Virgin plastic granules on some beaches of Eastern Canada and Bermuda

A survey has been made of the quantities of small virgin plastic pellets and granules present in the litter stranding on shores of eastern Canada and Bermuda. Whilst particularly abundant on beaches of Bermuda, they are most uncommon on those of Nova Scotia and Sable Island—this, it is interpreted, reflects broad oceanic circulation patterns, lengthy residence times and distant sources, for there are no significant local ones. The polyethylene character of the granules was confirmed through burning characteristics and infra-red spectrophotometry. Polystyrene spherules were not identified. These plastic granules are commonly associated with pelagic tar balls and many have a tarry coating.The granules support a restricted, encrusting pseudoplanktonic biota, including serpulid worms and coralline algae, similar to that found on floating Sargassum. It is concluded, however, that their environmental consequence is not great.Although plastic granules progressively disappear through oxidative ageing and other degradational processes, they are an unnecessary contaminant of marine waters and evidence of evergrowing oceanic litter.     

Relationships between bioturbation by Tylos spinulosus (Crustacea, Isopoda) and its distribution on sandy beaches of north-central Chile

The semi-terrestrial isopod, Tylos spinulosus Dana, is a common inhabitant of the upper shore levels of sandy beaches of north-central Chile (ca. 26–30°S). During daylight hours, this isopod remains buried in the sand, while during the night emerges for feeding on stranded organic detritus, leaving exit holes on the beach surface. After feeding, isopods return to dig in their burrowing zones leaving surface irregularities such as cone-shaped mounds of sand. The burrowing preference of T. spinulosus was studied in the field, by: (i) releasing 30 isopods on artificially prepared sand circles (2 m diameter) having exit holes and mounds similar to those left by the isopods and on circles without holes and mounds, and (ii) counting active and buried isopods 15 min after their release in the experimental arenas. The circles had two densities of holes and mounds: treatments 1 and 2 had 100 and 200 holes, respectively, while treatments 3 and 4 had 100 and 200 mounds, respectively. Other 30 isopods were released on sand circles without these holes and mounds (treatment 5). A significantly higher number of isopods buried in circles with holes and mounds (either inside or outside them), compared with experimental arenas without such structures. These results show that the beach surface heterogeneity resulting from holes and mounds would be one of the processes explaining the patchiness of T. spinulosus and thus, its zonation on the intertidal zones of sandy beaches of north-central Chile.     

The influence of the environmental status of Casa Caiada and Rio Doce beaches (NE-Brazil) on beaches users

This paper describes the environmental status and the social perception of Casa Caiada (bay 1) and Rio Doce (bay 2 and bay 3) as a consequence of the several impacts that these beaches have been suffering. The methodology adopted in this work was based on interviews with beach users and direct observations of the physical, biological and human aspects. The obtained result denotes that in Casa Caiada the better beach quality is a consequence of the better water quality, infrastructure and services permitting a higher investment in housing development, recreation, commercialization, fishing, tourism, amongst others. In contrast, northward of Rio Doce (bay 3), the beach has been considered of bad quality for the beach users. In Casa Caiada the users were the most demanding when describing the status of the beach and the necessary changes to mitigate the actual situation. On the other hand, in the most degradated area (bay 3) the users were less demanding when proposing possible changes to improve the beach/water and life quality.     

Magnitude and cross-shore distribution of bed return flow measured on natural beaches

Field measurements of cross-shore currents 0.25 m from the bed were made on two natural beaches under a range of incident wave conditions. The results indicated the presence of a relatively strong, offshore-directed mean current, both within and seaward of the surf zone. Typical velocities within the surf zone were of the order of 0.2–0.3 m/s. This bed return flow, or “undertow”, represents a mass conservation response, returning water seaward that was initially transported onshore in the upper water column, primarily above the trough of the incident waves. The measurements demonstrated that the bed return flow velocity increases with the incident wave height. In addition, the crossshore distribution of the bed return flow is characterised by a mid-surf zone maximum, which exhibits a strong decrease in velocity towards the shoreline and a more gradual decay in the offshore direction. Several bed return flow models based on mass continuity were formulated to predict the cross-shore distribution of the bed return flow under an irregular wave field and were compared with the field data. Best agreement was obtained using shallow water linear wave theory, after including the mass transport associated with unbroken waves. The contribution of the unbroken waves enables net offshore-directed bottom currents to persist outside the region of breaking waves, providing a mechanism, other than rip currents, to transport sediment offshore beyond the surf zone.     

Distribution and abundance of small plastic debris on beaches in the SE Pacific (Chile): A study supported by a citizen science project

The accumulation of large and small plastic debris is a problem throughout the world's oceans and coastlines. Abundances and types of small plastic debris have only been reported for some isolated beaches in the SE Pacific, but these data are insufficient to evaluate the situation in this region. The citizen science project "National Sampling of Small Plastic Debris” was supported by schoolchildren from all over Chile who documented the distribution and abundance of small plastic debris on Chilean beaches. Thirty-nine schools and nearly 1000 students from continental Chile and Easter Island participated in the activity. To validate the data obtained by the students, all samples were recounted in the laboratory. The results of the present study showed that the students were able to follow the instructions and generate reliable data. The average abundance obtained was 27 small plastic pieces per m² for the continental coast of Chile, but the samples from Easter Island had extraordinarily higher abundances (>800 items per m²). The abundance of small plastic debris on the continental coast could be associated with coastal urban centers and their economic activities. The high abundance found on Easter Island can be explained mainly by the transport of plastic debris via the surface currents in the South Pacific Subtropical Gyre, resulting in the accumulation of small plastic debris on the beaches of the island. This first report of the widespread distribution and abundance of small plastic debris on Chilean beaches underscores the need to extend plastic debris research to ecological aspects of the problem and to improve waste management.     

西沙海域甘泉岛和全富岛海滩上的塑料垃圾与微塑料分布特征

塑料污染现象在世界各地海滩随处可见, 日益成为海洋环境中的重要威胁。文章调查了西沙海域甘泉岛和全富岛海滩的塑料污染分布情况, 结果显示, 尽管研究区域远离大陆, 人类活动影响较小, 但是海岛海滩上的塑料污染普遍存在, 塑料垃圾(>5mm)的平均分布丰度为(85.07±70.48)个∙m^-2, 平均重量为(40.23±78.15)g∙m^-2; 微塑料(<5mm)的平均分布丰度为(1774.75±1534.37)个∙m^-2或(100.82±87.18)个∙kg^-1。塑料垃圾和微塑料在不同海岛间的丰度分布均无显著性的差异, 但无论是塑料垃圾的丰度还是微塑料的丰度, 在环礁内侧海滩都显著高于环礁外侧海滩。此外, 微塑料的丰度分布与塑料垃圾的丰度分布呈显著的线性相关。红外光谱分析得出塑料聚合物主要成分有聚苯乙烯、聚丙烯和聚乙烯等, 其中以聚苯乙烯泡沫的比例占优。甘泉岛和全富岛海滩的塑料污染主要是通过其他地区的外源性塑料输送而来, 其在海岛上的不均匀空间分布受到区域海流作用、水动力条件、塑料降解等多种因素的影响。     

Cytochromes P-450 in cod (Gadus morhua): Effects of induces on regiospecificity of phenanthrene metabolism and immunochemical properties

The metabolism of some xenobiotics can lead to the formation of reactive intermediates with mutagenic/carcinogenic properties. With the carcinogenic PAH these have been identified as bay-region diol-epoxides.¹ Phenanthrene, a non-carcinogenic, bay-region containing model PAH, is metabolised in vivo by bony fish at the proximate bay-region position, whereas mammals and other marine organisms mainly form the K-region metabolite 9,10-dihydro-9,10-dihydroxy-phenanthrene.² We wanted to investigate this difference more closely by studying the regiospecificity of phenanthrene metabolism in vitro both with microsomes from differently pretreated cod and with isolated cytochrome P-450 isozymes from BNF-induced cod.³ Secondly, by preparing antibodies to the major isozyme isolated (called cod P-450c), we investigated the immunochemical properties of the variously treated cod liver microsomes.     

Effects of morphodynamic state on macrofauna community of exposed sandy beaches on Galician coast (NW Spain)

It is known that the fauna of the exposed sandy beaches are primarily controlled by physical variables; but how these variables operate along and across the beach still remains fairly under discussion. In our study, we sampled a range of exposed sandy beaches along the Northwest coast of Spain to determine the relationship between the principal physical variables of the beaches (including beach morphodynamic state), and the macrofaunal community. The fauna of these beaches comprise truly marine species along the intertidal zone as well as semi-terrestrial species in the upper and supratidal environments. These two groups respond in a different manner to the physical environment. The first group is directly controlled by the morphodynamic state of the beach, and variations in the physical environment; the second group is not clearly affected by these physical conditions. In this case, other variables such as food availability and the human uses of the upper limits of the beach seem to be more relevant in explaining the patterns observed in the macrofaunal community.     

Spatial and temporal distribution patterns of suspended particulate matter and particulate organic carbon in the Saronikos Gulf (eastern Mediterranean, Greece)

In 1998–1999, beam attenuation coefficient (bac) profiles, suspended particulate matter (SPM) and particulate organic carbon (POC) concentrations were assessed during five cruises in the Saronikos Gulf, eastern Mediterranean, Greece. SPM and POC concentrations (0.05–1.84 mg l⁻¹ and 10.2–468.6 μg l⁻¹, respectively) exhibited strong spatial and temporal variations, related to the different environmental characteristics of various sectors of the gulf, including wind regime and biological productivity. The Elefsis and Keratsini bays, as well as the area around Psyttaleia Island, showed the highest POC concentrations. The vertical distribution of POC at stations in the western basin, as well as in the inner and outer Saronikos Gulf is characterised by higher POC concentrations in surface waters, associated with higher biological activity. The wastewater treatment plant effluents discharged south of the Psyttaleia Island are a major source of organic particles which directly influence the intermediate water layers, at least during the stratification period. Assessments of relationships between bac and SPM or POC concentrations revealed a relatively strong correlation between bac and POC. An equation converting bac readings to POC concentration was established which can be applied to historical and/or future bac measurements, independently of season. POC concentrations estimated from calibrated continuous transmissometer readings were used to estimate the standing stock of POC in the Saronikos Gulf, which varied between 6,110×10⁶ and 13,450×10⁶ g C during the period June 1998 to February 1999.     

Reproduction and recruitment patterns of the surf clam Donax serra (Bivalvia,Donacidae) on two Namibian sandy beaches

Reproduction and recruitment of the surf clam Donax serra on two Namibian beaches were studied over a period of two years. Histological examination of the gonads indicated a discontinous annual reproductive cycle, related to monthly mean sea surface temperature. The spawning season lasted from August/September to February, but juveniles (2 – 6 mm anterior-posterior shell length) were only present for three months in the intertidal zone. The condition index indicates that the species spawns during autumn and summer, but histological validation is needed. The period when juveniles are abundant is decoupled from the spawning period and therefore cannot be predicted clearly, even if the spawning period is known. Starvation, hydrodynamic processes, chemical parameters and different release times during the spawning period are thought to cause the differences in settlement time and recruitment strength between locations.     

海岛旅游效率空间格局演变及影响因素研究 ——以中国12个海岛县(区)为例

旅游产业是海岛地区的重要产业之一，借助 DEA 模型测度 12 个海岛县 （区） 的旅游效率，采用组合方法对海岛旅游效率的空间特征演变进行刻画，并通过 EVIEWS 软件分析海岛旅游效率的影响因素。 （1） 海岛旅游综合效率总体不高，技术效率是海岛旅游效率发展的主要驱动力，规模效率水平较低，海岛旅游发展能力未得到全面发挥。 （2） 海岛县 （区） 之间旅游效率总体差异不大，相对差异明显。海岛旅游效率空间状态演变由不稳定趋向于稳定，可能存在“贫困陷阱”和“俱乐部趋同”现象。 （3） 经济发展水平、生态环境、科技信息对海岛旅游效率的发展起到积极的推动作用，产业结构、交通条件、城镇化是海岛旅游效率发展的约束性因素。     

The recreational use of beaches and consequences for the development of new trends in management: the case of the beaches of the Metropolitan Region of Barcelona (Catalonia, Spain)

This article offers some reflections on beach management, on the basis of the results of a survey on the recreational use of beaches and beach users' perception, which was carried out in the Metropolitan Region of Barcelona in 1992. The first part outlines the situation of the beaches, recent metropolitan beach policy and the organization of administrative bodies responsible for beach management. Survey objectives and methods are also explained briefly. In the second part, the principal results of the survey are presented and different beaches are compared in an attempt to analyse the types of users, the uses they make and the perception they have of the beaches. The conclusions identify new emerging social needs which demonstrate that new trends in beach management are also needed. Practical recommendations, related to this emerging perception of beaches as natural systems, are suggested.     

Urbanised beaches of the Ligurian coastal area (NW Mediterranean): A classification based on organic-matter characteristics and hydrolytic enzymatic activities

The beaches of Liguria have been intensively affected by human activities for over a century, transforming nearly the entire coastline from natural to urbanised and significantly upsetting beach ecological properties. The present study aims to investigate 9 Ligurian beaches characterised by different degree of urbanisation, to test if and to what extent the organic-matter (OM) recycling processes can be linked to the human activity. Swash zone sediment, sampled during the spring–summer–autumn period, when the anthropogenic influence is at its maximum due to tourism, was analysed for OM features and recycling processes. Multivariate statistical analyses showed that huge amounts of detrital OM accumulated in the more urbanised sites, where the anthropogenic influence was at its peak, deriving from higher inhabitant number and density, from the presence of crowded roads very near to the swash zone and sewage treatment plants. The presence of torrent outlets on the beaches provided further OM accumulation. Lipids, carbohydrates and degraded autotrophic pigments were the OM fractions mainly responsible of the differentiation, and rather constant, high labile phosphorus contents were found in the more urbanised sites. The high activity values of the hydrolytic enzymes indicate the response of the microbial system to the OM accumulation in the urban sites. However, a decoupling of the trends of some enzymatic activities (namely glucosidase and lipase) and their target OM was observed in the highly urbanised conditions.     

Artificial neural network modeling of cross-shore profile on sand beaches: The coast of the province of Valencia (Spain)

The paper describes the training, validation, testing, and application of models of artificial neural networks (ANN) for computing the cross-shore beach profile of the sand beaches of the province of Valencia (Spain). Sixty ANN models were generated by modifying both the input variables as the number of neurons in the hidden layer. The input variables consist of wave data and sedimentological data. To select and evaluate the performance of the optimal model, the following parameters were used: R², absolute error, mean absolute percentage error, and percentage relative error. Finally, the results are compared with the numerical model proposed by Aragonés et al. (2016b Aragonés, L., Y. Villacampa, F. J. Navarro-González, and I. López. 2016b. Numerical modelling of the equilibrium profile in Valencia (Spain). Ocean Engineering, 123:164–73. doi:10.1016/j.oceaneng.2016.07.036[Crossref], [Web of Science ®] , [Google Scholar]) for the equilibrium profile in the study area. The results show a mean absolute error of 0.21?m compared to 0.33?m Aragones’ model, significantly improving the results of the numerical model in the bar area around de Valencia Port. In addition, when comparing the results with other methods currently used (Dean’s or Vellinga formulation), the errors of these compared to ANN are of the order of 167 and 1538% higher, respectively.     

On the displacement of marked pebbles on two coarse-clastic beaches during short fair-weather periods (Marina di Pisa and Portonovo, Italy)

The aim of the investigation was to define the mechanisms of sediment transport in the swash zone of microtidal coarse-clastic beaches in the very short term by evaluating the displacement rates of marked pebbles under low-energy wave conditions. Tests were performed at two sites (Marina di Pisa, Ligurian Sea, and Portonovo, central Adriatic Sea) to check the consistency of the data over a range of different grain sizes. Two recovery campaigns were carried out at both sites, one 6 h and the other 24 h after the injection. During the experiments wave action was at a minimum (wave heights never exceeded 0.3 m). The results show that 20% of pebbles ranging in diameter from 30–90 mm moved significantly (more than 0.5 m) already 6 h after the injection, with some tracers being lost (3%). After 24 h, 40% of the pebbles were significantly displaced and 10% were lost. The preferential downslope movement of tracers, which suggests that coarse sediment movement under low-energy conditions is mainly controlled by gravity processes enhanced by steep beachface slopes, represents the novelty of the results reported here. It would appear that swash processes on low-energy beaches cause a significant rate of pebble displacement through the destabilization induced by wave uprush and backwash. Despite the microtidal range, the position of the mean water level plays a major role in changing the beach level at which swash processes can actually trigger pebble movement. The results of this study show that considerable, and mostly seaward-directed, coarse sediment transport takes place even during short fair-weather periods.     

Sex-specific biochemical and histological differences in gonads of sea urchins (Psammechinus miliaris) and their response to phenanthrene exposure

Female and male individuals of the same species often differ with respect to their susceptibility to toxicant stress. In the present study, sea urchins (Psammechinus miliaris) of both sexes were exposed to high (150 μg L?1) and environmentally relevant (5 μg L?1) concentrations of phenanthrene over 10 days. While food intake was significantly decreased following exposure to 150 μg L?1 phenanthrene, histological indices (lipofuscin accumulation, fibrosis, oocyte atresia), energetic status (energy charge, sum adenylates, AMP/ATP ratio) as well as ascorbate levels in the gonads showed either little or no effect upon phenanthrene exposure. However, most parameters (vitamin C, energy charge, sum adenylates, AMP/ATP ratio, ATP and ADP concentrations, lipofuscin content, fibrosis) significantly differed between male and female animals. This study illustrates the difficulties to identify toxic injury in reproductive tissue as it may be superimposed by gametogenesis and spawning of gametes.     

A Qualitative and Quantitative Study of the Marine Algae in the Saronikos Gulf (Greece)

Abstract. One hundred ninety-seven macroalgal taxa, belonging to four classes, were identified at seven characteristic stations of the Saronikos Gulf.
Species diversity was higher in cleaner waters. From the outer to the inner section, the number of species and the coverage increased in Bryopsidophyceae and decreased in Phaeophyceae and Rhodophyceae.     

The effect of human use of sandy beaches on developmental stability of Talitrus saltator (Montagu, 1808) (Crustacea, Amphipoda). A study on fluctuating asymmetry

In recent years, there has been an increasing intensity of human use of coastal areas in Galicia (NW Spain). Actually, there is great concern about rapid and unplanned urban and industrial development on certain locations, as this can generate adverse impacts on those areas. In this study, we selected three sandy beaches along the Galician coast (Chanteiro, Insuela and Valieros) facing different levels of anthropic pressure, and we analysed Talitrus saltator individuals with the aim of elucidating whether anthropogenic pressures on beaches such as tourism or pollution have an influence on the incidence of morphological developmental alterations in sandhoppers in the field. Specifically, levels of fluctuating asymmetry were selected as indicators of environmental stress. Results of two sampling dates (May and September) show that individuals collected at the most touristy and polluted beach were those showing the highest asymmetry values, although results were only statistically significant for samples collected during spring. Results are in accordance with the hypothesis that beach management and pollution reduce symmetry in sandhoppers living in altered beaches.