that from 1992 to 2000 a significant increment of dumping operations have occurred. The current cliff has been subject to erosion and redeposition phases, developing a new beach composed of these polluted man-made sediments. The findings persuade the local authorities to close the beach requiring remediation interventions.

Relationships between benthic infauna and groundwater eutrophication on a sandy beach in southern Brazil

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.

Occurrence and contents of trace metals and rare earth elements on plastic pellets

We determined the occurrence of pellets (2-5 mm) and their composition in terms of trace metals and rare earth elements (REE) on nine sandy beaches of the coast of Bahia, northeastern Brazil. We compared the occurrence of pellets between oceanic and sheltered beaches and the effect of fluvial contribution on the occurrence of these microplastics. The number of pellets found was surprisingly low (i.e., max 45 pellets per m² in an oceanic beach without fluvial river inputs). Thus, the studied beaches exhibited a very low pollution index. Concentrations of ∑REE in pellets varied between 0.36 and 1.74 mg kg^-1 and were ~5-fold higher in white/transparent pellets than in brown pellets. The sum of trace metals (i.e., Fe, Cd, Cu, Ni, Pb, and Zn) was also highest in the white pellets (357 ± 12 mg kg^-1). Plastic pellets are a potentially important vector of REE exposition to biota.

Has the "Covid-19" lockdown an impact on beach faunal communities? The central Atlantic coast of Morocco as a case study

The restrictions related to the COVID-19 pandemic have led to a global hiatus in anthropogenic activities; several scientists have utilized this unique opportunity to assess the human impact on biological systems. In this study, the study describes for a period of five years (2018-2022) how the faunal community have been affected by human disturbances, as well as the effect of the "anthropause" period driven by the COVID-19 lockdown. The results confirmed human disturbances on faunal communities related to coastal urbanization. It was found that the "anthropause" period showed the highest values of abundance and biomass, hence the "COVID-19 lockdown" allowed recovery of faunal communities. The findings highlight the impact of human disturbances and that the community showed resilience. Overall, the authorities must perform restrictive measures aiming to mitigate the impact of anthropogenic activities in the study area including the banning of off-road and recreational vehicles, carrying out efficient cleaning and grooming operations, monitoring the severe harvesting of edible species, as well as penalizing the disposal of anthropogenic waste and sewage discharge from the touristic facilities. Likewise, management actions such as the temporal beach closures and the regular surveillance could be advantageous to provide a more sustainable exploitation of sandy beaches.

Plastic pellets make Excirolana armata more aggressive: Intraspecific interactions and mortality in field and laboratory ecotoxicological assays

Microplastics, including plastic pellets, get stranded on sandy beaches. They persist in the oceans for long periods and frequently carry contaminants. Acute and chronic toxicity has been observed when marine organisms are exposed to high densities of plastic pellets in laboratory assays. We investigated the toxicity of beach-stranded plastic pellets on macrobenthic populations (Excirolana armata; Crustacea; Isopoda) under natural conditions (in situ). We simulated different pellets densities on a beach not contaminated by pellets, exposing isopods for 6 h and testing possible behavioral responses (i.e., vertical displacement) and mortality effects. No effect was observed on vertical displacement, but higher mortality was reported for organisms exposed to plastic pellets. The lowest pellet density tested commonly found in coastal areas was sufficient to trigger mortality. We also observed that lethargic individuals (near-death) were preyed on by the healthy individuals remaining in the test chambers.

Hemocyanin as a biological indicator of artificial light at night stress in sandy beach amphipods

The influence of artificial light at night (ALAN) is becoming evident in marine sandy beaches. These habitats are dominated by species reliant on natural daylight/night regimes, making the identification of biological indicators a priority. We assessed the applicability of hemocyanin, an oxygen-transport protein in the hemolymph of many invertebrates, as an indicator of ALAN-related stress. Unlike total proteins, hemocyanins signal metabolic function and stress, so we expected them to increase in response to ALAN. We adapted spectrophotometry protocols to describe spatial variation in hemocyanins and total proteins in four populations of the talitroid amphipod Americorchestia longicornis. Then, a two-week experiment tested for changes in response to ALAN. Hemocyanin levels increased by 17 % and 40 % with respect to experimental controls after 7 and 14 d, respectively, and were higher than any measurements conducted in the field. These results suggest good prospects for hemocyanin as an indicator of ALAN effects.

Marine litter on sandy beaches with different human uses and waste management along the Gulf of Nicoya, Costa Rica

This study was a baseline with quantitative data of marine litter along the Gulf of Nicoya, Costa Rica. The objective of the study was to quantify marine litter and its association with human activities in this estuarine gulf. A total of fourteen sandy beaches were cataloged by the degree of urbanization, tourism intensity, beach cleaning programs, and tributary rivers as possible drivers of marine litter presence. The items of the marine litter were separated and weighted by type. Analysis by the clean coastal index (CCI) and multivariate statistics were applied to find spatial patterns in marine litter in the gulf. On beaches with the highest touristic activity, cigarette butts and straws were the main components. Locations with river plume influence, less frequent cleanup, or waste cans showed more bottles, plastic parts, and sanitary waste than beaches in other conditions. A beach in a fisherman town had recently utilized plastic bags, household goods, and boat parts in the marine litter. A wildlife refuge beach showed only small plastic and coffee foam cup fragments that came with currents from other points in the estuary. River basin management, solid waste disposal programs, and environmental education to avoid single-use items combined with correct waste disposal are needed to reduce marine litter in tropical countries focused on ecological tourism.

An overview on metal pollution on touristic sandy beaches: Is the COVID-19 pandemic an opportunity to improve coastal management?

The worldwide spread of the SARS-CoV-2 caused an unprecedented lockdown measures in most countries with consequences on the world society, economy, and sanitary systems. This situation provided an opportunity to identify the effects of human confinement on natural environments, like touristic sandy beaches, which are stressed due to anthropogenic pressures. Based on previous articles about heavy metals sources and levels in these ecosystems, this paper discusses the dynamic of these pollutants and a regulatory scenario associated with COVID-19 sanitation policies. The main findings suggest that 39% of the studies were on Asian sandy beaches, 16% from Europe, while America and Africa with 23% each. Also Co, Cd, Cu, Cr, Zn, Pb, Ni, Fe and Mn were the most frequently analyzed metals in sediments and in several cases their concentrations exceed international guidelines assessment. Finally, even though beaches are under several metals inputs, tourism plays a key role in these ecosystems quality. After analyzing the potential indirect effect of COVID-19 measures on metals dynamics, we propose some key recommendations and management strategies to mitigate heavy metal pollution on sandy tourist beaches. These proposals are useful for decision-makers and stakeholders to improve sandy beach management, mainly those beaches not addressed from a management perspective; and their implementation should be adapted according to the regulations and legislation of each country.

The influence of beach geology and morphodynamics on chemical pollution assessments following a mining accident

In the present study the distribution of chemical elements in beaches adjacent to the Doce River mouth hit by the tailings mud from a mining accident were assessed. Sedimentological and morphological coastal aspects were also considered. The results indicate that wave-exposed delta plain beaches exhibit high resiliency, despite their proximity to potential pollution sources. On the other hand, shore platform beaches tend to accumulate chemical elements, mainly due to limited cross-shore sediment exchanges. Arsenic concentrations in the evaluated shore platform beaches were significantly higher than the delta plain beach. Shore platform beaches are more susceptible to frequent flooding and to higher elemental concentrations at the berm and beach face. Thus, the morphological characteristics of the assessed shore platform beaches, and input from the mud plume must be considered in a joint assessment strategy in order to obtain a broad understanding of the actual scenario regarding beach contamination.

Microplastics in bivalves, water and sediments from a touristic sandy beach of Argentina

This study assesses for the first time the concentrations of microplastics (MPs) in sediments, water and two human-consumed mussels with different ecological traits (Amarilladesma mactroides and Brachidontes rodriguezii) in a touristic sandy beach of Argentina. MPs were characterized through FTIR and SEM/EDX techniques. All the samples presented MPs with similar concentrations as other human-impacted coastal areas of the world, being black and blue fibers of < 0.5 and 0.5-1 mm the most abundant. SEM images exhibited cracks and fractures with clay minerals and microorganisms adhered to MPs surface. EDX spectrums showed potentially toxic elements, such as Cr, Ti, and Mo. FTIR identified polymers such as cellulose, polyamides, and polyacrylates in most of the samples analyzed. Our study demonstrates that microplastic pollution is a common threat to sandy beaches in Argentina, worsened by plastic particles carrying metal ions with potential toxic effects to the biota, including A. mactroides, an endangered species.

Cigarette butts in beach litter: Snapshot of a summer holiday

Cigarette butts are considered the most common form of personal litter around the world. It is estimated that 5.5 trillion cigarettes are consumed globally each year and that 4.95 trillion are discarded in some natural or anthropic environment around the world. This study evaluated the pollution of urban beaches in the Brazilian Northeast by cigarette butts in relation to other types of litter. Samplings were conducted in a month of high season (January 2016), at eight heavily used beaches. In the place with the highest concentration of users in each beach, a 200 m transect (3 m width) was established parallel to the water on the most recent strandline. All items >1 cm were counted and classified into categories according to composition (plastic, cigarette butts, wood, glass, metal, paper and organic, such as food leftovers and coconuts) using a standard worksheet. Cigarette butts were considered as an isolated category of litter. A total of 10,880 items was registered. The most abundant items were plastics (44.96%) and cigarette butts (38.36%). Among plastics, the most abundant items were straws, metallic food packaging, sticks (lollipop and popsicle) and cups. Plastic fragments were also abundant in all beaches evaluated, corresponding to 14.5% of the total plastics.

Beach morphodynamics and its relationship with the deposition of plastic particles: A preliminary study in southeastern Brazil

This study describes the beach profile, characterizes microplastics and correlates their abundance with morphodynamics characteristics on three beaches from the state of São Paulo, Brazil. 745 particles were found in 4 m² of sediment, mostly styrofoam. Nearly 90% of the fragments were found in Boracéia, the most dissipative beach, while less than 1% were found in Juréia beach, the most reflective one. The chemical composition of microplastics was identified by near-infrared hyperspectral imaging (HSI-NIR). The correlation between the abundance of particles and the slope plus the extension of the sand strip was high, as well as that found with the waves' height. These preliminary results indicate that there might be an intrinsic relation among the morphodynamical forces, the movement and destination of microplastics in marine environments.

Feeding ecology and microplastic ingestion in Chelon richardsonii (Mugilidae) associated with surf diatom Anaulus australis accumulations in a warm temperate South African surf zone

The study aimed to explore ontogenetic dietary changes and microplastic ingestion in Chelon richardsonii associated with diatom Anaulus australis accumulations in a warm temperate South African surf zone. This species is commercially important and forms an important trophic link in southern African coastal waters. Postflexion larvae, juveniles and adults are dominant in surf zones and were used for comparison. Index of Relative Importance (%IRI) results showed an ontogenetic dietary shift, with postflexion larvae ingesting mostly copepods (%IRI = 52.0) and microplastic fibres (%IRI = 30.7); while older developmental stages fed predominantly on diatoms (%IRI ranging from 53.9 to 65.6) and sand (%IRI ranging from 34.2 to 46.0). Microplastic fibres were found in 40% of fish sampled, microplastic fragments in 5%, and both types were recorded across all developmental stages assessed. This study provides the first record of microplastics in C. richardsonii, adding to growing microplastic research in fishes.

Microplastics in Talitrus saltator (Crustacea, Amphipoda): new evidence of ingestion from natural contexts

Using Fourier transform infrared spectroscopy (FT-IR) measurements and comparing the spectrum peaks (range 4000-600 cm^-1) with reference spectra database and instrument libraries, we observed new evidence of the ingestion of microplastic particles analyzing the digestive tracts of Talitrus saltator. Specimens, sampled in central Italy, probably ingested the particles with natural detritus. Since worldwide many species of invertebrates and vertebrates (e.g., birds) feed on Amphipoda along coastal ecosystems, we hypothesized that microplastic in these crustaceans can be accumulated along the food chain.

Consistent patterns of debris on South African beaches indicate that industrial pellets and other mesoplastic items mostly derive from local sources

Identifying the sources of small plastic fragments is challenging because the original source item seldom can be identified. South Africa provides a useful model system to understand the factors influencing the distribution of beach litter because it has an open coastline with four equally-spaced urban-industrial centres distant from other major source areas. We sampled mesodebris (∼2-25 mm) at 82 South African beaches in 1994, 2005 and 2015. Plastic items comprised 99% by number and 95% by mass of litter items. Industrial pellets were the most abundant plastic items, but fragments of rigid plastic items comprised most of the mass of debris. Strong correlations between industrial pellets and other plastic items indicate that common factors influence the distribution of both pellets and secondary mesoplastics. The abundance of mesodebris at beaches also was correlated in successive surveys, suggesting that beach-specific factors (e.g. aspect, slope, local currents, etc.) influence the amounts of debris on each beach. Sample year had no effect on mesodebris abundance, indicating that there has been little change in the amounts of mesodebris over the last two decades. There were consistently higher densities of both industrial pellets and other plastic items at beaches close to urban-industrial centres; there were only weak correlations with human population density and no correlation with local runoff. The size of industrial pellets decreased away from local urban centres, further supporting the conclusion that, like macroplastic litter, most mesoplastic pollution on continental beaches derives from local, land-based sources. This finding means that local actions to reduce plastics entering the sea will have local benefits, and that it may be possible to assess the efficacy of mitigation measures to reduce marine inputs of mesoplastic items.

Comparisons of microplastic pollution between mudflats and sandy beaches in Hong Kong

Most of the previous studies of microplastic pollution on coastal habitats focused on high energy beaches although low energy areas such as mudflats are supposed to retain more microplastics, not to mention that mudflats are biologically more diverse. We quantified and characterized microplastics from 10 mudflats and 10 sandy beaches in Hong Kong spanning from the eastern to western waters. Sediment samples were collected at 1.0 m and 1.5 m above chart datum (CD) and at the strandline. Abundance of microplastics ranged between 0.58 and 2116 items kg^-1 sediment with that on mudflats being ten times more than on beaches. Polyethylene (46.9%) was the most abundant and followed by polypropylene (13.8%) and polyethylene terephthalate (13.5%). Expanded polystyrene was the most abundant in the strandline samples but not at 1.0 m and 1.5 m above CD. Although previous studies have concluded that the input from Pearl River is a major source of microplastics on Hong Kong shores, this study has demonstrated that the contribution of local pollution sources such as discharge from sewage treatment plants to microplastic pollution should not be neglected.

Infralittoral-sublittoral (submerged zone) macroinfauna community structure of high-impact, medium-impact and non-impact beaches on the Gulf of Cádiz coast (SW Spain). Evaluation of anthropogenic alterations: Nourishments, human impact and urbanization

Beaches are dynamic transitional environments subject to numerous natural and anthropic alterations. In these ecosystems, the infralittoral-sublittoral macrofauna communities play a key role in the food web. The objective of this study was to compare macrofauna communities on six beaches on the Gulf of Cádiz coast, which were classified according to the anthropic alterations they support, and evaluate the influence of abiotic factors on the species distribution. Sampling was done in the infralittoral-sublittoral zone of each beach using a modified manual dredge. Five perpendicular transects of 25 m, each separated by 10 m, were performed per beach, with a total sample area of 43.75 m² per beach. A total of 27 species were found, of which Donax trunculus, Diogenes pugilator, and Tritia grana were the most abundant. Anthropogenic effects are appreciable in the infralittoral-sublittoral although they are areas that are permanently submerged and less exposed than the intertidal. Beach nourishments carried out with large volumes of sand can alter the grain size, the most influential parameter on the distribution of the species, and consequently, affect the macrofauna community that inhabits these beaches.

Extreme storm wave influence on sandy beach macrofauna with distinct human pressures

We evaluated the influence of storm waves on the intertidal community structure of urbanized and non-urbanized areas of a sandy beach on the northern coast of Rio de Janeiro, Brazil. The macrofauna was sampled before (PREV) and after two storm wave events (POEV I; POEV II) in 2013 and 2014. Significant differences in community structure between PREV and POEV I in the urbanized sector demonstrate higher macrofauna vulnerability, and the community recovery within 41days on this scenario of less frequent events in 2013. On the other hand, significant differences in the macrofauna only in the urbanized sector between PREV and POEV II also highlight macrofauna vulnerability and community recovery failure within 42days on this scenario of more frequent storm in 2014. Urbanization and wave height were the variables that most influenced species, indicating that high storm wave events and increasing urbanization synergism are a threat to the macrofauna.

Disentangling the effects of solar radiation, wrack macroalgae and beach macrofauna on associated bacterial assemblages

Wrack detritus plays a significant role in shaping community dynamics and food-webs on sandy beaches. Macroalgae is the most abundant beach wrack, and it is broken down by the combination of environmental processes, macrofauna grazing, and microbial degradation before returning to the sea as nutrients. The role of solar radiation, algal species and beach macrofauna as ecological drivers for bacterial assemblages associated to wrack was investigated by experimental manipulation of Laminaria ochroleuca and Sargassum muticum. We examined the effects of changes in solar radiation on wrack-associated bacterial assemblages by using cut-off filters: PAR + UVA + UVB (280-700 nm; PAB), PAR + UVA (320-700 nm; PA), PAR (400-700 nm; P), and a control with no filter (C). Results showed that moderate changes in UVR are capable to promote substantial differences on bacterial assemblages so that wrack patches exposed to full sunlight treatments (C and PAB) showed more similar assemblages among them than compared to patches exposed to treatments that blocked part of the solar radiation (P and PA). Our findings also suggested that specific algal nutrient quality-related variables (i.e. nitrogen, C:N ratio and phlorotannins) are main determinants of bacterial dynamics on wrack deposits. We showed a positive relationship between beach macrofauna, especially the most abundant and active wrack-users, the amphipod Talitrus saltator and the coleopteran Phaleria cadaverina, and both bacterial abundance and richness. Moderate variations in natural solar radiation and shifts in the algal species entering beach ecosystems can modify the role of wrack in the energy-flow of nearshore environments with unknown ecological implications for coastal ecosystems.

Plastic in surface waters of the Inside Passage and beaches of the Salish Sea in Washington State

We summarize results of two independent studies on plastic pollution in the marine environment that overlap in time and space. One study evaluated the abundance of anthropogenic debris on 37 sandy beaches bordering the Salish Sea in Washington State while the other characterized plastic debris in surface waters of the Salish Sea and the Inside Passage to Skagway, Alaska. Both studies concluded that foam, primarily expanded polystyrene was the dominant pollutant. Plastic was found in surface waters the full length of the Inside Passage but was concentrated near harbors. At the wrack line, an average square meter of Washington's 1180km of sandy beaches in the Salish Sea had 61 pieces of anthropogenic debris weighing approximately 5g. The total loading for the entire 1m wide band is estimated to be 72,000,000 pieces and 5.8metric tons. Most anthropogenic debris on beaches is generated within the region.

Response of intertidal sandy-beach macrofauna to human trampling: An urban vs. natural beach system approach

Sandy beaches are subjected to intense stressors, which are mainly derived from the increasing pattern of beach urbanization. These ecosystems are also a magnet for tourists, who prefer these locations as leisure and holiday destinations, and such activity further increases the factors that have an adverse effect on beaches. In the study reported here the effect of human trampling on macrofauna assemblages that inhabit intertidal areas of sandy beaches was assessed using a BACI design. For this purpose, three contrasting sectors of the same beach were investigated: an urban area with a high level of visitors, a protected sector with a low density of users, and a transitional area with a high level of human occupancy. The physical variables were constant over time in each sector, whereas differences were found in the intensity of human use between sectors. Density variations and changes in the taxonomic structure of the macrofauna with time were shown by PERMANOVA analysis in the urban and transitional locations whereas the protected sector remained constant throughout the study period. The amphipod Bathyporeia pelagica appears sensitive to human trampling pressure and the use of this species as a bioindicator for these types of impact is recommended.

Metrics to assess ecological condition, change, and impacts in sandy beach ecosystems

Complexity is increasingly the hallmark in environmental management practices of sandy shorelines. This arises primarily from meeting growing public demands (e.g., real estate, recreation) whilst reconciling economic demands with expectations of coastal users who have modern conservation ethics. Ideally, shoreline management is underpinned by empirical data, but selecting ecologically-meaningful metrics to accurately measure the condition of systems, and the ecological effects of human activities, is a complex task. Here we construct a framework for metric selection, considering six categories of issues that authorities commonly address: erosion; habitat loss; recreation; fishing; pollution (litter and chemical contaminants); and wildlife conservation. Possible metrics were scored in terms of their ability to reflect environmental change, and against criteria that are widely used for judging the performance of ecological indicators (i.e., sensitivity, practicability, costs, and public appeal). From this analysis, four types of broadly applicable metrics that also performed very well against the indicator criteria emerged: 1.) traits of bird populations and assemblages (e.g., abundance, diversity, distributions, habitat use); 2.) breeding/reproductive performance sensu lato (especially relevant for birds and turtles nesting on beaches and in dunes, but equally applicable to invertebrates and plants); 3.) population parameters and distributions of vertebrates associated primarily with dunes and the supralittoral beach zone (traditionally focused on birds and turtles, but expandable to mammals); 4.) compound measurements of the abundance/cover/biomass of biota (plants, invertebrates, vertebrates) at both the population and assemblage level. Local constraints (i.e., the absence of birds in highly degraded urban settings or lack of dunes on bluff-backed beaches) and particular issues may require alternatives. Metrics - if selected and applied correctly - provide empirical evidence of environmental condition and change, but often do not reflect deeper environmental values per se. Yet, values remain poorly articulated for many beach systems; this calls for a comprehensive identification of environmental values and the development of targeted programs to conserve these values on sandy shorelines globally.

The effect of sand composition on the degradation of buried oil

The potential effects of the mineralogical composition of sediment on the degradation of oil buried on sandy beaches were investigated. Toward that purpose, a laboratory experiment was carried out with sandy sediment collected along NW Iberian Peninsula beaches, tar-balls from the Prestige oil spill (NW Spain) and seawater. The results indicate that the mineralogical composition is important for the physical appearance of the oil (tar-balls or oil coatings). This finding prompted a reassessment of the current sequence of degradation for buried oil based on compositional factors. Moreover, the halo development of the oil coatings might be enhanced by the carbonate concentration of the sand. These findings open new prospects for future monitoring and management programs for oiled sandy beaches.

Interception of nutrient rich submarine groundwater discharge seepage on European temperate beaches by the acoel flatworm, Symsagittifera roscoffensis

Submarine groundwater discharge (SGD) occurs in intertidal areas, representing a largely unquantified source of solute fluxes to adjacent coastal zones, with nitrogen being constantly the keynote chemical of concern. In Olhos de Água SGD is present as groundwater springs or merely sub-aerial runoff. The occurrence of the flatworm Symsagittifera roscoffensis is described for the first time in Olhos de Água in connection to seepage flows. To assess the impact of this symbiotic flatworm on the nitrogen associated to groundwater discharge flow at the beach, nitrate uptake experiments were conducted in laboratory microcosms. Our results show that S. roscoffensis actively uptakes nitrate at different rates depending on light availability, with rates ≈ 10 times higher than that of its symbiotic microalgae alone. This supports the hypothesis that S. roscoffensis could be an important in situ nitrate interceptor, potentially playing a biological role on the transformation of groundwater-borne nitrate loads at the land-ocean boundary.