Resumen. La mojarra (Eucinostomus currani) es un recurso importante de subsistencia en mercados locales de Ecuador. Sin embargo, poco es sabido sobre la historia de vida temprana y la biología reproductiva de esta especie. En 2016 y 2017, se recolectaron larvas de E. currani en 3 playas arenosas en el Golfo de Guayaquil, Ecuador, y se identificaron usando códigos de barras de ADN. La longitud estándar de las larvas osciló entre 4.00 y 15.78 mm. También recolectamos otolitos para comprender mejor la historia de vida temprana de E. currani. Los otolitos se usaron para estimar la edad, la tasa de crecimiento de la población (±EE), las fechas de eclosión y la época reproductiva. En promedio, la edad de los peces fue de 16.5 ± 4.5 días, mientras que la tasa de crecimiento promedio fue de 0.70 ± 0.05 y 0.22 ± 0.16 mm por día en marzo y mayo, respectivamente. En el Golfo de Guayaquil, la mayoría de las fechas de eclosión y la actividad reproductiva presunta de E. currani ocurrió durante la época húmeda (diciembre-abril) cuando aguas más calidas prevalecieron. Hasta donde tenemos conocimiento, este es el primer estudio que estima las fechas de eclosión y la tasa de crecimiento larval para una especie de la familia Gerreidae en el Océano Pacífico.

Abstract. The flagfin mojarra (Eucinostomus currani) is an important subsistence fishery resource in local Ecuadorian markets; however, very little is known about the early life history and reproductive biology of this species. In 2016 and 2017, E. currani larvae were collected at 3 sandy beaches in the Gulf of Guayaquil, Ecuador, and identified using DNA barcoding. Standard lengths ranged from 4.00-15.78 mm. We also collected otoliths to better understand the early life history of E. currani. Otoliths were used to estimate the age, population growth rate (±SE), hatch dates, and reproductive period. On average, the fish were 16.5 ± 4.5 days old, while the average growth rate was 0.70 ± 0.05 and 0.22 ± 0.16 mm per day in March and May, respectively. In the Gulf of Guayaquil, most hatch dates and the presumed reproductive activity of E. currani occurred during the wet season (December-April) when warmer water prevailed. To our knowledge, this is the first study to estimate the hatch dates and larval growth rate for a species of the family Gerreidae in the Pacific Ocean.

Resumen Introducción: Los equinoideos irregulares se caracterizan por tener una selección del sustrato en fondos blandos principalmente. En El Salvador se han registrado siete especies de equinoideos irregulares en las principales playas arenosas del país, M. stokesii es una de ellas. Objetivo: Determinar la abundancia, densidad y estructura de tallas, en playones de la bocana del estero El Tamarindo, El Salvador. Métodos: La investigación se realizó en época seca en el oriente del país en playones del estero El Tamarindo que se caracteriza por presentar grandes extensiones de arena mezclada con materia orgánica. En cada sitio, se trazaron transectos en banda paralelos a la costa mediante 9 cuadrantes de 10 m2 separados entre sí por 10 m (área total de 90 m2), en donde se contabilizaron y midieron los individuos de M. stokesii que se encontraran dentro del área delimitada. Resultados: Se contabilizaron 958 individuos de M. stokesii con una densidad total de 10.64 ± 13.22 ind/m2. El rango de tamaños fue de 1-6.5 cm. El hábitat se caracterizó por presentar arena con materia orgánica en los primeros mm del sustrato en compañía de otros invertebrados. Conclusiones: La abundancia y densidad de M. stokesii es similar a la registrada en otros estudios de la región.

Abstract Introduction: Irregular echinoids are characterized by having a selection of the substrate mainly on soft bottoms. In El Salvador, seven species of irregular echinoids have been recorded on the main sandy beaches of the country, M. stokesii is one of them. Objective: Determine the abundance, density and size structure of M. stokesii on beaches at the mouth of the El Tamarindo estuary, El Salvador. Methods: The research was carried out in the dry season in the east of the country on the beaches of the El Tamarindo estuary, which is characterized by large extensions of sand mixed with organic matter. At each site, band transects parallel to the coast were plotted by 9 quadrants of 10 m2 separated from each other by 10 m (total area of 90 m2), where individuals of M. stokesii found within the delimited area were counted and measured. Results: 958 individuals of M. stokesii were counted with a total density of 10.64 ± 13.22 ind/m2. The size range was 1-6.5 cm. The habitat was characterized by presenting sand with organic matter in the first mm of the substrate in the company of other invertebrates. Conclusions: The abundance and density of M. stokesii are similar to the ones recorded in other studies in the region.

Resumen Los modelos de clasificación de playa son ampliamente usados para describir el estado de la playa en respuesta a las condiciones ambientales reinantes y han establecido las bases teóricas sobre los modelos de perfil de equilibrio y en planta de una playa y sus diversas aplicaciones. En el estudio se determina el estado morfodinámico en 54 playas biogénicas arenosas del litoral nororiental de Cuba, a partir de la identificación de las geoformas litorales encontradas en trabajos de terrenos, para el periodo comprendido entre agosto de 2018 y marzo del año 2022, y las geoformas identificadas en imágenes satelitales de alta resolución de Google Earth Pro (CNES/Airbus, Maxar Technologies). Además, se comprobó en 12 playas representativas del litoral nororiental, si las geoformas litorales observadas en los trabajos de campo, indicativas de ciertos estados morfológicos, se corresponden con las pronosticadas mediante el parámetro adimensional Ω o Índice de Dean, que permite clasificar las playas en disipativas, reflejantes e intermedias. Como rasgos geomorfológicos fundamentales destacan un ancho medio de la playa superior a 50 m, una cara de 11 m de ancho y bermas estrechas o ausentes, con altura media de 1.35 m, sin la presencia de cúspides y topografías rítmicas, excepto en el 26% de las playas y únicamente en la etapa invernal. En la parte sumergida aparece una barra de arena de poca altura, sin la presencia de corrientes de resaca. La presencia de arrecifes coralinos que protegen las playas del oleaje de mayor altura, en el 93% de los casos, constituye el rasgo geomorfológico más significativo de las playas objeto de estudio. El cálculo del parámetro adimensional confirmó que las playas del litoral nororiental de Cuba corresponden a estados morfodinámicos de tipo intermedio y tienden más a estados modales reflejantes que disipativos, resultados que se corresponden con las geoformas litorales y la granulometría de los sedimentos encontrados en las playas objetos de estudio. Aun cuando las características reportadas por investigadores australianos, para playas intermedias coincidan con los valores pronosticados mediante el cálculo del parámetro adimensional Ω y con las características sedimentarias de las playas, las geoformas reportadas por estos, para playas intermedias, no fueron encontradas en las playas objeto de estudio. En ellas no aparecen corrientes de retorno, cadenas de surcos litorales, terrazas de bajamar, marcada topografía rítmica y cúspides. Otros estudios también han señalado que no siempre se cumple la clasificación de las playas, que tiene en cuenta las características de las olas y la velocidad de caída de los sedimentos, propuestas por investigadores australianos, debido particularmente a la presencia de arrecifes coralinos cercanos a la costa, la baja energía del oleaje y el control geológico. A ello habría que añadir el predominio del transporte longitudinal de arena sobre el transporte transversal en el área de estudio. Los resultados confirman que la clasificación de las playas, atendiendo a su estado morfodinámico es esencial para comprender la dinámica espacio-temporal de los procesos hidrodinámicos que tienen lugar en las playas y un mejor conocimiento local y regional de las mismas. Además, reafirman la necesidad de contar con estudios específicos de las características hidrodinámicas y sedimentarias propias de cada litoral, antes de extrapolar modelos de perfil de equilibrio en playas y las ecuaciones que se deriven de ellos en las actuaciones para el control de la erosión.

Abstract Beach classification models are widely used to describe the state of the beach in response to the prevailing environmental conditions and have set the theoretical grounds for equilibrium and in-plant profile models of a beach and their various applications. This study determined the morphodynamic state of 54 sandy biogenic beaches on the northeast coast of Cuba. This was done based on the identification of coastal geoforms found in land works between August 2018 and March 2022 and the geoforms identified in high-resolution satellite images from Google Earth Pro (CNES/Airbus, Maxar Technologies). In addition, on 12 representative beaches on the northeast coast, we explored whether the coastal geoforms indicative of certain morphological states observed during fieldwork match those predicted by the Ω dimensionless parameter or Dean’s index, which classified beaches as dissipative, reflective, and intermediate. The main geomorphological features include an average beach width of more than 50 m, an 11 m-wide face, and a narrow or absent flat zone with a mean height of 1.35 m, lacking cusps and rhythmic topography, except for 26 % of beaches and only in winter. The submerged zone shows a low sand bar without rip currents. Coral reefs that protect the beaches from the highest waves in 93 % of the cases represent the distinctive geomorphological feature of the beaches studied. The dimensionless parameter confirmed that the beaches of Cuba’s northeast coast correspond to intermediate morphodynamic states with a trend toward reflective rather than dissipative modal states. These findings correspond to the coastal geoforms and sediment granulometry on the beaches studied. The figures obtained with the dimensionless parameter Ω and the sedimentary characteristics of the beaches are consistent with the characteristics of intermediate beaches reported by Australian researchers, but we did not find the geoforms for intermediate beaches reported by them. The beaches studied showed no rip currents, chains of coastal furrows, low-tide terraces, marked rhythmic topography, and cusps. Other studies have also pointed out that the beach classification proposed by Australian researchers, which considers the characteristics of waves and the sedimentation rate, is not always applicable. In the study area, this is mainly due to the presence of coral reefs close to the coast, low wave energy, and the influence of geological factors, in addition to the prevalence of longitudinal over transverse sand transport. Our results confirm that beach classification considering their morphodynamic state is essential to understanding the spatio-temporal dynamics of the hydrodynamic processes on beaches and contributes to a better local and regional knowledge of them. In addition, they highlight that the hydrodynamic and sedimentary characteristics of each coastline should be studied before using beach equilibrium profile models and the equations derived from them for erosion control actions.

ABSTRACT Sandy beaches have different shoreline change rates (i.e., erosion/accretion rates). An erosive process on beaches poses risks for human-occupied areas. One example is Matinhos Beach (state of Paraná - Brazil), which has an average annual erosion rate of around 1.5 m yr-1 This study applied a methodology that combines in situ measurements and numerical modeling to simulate the physical processes in the coastal area of Matinhos during the 2018 Austral winter. Monthly DGPS surveys were carried out in the study area from June to September. The MOHID modeling system was applied to simulate hydrodynamics and sediment transport, considering waves and tidal forcing validated with in situ data. The WAVEWATCH III and SWAN models were applied in a nesting approach to simulate the waves at Matinhos Beach. The GFS was used to assess the wind conditions. The study period showed a dynamic evolution of accretion and erosion between monthly measurements with no clear pattern in most profiles. Significant sand accumulation was observed near the headland. Morphological changes were minor due to the predominance of low energy without significant storm events. The measured morphological changes are in line with the residual littoral drift obtained from the modeling results for the period. The residual current velocities were towards the southwest, with magnitudes ranging from 0.15 m s-1 to 0.2 m s-1. A slight variation in the angle of wave incidence (10°) may change the direction (southwest or northeast) and intensity of the littoral drift. The applied methodology can reduce uncertainty and support effective coastal management. However, the seasonal scales of wave climate cannot be disregarded, nor can the need for coastal oceanographic data. i.e., ie i e (i.e. erosionaccretion rates. . rates) humanoccupied human occupied areas state Brazil, Brazil , Brazil) 15 1 5 1. yr1 yr yr- 201 winter September transport data conditions profiles headland events southwest 015 0 0.1 s1 s s- 02 2 0. s1. 10° 10 (10° northeast management However disregarded i.e. (i.e 20 01 (10 i.e (1 (

Resumo O presente trabalho descreve as fitofisionomias e inventaria a diversidade florística remanescente da Área de Proteção Ambiental das Brisas, que se localiza no litoral da Baía de Sepetiba, no estado do Rio de Janeiro, possuindo cerca de 101 hectares. Foram identificadas e descritas três fitofisionomias, a saber, Restinga, a mais predominante, a Floresta Ombrófila Densa de Terras Baixas e o Manguezal. Para a Restinga pode-se reconhecer diferentes tipos de vegetação, como a de Praias e Dunas, as situadas sobre Cordões Arenosos, neste caso representadas por Florestas Baixa e Alta de Restinga, e a vegetação associada às depressões, como o Brejo de Restinga e a Floresta Paludosa. O levantamento florístico identificou 311 espécies, distribuídas em 231 gêneros e 86 famílias. As plantas herbáceas representam 29,26% da flora, seguido das trepadeiras (27,75%), arbóreas (27,33%), arbustivas (14,46%) e epífitas (4%). A Restinga abriga 81% da flora, seguida pela Floresta Ombrófila Densa de Terras Baixas (28,30%) e o Manguezal (2,25%). As famílias mais representativas foram Fabaceae (38 spp.), Euphorbiaceae (15 spp.), Asteraceae (14 spp.), Sapindaceae (14 spp.) e Malvaceae (13 spp). A área tem baixa similaridade florística com outras áreas do estado do Rio de Janeiro, porém apresenta maior agrupamento com restingas fluminenses. Brisas Sepetiba Janeiro 10 hectares saber predominante podese pode Dunas Arenosos depressões Paludosa 31 espécies 23 8 2926 29 26 29,26 flora 27,75%, 2775 27,75% , 27 75 (27,75%) 27,33%, 2733 27,33% 33 (27,33%) 14,46% 1446 14 46 (14,46% 4%. 4 4% . (4%) 81 28,30% 2830 28 30 (28,30% 2,25%. 225 2,25% 2 25 (2,25%) 38 (3 spp., spp spp. 15 (1 13 spp) fluminenses 1 3 292 29,2 277 27,75 7 (27,75% 273 27,33 (27,33% 14,46 144 (14,46 (4% 28,30 283 (28,30 22 2,25 (2,25% ( 29, 27,7 (27,75 27,3 (27,33 14,4 (14,4 (4 28,3 (28,3 2,2 (2,25 27, (27,7 (27,3 14, (14, 28, (28, 2, (2,2 (27, (28 (2, (27 (2

Abstract The present work describes the phytophysiognomies and inventories the remaining floristic diversity of the Brisas Environmental Protection Area, which is located on the coast of Sepetiba Bay in the state of Rio de Janeiro, Brazil, covering approximately 101 hectares. Three phytophysiognomies were identified and described, namely Restinga, the Lowland Dense Ombrophylous Forest and the Mangrove. Different types of vegetation can be recognized for Restinga, such as beaches and dunes, those located on sandy ridges, in this case represented by Low and High Restinga forests, and the vegetation associated with depressions, such as the Swampy Restinga and Swampy forest. The floristic survey identified 311 species, distributed in 231 genera and 86 families. Herbaceous plants represent 29.26% of the flora, followed by vines (27.75%), trees (27.33%), shrubs (14.46%) and epiphytes (4%). Restinga is home to 81% of the flora, followed by the Lowland Dense Ombrophylous Forest (28.30%) and the Mangrove (2.25%). The most representative families were Fabaceae (38 spp.), Euphorbiaceae (15 spp.), Asteraceae (14 spp.) and Sapindaceae (14 spp.). The area has low floristic similarity with other areas of the state of Rio de Janeiro, but it has a greater grouping with restingas from the state of Rio de Janeiro. Area Janeiro Brazil 10 hectares described dunes ridges forests depressions forest 31 species 23 8 2926 29 26 29.26 flora 27.75%, 2775 27.75% , 27 75 (27.75%) 27.33%, 2733 27.33% 33 (27.33%) 14.46% 1446 14 46 (14.46% 4%. 4 4% . (4%) 81 28.30% 2830 28 30 (28.30% 2.25%. 225 2.25% 2 25 (2.25%) 38 (3 spp., spp spp. 15 (1 spp.. 1 3 292 29.2 277 27.75 7 (27.75% 273 27.33 (27.33% 14.46 144 (14.46 (4% 28.30 283 (28.30 22 2.25 (2.25% ( 29. 27.7 (27.75 27.3 (27.33 14.4 (14.4 (4 28.3 (28.3 2.2 (2.25 27. (27.7 (27.3 14. (14. 28. (28. 2. (2.2 (27. (28 (2. (27 (2

Resumo Contaminação por microplásticos (MPs) é um impacto bem estabelecido nos oceanos, embora sejam escassos enfoques combinando análises simultâneas dos componentes bióticos e abióticos. Este estudo foi direcionado para esta lacuna, demonstrando a ingestão de MPs por Atherinella brasiliensis (espécie de peixe) e comparando com a presença do contaminante na água e sedimento. Três praias de Ubatuba (exposta, calma e estuário abrigado) foram amostradas para os componentes peixe, água e sedimento durante o verão e o inverno. Dados ambientais evidenciaram diferenças espaciais e sazonais (ACP/ANOVA). A presença de partículas sintéticas (PSs) em peixes foi alta (~38%). Concentrações máximas ocorreram no estuário, para água (490 PSs/m³), e na praia exposta, para sedimento (62 PSs/50g). O formato fibra predominou em todos os componentes. Preferência dos peixes pela cor azul parece ocorrer. Relações estatísticas significativas foram determinadas para comprimento dos peixes e tamanho das PSs e entre concentrações de PSs na água e nos peixes. As identidades químicas (μ-FTIR spectra), polipropileno, polietileno, poliamida, poliéster e celulose/papelão predominaram. Influências da hidrodinâmica local (e.g., tamanhos das PSs) e da redução do turismo durante a epidemia de Covid-19 (e.g., menos PSs no verão) são discutidas. Este estudo confirma a contaminação por PSs (a maioria MPs) nas praias de Ubatuba, afetando os peixes através da ingestão direta na coluna d’água. Ações urgentes por parte das autoridades e mudanças de hábitos dos usuários locais são cruciais. (MPs oceanos abióticos lacuna espécie peixe exposta (exposta abrigado inverno ACP/ANOVA. ACPANOVA ACP/ANOVA . ACP ANOVA (ACP/ANOVA) (PSs ~38%. 38 ~38% (~38%) 490 (49 PSs/m³, PSsm³ PSsm PSs/m³ , m³ m PSs/m³) 62 (6 PSs/50g. PSs50g PSsg PSs/50g 50g g PSs/50g) ocorrer μFTIR μ FTIR spectra, spectra spectra) polipropileno polietileno poliamida celulosepapelão celulose papelão predominaram e.g., eg (e.g. Covid19 Covid 19 Covid-1 discutidas dágua. dágua d água. d’água cruciais (ACP/ANOVA 3 ~38 (~38% 49 (4 PSs/m 6 ( e.g. (e.g Covid1 1 Covid- ~3 (~38 4 e.g ~ (~3 (~

Abstract Microplastics (MPs) contamination is a well-established impact in oceans, but integrated approaches combining simultaneous analyzes of biotic and abiotic components are scarce. This study addresses this gap, demonstrating Atherinella brasiliensis (fish species) ingestion of MPs and comparing with the contaminant presence in water and sediment. Three Ubatuba beaches (exposed, calm and sheltered estuary) were surveyed for fish, water, and sediment components in summer and winter. Environmental data evidenced spatial and seasonal differences (PCA/ANOVA). Presence of synthetic particles (SPs) in fish was high (~38%). Maximum concentrations occurred in the estuary, for water (490 SPs/m³), and in the exposed beach, for sediment (62 SPs/50g). Fibers format predominated in all components. Fish preference for blue color seems to occur. Significant statistical relationships were determined for fish length and SPs size and between SPs concentrations in water and fish. The chemical identities (μ-FTIR spectra) polypropylene, polyethylene, polyamide, polyester, and cardboard/cellulose predominated. Influences of local hydrodynamics (e.g., SPs sizes) and reduction in tourism during Covid-19 epidemic (e.g.,less SPs in summer) are discussed. This study confirms environmental contamination by SPs (mostly MPs) in Ubatuba beaches, affecting fish through direct water column ingestion. Urgent actions from authorities and changes in local user’s habits are crucial. (MPs wellestablished well established oceans scarce gap species exposed, (exposed estuary winter PCA/ANOVA. PCAANOVA PCA/ANOVA . PCA ANOVA (PCA/ANOVA) (SPs ~38%. 38 ~38% (~38%) 490 (49 SPs/m³, SPsm³ SPsm SPs/m³ , m³ m SPs/m³) beach 62 (6 SPs/50g. SPs50g SPsg SPs/50g 50g g SPs/50g) occur μFTIR μ FTIR spectra polypropylene polyethylene polyamide polyester cardboardcellulose cardboard cellulose e.g., eg e (e.g. sizes Covid19 Covid 19 Covid-1 e.g.,less egless less discussed mostly users user s crucial (PCA/ANOVA 3 ~38 (~38% 49 (4 SPs/m 6 ( e.g. (e.g Covid1 1 Covid- ~3 (~38 4 e.g ~ (~3 (~

Abstract This study aimed to conduct a comprehensive review of marine litter of Atlantic sandy beaches. We performed a bibliometric analysis from 1970 to 2023 to identify patterns, flaws, and knowledge gaps. A total of 185 studies were found but only 126 were included in the analysis according to exclusion criteria adopted. The earliest studies on Atlantic beaches were registered in the 1980s, being Marine Pollution Bulletin the major journal. Among the countries bordering the Atlantic Ocean, the highest number of studies were carried out in Brazil, Portugal, Mexico, and Spain. A significant finding that emerged from our study was the lack of standardized methodology adopted for studying anthropogenic litter on sandy beaches. This lack of standardization makes it difficult to compare results across different years and areas, highlighting the need for the development of new techniques and means to standardize future studies. Our study also discussed strategies for minimizing the presence of litter on beaches via coastal management and climate changes. It emphasized the importance of review studies in identifying gaps and guiding integrated and shared actions across the Atlantic region. Overall, this comprehensive review provides valuable insights into the status of anthropogenic litter in beaches of the Atlantic and highlights the need for standardization and collaborative efforts to address this persistent problem. By integrating scientific research with effective coastal management strategies, we can strive towards reducing anthropogenic litter and preserving the health and beauty of the Atlantic sandy beaches and worldwide. 197 202 patterns flaws 18 12 1980s s journal Ocean Brazil Portugal Mexico Spain areas changes region Overall problem worldwide 19 20 1 2

Abstract Despite their great importance, the sandy shores have not received the attention deserved. In Colombia they have been approached mainly from physical and geological standpoints, with few studies on the associated biodiversity, as is the case of the Johnny Cay Regional Natural Park in the Colombian Caribbean Region. To have a future frame of reference to evaluate and monitor the environmental impact on the sandy coast of Johnny Cay, the macrofaunal community of this ecosystem was characterized. Two stations were established, where three sediment samples were taken per beach zone (infralittoral, mesolittoral, and supralittoral), using a 16 cm diameter core, for a total of nine samples per station. The samples were sieved through a 500 µm mesh and processed in a laboratory. The macrofaunal community of Johnny Cay was represented by 1628 organisms, belonging to 20 families of the phyla Annelida, Nematoda, Mollusca, and Arthropoda (subphylum Crustacea). Annelids were the dominant group, representing 98% of total abundance, with two new family reports (Naididae and Enchytraeidae) for the Colombian Caribbean sandy beaches. The station EST_549 presented 67% of the macrofauna; this station is characterized by its hydro-dynamism, with a change of material due to the division in the opposite direction of the waves. Substrate samples were also taken in each beach zone for sedimentological analysis of grain size, carbonate content, organic matter content, and mineralogy; these variables were correlated with the community structure, obtaining a better correlation between the medium and coarse sands, and the width of the beach zone with the biological component. This work presents the baseline for the macrofaunal community of Johnny Cay sandy shore and sets the initial steps for its preservation and conservation. importance deserved standpoints biodiversity Region established infralittoral, infralittoral (infralittoral mesolittoral supralittoral, supralittoral , supralittoral) 1 core 50 laboratory 162 organisms 2 Annelida Nematoda Mollusca subphylum Crustacea. Crustacea . Crustacea) group 98 abundance Naididae Enchytraeidae beaches EST549 EST 549 EST_54 67 macrofauna hydrodynamism, hydrodynamism hydro dynamism, dynamism hydro-dynamism waves size content mineralogy structure sands component conservation 5 9 EST54 54 EST_5 6 EST5 EST_

We report radiocarbon dates obtained from on-shore marine and near-shore terrestrial deposits near Yzerfontein, on the West Coast of South Africa. These deposits include Late Pleistocene shell concretions from the southern end of 16 Mile Beach and a marine shell deposit inland of the coastal Rooipan (Red Pan); mid-Holocene coastal pan deposits exposed by modern storm erosion of the sandy 16 Mile Beach; and four Holocene storm beach deposits on a rocky shore to the south. We interpret the results in terms of local geomorphology constraints on sea-level fluctuations. The eastern margin of Rooipan is a >40 ka elevated beach deposit in a dune cordon that separates it from the adjacent Yzerfonteinpan. Both pans have gypsum deposits up to 2 m thick formed by repeated marine overwash. Saline pan deposits that are exposed intermittently on the beach are mid-Holocene and indicate a former westward extension of Rooipan. This is in contrast to storm beaches dating 8000-2600 cal BP at higher elevations on a rocky platform further south. This suggests that a dune barrier existed seaward of the present shoreline near Rooipan at this time. The coastal changes described here show that deposition and erosion can be affected significantly by the local palaeogeomorphology and cannot be ascribed solely to sea-level change. SIGNIFICANCE: Mollusc shells from Yzerfontein, Western Cape Province, South Africa, show radiocarbon ages ranging from >40 000 years to a few decades before present. There is evidence for elevated sea levels between 8000 and 2600 years ago, and sea levels similar to the present in the last 2000 years. Neither the elevation of the deposits nor their ages conform to published sea-level change curves for the Western Cape coast. Inundation by rising sea levels in the Holocene was not spatially uniform. Former and present geomorphology have had a significant effect on deposition and preservation of indicators of sea-level change.

Resumen Introducción: La contaminación por microplásticos es un problema global en los ecosistemas marinos, con impacto sobre microorganismos y ecosistemas en varios niveles espaciales. Las playas arenosas son ambientes de deposición donde se tiende a acumular gran cantidad de microplásticos. La co-ocurrencia de meiofauna intersticial y microplásticos en granos de arena plantea la pregunta de que si la acumulación de microplásticos en sedimentos afecta la abundancia y composición de comunidades de meiofauna. Objetivo: Probar la hipótesis de que microplásticos afectan la meiofauna de playas arenosas urbanas. Métodos: Estudiamos las tres principales playas arenosas urbanas de Santa Marta, Colombia: El Rodadero, Bahía Santa Marta y Taganga. Estas son similares en morfología y presiones externas, y difieren de las otras playas de la región. En abril 2019 recolectamos 81 muestras de arena, distribuidas de manera equidistante en la zona intermareal (nivel intermareal superior, medio y bajo). Aplicamos modelos lineales generalizados de abundancia, y pruebas permutacionales multivariantes a la composición de comunidades. Resultados: Identificamos 17 grupos taxonómicos de meiofauna, y partículas de microplástico (principalmente fibras de 45-500 micras) distribuidos equitativamente a lo largo de las playas y niveles intermareales. Hubo más meiofauna en el nivel intermareal medio, y en sedimentos de grano mediano y fino. A niveles intermareales más bajos, sitios con más microplásticos tuvieron menos meiofauna. La abundancia de los microplásticos explicó el 39 % de la variación en comunidades de meiofauna a niveles intermareales bajos. Conclusión: La acumulación de microplásticos podría tener un impacto negativo sobre las comunidades de meiofauna intersticial. Esto no es de sorprender: si los microplásticos ocupan el mismo volumen físico que estos animales, estos podrían presuntamente modificar la estructura de sedimentos y la composición del agua intersticial.

Abstract Introduction: Pollution by microplastics is a global problem in marine environments, which impacts microorganisms and ecosystems at several spatial levels. Sandy beaches are depositional environments where microplastics tend to accumulate in large quantities. The co-occurrence of interstitial meiofauna and microplastics in sand grains raises the question on whether the accumulation of microplastics in the sediments affects the abundance and composition of the meiofaunal communities. Objective: To test the hypothesis that microplastics affect the meiofauna of urban sandy beaches. Methods: We studied the three main urban sandy beaches of Santa Marta, Colombia: El Rodadero, Santa Marta Bay, and Taganga. All are similar in morphology and external pressures, and differ from other beaches in the region. In April 2019 we collected 81 sand samples, equally distributed in the intertidal zone (upper, mid, and lower intertidal levels). We applied generalized linear models to abundance, and multivariate permutational tests to community composition. Results: We identified 17 taxonomic groups of meiofauna, and microplastic particles (mainly 45-500 micron fibres) evenly distributed across beaches and intertidal levels. There was more meiofauna at the mid intertidal level, and in fine and medium grain sediment. At the lower intertidal level, sites with more microplastics had less meiofauna. Abundance of microplastics explained 39 % of the variation in meiofaunal community composition at lower intertidal levels. Conclusions: The accumulation of microplastics might have a negative impact on these meiofaunal interstitial communities. This is not surprising: if microplastics occupy the same physical space as these animals, they might presumably modify the structure of sediments and the composition of interstitial water.

Resumen. Las playas arenosas son uno de los ecosistemas costeros más extensos de Brasil y constituyen importantes zonas de amortiguamiento entre el ambiente terrestre y el marino. El presente estudio tuvo como objetivo analizar la distribución y la variación espaciotemporal de la comunidad meiofaunal de una playa arenosa tropical urbana con particular énfasis en la nematofauna. Establecimos 4 transectos durante 2 periodos de muestreo para evaluar diferentes zonas de playa. La meiofauna estuvo compuesta por 8 taxones, y la nematofauna consistió en 5 órdenes, 16 familias y 45 géneros. Las comunidades meiofaunales siguieron los estándares cualitativos-cuantitativos de las de otras playas arenosas tropicales en el noreste de Brasil. La comunidad nematofaunal presentó variación en su composición y estructura trófica entre los meses secos y los lluviosos, los cuales no presentaron correlación significativa con las características granulométricas. Esto sugiere que otras variables pueden influir en la estructura de las comunidades nematofaunales en la playa de Gaibu. Se requieren urgentemente más estudios de investigación sobre la biodiversidad de las comunidades meiofaunales en las playas arenosas del noreste de Brasil debido a la falta de información disponible sobre estos ambientes y el estrés extremo bajo al que están sujetas.

Abstract. Sandy beaches are among the most extensive coastal ecosystems in Brazil and constitute important buffer zones between terrestrial and marine environments. The present study aimed to analyze the distribution and spatiotemporal variation of the meiofaunal community of an urban tropical sandy beach in northeastern Brazil with a particular focus on nematofauna. We set up 4 transects during 2 sampling periods to evaluate different beach zones. The meiofauna comprised 8 taxa, and the nematofauna consisted of 5 orders, 16 families, and 45 genera. The meiofaunal communities followed the qualitative-quantitative standards of those of other tropical sandy beaches in northeastern Brazil. The nematofaunal community showed variation in its composition and trophic structure between dry and rainy months, which were not significantly correlated with granulometric characteristics. This suggests that other variables may influence the structure of nematofaunal communities in Gaibu Beach. Further research on the biodiversity of the meiofaunal communities on sandy beaches in northeastern Brazil is urgently needed given the lack of available information of these environments and the extreme stress they are currently under.

Resumen: El modelado de la línea de costa es indicativo de las tendencias a las que está sometido el sistema costero, ya que es la zona de contacto de la transición continente-océano. En este contexto, los arcos de las playas de Restinga de Marambaia y Macumba/Recreio-Barra da Tijuca (SE de Brasil) fueron evaluados en cuanto a la respuesta de la línea de costa a los forzamientos meteoceanográficos en las escalas temporales de largo y medio plazo, así como se mapearon sus grados de vulnerabilidad. En la escala de largo plazo (1986-2018), se utilizaron imágenes satelitales Landsat, datos de reanálisis de olas del modelo WaveWatch3, registros meteorológicos y mediciones del nivel medio del mar. En la escala de mediano plazo (2016-2018), se levantaron once perfiles topográficos, con muestreo de sedimentos, en las playas de Macumba/Recreio-Barra, además del análisis de registros de boyas oceanográficas en aguas profundas y poco profundas. Por último, estas informaciones permitieron la elaboración de un Índice de Vulnerabilidad de la Costa a la erosión y a las inundaciones. En general, el 18% de la línea de costa está erosionada, el 52% está estable y el 30% avanza. En el periodo analizado, se contabilizaron unos 400 eventos de tormentas, que durante los años de La Niña fueron más enérgicos y culminaron en una erosión más severa. El nivel del mar en la región muestra una tendencia al aumento (1,93 mm/año). La combinación de estos resultados y el grado de ocupación urbana de las playas estudiadas muestran una baja vulnerabilidad en el sector occidental de Marambaia, mientras que los sectores centrales y extremo oriental son altamente vulnerables. En Macumba, el sector oeste presenta una baja vulnerabilidad, en contraste con el sector este que es muy vulnerable. En el arco Recreio-Barra, la vulnerabilidad aumenta de oeste a este. Esto indica que la influencia humana desempeña un papel importante en las zonas que son naturalmente propensas a una alta vulnerabilidad, lo que requiere una mayor comprensión de las condiciones naturales asociadas a las intervenciones humanas.

Resumo: O comportamento da linha de costa é um indicativo das tendências à que o sistema costeiro está submetido, pois é a interface de contato da transição continente-oceano. Neste sentido, a Restinga da Marambaia e os arcos praiais Macumba/Recreio-Barra da Tijuca (SE do Brasil) foram avaliados quanto à resposta da linha de costa às forçantes meteo-oceanográficas nas escalas temporais de longo e médio prazo, bem como foram mapeados seus graus de vulnerabilidade. Na escala de longo prazo (1986-2018), foram utilizadas imagens de satélite Landsat, dados de reanálise de ondas do modelo WaveWatch3, registros meteorológicos e medições do nível médio do mar. Na escala de médio prazo (2016-2018), foram levantados onze perfis topográficos, com coleta de amostras de sedimentos, nas praias Macumba/Recreio-Barra, além da análise dos registros de boias oceanográficas em águas profundas e rasas. Por fim, estas informações permitiram elaborar um Índice de Vulnerabilidade Costeira à erosão e inundação. De modo geral, 18% da linha de costa encontra-se sob erosão, 52% encontra-se estável e 30% está avançando. No período analisado, foram contabilizados cerca de 400 eventos de tempestade, que durante os anos de La Niña foram mais energéticos e culminaram em uma erosão mais severa. O nível do mar na região apresenta tendência de aumento (1,93 mm/ano). O reflexo destes resultados, somado aos graus de ocupação urbana nas praias estudadas, exibem baixa vulnerabilidade no setor oeste da Marambaia, enquanto que os setores central e extremo leste configuram-se como altamente vulneráveis. Na Macumba o setor oeste exibe baixa vulnerabilidade, em contraste com o setor leste que é muito vulnerável. No arco Recreio-Barra nota-se o aumento da vulnerabilidade de oeste para leste. Estes resultados indicam que a influência antrópica tem um papel importante em áreas que são naturalmente propensas à alta vulnerabilidade, exigindo uma maior compreensão das condições naturais associadas às intervenções antrópicas.

Abstract: The coastline pattern is indicative of the trends to which the coastal system is subjected, since it is the contact interface of the continent-ocean transition. In this context, the Restinga da Marambaia and the Macumba/Recreio-Barra da Tijuca beach arcs (SE Brazil) were evaluated as to shoreline response to meteo-oceanographic forcings at the long and medium term time scales, as well as their vulnerability degrees were mapped. On the long-term scale (1986-2018), Landsat satellite imagery, wave reanalysis data from the WaveWatch3 model, meteorological records, and mean sea level measurements were used. At the medium-term scale (2016-2018), eleven topographic profiles were surveyed, with sediment sampling, at Macumba/Recreio-Barra beaches, in addition to the analysis of oceanographic buoy records in deep and shallow waters. Finally, this information allowed the elaboration of a Coastal Vulnerability Index to erosion and flooding. In general, 18% of the coastline is eroded, 52% is stable, and 30% is advancing. In the analyzed period, about 400 storm events were accounted for, which during the La Niña years were more energetic and culminated in more severe erosion. The sea level in the region shows a tendency to increase (1.93 mm/year). The combination of these results and the degree of urban occupation of the studied beaches show low vulnerability in the western sector of Marambaia, while the central and extreme eastern sectors are highly vulnerable. In Macumba the western sector exhibits low vulnerability, in contrast with the eastern sector that is very vulnerable. In the Recreio-Barra arc, vulnerability increases from west to east. These are indicative that human influence plays an important role in areas that are naturally prone to high vulnerability, requiring a greater understanding of the natural conditions associated with human interventions.

RESUMEN Los microplásticos (MP) han sido registrados en los ecosistemas marinos alrededor del mundo; sin embargo, poco se conoce sobre la variación temporal y espacial de los MP en playas marinas de Perú. En este trabajo se evaluaron los MP en Emerita analoga (Crustacea: Hippidae) y en los sedimentos de ocho playas arenosas, al norte y sur de la ciudad de Lima, en dos temporadas. Se colectaron 30 individuos de E. analoga y muestras de sedimento de cada una de las ocho playas por cada temporada (invierno y verano). Los MP fueron extraídos, contabilizados y caracterizados. Se observó una abundancia de 0.02 ± 0.13 a 1.82 ± 6.31 items de MP/individuo en E. analoga y en los sedimentos variaron de 41 ± 31.07 a 5353 ± 4013 ítems de MP/kg. Los fragmentos fueron el tipo predominante en los sedimentos, mientras que las fibras lo fueron en E. analoga. El transparente fue el color más frecuente. Los tamaños de las partículas en el sedimento oscilaron principalmente entre 1000 y 3000 µm, y en E. analoga fueron menores a 1000 µm. Se puede afirmar que la variación espacio-temporal juega un rol más importante en la dinámica de los MP en sedimentos en comparación con E. analoga. La abundancia de MP en el sedimento de la playa no guardó relación con la proporción de los individuos en E. analoga que los ingirieron, ni con la cantidad ingerida.

ABSTRACT Microplastics (MP) have been recorded in marine ecosystems around the world; however, little is known about the temporal and spatial variation of PM on marine beaches in Peru. In this work, PM were evaluated in Emerita analoga (Crustacea: Hippidae) and in the sediments of eight sandy beaches, north and south of the city of Lima, in two seasons. Thirty individuals of E. analoga and sediment samples were collected from each of the eight beaches for each season (winter and summer). The PM were extracted, counted and characterized. An abundance of 0.02 ± 0.13 to 1.82 ± 6.31 PM items/individual was observed in E. analoga and in the sediments they varied from 41 ± 31.07 to 5353 ± 4013 PM items/kg. Fragments were the predominant type in the sediments, whereas fibres were the predominant type in E. analoga. Transparent was the most frequent color. Particle sizes in the sediment ranged mainly between 1000 and 3000 µm, and in E. analoga less than 1000 µm. It can be affirmed that spatio-temporal variation plays a more important role in the dynamics of PM in sediments compared to E. analoga. The abundance of PM in the beach sediment was not related to the proportion of individuals in E. analoga that ingested them, nor with the amount ingested.

Resumen El gasterópodo Pachyoliva columellaris (antes Olivella columellaris) es particularmente común en las playas arenosas del norte de Perú. En la región estudiada al norte de Paita, provincia de Piura, la especie alcanza densidades de más de 80.000 individuos por metro de playa. Los caracoles realizan migraciones mareales durante todo el ciclo lunar, aunque las amplitudes de marea difieren cuatro veces entre la marea muerta y la marea viva. No todos los animales completan sus migraciones mareales y un número significativo permanece por encima del nivel del agua en marea baja. Durante todo el ciclo de marea, la proporción de individuos pequeños aumenta cerca del nivel del agua, mientras que los animales grandes dominan en las zonas bajas de la playa. Concluyo que las playas arenosas al norte de Paita son apropiadas para estudios adicionales de P. columellaris y los mecanismos de las migraciones de marea en invertebrados.

Abstract The gastropod Pachyoliva columellaris (formerly Olivella columellaris) is particularly common on many sandy beaches in North Peru. In the studied region north of Paita, Piura province, the species reaches densities of over 80,000 individuals per beach meter. The snails perform tidal migrations throughout the lunar cycle although tidal amplitudes differ four-fold between neap and spring tide. Not all animals complete their tidal migrations, and significant numbers remain above the water line at low tide. Throughout the tidal cycle, the proportion of small individuals is increased near the water line whereas large animals dominate in lower beach zones. I conclude that the sandy beaches north of Paita are well-suited for further studies of P. columellaris and the mechanisms underlying tidal migrations in invertebrates.

RESUMEN L as playas arenosas brindan gran variedad de servicios ecosistémicos sosteniendo el bienestar humano en áreas costeras. Estos ecosistemas dinámicos dependen de la interacción entre: el oleaje, las mareas y los regímenes de viento. Su alta variabilidad los hace vulnerables a las modificaciones físicas y el cambio climático, amenazando la estabilidad de las funciones ecosistémicas. El análisis de la dinámica costera requiere una gran cantidad de información, este estudio utiliza una metodología de acceso libre para estimar el área de playa a través de imágenes satelitales de la colección Landsat. El área de las playas es una variable relevante para dilucidar la dinámica costera, los atributos ecosistémicos y el potencial turístico. La arena (mediante Random Forest) y la cobertura vegetal (mediante el índice de diferencias normalizadas de vegetación) se consideraron como componentes del ecosistema de playa. Se validó el método para la costa de Montevideo, comparando los resultados con medidas independientes, y se estimó el área de 20 playas de para un período de 35 años. Esta metodología está disponible para su aplicación a un costo operativo bajo, representado una oportunidad para aumentar la información disponible y mejorar el manejo en materia de dinámica costera y uso de las playas arenosas.

ABSTRACT S andy beaches provide a variety of ecosystem services that support human well-being at coastal areas. These ecosystems are highly dynamic and primarily defined by the interaction between waves, tides and wind regimes. High variability makes beaches vulnerable to physical modifications and climate change, jeopardizing ecosystems functions. This has resulted in accelerated erosion rates and ecological degradation with widespread socioeconomic implications. Coastal dynamic analysis is a data demanding process that requires long term monitoring programs; this study applies an open access methodology to the Landsat collection in order to estimate beach area. This informative variable can help elucidate coastal dynamics, ecosystem attributes and touristic potential. Sand (through Random forest classification) and vegetation (through a threshold of the normalized difference vegetation index) were considered as components of the beach ecosystem. The method was calibrated for the Montevideo coast by testing results against independent estimations of beach area, the area of 20 beaches of the Montevideo coast was estimated for a 35 years’ period. This methodology can be applied anywhere at a very low operational cost, potentially multiplying the available information and allowing better management on the pressing matters of coastal dynamics and sandy beach use.