Vertical distribution of meiofauna on reflective sandy beaches

Extreme physical conditions usually limit the meiofauna occurrence and distribution in highly hydrodynamic environments such as reflective beaches. Despite sediment grains of the upper layers being constantly resuspended and deposited, the high energy of the swash zone besides depositing coarse sediments allows an ample vertical distribution of meiofaunal organisms. The effect of physical, chemical and sediment variables on the vertical distribution of meiofaunal organims and nematodes was analysed on two reflective exposed beaches. Sampling was conducted at three sampling points on each beach in the swash zone. The sediment collected was divided into four 10-cm strata (0-10 cm, 10-20 cm, 20-30 cm, 30-40 cm). The statistical differences between strata due to factors previously established (i.e. meiofaunal composition, density of most abundant taxa) were tested using a hierarchical PERMANOVA applied under similarity and euclidian distances. An inverse relation among average grain size, content of organic matter and sediment sorting was evident. Coarser sediment characterized the upper layers, while at deeper layers the sediment was very poorly sorted and presented a higher content of organic matter. A similar pattern in the vertical distribution of meiofaunal and nematofaunal composition and density was detected. The lowest densities were associated with the first stratum (0-10 cm), highly affected by hydrodynamics. The vertical distribution of organisms was statistically different only when the interaction among factors was considered. This result suggests that zonation and vertical distribution of meiofaunal organisms are determined by the within-beach variability.A ocorrência e distribuição da meiofauna em ambientes com alta energia hidrodinâmica, tais como praias refletivas, são normalmente limitadas por extremos físicos. Apesar de as camadas superficiais do sedimento serem afetadas, a alta energia na zona de espraiamento e a presença de areia grossa possibilitam que a meiofauna tenha ampla distribuição vertical. Para testar o padrão de distribuição vertical da meiofauna e de nemátodos em relação às variáveis físicas, químicas e sedimentológicas, duas praias refletivas expostas foram analisadas. As coletas ocorreram na zona de espraiamento em três pontos de cada uma dessas praias. O sedimento coletado foi dividido em quatro estratos de 10 cm (0-10, 10-20, 20-30 e 30-40 cm). A diferença entre os estratos foi analisada com o uso de PERMANOVA com modelo hierarquizado. A análise foi aplicada em matrizes de similaridade e de distância euclidiana, para estudo da composição da meiofauna e densidades específicas de táxons mais abundantes, respectivamente. O padrão granulométrico evidenciado caracterizou-se pela relação inversa entre o tamanho médio do grão e o teor de matéria orgânica aliado ao grau de selecionamento. Sedimentos mais grosseiros foram encontrados nos estratos superficiais e a maior concentração de matéria orgânica e sedimentos menos selecionados localizaram-se nos estratos inferiores. A composição e densidade da meiofauna e da nematofauna apresentaram padrão de distribuição vertical semelhantes, sendo que a camada superficial (0-10 cm), mais afetada pela energia hidrodinâmica, mostrou os mais baixos valores. Diferenças significativas na distribuição vertical dos organismos só foram detectadas quando considerada a menor interação entre os fatores, indicando que a variabilidade entre os pontos dentro de uma mesma praia são responsáveis pela estruturação espacial e vertical dos organismos meiofaunais

Influência do ambiente na estrutura de tamanho e biomassa da Emerita brasiliensis (Schimitt, 1935) na praia Brava e Guarda do Embaú

Emerita brasiliensis is an important species of Brazilian macrofauna, they are inhabitants of the intertidal areas, and have important components that enable their use as biological indicators environmental. Therefore, the objective was to analyze the relationship between population and size of individuals of Eremita brasiliensis, comparing two beaches on the coast of Santa Catarina, being Praia brava in Itajaí, with an increasing level of urbanization and Guarda do Embaú Beach in Paulo Lopes, which has a stationary degree. The collections took place in March and September 2016, with the sample area parallel to the sand and intertidal strips for a systematic sampling observing the estimated time for low tide. For collection, a 20cm diameter PVC cylinder was used and buried at a depth of 20cm. The samples were arranged in a 0.5mm opening mesh and sent to the laboratory, where the organisms of the genus Emerita brasiliensis were separated and identified for the measurement of biomorphometric data, observing the lateral diameter and rostro-caudal length of the carapace. The biomass weighing was performed before and after the drying procedure, performed in a controlled temperature oven at 37ºC for 48 hours. For statistical analysis, the ANOVA test was used. Based on the individuals collected, it is observed Guarda do Embaú beach with more individuals when compared to Brava Beach. Statistical data show a significant difference between the months and the beaches, which is justified by the state of conservation of Guarda do Embaú beach, which remains static due to its low urbanization. Therefore, it is concluded that the difference between Emerita Brasiliensis communities is due to changes in local dynamics, such as anthropic trampling and sediment change. The results were not accurate due to the low number of samples, but are significant and relevant for further research

Brazilian sandy beaches: characteristics, ecosystem services, impacts, knowledge and priorities

As praias brasileiras fornecem bens e serviços ecossistêmicos fundamentais, desempenhando papel importante para a manutenção de populações humanas e para a conservação da biodiversidade. Entretanto, apesar da sua importância ecológica e social, essas praias são amplamente impactadas por alterações humanas, turismo, poluição química e orgânica e mudanças climáticas globais. Esses fatores tornam urgente a melhor percepção e compreensão das mudanças ambientais nas praias brasileiras, assim como de suas consequências na biota. Com o objetivo de promover estudos integrados que possam detectar variações nas características das praias e de outros habitats bentônicos do litoral do Brasil, foi estabelecida a Rede de Monitoramento de Habitats Bentônicos Costeiros (ReBentos). Para fornecer subsídios para o planejamento amostral da ReBentos, realizamos um intenso levantamento sobre os estudos conduzidos nas praias brasileiras e sintetizamos o atual conhecimento relativo a esse ambiente. Os resultados do levantamento são apresentados no presente trabalho e demonstram as principais características físicas, biológicas e socioeconômicas dessas praias. A partir das informações, assim como de nossa experiência e de pesquisas realizadas em diversos países, apontamos estudos e medidas que devem ser considerados prioritários para a avaliação dos efeitos das mudanças regionais e globais sobre as praias brasileiras. Esperamos que esse trabalho possa fornecer subsídios para futuros estudos e que constitua um importante passo em direção à conservação das praias do Brasil e de sua biodiversidade.Sandy beaches constitute a key ecosystem and provide socioeconomic goods and services, thereby playing an important role in the maintenance of human populations and in biodiversity conservation. Despite the ecological and social importance of these ecosytems, Brazilian sandy beaches are significantly impacted by human interference, chemical and organic pollution and tourism, as well as global climate change. These factors drive the need to better understand the environmental change and its consequences for biota. To promote the implementation of integrated studies to detect the effects of regional and global environmental change on beaches and on other benthic habitats of the Brazilian coast, Brazilian marine researchers have established The Coastal Benthic Habitats Monitoring Network (ReBentos). In order to provide input for sample planning by ReBentos, we have conducted an intensive review of the studies conducted on Brazilian beaches and summarized the current knowledge about this environment. In this paper, we present the results of this review and describe the physical, biological and socioeconomics features of Brazilian beaches. We have used these results, our personal experience and worldwide literature to identify research projects that should be prioritized in the assessment of regional and global change on Brazilian sandy beaches. We trust that this paper will provide insights for future studies and represent a significant step towards the conservation of Brazilian beaches and their biodiversity

Distribuição Espacial da Macrofauna e Sua Interação Com o Sedimento no Parque Aquícola da Enseada da Armação do Itapocoroy/SC

The distribution of the benthic macrofauna of Itapocoroy Bay and the factors that influence it were analyzed within 50 sampling stations determined in a grid, covering the whole extent of the Bay. Two temporal sampling were done – one in July 2010 and the other in February 2011. Numeric describers of the community were associated with sediment characteristics, depth, salinity and temperature according to multivariate statistical analysis. A total of 4338 organisms were collected whereby 97 species were identified and classified in Polychaeta, Crustacea and Mollusca. Four faunal assemblages were found, and their spatial distribution was mainly related to depth and sediment characteristics. The first assemblage was the deepest and showed higher concentration of fine sediments, dominated by Kinbergonuphis sp.; the second assemblage - located under the mussel farm - showed high heterogeneity of sediments and was dominated by Ampelisca spp.; the third assemblage, shallower and with pebble concentration, was dominated by species of the Syllidae family; and the fourth assemblage was characterized by well sorted sediment with high percentage of sand, dominated by Prionospio sp. 1. Although the Bay is a sheltered site, the distribution of sediments showed that high energetic hydrodynamics processes operate inside it, which is able to avoid the formation of biodeposits. Nevertheless, the constant supply of organic matter and shell fragments accumulation from mussel farms are a source of stress, increasing the abundance and diversity values near the mussel farms

Structure and succession of the surf-zone phytoplankton in Cassino beach, southern Brazil

Cassino Beach, in Southern Brazil, is an exposed, intermediate to dissipative sandy beach, which presents conspicuous accumulations of the diatom Asterionellopsis glacialis in the surf-zone. Despite this phenomenon represents a very high input of organic matter to the beach trophic chains, it is only occasional and during most of the time, surf-zone phytoplankton is influenced by coastal and oceanic assemblages. The present work attempted to identify the phytoplankton assemblages structure (“community structure”) and the environmental factors that control its succession. An one year weekly sampling was carried out at a fixed point in the surf-zone, for determination of phytoplankton (qualitative and quantitative analysis), physical-chemical variables of surf-zone water, beach morphodynamics features and local meteorological conditions. Multivariate analyses were conducted(correspondence analysis and canonic correspondence analysis) and the results discriminated four distinct groups of species: group (1) benthic species, group (2) benthic and epibenthic species associated with A. glacialis patches, group (3) neritic planktonic chain forming diatoms and group (4) neritic planktonic species. A. glacialis dominated in biomass, but was always accompanied by other benthic species. The A. glacialis accumulations have been identified as local interferences (at the surf-zone) in the succession patterns of regional neritic phytoplankton, increasing biomass while decreasing diversity and the relative importance of neritic species. The most important environmental variables controlling this complex succession were dissolved inorganic nitrogen, dissolved silicate, water temperature and surf-zone width