Abstract The richness and biomass distribution of mangrove macroalgae were evaluated along the main salinity gradient of the Paranaguá Bay subtropical estuarine complex in southern Brazil. We used a spatially hierarchical design to investigate the spatial scales that contributed most to the variation in richness and biomass within the association. A total of eighteen taxa of macroalgae and cyanobacteria were identified with nonlinear patterns of distribution. While richness correlated with the salinity gradient, algal biomass did not follow the predicted pattern. Conversely, most of the mangrove macroalgae distribution patterns were more related to small-scale processes than to salinity variation. These results indicated that even though coastal regions are exposed to large-scale environmental processes, the somewhat disregarded small-scale processes should be also considered to unravel patterns in biological distributions.

ABSTRACT We re-assess the taxonomic status of Owenia Delle Chiaje, 1841 from Southern Brazil based on estuarine specimens from Paranaguá Bay (Paraná) and Babitonga Bay (Santa Catarina), and literature records. Owenia caissara sp. n. is diagnosed by a branchial crown with five pairs of tentacles, branched close to the base of the crown, rectilinear collar with a pronounced lateral slit, two ventrolateral ocelli partially covered by the collar, up to 23 hooks on a single row in the first abdominal segment, regularly curved nuchal shape, regularly moderate teeth curvature, and long and thin scales with oval transition. The description of Owenia caissara sp. n. reinforces the idea that Owenia fusiformis sensu lato is a complex of closely related species that can be distinguished on the basis of both macro- and micro- morphological traits.

Resumo Pradarias de gramas marinhas e vegetação aquática submersa (VAS) estão entre os ecossistemas mais ameaçados do planeta, gerando preocupação sobre o equilíbrio dos ecossistemas costeiros e a sustentabilidade das pescarias. A presente revisão avaliou o estado do conhecimento sobre as pradarias marinhas e VAS do Brasil, considerando as respostas das plantas às condições ambientais, e o possível papel da geomorfologia costeira e variabilidade climática sobre a distribuição e abundância das populações. Apesar do crescente aumento no número de publicações, a comunicação dos resultados ainda é relativamente limitada e destina-se principalmente ao público nacional ou regional. Como resultado, as pradarias de gramas marinhas da América do Sul raramente são incluídas ou citadas em revisões e modelos globais. A escassez de estudos em larga escala e de longo prazo, permitindo a detecção de mudanças na estrutura, abundância e composição dos habitats e espécies associadas, limita a investigação das comunidades no que diz respeito aos efeitos potenciais das mudanças climáticas. Pradarias marinhas e VAS ocorrem ao longo de toda a costa brasileira, mas a distribuição e abundância das espécies são influenciadas pela oceanografia regional, massas de água costeiras, descarga de rios e geomorfologia costeira. Com base nas características oceanográficas, geomorfológicas, hidrológicas e ecológicas, o estudo discutiu a distribuição e abundância dos habitats vegetados pelas distintas regiões costeiras. O estado de conservação das pradarias marinhas e VAS no Brasil é extremamente crítico. A exploração insustentável e ocupação da zona costeira durante os últimos 100 anos conduziram à rápida degradação e perda de muitos dos habitats bentônicos marinhos e costeiros, outrora favoráveis para a ocupação da vegetação aquática. O conhecimento sobre os padrões e processos que regem a estrutura e o funcionamento destas populações e comunidades é fundamental para prever e compreender os efeitos das mudanças climáticas. A presente avaliação é um primeiro passo, necessário para uma abordagem mais integrada e inclusiva sobre a diversidade de formações vegetais costeiras ao longo do Atlântico Sudoeste, bem como um alerta regional a respeito dos efeitos previstos das mudanças climáticas das mudanças globais sobre os produtos e serviços ecossistêmicos prestados pelas pradarias marinhas.

Abstract Seagrass meadows are among the most threatened ecosystems on earth, raising concerns about the equilibrium of coastal ecosystems and the sustainability of local fisheries. The present review evaluated the current status of the research on seagrasses and submerged aquatic vegetation (SAV) habitats off the coast of Brazil in terms of plant responses to environmental conditions, changes in distribution and abundance, and the possible role of climate change and variability. Despite an increase in the number of studies, the communication of the results is still relatively limited and is mainly addressed to a national or regional public; thus, South American seagrasses are rarely included or cited in global reviews and models. The scarcity of large-scale and long-term studies allowing the detection of changes in the structure, abundance and composition of seagrass habitats and associated species still hinders the investigation of such communities with respect to the potential effects of climate change. Seagrass meadows and SAV occur all along the Brazilian coast, with species distribution and abundance being strongly influenced by regional oceanography, coastal water masses, river runoff and coastal geomorphology. Based on these geomorphological, hydrological and ecological features, we characterised the distribution of seagrass habitats and abundances within the major coastal compartments. The current conservation status of Brazilian seagrasses and SAV is critical. The unsustainable exploitation and occupation of coastal areas and the multifold anthropogenic footprints left during the last 100 years led to the loss and degradation of shoreline habitats potentially suitable for seagrass occupation. Knowledge of the prevailing patterns and processes governing seagrass structure and functioning along the Brazilian coast is necessary for the global discussion on climate change. Our review is a first and much-needed step toward a more integrated and inclusive approach to understanding the diversity of coastal plant formations along the Southwestern Atlantic coast as well as a regional alert the projected or predicted effects of global changes on the goods and services provided by regional seagrasses and SAV.

Resumo Estuários são ecossistemas costeiros que sustentam uma ampla variedade de serviços ambientais para a humanidade. Estuários abrigam muitos ambientes bentônicos com características específicas e seriamente ameaçados globalmente. Manguezais, marismas e planícies de maré são amplamente impactados por poluentes domésticos e industriais, por atividades comerciais que levam à perda de habitat e pela sobrepesca. Os diversos impactos locais, associados a mudanças regionais e globais na hidromorfologia estuarina e potenciais efeitos de mudanças climáticas, colocam sérias ameaças a ecossistemas estuarinos. A rede Bentos foi criada para estudar o efeito de mudanças no clima em ecossistemas bentônicos costeiros brasileiros. Este trabalho faz parte dos esforços iniciais do Grupo de Trabalho Estuários em rever o conhecimento sobre comunidades bentônicas estuarinas no Brasil. Aqui apresentamos uma breve revisão crítica sobre os trabalhos realizados objetivando o estudo, em nível de comunidades, do bentos estuarino e processos ecológicos associados. A partir do cenário atual, realizamos recomendações de estudo para responder questões científicas sobre efeitos de mudanças climáticas em comunidades bentônicas estuarinas, e enfatizamos a necessidade de bases de dados contínuas e de longa duração e o estabelecimento de parcerias internacionais com foco específico nos estuários brasileiros.

Abstract Estuaries are unique coastal ecosystems that sustain and provide essential ecological services for mankind. Estuarine ecosystems include a variety of habitats with their own sediment-fauna dynamics, all of them globally undergoing alteration or threatened by human activities. Mangrove forests, saltmarshes, tidal flats and other confined estuarine systems are under increasing stress due to human activities leading to habitat and species loss. Combined changes in estuarine hydromorphology and in climate pose severe threats to estuarine ecosystems on a global scale. The ReBentos network is the first integrated attempt in Brazil to monitor estuarine changes in the long term to detect and assess the effects of global warming. This paper is an initial effort of ReBentos to review current knowledge on benthic estuarine ecology in Brazil. We herein present and synthesize all published work on Brazilian estuaries that has focused on the description of benthic communities and related ecological processes. We then use current data on Brazilian estuaries and present recommendations for future studies to address climate change effects, suggesting trends for possible future research and stressing the need for long-term datasets and international partnerships.

Storms, associated with strong winds and heavy rains, are often the most severe physical disturbances in shallow coastal areas causing instability to sedimentary environments. We hypothesized herein that if storms influence short-term assemblage structure of macrofauna, then assemblages should change after storms, while remaining relatively stable over calm weather conditions. The study was conducted at the subtropical Paranaguá Bay, in southern Brazil. We selected four 700 m² sites, at the estuarine outlet, to monitor changes in number of species, number of individuals and Shannon diversity. Sampling was arranged considering the weather forecast so that both before and after conditions could be recorded. Data of each site was tested separately to access the significance of specific (before/after) comparisons using t tests. There were no clear effects of storms on macrofaunal species richness, abundance and diversity at the four sampled sites. Conversely, we showed that short-term variation in abundances occurred regardless of weather conditions. Increased dispersal may be the most common process associated with storms instead of mortality. Storms that intermittently affect the southern coast of Brazil can be thus seen as minor driving forces of shallow-water estuarine macrofauna. Effects of extreme meteorological events remain to be assessed.

We tested experimentally the hypothesis that prevailing locomotion/feeding strategies and body morphology may lead to more active dispersal of free-living marine nematodes, besides passive transport. Neutral Red was applied to the sediment inside cores and the red plume formed during the flood tide was divided into near, middle, and distant zones. At 0.5 m and 1 m from the stained cores, sampling nets were suspended 5 and 10 cm above the sediment-water interface. Dispersion behaviors were defined as a function of a) the numbers of stained recaptured nematodes in comparison to their mean densities in the sediment, b) movement in the sediment or swimming in the water column, and c) body morphology. Tidal currents with average velocities of 9 cm/s resuspended the numerically dominant nematode taxa Sabatieria sp., Terschellingia longicaudata de Man, 1907, Metachromadora sp. and Viscosia sp. The recapture of stained nematodes as far as 2 m from the original stained cores showed that, despite their small body size, they can disperse through relatively large distances, either passively or actively, via the water column during a single tidal event. Recapture patterns in the sediment and in the water column indicate that nematode dispersal is directly influenced by their body morphology and swimming ability, and indirectly by their feeding strategies, which ultimately define their position in the sediment column. Besides stressing the role played by passive transport in the water column, our experiment additionally showed that mobility and feeding strategies also need to be considered as determinant of short-scale nematode dispersal.

The nereidid polychaete Laeonereis acuta (Treadwell, 1923) is either considered to be a valid species, or a synonym of Laeonereis culveri (Webster, 1879). The species epithet, acuta, refers to the acuminate anterior region of the body followed by a widening that is visible up to the 10th setiger. The relative width of the anterior region of the body, however, has been reported in the taxonomic literature as variable for Laeonereis Hartman, 1945, a genus known from the eastern coast of North America to Patagonia (southern South America). To test whether variations in this character are real, or whether they correspond to an artifact, we analyzed morphological changes associated with different anesthesia and fixation techniques regularly used to prepare specimens of Laeonereis from southern Brazil (formerly reported as L. acuta). Six treatments, including combinations of anesthetics and fixative agents, and a control, were evaluated in groups of 25 adult animals. A simple model II regression analysis on living specimens showed that the growth is approximately isometric. One-way ANOVA was used to compare the treatment effect on the ratio of peristome width: setiger 6 width. This ratio was smaller in non-anesthetized individuals, especially when prepared in formalin and freshwater. When anesthetized with menthol and fixed in formalin with sea water, individuals retained a shape that was closest to their in vivo shape. Consequently, our results suggest that fixation without prior anesthesia is not recommended for morphological and taxonomical studies. Since morphology and morphometrics of the anterior region are consistently influenced by preparation techniques, it is likely that inadequate fixation routines have introduced several errors in the taxonomic and ecological literature of Laeonereis.

This paper describes, for the first time, the cytogenetic characteristics of some South Atlantic nereidid polychaetes, collected in Paranaguá Bay, southeast Brazil. Mitotic chromosomes were obtained from regenerative tissue after amputation of the posterior tips of the animals. Seven species, of five genera, were analyzed: 1) Platynereis dumerilii (2n=28; FN=56), which is considered cosmopolitan but is suspected to be a species-complex. Karyotypic divergences were detected when comparing chromosome morphology and NOR distribution from Paraná and North American populations (2n=28; FN=56), 2) Perinereis vancaurica (2n=28; FN=56), P. anderssoni (2n=28; FN=56) and P. ponteni (2n=28; FN=54). Karyotypes and NOR distribution allowed us to relate P. anderssoni (Paraná, Brazil) to P. macropus (Italy), the former showing a derived karyotype. The remaining karyotypes of species of Perinereis showed independent divergences; 3) Pseudonereis palpata (2n=28; FN=56), known from the south and south-east coast of Brazil; 4) Nereis oligohalina (2n=28; FN=50), occurring in the South Atlantic. The last two species share the conservative chromosome number of the family; and 5) Laeonereis culveri, occurring in both the South and North Atlantic, has the highest chromosome number in the family (2n=38). We discuss the important role of karyotypic evolution in the origin of modern families of polychaetes, when the current chromosomal diversity (2n=6 to 2n=64) was developed, followed by a period of chromosomal stability of nereidid polychaetes during the dispersion which followed the Pangea breakup, with the predominance of divergences of neutral chromosomal changes, involving mainly pericentric inversions and NOR amplifications.

Se describen por primera vez, las características citogenéticas de poliquetos nereidídeos provenientes de la Bahía de Paranaguá, sudeste de Brazil. Cromosomas mitóticos fueron obtenidos a partir de tejido regenerativo después de amputar la región posterior. Fueron analizadas siete especies pertenecientes a cinco géneros: 1) Platynereis dumerilii (2n=28; FN=56), considerada cosmopolita pero que probablemente constituya un complejo de especies. Fueron detectadas divergencias cariotípicas al comparar morfología cromosómica y distribución de NORs entre poblaciones de Paraná y Atlántico Norte, 2) Perinereis vancaurica (2n=28; FN=56), P. anderssoni (2n=28; FN=56) y P. ponteni (2n=28; FN=54). Los cariotipos y distribución de NOR permitieron relacionar P. anderssoni (Paraná, Brazil) con P. macropus (Italia), presentando la primera un cariotipo derivado. Los restantes cariotipos del género mostraron divergencias independientes; 3) Pseudonereis palpata (2n=28; FN=56), distibuída en el sur y sudeste de la costa brasilera; 4) Nereis oligohalina (2n=28; FN=50), que ocurre en el Atlántico sur. Las últimas dos especies comparten el número cromosómico conservado de la familia, y 5) Laeonereis culveri, que ocurre en toda la costa Atlántica, mostró el número cromosómico más alto de la familia (2n=38). Se discute la evolución cariotípica como rol importante durante el origen de las familias modernas de Poliquetos, cuando surge la actual diversidad cromosómica (2n=6 a 2n=64), seguido de un período de establidad cariotípica dentro de la familia Nereididae durante su dispersión, posterior a la ruptura de la Pangea, a partir de la cual pasan a predominar divergencias cromosómicas neutras, involucrando principalmente inversiones pericéntricas y amplificaciones de NORs.

A protocol using the computer program Adobe Photoshop CS2 (version 9.0) is proposed for determining the level of herbivory on intact and consumed leaves, using mangroves as an example. The usual manual methods consist of drawing the leaf on graph paper, restoring the original shape in cases of damaged edges. The computerized methods are intended to accelerate the leaf measurement time with applications, digitalization equipment, and portable area measurers that are more efficient, faster, and more economically viable than the manual methods. The need to restore the edges of the consumed leaves is an obstacle to all methodologies. Nonetheless, the reconstruction of the consumed foliar edges is shown to be more realistic with Adobe Photoshop, as this allows a better fit to the original shape of the leaf. Moreover, this application allows the use of compacted files such as JPEG, permitting a simple, rapid, and precise method for determining the levels or rates of foliar herbivory

Se propone un protocolo de utilización del programa computacional Adobe Photoshop CS2, versión 9,0, para la determinación de los niveles de herbivoría en hojas intactas y consumidas, tomando como ejemplo árboles de manglar. Los métodos manuales usuales consisten en el dibujo de la forma de la hoja en papel milimetrado, restaurando el formato original en caso que tenga los márgenes damnificados. Los métodos computacionales tienen como objetivo acelerar el tiempo de medición de la hoja con aplicativos, digitalizadores y medidores de áreas portátiles, que son más eficientes, veloces y económicamente viables que los manuales. La necesidad de restaurar los bordes de las hojas ya consumidas es un obstáculo en todas las metodologías. Sin embargo, la reconstrucción de los márgenes foliares consumidos se mostró más realista en el Adobe Photoshop por posibilitar un mayor ajuste al formato original de la hoja. Además, esta aplicación soporta la utilización de archivos compactados, como el formato JPEG, posibilitando un método sencillo, rápido y preciso para la determinación de los niveles o tasas de herbivoría foliar

Terebellides sepultura sp. nov. is described from the continental shelf bottoms off southern Brazil. Terebellides carmenensis Solis-Weiss, Fauchald & Blankensteyn, 1991 is newly recorded for the Brazilian coast and notes on T. anguicomus F. Müller, 1858 and T. klemani Kinberg, 1867 are provided. A key to 28 species of Terebellides is given.

Ten species belonging to the genera Ceratonereis Kinberg, 1866 and Nereis Linnaeus, 1758 were recorded in estuaries, exposed sandy beaches, shelly soft bottoms, atolls and coral reefs of the Brazilian northeastern coast. Two new species, Nereis serrata, from Ceará coast, and Nereis pseudomoniliformis, from Sergipe coast, are described.

Six polychaete species belonging to the genera Namalycastis Hartman, 1959, Ceratocephale Malmgren, 1867, Laeonereis Hartman, 1945, and Rullierinereis Pettibone, 1970 were recorded as part of a systematic survey of the family Nereididae in estuaries, exposed sandy beaches, shelly soft bottoms, atolls and coral reefs of the Brazilian northeastern coast. Two new species, Rullierinereis auxiliadorae, from Ceará coast and Ceratocephale rocaensis, from Atol das Rocas, are described.