Short-term buoyant microplastic transport patterns driven by wave evolution, breaking, and orbital motion in coast

Recently, there has been a notable rise in social and scientific interest regarding microplastic pollution in coasts where waves significantly influence flow patterns and material transport. This study explores typical short-term movement of buoyant microplastics driven by surf zone processes including wave transformation, breaking, and orbital motion. To track microplastics, Lagrangian Particle Tracking Model (PTM) coupled with Eulerian wave-current interaction model appropriate for coastal hydrodynamics was used. From the simulations, several important findings were observed. (i) In alongshore uniform beaches, lighter and larger buoyant microplastics tended to reach beach more readily. (ii) Accurate predictions of microplastic transport in the surf zone required the consideration of wave breaking. (iii) In alongshore non-uniform coastal bathymetry, rip-currents can send buoyant microplastics offshore, beyond the surf zone.

Occurrence, dietary influence and risks of selected trace metals in different coastal predatory species

The global issue of ongoing trace metal emissions and legacy accumulation from diverse sources is posing threats to coastal wildlife. This study characterized the distribution of five metals in relation to dietary ecology (carbon and nitrogen stable isotopes: δ15N and δ13C) in representative predatory species (starfish, fish, and seabird) collected from the coast of Qingdao, northeastern China. Zinc (Zn) was the most abundant metal across species, followed by copper (Cu), chromium (Cr), cadmium (Cd), total and methylated mercury (THg and MeHg). Among the studied species, black-tailed gulls (Larus crassirostris) occupied the highest trophic position, followed by three predatory fish species, whereas the northern Pacific seastar (Asterias amurensis) had the lowest trophic position. The starfish exhibited high capacity to accumulate Cd, Cr and Cu. Conversely, black-tailed gulls exhibited high levels of Zn, while Hg was highest in predatory fishes. Across species, Cr, MeHg, THg and MeHg:THg showed significant positive correlations with δ13C, suggesting the influence of inshore food sources on their accumulation. Both MeHg and THg were significantly and positively correlated with δ15N, with MeHg demonstrating a greater slope, indicating their potential trophic magnification. We assessed health risks from the studied metals using established toxicity reference thresholds. Elevated risks of Hg were identified in three predatory fish species, while other metals and species remain within safe limits. These findings emphasize the significance of foraging patterns in influencing trace metal accumulation in coastal predators and highlight the importance of further monitoring.

Dataset on mesoplastics and microplastics abundances and characteristics from sandy beaches before and after typhoon events in northern Taiwan

A comprehensive dataset is presented, which describes the abundance, shapes, and colors of meso- and microplastic particles collected from two sandy beaches situated on the north coast of Taiwan. The sampling of beach sand was conducted repetitively at fixed locations over a time period of 20 months, commencing from April 2018 to November 2019, with the aim of monitoring the variations in distribution and composition of plastic particles. A total of three adjacent transects perpendicular to the waterline were sampled, with bulk sand samples collected from 50 × 50 cm quadrats. The samples were subjected to drying, weighing, and sieving to obtain mesoplastic fractions (5-25 mm) and microplastic fractions (1-5 mm). Visual identification was employed to extract mesoplastic particles, while density separation using a saturated NaCl solution was utilized to extract microplastic particles. The particles were counted visually under a stereo microscope, and subsequently classified based on their shape and color. Any unknown particles were subjected to FTIR spectroscopy. Particle count data are presented as particles per unit area (0.25 m2) but can be converted to particles per kg d.w. by employing the weight of dry sand, as provided in the tables. The dataset encompasses a time series and delineates the changes in particle distribution and composition following extreme weather events. It can be utilized for further research by reanalyzing the data from different perspectives or by incorporating other factors.

From UAV to PlanetScope: Upscaling fractional cover of an invasive species Rosa rugosa

Invasive plant species pose a direct threat to biodiversity and ecosystem services. Among these, Rosa rugosa has had a severe impact on Baltic coastal ecosystems in recent decades. Accurate mapping and monitoring tools are essential to quantify the location and spatial extent of invasive plant species to support eradication programs. In this paper we combined RGB images obtained using an Unoccupied Aerial Vehicle, with multispectral PlanetScope images to map the extent of R. rugosa at seven locations along the Estonian coastline. We used RGB-based vegetation indices and 3D canopy metrics in combination with a random forest algorithm to map R. rugosa thickets, obtaining high mapping accuracies (Sensitivity = 0.92, specificity = 0.96). We then used the R. rugosa presence/absence maps as a training dataset to predict the fractional cover based on multispectral vegetation indices derived from the PlanetScope constellation and an Extreme Gradient Boosting algorithm (XGBoost). The XGBoost algorithm yielded high fractional cover prediction accuracies (RMSE = 0.11, R² = 0.70). An in-depth accuracy assessment based on site-specific validations revealed notable differences in accuracy between study sites (highest R² = 0.74, lowest R² = 0.03). We attribute these differences to the various stages of R. rugosa invasion and the density of thickets. In conclusion, the combination of RGB UAV images and multispectral PlanetScope images is a cost-effective method to map R. rugosa in highly heterogeneous coastal ecosystems. We propose this approach as a valuable tool to extend the highly local geographical scope of UAV assessments into wider areas and regional evaluations.

Coastal landscape classification using convolutional neural network and remote sensing data in Vietnam

The length of global coastline is about 356 thousand kilometers with various dynamic natural and anthropogenic. Although the number of studies on coastal landscape categorization has been increasing, it is still difficult to distinguish precisely them because the used methods commonly are traditional qualitative ones. With the leverage of remote sensing data and GIS tools, it helps categorize and identify a variety of features on land and water based on multi-source data. The aim of study is using different natural - social profile data obtained from ALOS, NOAA, and multi-temporal Landsat satellite images as input data of the convolutional-neural-network (CvNet) models for coastal landscape classification. Studies used 900 cut-line samples which represent coastal landscapes in Vietnam for training and optimizing CvNet models. As a result, nine coastal landscapes were identified including: deltas, alluvial, mature and young sand dunes, cliff, lagoon, tectonic, karst, and transitional landscapes. Three CvNet models using three different optimizer types classified the landscapes of other 1150 cut-lines in Vietnam with the accuracies about 98% and low loss function value. Excepting dalmatian, karst and delta coastal landscapes, five others distribute heterogeneous along the coasts in Vietnam. Therefore, the evaluation of additional natural components is necessary and CvNet model have ability to update new landscape types in variety of tropical nation as a step toward coastal landscape classification at both national and global scales.

Distribution, sources and risk assessment of polycyclic aromatic hydrocarbons in surface sediments from the Yellow Sea coast, China

To study the distribution, sources, ecological/health risks, and the impact of regional economic variations on polycyclic aromatic hydrocarbons (PAHs) contaminations along the coast of the Yellow Sea in China, sediments from a broad coastal coverage were collected and analyzed. The total contents of 16 priority PAHs varied between 1.4 and 1675.9 ng/g except in the site of H18 (3191.4 ng/g) adjacent to Qingdao City, with an average value of 295.7 ng/g. PAH pollution along the coast presented a distinctive geographical feature, which was closely linked to local human activities, such as Rongcheng with industrial zones and aquacultural areas, and Yancheng Wetland with developed aquaculture. The source analysis results indicated that PAHs were mainly from pyrolytic sources, with smaller contributions from petroleum spills and combustion. Risk assessment suggested that PAH pollution along the Yellow Sea coast showed negligible biological risks and health risks in most areas.

Enrichment of geogenic phosphorus in a coastal groundwater system: New insights from dissolved organic matter characterization

High concentrations of geogenic phosphorus (P) in coastal aquifer systems pose a serious and continuous threat to the health of marine ecosystems. A major source for geogenic P enrichment in aquifer systems is the mineralization of P-containing organic matter. However, the mechanisms that drive the enrichment remain unclear. Therefore, our study sought to characterize the occurrence, sources, and enrichment mechanisms of geogenic P in a coastal confined aquifer system of the Pearl River Delta, southern China. To achieve this, we conducted Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) and fluorescence excitation-emission-matrix spectra (EEMs) as well as hydrochemistry and stable carbon isotope analyses. Our findings indicated that intense degradation of P-containing organic matter produced up to 8.07 mg/L of geogenic P in a reducing environment with abundant organic matter. The dissolved organic matter (DOM) of high-P groundwater (P > 1 mg/L) contained more humic-like fluorophores and exhibited higher humification. Groundwater with high P concentrations contained more aliphatic compounds and highly unsaturated-low O compounds, and the enrichment of P was mostly associated with CHOP compounds in the region of aliphatic compounds and CHON2P compounds in the region of highly unsaturated-low O compounds. Different types of dissolved organic phosphorus (DOP) can be mineralized into P, and even the mineralization of phosphonates takes precedence over the more unstable phosphate esters. P produced by the metabolism of different types of DOP was assimilated by marine microorganisms (e.g., heterotrophic bacteria and archaea), and the newly synthesized organic P compounds by chemosynthesis were subsequently released into the groundwater. Over time, P continues to be enriched in the aquifer system. This study provides new insights into subsurface P cycling in coastal aquatic systems.

Vertical distribution of inorganic nanoparticles in a Norwegian fjord

Due to the analytical challenges of detecting and quantifying nanoparticles in seawater, the data on distributions of NPs in the marine environment is limited to qualitative studies or by ensemble measurements subject to various analytical artifacts. Single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) allows determination of individual inorganic NPs at environmentally relevant concentrations, yet only few studies have been conducted on selected elements in surface sea water. Here, a sequential multi-element screening method was developed and implemented to provide a first survey of the horizontal and vertical distributions of inorganic nanoparticles and trace elements in a pristine Norwegian fjord prospect for submarine tailings deposition. Statistical control of false-positive detections while minimizing the size detection limit was ensured using a novel raw signal processing. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) gave confirmative and qualitative information regarding particle morphology and composition. Following SP-ICP-MS screening for particles of 16 elements, particulate Al, Fe, Mn, Pb, Si and Ti were found and determined to mass concentrations in ng/L of 1-399, 1-412, below limit of detection (<LOD) - 269, <LOD - 1, <LOD - 1981 and <LOD - 127 ng/L with particle number concentrations up to 10⁸ particles per liter. Total metals concentrations were at least an order of magnitude higher, at concentrations in μg/L of 1-12 for Al, 2-13 for Fe, 0.3-11 Mn, 0.02-0.5 for Pb, 46 to 318 Si and 0.04-0.4 for Ti. A strong depth dependence was observed for both trace elements and particles with concentrations increasing with depth. Our results provide a baseline for the fjord and new data on environmental levels of both total metals and metal containing nanoparticles including the vertical and horizontal distribution of natural nanoparticles.

Integrated biomarker responses and metal contamination survey in the wedge clam Donax trunculus from the Atlantic coast of Morocco

In Morocco, the marine environment has always been a major occupation for socioeconomic activities (industry, tourism, urbanization, etc.). Thus, this work displays a case study of Taghazout coast in the central Atlantic part of the country, which becomes the center of several development projects, such as the touristic resort Taghazout Bay. In the aim to assess the health status of this coastal ecosystem, a multi-indicator approach based on the response of biomarkers in the wedge clam Donax trunculus was adopted during two years (2016/2017). The undertaken investigations on the response of biomarkers (AChE, GST, MDA, and CAT) in the sentinel species D. trunculus showed an activation of defense mechanisms in this bivalve, which would imply exposure to chemical stress in this ecosystem. The monitoring of seasonal bioaccumulation of cadmium (Cd), lead (Pb), and copper (Cu) by D. trunculus indicates that the bivalves collected have been exposed to these metal sources in the study area. In addition, the correlation study has reported a significant effect of environmental parameters on biomarker response. Overall, the multi-indicator approach has clearly revealed the health status of Taghazout coast registered in a coastal urbanization.

Influence of wastewater treatment plants and water input sources on size, shape, and polymer distributions of microplastics in St. Andrew Bay, Florida, USA

Microplastic (MP) pollution is an ongoing problem in coastal systems, where wastewater treatment plants (WWTPs) deposit particles daily. This study examined MP characteristics at WWTP outflow and control sites in St. Andrew Bay in Northwestern Florida, USA. WWTP sites contained mostly polypropylene fragments (180.1 μm avg. size), while reference sites contained polypropylene fragments, and polyethylene and polyester fibers (315.3 μm avg. size). MP sizes were strongly linked to distance from the nearest WWTP, while shape and polymer compositions were more closely related to dissolved oxygen concentrations and distance to the nearest water input source. The prevalence of polypropylene fragments at WWTP sites suggests that extreme weather events during the study flushed land-based debris into the system, where it was buried in the sediments. Increased abundances of polyester and polyethylene terephthalate in the winter at WWTP sites are indicative of the role that laundering synthetic textiles plays in coastal MP pollution.

Identification and quantification of the sea spray effect on isotopic systems in α-cellulose (δ13C, δ18O), total sulfur (δ34S), and 87Sr/86Sr of European beach grass (Ammophila arenaria, L.) in a greenhouse experiment

The sea spray effect can severely influence the isotopic signature of terrestrial individuals in coastal regions. To further specify this effect, beach grass was grown in a greenhouse under controlled environmental conditions and sprayed with mineral salt solution containing different mineral salts but only traces of NaCl (group 1). Another group of plants was sprayed with salty water from the Schlei inlet and the Baltic Sea, respectively (group 2). Control plants were only sprayed with tap water. Isotope analyses were conducted on the unwashed and washed plants (δ¹³C_cellulose, δ¹⁸O_cellulose, δ³⁴S_{total S}, ⁸⁷Sr/⁸⁶Sr), soil (δ¹⁸O_sulfate, δ³⁴S_sulfate, ⁸⁷Sr/⁸⁶Sr), and spray as well as irrigation water (δ¹⁸O_sulfate, δ³⁴S_sulfate, ⁸⁷Sr/⁸⁶Sr). Moreover, elemental analyses were performed on the water samples. The sea spray effect was visible in all isotopic systems under study. The uptake of SO₄^2-, HCO₃^-, and Sr²⁺ directly affected plants of group 1, while plants of group 2, sprayed with salty water, additionally showed salinity stress in the case of α-cellulose and total sulfur due to biochemical reactions of the plants. Very high concentrations in HCO₃^- or SO₄^2- also affected the plants' isotopic signatures. The impact of the sea spray and additional stress reactions were quantified. Our study is the first experiment creating an artificial sea spray effect in a greenhouse. This experiment for the first time enables the identification and quantification of the sea spray effect in environmental samples. The marine signature taken up by the plants and recorded by the investigated isotopic systems is apparently high and should have an impact on the isotopic fingerprints of animal consumers at the coast, as evidenced for archaeological animals from the Viking Haithabu and the early medieval Schleswig sites located close to the Baltic Sea. This result demonstrates the potential of greenhouse experiments as an isotopic predictor of the past local sea spray effect.

Trace metals in urbanized coasts: The central Atlantic of Morocco as a case study

This study describes the contamination, accumulation, and ecological risk assessment of five trace metals (Cd, Pb, Cu, Zn, and Cr) in sediments of an urbanized beach in the central Atlantic coastline of Morocco. The two-year investigation (2018 and 2019) included six sampling sites along a 6 km coastal reach. In both years, none of the studied trace metals exceeded the background or the sediment quality guidelines (SQGs). The eco-toxicological indices revealed low degree of contamination, unpolluted ecosystem, and low ecological risk of metals. However, Cd exceeded the background value and some SQGs following the increase of anthropogenic activities in 2019. Likewise, it indicated unpolluted to moderately polluted sediment as well as moderate ecological risk. Overall, it is highly recommended to mitigate the avoidable anthropogenic activities (marine litter generation, sewage discharge, intense urbanization, and vehicle traffic on the beach) that lead to the elevation of metal pollution in the study area.

Application of deep learning models to detect coastlines and shorelines

Identifying and monitoring coastlines and shorelines play an important role in coastal erosion assessment around the world. The application of deep learning models was used in this study to detect coastlines and shorelines in Vietnam using high-resolution satellite images and different object segmentation methods. The aims are to (1) propose indicators to identify coastlines and shorelines; (2) build deep learning (DL) models to automatically interpret coastlines and shorelines from high-resolution remote sensing images; and (3) apply DL-trained models to monitor coastal erosion in Vietnam. Eight DL models were trained based on four artificial-intelligent-network structures, including U-Net, U2-Net, U-Net3+, and DexiNed. The high-resolution images collected from Google Earth Pro software were used as input data for training all models. As a result, the U-Net using an input-image size of 512 × 512 provides the highest performance of 98% with a loss function of 0.16. The interpretation results of this model were used effectively for the coastline and shoreline identification in assessing coastal erosion in Vietnam due to sea-level rise in storm events over 20 years. The outcomes proved that while the shoreline is ideal for observing seasonal tidal changes or the immediate motions of current waves, the coastline is suitable to assess coastal erosion caused by the influence of sea-level rise during storms. This paper has provided a broad scope of how the U-Net model can be used to predict the coastal changes over vietnam and the world.

An inclusive multiple model for predicting total sediment transport rate in the presence of coastal vegetation cover based on optimized kernel extreme learning models

Predicting sediment transport rate (STR) in the presence of flexible vegetation is a critical task for modelers. Sediment transport modeling methods in the coastal region is equally challenging due to the nonlinearity of the STR-vegetation interaction. In the present study, the kernel extreme learning model (KELM) was integrated with the seagull optimization algorithm (SEOA), the crow optimization algorithm (COA), the firefly algorithm (FFA), and particle swarm optimization (PSO) to estimate the STR in the presence of vegetation cover. The rigidity index, D₅₀/wave height, Newton number, drag coefficient, and cover density were used as inputs to the models. The root mean square error (RMSE), the mean absolute error (MAE), and percentage of bias (PBIAS) were used to evaluate the capability of models. This study applied the novel ensemble model, and the inclusive multiple model (IMM), to assemble the outputs of the KELM models. In addition, the innovations of this study were the introduction of a new IMM model, and the use of new hybrid KELM models for predicting STR and investigating the effects of various parameters on the STR. At the testing level, the MAE of the IMM model was 22, 60, 68, 73, and 76% lower than those of the KELM-SEOA, KELM-COA, KELM-PSO, and KELM models, respectively. The IMM had a PBIAS of 5, whereas the KELM-SEOA, KELM-COA, KELM-PSOA, and KELM had PBIAS of 9, 12, 14, 18, and 21%, respectively. The results indicated that the increasing drag coefficient and D₅₀/wave height had decreased the STR. From the findings, it was revealed that the IMM and KELM-SEOA had higher predictive ability for STR. Since the sediment is one of the most important sources of environmental pollution, therefore, this study is useful for monitoring and controlling environmental pollution.

Scenery evaluation as a tool for the determination of visual pollution in coastal environments: The Rabigh coastline, Kingdom of Saudi Arabia as a study case

Visual pollution is the visible deterioration and negative aesthetic quality of the landscape. Erosion, marine wrack, litter, sewage, and beach driving are affecting the coastal scenery and are generating a visual pollution problem on the Rabigh coastal area, Kingdom of Saudi Arabia. This work provides the scenic evaluation of 31 coastal sites using the Coastal Scenery Evaluation System (CSES) to determine the current state of this situation and give management inputs. The CSES assesses values from a checklist of 18 physical and 8 human parameters and allows the calculation of a scenic evaluation index (D Value), which classifies coastal sites into five classes: Class I, usually natural areas of top scenic characteristics, to Class V, poor scenic natural areas with a higher impact of human interventions. Along the study area, three sites (9.7 %) appeared in Class II; five (16.1 %) in Class III; 15 (48.4 %) in Class IV, and eight sites (25.8 %) in Class V. Class I sites were not found in the study area. Assessment presented in this work provides a complete overview of the Rabigh coastal scenery and serves as a baseline for implementing management strategies to cope the visual pollution problem.

The wedge clam Donax trunculus L., 1758 as a bioindicator of microplastic pollution

This study describes the use of D. trunculus as a bioindicator of microplastic (MPs) pollution due to beach urbanization related to the development of the Taghazout Bay tourist resort in Morocco. In six sites located on the coast, MPs densities ranged from 1.75 to 5.93 items per gram of D. trunculus wet weight. MPs contamination was significantly influenced spatiotemporally by the urbanization degree in the area. The shapes found were fibers (90.5%) and fragments (9.5%). The Fourier Transform Infrared Spectroscopy (FTIR) analysis reported two polymers: polyethylene (65%) and polypropylene (35%). MPs colors were dark and light, with a predominance of light blue (23.8%). The species ingested different sizes of MPs, mainly the 0.1 and 0.5 mm fractions. Scanning Electron Microscope coupled with an energy dispersive X-ray analyzer (SEM/EDX) revealed weathered MPs with chemical elements adhered to their surface (Cu, Fe, Mg, S, Cl, etc.). The results of this study recommend the use of D. trunculus as a new bioindicator of MPs pollution following an urban change in the coastal scenery. Also, a sustainable coastal management must be implemented in the study area.

Litter in coastal and marine environments

Litter is one of the most pervasive and fastest-growing anthropogenic alterations of the World's coasts and oceans. Along with climate change, litter has been identified as one of humankind's most critical environmental problems that demand urgent solutions. Litter magnitudes and distribution, and the related detrimental environmental effects, have been documented in all existing coastal and marine environments (e.g., beaches, dunes, abyssal plains and submarine canyons, among others). Litter's presence is now so ubiquitous in the environment that it serves as a geological indicator of the Anthropocene. As part of the solution to this out-of-hand problem, Marine Pollution Bulletin has produced this Special Issue entitled "Litter in Coastal and Marine Environments". This collection of 37 papers provides a focal point for such related current studies and, in part, seeks to discuss implementing specific management strategies under different scenarios. No single solution exists to cope with the litter issue. However, legally binding global governance that will effectively limit and control the magnitude of litter pollution is greatly needed. The topical range of this collection of papers includes case studies focussing on litter types (mainly dominated by plastics), sources, impacts and solutions.

Organic contaminants in marine sediments and seawater: A review for drawing environmental diagnostics and searching for informative predictors

Marine ecosystems represent major sinks for persistent organic pollutants (POPs). Yet, while their regulations fit localized activity and emissions, POPs are mobile and can persist away from their source. The present review draws an environmental diagnostic of the organic substances studied over the past forty months, which ones accumulated the most, and where. Maximum reported concentration was used as a proxy for the accumulation of contaminants. POPs occurrences studied in the Jan 2018-April 2021 period were recorded into a database, along with (i) the geographical location of the sample and its coastal or offshore origin, (ii) the type of compartment analyzed (water vs sediment), as well as (iii) the POPs and the sample physical-chemical parameters reported. In the articles reviewed, maximum reported concentrations of POPs were in the ng/L range in seawater and in the μg/kg range in sediments. Some hotspots presented concentrations high enough to represent a hazard for sea organisms in the water columns (μg/L range) or in surficial sediments (mg/kg range). On a global scale, offshore (>1 km from the coast) maximum reported concentrations were, for the majority of the POPs, equivalent or higher than coastal ones. Finally, a POP solubility threshold (900 mg/L) was observed above which POPs would not be found in offshore waters, but only in sediments. This review highlights that studying POP accumulation away from their sources is fundamental for the diagnostic of long-lasting marine POPs contaminations. Further, POPs lipophilicity is a good predictor for offshore transport, and an indicator of interest for predicting sediment accumulation. Although POPs fate and transport in oceans is complex and require a finer analysis that this review could provide, the present work is a step forward identifying the hotspots in which POPs could be of particular concern, along with chemical indicators to predict for POPs accumulation in marine reservoirs.

Influences of energetic typhoons on the redistributions of heavy metals in sediments along the Leizhou Peninsula coast, southern China

The southern China coast areas are often invaded by typhoons, probably causing the redistribution of heavy metals in sediments. The knowledge of the influence of typhoons on the redistribution of heavy metals along the coasts is limited. The sea-floor sediments from the Leizhou Peninsula (LP) coast, southern China, were sampled to test the spatial distribution of the heavy metal before and after typhoons Barijat and Mangkhut in 2018. Results indicated that the coast suffered from varying levels of As contamination, while only minor enrichments were found in a few locations for other heavy metals. The pollution level on the western LP coast seemed to be higher than on the eastern coast. All heavy metals were mainly provided by terrigenous materials from the natural processes and were less affected by grain sizes. After the typhoon landings, more oxidation conditions promoted the deposits of As and the adsorption of Mo by MnO₂.

Harmful algal blooms caused by Phaeocystis globosa from 1997 to 2018 in Chinese coastal waters

From 1997 to 2018, Phaeocystis globosa caused harmful algal blooms in Chinese coastal waters almost every year. In this study, the spatial and temporal distribution of P. globosa blooms and its influencing factors were discussed. The results showed that 80.6% of the P. globosa blooms happened in the South China Sea and 72.5% happened in the period from November to March of the following year. But in the Yellow Sea, P. globosa blooms might be limited by green tides. Among the influencing factors, temperature might be an important one that affected the spatial and temporal distribution of P. globosa blooms. Furthermore, eutrophication provided material basis and El Nino events might also stimulate the occurrence of P. globosa blooms. This study is helpful to reveal causes and mechanisms of P. globosa blooms and reduce the negative impacts of blooms on ecological environment, economic development and the safety of nuclear power plants.

Comparing marine anthropogenic debris on inhabited mainland beaches, coastal islands, and uninhabited offshore islands: A case study from Queensland and the Coral Sea, Australia

Anthropogenic debris (AD) including plastics, foams and fishing debris, are an undesirable accompaniment to beaches worldwide, arriving through direct deposition (littering) and oceanic transport. We investigated the standing stocks of 12 types of AD on inhabited islands, uninhabited islands and mainland locations, and the potential factors relating to AD deposition. We undertook beach-transects and sea-surface trawl surveys; comparing 13 uninhabited offshore islands, four inhabited/touristed coastal islands and 81 mainland beaches in Queensland, Australia. The abundance and type of AD differed between sites. Geographic factors had stronger relationships with AD density on islands than mainland beaches. Hard plastic density was linked with forcing from wind and sea surface currents. Beach width and onshore/side-shore forcing were the most important factors affecting AD loads (predominantly hard plastics) on islands. We found an inverse relationship between the density of beached plastic and plastic floating at the sea surface nearby and suggest that islands may act as a local sink for buoyant plastic.

Microplastic Pollution in Nearshore Sediment from the Bohai Sea Coastline

Microplastics are recognized as an emerging global issue in marine environments. In this study, microplastic pollution in subtidal sediments from nine typical stations in the Bohai Sea was investigated. The mean concentration was 458.6 ± 150.0 items/kg of dry weight, varying from 280.0 to 773.4 items/kg. All of the microplastics were categorized according to shape, color and size. Among these microplastics, fiber (77.1%), white/blue/black (85.0%) and small microplastics (< 1500 μm) (82.9%) were the most abundant types. Seven polymer types were identified and were, in decreasing order of abundance, rayon > PE > PS > PP > PET > ABS > PA. The microplastics abundance was of the same order of magnitude as that of other similar areas. The microplastic characteristics suggest that tourism, maritime activities and sewage discharge are possible sources. Our results provide useful information for performing an environmental risk assessment of microplastic pollution in this area.

Development a new index for littered waste assessment in different environments: A study on coastal and urban areas of northern Iran (Caspian Sea)

The coastal pollution has been evaluated using indexes like Clean Coast Index (CCI) in many countries. In this study, several coasts and urban areas in northern of Iran along the Caspian Sea, were assessed in terms of number and composition of litters. Furthermore, Clean Environment Index (CEI) was used for the first time to interpret the results. The results indicated that 60% of the coasts and 50% of the urban areas were in a dirty status and only 22% of the total surveyed areas were found to be in a clean status. The highest number of litters observed in the study areas was cigarette butt. Due to the impact of risk factor of different types of littered waste, it was obviously clear that CEI offers a more realistic and rigorous interpretation than CCI. Therefore, this new index can be considered to evaluate litters pollution in various areas.

Seasonal variation of diversity, weathering, and inventory of microplastics in coast and harbor sediments

Spatiotemporal variations in the abundance of microplastics (MPs) in surface sediments along the southwestern coast of Taiwan (including harbor and coastal regions) were investigated and the diversity, degree of weathering, and inventory of MPs in the sediments further quantified. The spatiotemporal variations of MP characteristics were used to assess possible transport routes of MPs. Results indicated that the average MP abundance in the partially-enclosed harbor region was 79.3 MPs in 1 kg dry sediment (item/kg dw), which was 3-5 times higher than that in the coastal region. Average MP abundance during the dry season (36.5 ± 52.2 item/kg dw) was relatively higher than that during the wet season (22.3 ± 23.2 item/kg dw). The dominant MPs were small (0.1-1.0 mm, 90%), colored (62.3%), and consisted mainly of fibers (54.1%) and fragments (40.5%). Analysis by μFTIR revealed the presence of ten types of polymers in the MPs, with the most abundant being polypropylene (35.1%), rayon (33.2%), and polystyrene (10.0%). Values of the microplastic diversity integrated index (MPDII) indicated that MP diversity was greater in the harbor region (MPDII = 0.62) than in the coastal region (MPDII = 0.51-0.54), and greater during the wet season (MPDII = 0.60) than during the dry season (MPDII = 0.50). As indicated by values of the MP carbonyl index (CI), the MPs exhibited a high degree of oxidation (CI >0.31) that appeared unrelated to spatiotemporal variations. In the dry season, MP inventory was 12.2 tons and the wet season inventory was 8.1 tons. The hydrodynamic forces may be an influenced force for the spatiotemporal distribution patterns of the MPs in surface sediments. MPs could accumulate in the surface sediments during the dry season and resuspend in the wet season with the higher rainfall and then migrate towards the deep sea following the water flow.

A fragmented sense of home: Reconfiguring therapeutic coastal encounters in Covid-19 times

A growing body of research suggests positive links between coastal proximity, interaction, human health and wellbeing. In 2020, following the onset of the Covid-19 pandemic, many people in the UK could not engage in their usual coastal practices due to a national lockdown and associated restrictions, including government bans in entering the sea. This paper shares findings from an exploratory study examining how these restrictions shaped the recreational coastal practices, perceptions and emotions of residents in the case study region of Devon, South West England. In-depth semi-structured interviews were conducted with a purposive sample of 12 residents, with varying domestic and employment circumstances in the pandemic. We foreground three key themes identified through an inductive thematic analysis of the interviews: feeling 'at home' with the sea, experiencing a fragmented sense of home with Covid-19, and reconfiguring the coast as a therapeutic landscape. While important to understand the links between coastal proximity, health and wellbeing, we highlight the value of gaining more nuanced insights into the emotional, social, material and temporal dynamics that can re-shape the therapeutic potential of coastal encounter in the largely unprecedented situation of a global pandemic.

Terrestrial inputs govern spatial distribution of polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB) in an Arctic fjord system (Isfjorden, Svalbard)

Considerable amounts of previously deposited persistent organic pollutants (POPs) are stored in the Arctic cryosphere. Transport of freshwater and terrestrial material to the Arctic Ocean is increasing due to ongoing climate change and the impact this has on POPs in marine receiving systems is unknown This study has investigated how secondary sources of POPs from land influence the occurrence and fate of POPs in an Arctic coastal marine system. Passive sampling of water and sampling of riverine suspended particulate matter (SPM) and marine sediments for analysis of polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB) was carried out in rivers and their receiving fjords in Isfjorden system in Svalbard. Riverine SPM had low contaminant concentrations (<level of detection-28 pg/g dw ΣPCB₁₄, 16-100 pg/g dw HCB) compared to outer marine sediments 630-880 pg/g dw ΣPCB₁₄, 530-770 pg/g dw HCB). There was a strong spatial gradient in sediment PCB and HCB concentrations with lowest concentrations in river estuaries and in front of marine-terminating glaciers and increasing concentrations toward the outer fjord. This suggests that rather than leading to increased concentrations, inputs of SPM from land lead to a dilution of contaminant concentrations in nearshore sediments. Preliminary estimates of SPM:water activity ratios suggest that terrestrial particles (with low contaminant concentrations) may have the potential to act as sorbents of dissolved contaminants in the coastal water column, with implications for bioavailability of POPs to the marine food web. There is concern that ongoing increases in fluxes of freshwater, sediments and associated terrestrial material (including contaminants) from land to the Arctic Ocean will lead to increased mobilization and transport of POPs to coastal ecosystems. However, the results of this study indicate that on Svalbard, inputs from land may in fact have the opposite effect, leading to reduced concentrations in coastal sediments and waters.

Anthropogenic litter density and composition data acquired flying commercial drones on sandy beaches along the Saudi Arabian Red Sea

Anthropogenic litter density and composition data were obtained by conducting aerial surveys on 44 beaches along the Saudi Arabian Coast of the Red Sea [1]. The aerial surveys were completed with commercial drones of the DJI Phantom suite flown at a 10 m altitude. The stills have a resolution of less than 0.5 cm pixels-1, hence, litter objects of few centimetres like bottle caps are easily detectable in the drone images. We here provide a subsample of the drone images acquired. To spare the time needed to visually count the litter objects in the thousands of drone images acquired, these were automatically screened using an object detection algorithm, specifically a Faster R-CNN, able to perform a binary classification in litter and non-litter and to categorize the objects in classes. The multi-class classification, however, is a challenging problem and, hence, it was conducted only on the 15 beaches that showed the highest performance after the binary classification. The performance of the algorithm was calculated by visually screening a subsample of images and it was used to correct the output of the Faster R-CNN. The described steps allowed to obtain an estimate of the litter density in 44 beaches and the litter composition in 15 beaches. By multiplying the relative abundance of each litter class and the median weight of objects belonging to each class, we obtained an estimate of the total mass of plastic beached on 15 beaches. Possible predictors of litter density and mass are the population and marine traffic densities at the site, the exposure of the beach to the prevailing wind and the wind speed, the fetch length and the presence of vegetation where litter could get trapped. Making such raw data (i.e. litter density and composition and their predictors) available can help building the base for a robust global estimate of anthropogenic litter in coastal environments and it is particularly important if data regards an understudied region like the Arabian Peninsula. Moreover, we share a subsample of the original drone images to allow usage from stakeholders.

Coastal ecosystem services & human wellbeing

Coastal areas are home to diverse ecosystems that provide essential goods and services for human wellbeing. Recognition, understanding and appreciation of the various goods and services provided by coastal ecosystems, especially the provisioning and cultural services are of utmost importance today. Systematic exploration of bioactive compounds from marine flora and fauna and deriving pharmaceuticals and nutraceuticals, as well as promotion of concepts such as the blue gym are essentially linked to human health and sustenance, necessitating measures towards preservation of these ecosystems. They also link Sustainable Development Goals, SDG 3: good health and wellbeing and, SDG-14: life below water.

Occurrence and toxicity of perfluoroalkyl acids along the estuarine and coastal regions under varied environmental factors

Due to the significant economic and ecological value, the increasing pollution threat to estuarine and coastal regions is of great concern. Perfluoroalkyl acids (PFAAs) are emerging pollutants which possess adverse ecological risk. In this review, we have compiled the data on the levels of PFAAs in environmental samples, mainly in estuarine and coastal zones. A worldwide map was generated to show the distribution of PFAAs. The experimental results have also been considered, which, together with those of environmental samples, has allowed us to infer about the factors that intervene in the behavior of PFAAs. The presence of PFAAs is determined primarily by the source of pollution. Salinity is as well shown as a significant condition, dependent too on the sampling environment. The analysis of PFAAs from environmental samples constitutes a fundamental tool for the surveillance of these pollutants, but the lack of homogeneity of protocols for sampling, as well as for the results presentation, limits the comparative capacity. Laboratory studies are also an essential tool in the analysis of particular aspects related to PFAAs, but many times the conditions tested are not environmentally significant. In this way, it would not be prudent to establish "paradigms" about the behavior of the PFAAs in certain areas or organisms, instead to suggest the points that can be considered fundamental for each issue addressed. The main variables that appear to intervene in estuarine and coastal regions are mainly the proximity to the source of pollution, salinity, pH, precipitation (rain) as well as types of PFAAs. All these can synergistically lead to different impacts on the ecosystem. Therefore, the particular risks of PFAAs in estuarine and coastal regions is a set of multiple variables, dependent on each sampling condition and according to the previously named parameters.

Microplastic pollution in surface water from east coastal areas of Guangdong, South China and preliminary study on microplastics biomonitoring using two marine fish

Microplastic pollution, one of the major global challenges, is a severe threaten to aquatic organisms. The purpose of this study was to investigate the abundance, distribution and characteristics of microplastics in coastal surface waters from eastern Guangdong, south China. We chose pelagic Konosirus punctatus and demersal Mugil cephalus from different sampling sites as candidate monitoring species for the ingestion of marine microplastics, and talked about the relationship between water samples and fish samples. We tried to find out the regulation about microplastics characteristics in fish samples and fish own traits. The mean abundance of microplastics in surface water was 8895 items/m³, small white fragments were dominating character. We need to increase the amount of fish data to further explore. This study would not only provide a detailed reference for a better understanding of microplastic pollution in Guangdong coastal areas, but also shed an insight in prospect of using fish as biomonitoring of microplastic wastes.

Gaining or losing ground? Tracking Asia's hunger for 'new' coastal land in the era of sea level rise

Many coastal cities are short of land for development and, coupled with the need to mitigate the impact of extreme events against a background of ongoing sea-level rise, coastal land reclamation (CLR) has emerged as a frequently applied solution, most especially in Asia. However, the sustainability of these newly reclaimed lands under the combined onslaught of increasing population pressure, SRL, greater frequency of extreme events, and land subsidence is largely unknown. In order to assess the spatial extent and temporal trends in recent CLR projects, we mapped and tabulated the annual magnitude of change in coastal land gain from 1988 to 2018 for eight major Asian coastal cities. Across these cities, both the spatial extent and rate of CLR is remarkable; some 700 km² has been reclaimed in just three decades. >35% of this new coastal land has been constructed in Shanghai alone (562 km²), while Singapore and Incheon have also experienced substantial land gains. These three cities alone account for almost 10% of all the land gained globally over the last three decades. An analysis of the spatio-temporal patterns reveals that, since recently reclaimed areas are predominantly characterized by construction, including ports, airports, commercial and residential uses, economic development is the most prominent driver. Shanghai, however, represents a significant departure from this trend, whereby >50% of the new coastal land gained during the recent past has not been devoted to construction projects and is vegetated, suggesting a different policy context. Commercial or otherwise, subsidence is widely reported as a major characteristic of recently reclaimed coastal land and is a major environmental challenge. Mapping recent rates of land subsidence over these newly reclaimed lands reveal that most are subject to significant levels of deformation, in the case of the international airport at Incheon, Republic of Korea, exceeding 25 cm annually.

Microplastic pollution in the sediment of Jagir Estuary, Surabaya City, Indonesia

This study was aimed to investigate the abundance and characteristics of microplastics (MP) in the sediment of Jagir estuary and Wonorejo coast, Surabaya, Indonesia. Sediment samples from 5 sites in the estuary and the adjacent coast were collected in replicates using Ekman dredge sampler. The MP particles were extracted using density separation method. Then the MP particles were counted and categorized according to shape, size, and color under a Zeiss Discovery V.12 stereomicroscope. Identification was done using Thermo Scientific Nicolet iS10 FTIR Spectrometer. The MP shapes comprised fiber (57%), film (36%), and fragment (7%). Abundance of the MP was highest in the Wonorejo coast sediment (590 particles/kg dry weight). The MP particles consisted of 68% large and 25% small sizes and comprised 56.7% polyester, 24.6% low-density polyethylene, and 18.8% polypropylene. The MP colors were 43% transparent, 21% black, 14% blue, 10% white, 8% red, and 4% yellow.

Effect of metals on zooplankton abundance and distribution in the coast of southwestern Taiwan

Three transects were established along the southwestern coast of Taiwan; transects from north to south were respectively extended from the Kaohsiung Harbor, Kaoping River estuary, and Fangshan River estuary. Six metals including Pb, Cd, Cr, Cu, Zn, and Ni were analyzed in the zooplankton and seawater samples. A total of 24 groups of zooplankton were identified. Calanoid was the frequently collected group and accounted for greater than 40% of the relative abundance of zooplankton. Results showed that metal concentrations in seawater close to coast were higher than those in the outside of transect. The mean of metal concentrations in zooplankton followed the hierarchy: Zn > Cu > Pb > Ni > Cr > Cd. On the whole, metal concentrations in zooplankton from sampling sites in the coastal region were observed to be higher than those in the offshore region. The bioconcentration factor of zooplankton ranged within 10³-10⁵ for all studied metals and indicated that zooplankton in the seawater of southwestern Taiwan can accumulate metal even at background concentrations of metals. The value of diversity indices exhibited an increase in the distance to the coast, whereas the abundance showed no significant correlation with that. Consequently, the lowest mean abundance of zooplankton and the highest average metal bioaccumulation were found in transect outside Kaohsiung Harbor, representing that Kaohsiung Harbor has the contamination of anthropogenic metals that results in the impact on zooplankton.

Storms do not alter long-term watershed development influences on coastal water quality

A twelve year (2000-2011) study of three coastal lagoons in the Gulf of Mexico was conducted to assess the impacts of local watershed development and tropical storms on water quality. The lagoons have similar physical and hydrological characteristics, but differ substantially in the degree of watershed urban development and nutrient loading rates. In total the lagoons experienced 22 storm events during the period studied. Specifically, we examine (1) whether there are influences on water quality in the lagoons from watershed development, (2) whether there are influences on water quality in the lagoons from storm activity, and (3) whether water quality is affected to a greater degree by watershed development versus storm activity. The two urbanized lagoons typically showed higher water-column nitrate, dissolved organic nitrogen, and phosphate compared with the non-urbanized lagoon. One of the urbanized lagoons had higher water-column chlorophyll a concentrations than the other two lagoons on most sampling dates, and higher light extinction coefficients on some sampling dates. The non-urbanized lagoon had higher water-column dissolved oxygen concentrations than other lagoons on many sampling dates. Our results suggest long-term influences of watershed development on coastal water quality. We also found some evidence of significant storm effects on water quality, such as increased nitrate, phosphate, and dissolved oxygen, and decreased salinity and water temperature. However, the influences of watershed development on water quality were greater. These results suggest that changes in water quality induced by human watershed development pervade despite the storm effects. These findings may be useful for environmental management since they suggest that storms do not profoundly alter long-term changes in water quality that resulted from human development of watersheds.

The consequences of landscape change on fishing strategies

We show how land-use change can affect fisher-harvesting behavior. We test whether fisher harvesting behavior can be predicted by landscape change patterns at local (~200km) and regional (~1200km) levels. Our data suggest that fishers harvesting in areas near tree plantations reduced benthic-invertebrate harvests in favor of demersal and pelagic finfish that are usually located further offshore. Fishers' management areas, which were near tree plantations, had higher chlorophyll-a values, and contained shellfish with more endobionts. Technology (owning a boat) and experience (age, years fishing, and alternative livelihoods) explained little in fisher-harvesting behavior. The flagship Chilean fisheries management program and seafood companies sourcing from these areas will need to respond to these new challenges. Despite complexities in designing cross-scale, social-ecological studies, we can no longer ignore the interconnectedness of commodities in the biosphere.

Distribution, sources, and ecological risk assessment of polycyclic aromatic hydrocarbons in surface sediments from the Nantong Coast, China

The distribution, sources, and ecological risk assessment of 16 polycyclic aromatic hydrocarbons (PAHs) in surface sediments from the Nantong coast in China were investigated. The results indicated that the total concentrations of the 16 PAHs in the surface sediments from the study area ranged from 1.4 to 87.1ngg^-1 dw (mean value 19.9ngg^-1 dw), which were generally low compared to the adjacent offshore area and other coastal zones around the world. The selected PAH ratios and the principal components analysis for each site showed that petroleum combustion and petrogenic pollution (mainly caused by petroleum spills) were the dominant PAHs sources in the surface sediments of the coast. The ecological risk assessment indicated that most of the individual PAHs had few negative effects in this area.

Bile metabolites of polycyclic aromatic hydrocarbons (PAHs) in three species of fish from Morocco

BACKGROUND

Polycyclic aromatic hydrocarbons (PAH) are environmental contaminants that pose significant risk to health of fish. Environmental pollution of fish is a topic of rising attention in Morocco. However, only few studies have been carried out so far, describing the potential threat of organic pollution to Moroccan aquatic ecosystem. Two polycyclic aromatic hydrocarbon (PAH) metabolites, 1-hydroxypyrene (1-OH-Pyr) and 1-hydroxyphenanthrene (1-OH-Phen), were identified and quantified from the bile of 18 European eels (Anguilla anguilla), 7 Moray (Muraenidae), and 28 Conger eels (Conger conger) collected from Moulay Bousselham lagoon and Boujdour coast. The bile metabolites were separated by high-performance liquid chromatography with fluorescence detection. The present study aims to compare the levels of PAH metabolites in fish from the lagoon and the open sea and to compare levels of PAH metabolites in different fish species.

RESULTS

The major metabolite present in all fish was 1-hydroxypyrene (<LOD-15.56 ng/mL) with lower concentration of 1-hydroxyphenanthrene (<LOD-9.6 ng/mL). These concentrations of PAH metabolites are low compared to studies published before.

CONCLUSION

The data confirm the importance of 1-hydroxypyrene as the key PAH metabolite in fish bile and suggest that the European eel is an ideal species for monitoring PAHs in Moroccan waters. The present study provides valuable information on concentrations of PAH metabolites in fish from Morocco, especially for the first time for Conger eels and Moray.

Assessment of heavy metal contamination levels and toxicity in sediments and fishes from the Mediterranean Sea (southern coast of Sfax, Tunisia)

Contamination of heavy metals in sediment is regarded as a global crisis with a large share in industrializing cities like Sfax (Tunisia). Seven heavy metals such as Cadmium (Cd), Copper (Cu), Iron (Fe), Mercury (Hg), Nickel (Ni), Lead (Pb), and Zinc (Zn), and one metalloid such as Arsenic (As) in sediments and fish (D. annularis, L. aurata, and S. vulgaris) were investigated from the Southern coast of Sfax in Tunisia. The range of metals in sediments were 13.11-36; 4.42-7.92; 8.23-28.56; 50,564-11,956; 2.9-6.8; 9.13-30.51; 65.06-151.50, and 47-546 kg(-1) DW for As, Cd, Cu, Fe, Hg, Ni, Pb, and Zn. The level of studied metals in sediment samples exceeded the limits of the quality assessment guidelines (SQGs). The potential ecological risk index (PERI) proved that the investigated region could pose moderate risk for the aquatic biota. Metal bioaccumulation in the fish muscles varied significantly among species. Indeed, S. vulgaris and D. annularis accumulated higher amount of metal than L. aurata. The target hazard quotients (THQ) of individual heavy metals in fish, except for As and Hg, revealed safe levels for human consumption. Nevertheless, the total THQ indexes exceeded 1 suggesting the combined effects on muscles fish, which may constitute a risk to population's health.

Impact of sewage discharges on coastal water quality of Mumbai, India: present and future scenarios

The simulation study assesses the impact of sewage discharges on the present and predicted water quality of the Mumbai coast using MIKE 21. Water quality parameters in terms of dissolved oxygen (DO), biochemical oxygen demand (BOD) and faecal coliform (FC) are checked against specified standards. The simulation is validated for the present coastal hydrodynamics and observed water quality parameters. The validated model is further used for predicting scenarios in terms of upgradation in a pumping station and improvement in wastewater collection, treatment level and disposal systems. The water quality of the existing coastal environment does not conform to the stipulated standards but improves considerably in the prediction scenarios. However, despite a marked improvement in FC, it is not as per desired standards as no treatment for bacteria removal is considered. The simulation study emphasizes the need for exploring options like the reuse or recycle of treated effluent, as an effort for water conservation.

Trace elements in eggs of common eiders (Somateria mollissima) breeding in Nova Scotia, Canada

We provide the first report on trace element concentrations in eggs of common eiders (Somateria mollissima), a coastal benthic foraging sea duck, from Nova Scotia, Canada, and compare those to known values from this species elsewhere. Most trace elements of toxicological concern (Hg, Se, Cd, Cu, Zn) were lower in eider eggs from Nova Scotia than from eider eggs collected farther north in Canada, although As was elevated. Our data provide strong support for a pattern of increasing Hg at higher latitudes for this species.

Assessment of trace metals contamination level, bioavailability and toxicity in sediments from Dakar coast and Saint Louis estuary in Senegal, West Africa

Trace metals have the potential to associate with sediments that have been recognised as significant source of contamination for the benthic environment. The current study aims assessing the trace metals contamination level in sediments from Dakar coast and Saint Louis estuary, and to examine their bioavailability to predict potential toxicity of sediments. Surface sediment samples were collected between June 2012 and January 2013 in three sampling periods from eight stations. Trace metals were analysed using inductively coupled plasma-optical emission spectrometer. Geoaccumulation indexes (Igeo) showed strong pollution by Cd, Cr, Cu and Pb confirmed by enrichment factor (EF) suggesting that these metals derived from anthropogenic sources. Toxicity indexes exceeded one in several sites suggesting the potential effects on sediment-dwelling organisms, which may constitute a risk to populations' health. However, seasonal variability of metal bioavailability was noted, revealing the best period to monitor metal contamination. From an ecotoxicological point of view, concentrations of Cd, Cr, Cu and Pb were above the effects range low threshold limit of the sediment quality guidelines for adverse biological effects. In addition, with Pb concentrations above the effect range medium values in some sites, biological effects may occur.

Energy expenditure on recreational visits to different natural environments

Physical inactivity poses a significant challenge to physical and mental health. Environmental approaches to tackle physical inactivity have identified natural environments as potentially important public health resources. Despite this, little is known about characteristics of the activity involved when individuals visit different types of natural environment. Using Natural England's Monitor of Engagement with the Natural Environment Survey, we examined 71,603 English respondents' recreational visits to natural environments in the past week. Specifically, we examined the intensity of the activities they undertook on the visits (METs), the duration of their visit, and the associated total energy expenditure (MET minutes). Visits to countryside and urban greenspace environments were associated with more intense activities than visits to coastal environments. However, visits to coastal environments were associated with the most energy expenditure overall due to their relatively long duration. Results differed by the urbanity or rurality of the respondent's residence and also how far respondents travelled to their destination. Knowledge of what types of natural environment afford the highest volumes and intensities of physical activity could inform landscape architecture and exercise prescriptions. Isolating activity-supporting characteristics of natural environments that can be translated into urban design is important in providing physical activity opportunities for those less able to access expansive environments.

Variability in δ¹⁵N of intertidal brown algae along a salinity gradient: differential impact of nitrogen sources

While it is generally agreed that δ(15)N of brown macroalgae can discriminate between anthropogenic and natural sources of nitrogen, this study provides new insights on net fractionation processes occurring in some of these species. The contribution of continental and marine sources of nitrogen to benthic macroalgae in the estuary-ria system of A Coruña (NW Spain) was investigated by analyzing the temporal (at a monthly and annual basis) and spatial (up to 10 km) variability of δ(15)N in the macroalgae Ascophyllum nodosum and three species of the genus Fucus (F. serratus, F. spiralis and F. vesiculosus). Total nitrate and ammonium concentrations and δ(15)N-DIN, along with salinity and temperature in seawater were also studied to address the sources of such variability. Macroalgal δ(15)N and nutrient concentrations decreased from estuarine to marine waters, suggesting larger dominance of anthropogenic nitrogen sources in the estuary. However, δ(15)N values of macroalgae were generally higher than those of ambient nitrogen at all temporal and spatial scales considered. This suggests that the isotopic composition of these macroalgae is strongly affected by fractionation during uptake, assimilation or release of nitrogen. The absence of correlation between macroalgal and water samples suggests that the δ(15)N of the species considered cannot be used for monitoring short-term changes. But their long lifespan and slow turnover rates make them suitable to determine the impact of the different nitrogen sources integrated over long-time periods.

Natural radioactivity level in beach sand along the coast of Xiamen Island, China

The activity concentration of (40)K, (232)Th and (226)Ra was determined in beach sand samples collected from Xiamen Island, China using gamma ray spectrometry. The activity concentrations of (40)K, (232)Th and (226)Ra in the beach sand range from 197.4 to 487.6, 6.5 to 41.4 and 7.9 to 25.7 Bq kg(-1) with the mean of 401.0, 11.3 and 14.1 Bq kg(-1), respectively, which are lower than the averages of Chinese soil and world soil. The radium equivalent activity values in all beach sand samples are lower than the recommended limit of 370 Bq kg(-1). The external hazard index values are less than unity. The outdoor air absorbed dose rate and the corresponding annual effective dose rate of beach sand investigated are lower than the worldwide average.

Assessment of contamination, distribution and chemical speciation of trace metals in water column in the Dakar coast and the Saint Louis estuary from Senegal, West Africa

The water column from Dakar coast and Saint Louis estuary in Senegal, West Africa, was sampled in order to measure the contamination level by trace metals. The speciation of metals in water allowed performing a distribution between dissolved and particulate trace metals. For the dissolved metals, the metallic concentration and repartition between the organic fraction and the inorganic fraction were performed. The results show that the pollution of the estuary was more serious than in Dakar coast for Co, Cr, Ni, Pb and Zn; while, Cd and Cu were higher in Dakar coast. A strong affinity between metals and suspended particles has been revealed. Dissolved metals that have a tendency to form organic metal complexes are in decreasing order: Cd, Zn, Pb, Co=Cr=Mn, Cu and Ni. The results showed that the mobility of trace metals in estuary is controlled by dissolved organic carbon, while in coast it depends on chlorides.

Analysis of water quality and circulation of four recreational Miami beaches through the use of Lagrangian Coherent Structures

Four popular, recreational beaches in Miami, FL are Hobie Beach, Virginia Key Beach, Crandon Park Beach, and Bill Baggs Cape Florida State Park. While all of the beaches are within a few miles of each other in Biscayne Bay, they have greatly differing water qualities, as determined by the testing for fecal indicator bacteria performed by the Florida Department of Health. Using the geodesic theory of transport barriers, we identify Lagrangian Coherent Structures (LCSs) in each area. We show how these material curves, which shape circulation and mixing patterns, can be used to explain the incongruous states of the water at beaches that should be comparable. The LCSs are computed using a hydrodynamic model and verified through field experimentation at each beach.