Abstract Continental margins usually have a high degree of environmental heterogeneity, which, in turn, promotes high benthic biodiversity. The South-Southeast regions concentrate the most well-mapped areas of the Brazilian continental margin regarding seafloor geomorphology and physical oceanography. However, the structure of the soft-sediment benthic fauna of the continental slope is still unknown. Characterization and understanding of the Brazilian continental slope biota are imperative since human activities are increasing in the last decades, especially after the discovery of the pre-salt reservoir in Santos Basin. In this study, we aimed to establish a baseline of the spatial distribution of the benthic macrofaunal communities regarding their latitudinal and bathymetric patterns in the Santos Basin to support future environmental monitoring activities in the region. As part of the Santos Project – The Santos Basin Regional Environmental Characterization (PCR-BS) – coordinated by CENPES/PETROBRAS, a benthic oceanographic cruise was carried out in 2019. Sediment samples were collected using a GOMEX-type box corer in 47 stations distributed in eight transects (400– 2,400 m depth range). In total, 12 additional stations (1,300–2,200 m) were defined to cover an area where oil and gas are exploited. Our results showed that macrofaunal assemblages of the Santos Basin present strong depth zonation related to changes in organic matter input, as well as to temperature, carbonate, and grain size. At local scale, the northern sector stood out for having a higher abundance of macrofauna in the upper slope (400 m) and it probably reflects the oceanographic processes and the organic enrichment caused by the upwelling events that occur at Cabo Frio region. The zonation pattern and the dominance of some polychaete, peracarid crustacean, and bivalve families were similar to other SE Brazilian continental margins.

Abstract Aim The present study investigated the influence of environmental variables on macrobenthic fauna in the Achenkovil River, Southern Western Ghats, Kerala. The knowledge of aquatic ecosystems in many remote areas is very scanty and no one has yet made an attempt to study the macrobenthic fauna of Achenkovil river. Since, macrobenthos play an important role in the benthic community structure a better knowledge of their ecology and distributional patterns in remote freshwater ecosystems would be of great interest for a better understanding of their functioning. Methods A bimonthly sampling was conducted from February 2019 to January 2020. Water samples for physicochemical analysis were carried to the laboratory in clean polyethylene bottles. The macrobenthic fauna was collected using Van Veen grab (0.025m2). Multivariate statistical technique such as Principal Component Analysis was used to monitor the variation in environmental parameters. The diversity of macrobenthic fauna was studied using Simpson_1-D, Shannon_H, Evenness_e^H/S, and Margalef’s indices. We analyzed the relationship between environmental variables and macrobenthic fauna, using Canonical Correlation Analysis and Pearson correlation. Results A total of 3563 individuals belonging to 9 orders, 32 families, 32 genera, and 32 species were identified. The most dominant order was Ephemeroptera followed by Coleoptera and Trichoptera and the least dominant was Zygoptera. The maximum number of macrobenthic fauna was observed in station 1(S1), (1461 Ind/m2) and the least in station 9 (S9), (37 Ind/m2). Station 1 (S1) is a pristine forest area, so this area is considered the reference site. The macrobenthic fauna in the pristine headwater forests (S1) was much more diverse than in the river mouth (S9) which is a highly impacted region. This region is facing various kinds of anthropogenic stress resulting in pollution and deterioration of water quality. The macrobenthic community structure in the Achenkovil River was significantly associated to the variations in water quality due to various natural as well as anthropogenic stresses. Conclusions It can be concluded that Ephemeroptera, Coleoptera, and Trichoptera were the most dominant groups in the undisturbed habitats in the river during the study period. The predominance of Chironomidae species, especially from the Chironomus genus in the midstream and downstream segments of the river is possibly due to their ability to adapt to various environmental conditions or habitats and their tolerance to the low oxygen content in anoxic conditions of the bottom sediment. The lowest abundance of macrobenthos at all the studied stations was observed at station 9 (S9) during dry seasons. S9 is a highly impacted region, characterized by high temperature, turbidity, TDS, pH, conductivity, nitrate, and phosphate values. For this reason, anthropogenic stress and changing environmental conditions are the main factors affecting the distribution of the macrobenthic fauna of the Achenkovil River basin, Kerala.

Resumo Objetivo O presente estudo investigou a influência de variáveis ambientais na fauna macrobêntica no rio Achenkovil, Southern Western Ghats, Kerala. O conhecimento dos ecossistemas aquáticos em muitas áreas remotas é muito escasso e ninguém ainda fez uma tentativa de estudar a fauna macrobentônica do rio Achenkovil. Uma vez que os macrobenthos desempenham um papel importante na estrutura da comunidade bentônica, um melhor conhecimento de sua ecologia e padrões de distribuição em ecossistemas remotos de água doce seria de grande interesse para uma melhor compreensão de seu funcionamento. Métodos Foram realizadas coletas bimensais de fevereiro de 2019 a janeiro de 2020. As amostras de água para análises físico-químicas foram levadas ao laboratório em frascos de polietileno limpos. A fauna macrobentônica foi coletada usando garrafa de Van Veen (0,025m2). A técnica estatística multivariada, como a Análise de Componentes Principais, foi utilizada para monitorar a variação dos parâmetros ambientais. A diversidade da fauna macrobêntica foi estudada usando os índices Simpson_1-D, Shannon_H, Evenness_e^H/S e Margalef. Analisou-se a relação entre as variáveis ambientais e a fauna macrobêntica, utilizando a Análise de Correlação Canônica e a Correlação de Pearson. Resultados Foram identificados 3.563 indivíduos pertencentes a 9 ordens, 32 famílias, 32 gêneros e 32 espécies. A ordem mais dominante foi Ephemeroptera seguida por Coleoptera e Trichoptera e a menos dominante foi Zygoptera. O número máximo de fauna macrobentônica foi observado na estação 1(S1), (1461 Ind/m2) e o menor na estação 9 (S9), (37 Ind/m2). A Estação 1 (S1) é uma área de floresta intocada, portanto esta área é considerada o local de referência. A fauna macrobentônica nas florestas virgens da cabeceira (S1) foi muito mais diversa do que na foz do rio (S9), que é uma região altamente impactada. Esta região enfrenta vários tipos de estresse antropogênico, resultando em poluição e deterioração da qualidade da água. A estrutura da comunidade macrobentônica no rio Achenkovil foi significativamente associada às variações na qualidade da água devido a vários estresses naturais e antrópicos Conclusões Pode-se concluir que Ephemeroptera, Coleoptera e Trichoptera foram os grupos mais dominantes nos habitats não perturbados no rio durante o período de estudo. A predominância de espécies de Chironomidae, principalmente do gênero Chironomus nos segmentos médio e jusante do rio, possivelmente se deve à sua capacidade de adaptação a diversas condições ambientais ou habitats e sua tolerância ao baixo teor de oxigênio em condições anóxicas do sedimento de fundo. A menor abundância de macrobentos em todas as estações estudadas foi observada na estação 9 (S9) durante as estações secas. S9 é uma região altamente impactada, caracterizada por alta temperatura, turbidez, TDS, pH, condutividade, nitratos e valores de fosfato. Por esta razão, o estresse antropogênico e a mudança das condições ambientais são os principais fatores que afetam a distribuição da fauna macrobentônica da bacia do rio Achenkovil, Kerala.

Abstract The continental margin off the southeastern Brazilian coast is punctuated by a series of geological-geomorphological features, such as subsurface saline diapirs and pockmarks at the seafloor interface, which evidence the abundant presence of oil and gas in the region. In several of these sites, hydrocarbons can be naturally released into the water column, areas are cold seep areas. These are marked by the presence of oil- and gas-dependent ecosystems, where specific organisms are able to fix carbon from hydrocarbon chemosynthesis. In addition, light hydrocarbon fluid flow through the sediment may build up authigenic carbonates that can be further colonized by cold-water corals, generating large carbonate mounds over geological time, normally positioned at the border of these pockmark features. The present work reports on a multidisciplinary oceanographic cruise carried out in the Santos Basin, SW Atlantic, to seek, map, and collect geological, chemical, and biological data from different deep-sea habitats. The cruise occurred in November 2019 on the R/V Alpha Crucis of the Oceanographic Institute of the University of São Paulo (IOUSP). We intended to discover and detail different geomorphological features, characterize free-living and symbiotic microorganisms, determine the chemosynthetic rates in relation to heterotrophic microbial production, and characterize the fauna and study their ecological and evolutionary links within and across ocean basins. All discoveries made during the cruise and their respective results will be presented separately in several papers that comprise this special volume.

Resumo A distribuição espacial e temporal de duas espécies de ostracodes adultos (Cyprideis sp. e Cyprideis salebrosa) foi estudada em função do padrão pluviométrico na Baía de Guanabara, Rio de Janeiro, Brasil. As amostras foram coletadas em dez estações ao longo de seis campanhas, representando três períodos (Seco, Pré e Pós Chuvoso) por dois anos. As estações foram agrupadas em quatro áreas (Externo, Central, EPA Guapimirim e Impactado). A água do fundo (temperatura, salinidade, oxigênio dissolvido e saturação de oxigênio) foi medida em cada área para caracterizar a influência das variações sazonais pela chuva. Cyprideis sp. e Cyprideis salebrosa mostrou distribuição de padrões para sazonalidade/campanhas (p = 0,002 e p <0,001, respctivamente). A distribuição espacial de Cyprideis sp. foi significativamente diferente das áreas estudadas (p <0,001) indicou áreas bem definidas e distribuição ao longo das campanhas. No entanto, C. salebrosa mostrou distribuição homogênea ao longo das áreas dentro de cada campanha (p <0,001). A Análise de Redundância (RDA) para os dois anos evidenciou a preferência ambiental dos Cyprideis sp. para áreas com condições marinhas (alta influência para o canal central) e C. salebrosa para águas salobras (alta influência dos rios). Essa observação reforça a existência de áreas criadas pela sazonalidade do regime pluviométrico, uma possível dispersão dos adultos de ostracodes e a possibilidade do uso como bioindicadores.

Abstract Spatial and temporal distribution of two species of adult´s ostracods (Cyprideis sp. and Cyprideis salebrosa) were studied as a function of the rainfall patterns in the Guanabara Bay, Rio de Janeiro, Brazil. Samples were taken in ten stations, along six surveys representing three periods (Dry, Early and Late Rainy) for two years. Stations were nested in four areas (Outer, Central, EPA Guapimirim and Impacted). The bottom water (temperature, salinity, dissolved oxygen and oxygen saturation) were measured in each area to characterize the influence of seasonal variations by rainfall. Cyprideis sp. and Cyprideis salebrosa showed patterns distribution to seasonality/surveys (p = 0,002 and p <0,001, respectly). The spatial distribution of Cyprideis sp was significantly different areas studied (p <0.001) indicated well defined areas and distribution in along of the surveys. However, C. salebrosa showed homogeneous distribution in along of the areas within of each survey (p <0.001). Redundancy Analysis (RDA) for the two years evidenced environment preference of the Cyprideis sp. for areas with marine conditions (high influence for channel central) and C. salebrosa for brackish water (high influence of the rivers). This observation reinforces of the existence of areas created by the seasonality of pluviometric regime, a possible dispersion of the adult’s ostracods and possibility the use with bioindicators.

Resumen Introducción: La laguna Río Lagartos, ubicada en la Reserva de la Biosfera Ría Lagartos, Yucatán, Golfo de México, es un sistema costero hipersalino con una longitud aproximada de 80 km (este-oeste). La laguna está conformada por tres cuencas (Río Lagartos, Las Coloradas y El Cuyo) comunicadas entre sí por canales naturales extremadamente estrechos. Aunque existen varios estudios sobre la fauna vertebrada asociada a la laguna, los invertebrados acuáticos, y especialmente la poliquetofauna, son todavía desconocidos. Objetivo: El objetivo de este estudio es analizar la composición y distribución de los poliquetos bentónicos, y su relación con las condiciones ambientales. Metodología: El material biológico fue recolectado en 16 estaciones a lo largo del sistema lagunar durante la época climática de “lluvias” (septiembre 2017). Se tomaron dos réplicas por estación con una draga Ponar standard o un nucleador de PVC (diámetro= 6”). En cada estación se midieron distintas variables ambientales p. ej., granulometría, carbono orgánico en sedimento, salinidad, entre otras. Resultados: Se identificaron 827 ejemplares pertenecientes a 26 especies y 16 familias. De éstas, 23 especies son nuevos registros para la laguna Río Lagartos. La composición de la comunidad varió entre las distintas cuencas de la laguna en relación con importantes gradientes de salinidad, de la proporción de vegetación (algas y pastos) en la muestra y del tamaño de grano. En la cuenca este, El Cuyo, donde el rango de salinidad fue 67-80 ups, no se encontraron poliquetos. En el resto de la laguna, la distribución de los poliquetos fue heterogénea, especialmente cerca de la boca (cuenca de Río Lagartos), donde se registraron los valores más altos y más bajos de densidad, riqueza específica y diversidad. La densidad más alta se registró en la estación 6, donde la muestra estuvo dominada por densos lechos de algas del género Avrainvillea. Las familias Syllidae y Nereididae fueron las más abundantes y ampliamente distribuidas en la laguna. Las especies Syllis lagunae y Nereis pelagica dominaron en la cuenca de Río Lagartos y Prionospio heterobranchia y Sphaerosyllis taylori, en Las Coloradas. Conclusiones: Los rangos de salinidad reportados para algunas de las especies fueron mucho más altos que registros anteriores, estableciendo el carácter eurihalino de varias especies en la región.

Abstract Introduction: The Río Lagartos lagoon, located in the Ría Lagartos Biosphere Reserve, Yucatán, Gulf of Mexico, is a coastal hypersaline system ca. 80 km long (east-west). It comprises three basins: western (close to Río Lagartos fishermen village), middle (Las Coloradas) and eastern (close to El Cuyo fishermen village), that communicate through very narrow natural channels. Despite several studies have been performed on the vertebrate fauna, the aquatic invertebrates, and especially polychaetes, remain largely unknown. Objective: The objective of this study is to describe the composition and distribution of the benthic polychaete community, and to analyse potential environmental drivers. Methods: The biological material was collected in 16 stations distributed along the lagoon during the rainy season (September 2017). Two replicates per station were obtained using a Ponar standard dredge or cores (6” diameter). Environmental variables such as grain size, organic carbon content in the sediments, and salinity, among others, were measured. Results: A total of 827 specimens belonging to 26 species and 16 families were identified. Of these, 23 species are new records for the Río Lagartos lagoon. Community composition changed between the different basins associated with strong gradients in salinity, subaquatic vegetation (algae and seagrasses) proportions in the samples and grain size. No polychaetes were recorded at the easternmost basin (El Cuyo basin), where salinity was between 67-80 psu. In the rest of the lagoon, the distribution of polychaetes was heterogeneous, especially near the mouth (western basin), where the highest and lowest density, species richness and diversity were recorded. The highest density was found at station 6, where dense algal mats of the genus Avrainvillea dominated. The families Syllidae and Nereididae were the most abundant and widely distributed families in the lagoon. The species Syllis lagunae and Nereis pelagica dominated the western basin and Prionospio heterobranchia and Sphaerosyllis taylori dominated the middle basin. Conclusions: The salinity records associated with some species were well above the top limits previously reported, establishing the euryhaline character of many species in the region.

Abstract. The soft-bottom macrobenthos of Bahía San Julián intertidal was surveyed to identify infaunal assemblages and analyze their relationships with the main environmental factors determining species distribution. Four seasonal surveys (summer, autumn, winter and spring) were performed in the middle and lower intertidal levels at seven sampling stations established on both sides of the sewage discharge point, and water and sediment variables were measured. To explore possible spatial variations in the community, environmental and biological data were analyzed using univariate and multivariate statistics. Community composition varied with intertidal level, sediment characteristics and distance to sewage discharge site. In sediment with high mud content, the community was characterized by Darina solenoides, Mysella patagona, Eteone sculpta, Scolecolepides uncinatus and Capitella sp., in the middle intertidal, and was characterized by M. patagona and Ampelisca sp. in the lower intertidal. In sediment with dominance of fine sand, the community was characterized by Aricidea sp. at both intertidal levels. Near the effluent discharge site, the community was largely dominated by M. patagona. Intertidal level and sediment particle size are the main factors determining the composition of benthic assemblages in the study area. Sewage discharge also affects the composition of the infaunal community, possibly as a result of the contribution of particulate organic matter in suspension that stimulates the populations of detritus feeders.

Resumen. El macrobentos intermareal de fondos blandos de Bahía San Julián fue estudiado para identificar las asociaciones infaunales y para analizar su relación con los principales factores ambientales que determinan la distribución de las especies. Se realizaron 4 muestreos estacionales (verano, otoño, invierno y primavera) en los niveles intermareales medio e inferior en 7 estaciones de muestreo establecidas a ambos lados de un sitio de descarga de efluentes urbanos, y se midieron variables del agua y del sedimento. Para explorar las posibles variaciones espaciales en la comunidad, se analizaron los datos ambientales y biológicos utilizando estadística univariada y multivariada. La composición de la comunidad varió con el nivel intermareal, las características del sedimento y la distancia al sitio de descarga de efluentes. En sedimento con alto contenido de fango, la comunidad estuvo caracterizada por Darina solenoides, Mysella patagona, Eteone sculpta, Scolecolepides uncinatus y Capitella sp., en el intermareal medio, y por M. patagona y Ampelisca sp. en el intermareal inferior. En sedimentos con predominio de arena fina, la comunidad estuvo caracterizada por Aricidea sp. en ambos niveles intermareales. Próximo al sitio de descarga de efluentes, la comunidad estuvo ampliamente dominada por M. patagona. El nivel intermareal y el tamaño de partícula del sedimento son los principales factores determinantes de la composición de las asociaciones bentónicas en el área de estudio. El vertido de efluentes también afecta la composición de la comunidad infaunal, posiblemente como resultado del aporte de materia orgánica particulada en suspensión, que estimula a las poblaciones de organismos detritívoros.

Resumen Introducción: La Reserva Marina El Pelado es una importante área protegida de la costa ecuatoriana debido a la conectividad que tiene con otras áreas marinas protegidas. Objetivo: Identificar patrones de variación espacial en la estructura comunitaria del macrobentos de fondos someros. Materiales y Métodos: Se muestrearon diez sitios en la zona cercana a la costa y al Islote El Pelado. La abundancia de macroinvertebrados y organismos sésiles se estimó visualmente mediante buceo a lo largo de dos transectos en banda paralelos a la costa. Cada transecto fue de 50 m de longitud y 5 m de ancho, con una superficie total de 500 m2 por localidad. Se registró salinidad, pH, cloro residual, oxígeno, material flotante, coliformes fecales, mercurio, aceites y grasas en la superficie del mar. Resultados: Se identificaron 92 especies (86 especies de invertebrados y 6 especies de macroalgas); el grupo mejor representado fue el de los cnidarios con 31 especies de 13 familias, seguido de los moluscos con 15 especies de 11 familias. Las especies con mayores abundancias media fueron de macroinvertebrados Echinometra vanbrunti (21.54%), de organismos sésiles Bugula californica (34.2%). Conclusiones: No se encontraron diferencias significativas en la diversidad, riqueza y equidad de especies del macrobentos entre las zonas de estudio.

Abstract Introduction: The El Pelado Marine Reserve is an important protected area of the Ecuadorian coast due to the connectivity it has with other marine protected areas. Objective: Identify patterns of spatial variation in the community structure of shallow fund macrobenthos. Materials and Methods: Ten sites were sampled in the area near the coast and the El Pelado Islet. The abundance of macroinvertebrates and sessile organisms was estimated visually by diving along two parallel transects parallel to the coast. Each transect was 50 m long and 5 m wide, with a total area of 500 m2 per location. Salinity, pH, residual chlorine, oxygen, floating material, fecal coliforms, mercury, oils and fats were recorded on the sea surface. Results: 92 species were identified (86 species of invertebrates and 6 species of macroalgae); the best represented group was the cnidarians with 31 species from 13 families, followed by the molluscs with 15 species from 11 families. The species with higher average abundances were of macroinvertebrates Echinometra vanbrunti (21.54%), sessile organisms Bugula californica (34.2%). Conclusions: No significant differences were found in the diversity, richness and equity of macrobenthic species between study areas.

Resumo Introdução: A Reserva Marinha El Pelado é uma importante área protegida da costa equatoriana, devido à conectividade que tem com outras áreas marinhas protegidas. Objetivo: Identificar padrões de variação espacial na estrutura da comunidade de macrobentos fundos rasos. Materiais e Métodos: Dez locais foram amostrados na área próxima à costa e na Ilhota de El Pelado. A abundância de macroinvertebrados e organismos sésseis foi estimada visualmente mergulhando-se ao longo de dois transectos paralelos paralelos à costa. Cada transecto tinha 50 m de comprimento e 5 m de largura, com uma área total de 500 m2 por localização. Salinidade, pH, cloro residual, oxigênio, material flutuante, coliformes fecais, mercúrio, óleos e gorduras foram registrados na superfície do mar. Resultados: foram identificadas 92 espécies (86 espécies de invertebrados e 6 espécies de macroalgas); O grupo mais bem representado foi o de cnidários com 31 espécies de 13 famílias, seguido dos moluscos com 15 espécies de 11 famílias. As espécies com maior abundância média foram de macroinvertebrados Echinometra vanbrunti (21,54%), organismos sésseis Bugula californica (34,2%). Conclusões: Não foram encontradas diferenças significativas na diversidade, riqueza e equidade das espécies macrobênticas entre as áreas de estudo.

Resumen Los estuarios tropicales de países en desarrollo han experimentado un aumento en los niveles de estrés debido a la presión humana. El sitio Ramsar pantano Caroní, el manglar más grande de la costa oeste de Trinidad, ha estado sujeto a altos niveles de impacto antropogénico, incluyendo alteraciones hidrológicas y contaminación de fuentes terrestres desde la década de 1920. Aunque la mayoría de estos impactos han sido bien documentados, existe información limitada sobre las comunidades macrobentónicas en el pantano. Este estudio aborda esta escasez de información. Se muestreó la fauna macrobentónica en el canal principal del pantano Caroní en 12 localidades utilizando una draga Van Veen de 0.025 m2, una vez durante la época seca (Abril) y la época lluviosa (Agosto) 2015, con un total de 144 muestras. Las muestras fueron ordenadas, contadas y las especies se identificaron al menor nivel taxonómico posible. Se identificaron un total de 55 taxa, siendo los poliquetos el taxa más abundante. El estatus ecológico del macrobentos se evaluó utilizando el Índice Marino Biótico de AZTI (AMBI) y el AMBI-multivariado (M-AMBI). Los parámetros fisicoquímicos se midieron con un multiparámetro YSI. Los análisis químicos también se realizaron para nitratos, nitritos, amonio y fostatos activos utilizando métodos estándar. En conjunto, el índice AMBI caracterizó el pantano Caroní como “levemente alterado” con una comunidad macrobentónica de categoría “pobre” de acuerdo al M-AMBI. Generalmente, la calidad de los ambientes incrementa desde la época seca hasta la época lluviosa. Sin embargo, las variaciones estacionales en los índices AMBI y M-AMBI fueron específicas a la localidad, mostrando algunas un incremento en el estatus ecológico y calidad del macrozoobentos, mientras que otros mostraron una degradación de la época seca a la época lluviosa. Las estaciones al norte del pantano mostraron una mejora de la época seca a la época lluviosa, mientras que se presentó lo contrario en las estaciones más al sur. Una característica notable del pantano fueron los altos niveles de contaminantes, particularmente amonio, registrado en uno de los canales principales del río Caroní. Esto contrasta con los otros canales del pantano que experimentan niveles menores de aporte de contaminantes de fuentes terrestres. La evaluación del pantano Caroní utilizando los índíces AMBI y M-AMBI puede ser una base útil de información para las estrategias de manejo y conservación del humedal y mejorar su calidad ambiental.

Abstract Human pressures have placed many tropical estuaries in developing countries under increased levels of stress. The Caroni Swamp Ramsar Site, the largest mangrove swamp along the west coast of Trinidad, has been subjected to high levels of anthropogenic impacts including hydrological alteration and pollution from land-based sources since the 1920’s. While most of these impacts have been well documented, limited information exists on the macrobenthic communities in the swamp. This study addresses the paucity of information. The macrobenthic fauna in the main waterways of Caroni Swamp was sampled at 12 locations using a Van Veen 0.025 m2 grab, once in the dry (April) and wet (August) season of 2015 with a total of 144 samples. The samples were sorted, counted and species were identified to the lowest possible taxonomic level. A total of 55 taxa were identified with polychaetes being the most abundant taxa. The ecological status of the macrobenthos was assessed using AZTI’s Marine Biotic Index (AMBI) and the multivariate-AMBI (M-AMBI). Physicochemical parameters were measured with a YSI multiparameter metre. Chemical analyses were also conducted on nitrates, nitrites, ammonia and reactive phosphates using standard methods. Overall, AMBI characterised the Caroni Swamp as “slightly disturbed” with a macrobenthic community of “poor” ecological status according to M-AMBI. Generally, the quality of the environment improves from the dry season to the wet season. However, seasonal variations in AMBI and M-AMBI were found to be site specific as some showed improvement in ecological status and macrozoobenthos quality while others showed degradation from the dry season to the wet season. The stations to the North of the swamp showed improvement from the dry season to the wet season while the opposite was observed in the more Southern stations. One notable characteristic of the swamp was the high levels of pollutants, particularly ammonia, recorded in one of its major waterways, the Caroni River. This is in contrast to the other waterways within the swamp which experience much lower levels of pollutant input from land-based sources. The assessment of the Caroni Swamp using AMBI and M-AMBI may be useful for informing management strategies to conserve the wetland and improve environmental quality. Rev. Biol. Trop. 66(3): 1101-1117. Epub 2018 September 01.

Abstract: Biofouling affects global aquaculture with significant impacts on productivity and profitability, especially in marine shellfish culture, where both the target culture species and/or infrastructure are exposed to a diverse array of fouling organisms. In oyster culture, fouling of stock causes physical damage, mechanical interference, biological competition and environmental modification, with infrastructure also colonized. The present study describes the composition of the biofouling community inhabiting the surface of the mangrove oyster Crassostrea rhizophorae, cultivated in an Amazon estuary, in the state of Pará, northern Brazil. In total, 6,124 macroinvertebrates were collected during July, August, October and December 2013. Collected epifauna was represented by 5 groups (Bivalvia, Gastropoda, Polychaeta, Crustacea and Anthozoa), 20 families and 37 species. Bivalvia was the most abundant class, with the mussel Mytella charruana by far the most dominant species with 5,183 individuals. Knowledge about the composition of biofouling as well as identifying the main species that cause direct impacts allows more tailored and strategic management options, minimizing the often-significant costs associated with biofouling control (antifouling).

Resumen: La contaminación biológica afecta a la acuicultura mundial con importantes impactos de productividad y rentabilidad, especialmente en el cultivo de moluscos, donde tanto la especie de cultivo objetivo como la infraestructura están expuestas a una diversidad de organismos contaminantes. En el cultivo de ostras, el impacto clave es la adherencia directa de organismos causando daño físico, interferencia mecánica, competencia biológica y modificación ambiental, mientras que también se efectúa la infraestructura. El presente estudio describe la composición de la bioincrustación en la superficie de la ostra de mangle Crassostrea rhizophorae, cultivada en un estuario Amazónico, ubicado en el estado de Pará, norte de Brasil. En total, 6.124 macroinvertebrados fueron muestreados en julio, agosto, octubre y diciembre de 2013. La epifauna recolectada estuvo representada por 5 grupos principales (Bivalvia, Gastropoda, Polychaeta, Crustacea y Anthozoa), 20 familias y 37 especies. Bivalvia fue la clase más abundante, presentando 5.183 mejillones de la especie Mytella charruana. El conocimiento sobre la composición de la incrustación biológica, así como la identificación de las principales especies que causan impactos directos, permite opciones de gestión más personalizadas y estratégicas, minimizando los costos, a menudo significativos, asociados con el control de la bioincrustación (antifouling).

ABSTRACT The biology and ecology of Darina solenoides, an abundant bivalve of sandy sediments along Patagonian coasts, is poorly known. Here, we investigated the population dynamics and secondary production of this species in Río Gallegos Estuary (Southern Patagonia, Argentina, 51°35’S, 69°01’W). Sampling was conducted monthly, from April 2014 to June 2015, by collecting 10 samples from the intertidal fringe using a core of 10 cm inner diameter. The sediment was mainly composed of fine and very fine (77.5%) sand; total organic matter content was 1.8%. The average population density was 779.4 ± 56.4 ind m-2 the population was composed of four modal groups. The settlement of a new cohort occurred in April-May each year. The von Bertalanffy growth function was L∞ = 49.4 mm; K = 0.5; the calculated lifespan was 4.2 years. Population somatic production was 80.6 g dry mass m-2 yr−1 and the production-to-biomass (P/B) ratio was 0.96. The observed high production supports the hypothesis that D. solenoides is an important resource for many marine species.

The macrobenthic assemblages with mytilids of San Julián bay (Southern Patagonia, Argentina) were sampled in summer 2007 to know its structure, diversity and distribution, and to determine their relationship to different environmental factors. The study was conducted in 3 locations with different types of substrate and slope. Sampling at each site was performed in a transect to cover different levels of intertidal and shallow subtidal. A total of 46 species belonging mainly to molluscs (20), crustaceans (12) and polychaetes (10) were found. Three main macrofaunal assemblages were identified. Platynereis-Clunio-Darina assemblage was distributed in the upper intertidal of muddy and gentle slopes substrate, and had the lowest values of number of species, diversity and abundance of individuals. The Mytilus-Perumytilus assemblage was distributed in the middle and lower intertidal levels in rocky substrate or muddy substrate with abundant support elements and medium slope. This assemblage presented intermediate values of diversity and greater abundance of individuals. The Aulacomya-Exosphaeroma assemblage had the highest number of species and the greatest diversity, but low abundance of individuals, being related to rocky substrate or muddy substrate with support elements and low slopes in the upper subtidal. Species richness and diversity of these assemblages increases from the upper intertidal to subtidal, possibly because of a complex gradient of stress, mainly caused by desiccation and exposure to extreme temperatures.

Las asociaciones de macrobentos con presencia de mitílidos de la bahía San Julián (Patagonia austral, Argentina) fueron muestreadas durante el verano de 2007 para conocer su estructura, diversidad y distribución, y para determinar su relación con diversos factores ambientales. El estudio fue realizado en 3 localidades con diferentes tipos de sustrato y distinta pendiente. El muestreo en cada localidad se realizó en una transecta abarcando diferentes niveles del intermareal y del submareal somero. Se hallaron un total de 46 especies pertenecientes principalmente a moluscos (20), crustáceos (12) y poliquetos (10). Se identificaron 3 asociaciones principales: la asociación Platynereis-Clunio-Darina se distribuyó en el nivel intermareal superior de sustrato fangoso y pendientes suaves y presentó los valores más bajos de número de especies, de diversidad específica y de abundancia de individuos; la asociación Mytilus-Perumytilus se distribuyó en los niveles intermareales medio e inferior en sustrato rocoso o en sustrato fangoso con abundantes elementos de soporte y pendiente media; presentó diversidad específica intermedia y la mayor abundancia de individuos; la asociación Aulacomya-Exosphaeroma presentó el mayor número de especies y la mayor diversidad, pero baja abundancia de individuos, encontrándose relacionado a sustratos rocosos o sustratos fangosos con elementos de soporte y baja pendiente del submareal superior. La riqueza específica y la diversidad de estas asociaciones aumentan desde el nivel superior del intermareal hacia el submareal, posiblemente por efecto de un gradiente complejo de estrés, principalmente ocasionado por la desecación y exposición a temperaturas extremas.

RESUMO Fragmentos dos recifes de coral constituem parte do sedimento ao redor dos mesmos, ampliando os limites do recife. Modelos estatísticos foram criados para investigar se a comunidade de poliquetas ao redor do recife Sebastião Gomes (Banco dos Abrolhos, Brasil) é influenciada pelas características do sedimento e/ou pela posição ao redor do recife, que são variáveis relacionadas à influência do aporte terrígeno. Em julho de 2007, período dominado por ventos que ressuspendem o sedimento fino da costa para os recifes, amostras de sedimento foram coletadas em quatro transectos perpendiculares ao recife (S, O, N e L). A espécie de poliqueta mais abundante foi o carnívoro Goniadides carolinae e o modelo selecionado para descrever a distribuição desta espécie foi muito semelhante aos ajustados tanto para a abundância de macrofauna quanto de poliquetas. Estes modelos apresentaram alta abundância em sedimentos carbonáticos grossos na face do recife exposta aos ventos, onde quase não há sedimento terrígeno. Por outro lado, a riqueza de poliquetas não foi influenciada pela posição dos transectos. Sebastião Gomes é um dos muitos recifes costeiros do Banco dos Abrolhos, cuja saúde está prejudicada devido ao aumento de lama relacionada a atividades humanas, como desmatamento e, recentemente, rejeitos da mineração.

ABSTRACT Erosion on coral reefs produces fragments of the constructor organisms that are scattered all around, thus enlarging the reef boundaries. Statistical modelling approach was used to investigate whether the Polychaeta community around Sebastião Gomes reef (Abrolhos Bank, Brazil) is influenced equally by sediment characteristics and/or by position related to the reef, that are variables related to the terrigenous input influence. In July 2007, a period dominated by winds that resuspend fine sediment from the land to coastal reefs, sediment samples were taken on four transects perpendicular to the reef (S, W, N and E) and a total of 121 species of polychaetes were recorded. The most abundant species was the carnivorous Goniadides carolinae and the model selected for it approximates to the best models fitted for both total macrofauna and polychaete abundance. These models represented higher abundance in coarse carbonate sediments on windward reef faces, where there is almost no terrigenous sediment. On the other hand, the Polychaeta richness did not depend on the transects. Sebastião Gomes reef is one of the many coastal reefs from Abrolhos Bank, whose healthy is probably in danger because of the increase of mud related to human activities, as deforestation and, recently, mining waste.

Resumo Fragmentos dos recifes de coral constituem parte do sedimento ao redor dos mesmos, ampliando os limites do recife. Modelos estatísticos foram criados para investigar se a comunidade de poliquetas ao redor do recife Sebastião Gomes (Banco dos Abrolhos, Brasil) é influenciada pelas características do sedimento e/ou pela posição ao redor do recife, que são variáveis relacionadas à influência do aporte terrígeno. Em julho de 2007, período dominado por ventos que ressuspendem o sedimento fino da costa para os recifes, amostras de sedimento foram coletadas em quatro transectos perpendiculares ao recife (S, O, N e L). A espécie de poliqueta mais abundante foi o carnívoro Goniadides carolinae e o modelo selecionado para descrever a distribuição desta espécie foi muito semelhante aos ajustados tanto para a abundância de macrofauna quanto de poliquetas. Estes modelos apresentaram alta abundância em sedimentos carbonáticos grossos na face do recife exposta aos ventos, onde quase não há sedimento terrígeno. Por outro lado, a riqueza de poliquetas não foi influenciada pela posição dos transectos. Sebastião Gomes é um dos muitos recifes costeiros do Banco dos Abrolhos, cuja saúde está prejudicada devido ao aumento de lama relacionada a atividades humanas, como desmatamento e, recentemente, rejeitos da mineração.

Abstract Erosion on coral reefs produces fragments of the constructor organisms that are scattered all around, thus enlarging the reef boundaries. Statistical modelling approach was used to investigate whether the Polychaeta community around Sebastião Gomes reef (Abrolhos Bank, Brazil) is influenced equally by sediment characteristics and/or by position related to the reef, that are variables related to the terrigenous input influence. In July 2007, a period dominated by winds that resuspend fine sediment from the land to coastal reefs, sediment samples were taken on four transects perpendicular to the reef (S, W, N and E) and a total of 121 species of polychaetes were recorded. The most abundant species was the carnivorous Goniadides carolinae and the model selected for it approximates to the best models fitted for both total macrofauna and polychaete abundance. These models represented higher abundance in coarse carbonate sediments on windward reef faces, where there is almost no terrigenous sediment. On the other hand, the Polychaeta richness did not depend on the transects. Sebastião Gomes reef is one of the many coastal reefs from Abrolhos Bank, whose healthy is probably in danger because of the increase of mud related to human activities, as deforestation and, recently, mining waste.

Abstract Background. The lakes’ littoral zone shows high spatial heterogeneity characterized by physical and chemical parameters of the water column and sediment which in the present study allow us to describe the structure and variability of the spatial distribution of the benthic macroinvertebrates (BMI) community of Lake Alchichica, Puebla. At Alchichica, the lake’s water level reduction and the presence of al almost continues stromatolites ring has generated a heterogeneous littoral zone with regions in direct contact with the limnetic zone of the lake but in the other extreme, regions totally isolated from it. In this way, the littoral zone allows us to recognize a desiccation process of the lake. Goals. Thus, the study allows us to describe the effects of the desiccation process on the BMI community structure. Methods. Eleven sampling stations were located along the littoral zone. At each station environmental variables were measured and benthic macroinvertebrates were sampled. Results. We identified 21 BMI taxa among which the dominant in density and frequency are the oligochaete Limnodrilus hoffmeisteri and the amphipod Hyalella azteca. Environmentally, the sampling stations could be divided in those stations with open communication with the limnetic zone and others almost or totally separated from the main water body. Conclusions. There is a decline in the taxonomic richness, diversity, maximum diversity, and evenness but not in density, as the communication with the limnetic zone decreases. The sediment texture changes from sandy bottom in the communicated stations to clayed-silt in those isolated which in turn favors a change in the dominant taxon from H. azteca in sandy bottoms to L. hoffmeisteri in silty-clayed bottoms.

Resumen Antecedentes. La zona litoral de un lago provee hábitats con heterogeneidad espacial caracterizada por las variables físicas y químicas del agua y sedimento que en el presente estudio han permitido describir la estructura y variabilidad de la distribución espacial de la comunidad de macroinvertebrados bentónicos (MIB) del lago Alchichica, Puebla. El descenso del nivel del lago y la presencia de un anillo discontinuo de estromatolitos ha generado una zona litoral heterogénea con regiones totalmente comunicadas con la zona limnética hasta zonas totalmente aisladas del resto del lago. De esta forma, se presenta un gradiente en el proceso de desecación del lago. Objetivos. Lo anterior, permite describir el efecto de la desecación sobre la estructura comunitaria de los MIB. Métodos. Se establecieron 11 estaciones a lo largo de la zona litoral del lago. En cada estación se midieron variables ambientales y se muestrearon los macroinvertebrados bentónicos. Resultados. Se reconocieron 21 taxones de MIB entre los cuales predominaron por su abundancia y frecuencia el oligoqueto Limnodrilus hoffmeisteri y el anfípodo Hyalella azteca. Ambientalmente se distingue una separación entre las estaciones que muestran un mayor grado de comunicación con el cuerpo principal del lago de las que están casi o totalmente aisladas del mismo. Conclusiones. Conforme se incrementa el grado de aislamiento decrece la riqueza taxonómica, la diversidad, la diversidad máxima y la equidad pero no así la abundancia. La textura sedimentaria también cambia de un sustrato arenoso en las estaciones comunicadas, a uno limo-arcilloso en las aisladas, lo cual favorece un cambio del taxón dominante que va de H. azteca en las arenas a L. hoffmeisteri en el limo-arcilloso.

Resumo O objetivo do presente estudo foi investigar a relação sazonal entre macrobentos e características do sedimento, tais como textura e material orgânico, na lagoa costeira Budi Lagoon, sul do Chile. Medidas físico-químicas e amostragem do macrobentos foram realizadas durante um ano em nove localidades. Sedimento arenoso-lodoso foi o mais comum na lagoa, e percentagens elevadas de material orgânico foram registradas, variando significativamente entre as estações e locais de coleta. Em relação a fauna, foram identificados 28 taxas bentônicos e 7092 indivíduos, que apresentaram variação temporal e espacial. As espécies mais abundantes durante todo o ano foram os moluscos Littoridina cumingii e Kingiella chilenica, e o poliqueta Prionospio patagonica. Os resultados obtidos evidenciaram o importante impacto da matéria orgânica sobre o macrobentos, com riqueza e abundância da fauna diminuindo em presença de alto teor de matéria. As variações encontradas para os diferentes taxons indicaram resposta da fauna ao uso da terra ao redor de Budi Lagoon, que intensamente utilizada para agricultura e atividades turísticas.

Abstract The purpose of the present study was to investigate the seasonal relationship of macrobenthos richness and abundance with sediment characteristics (i.e. texture and organic material) for the coastal Budi Lagoon in southern Chile. Physicochemical measurements and macrobenthos samples were taken over the course of a year at nine sampling stations. Sandy-muddy sediment was the most common, and high percentages of organic material were registered, varying significantly between seasons and stations. The recorded organic material was related to natural (resident wild birds) and anthropogenic (agriculture) sources. Regarding fauna, 28 benthonic taxa and 7092 individuals were identified, with temporal and spatial variations. The most abundant taxa year-round were the molluscs Littoridina cumingii and Kingiella chilenica and the bristle worm Prionospio patagonica. Together, the obtained results evidence the important impact of organic material on the macrobenthos, with macrobenthic richness and abundance decreasing in conditions of high organic material content. The recorded variations for different taxa may indicate a response to the land use around the Budi Lagoon, which is intensely subjected to agricultural and tourist activities.