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A small amphipod, Curidia japonica sp. nov., is described from Mie and Wakayama Prefectures, central Japan. The discovery is the first record of the family Ochlesidae from the Northwest Pacific. This new species can be clearly distinguished from its congeners by the very short posterodistal process of the antenna 2 peduncular article 4. A key to the species of Curidia Thomas, 1983 in the world is provided.

The population biology of the three sympatric species of caprellids (Caprella danilevskii, C. equilibra and C. scaura) associated with a Sargassum bed was studied in the northern coast of São Paulo state, Brazil. Samplings were carried out monthly from October 2010 to February 2012. In each month, 25 fronds of Sargassum were randomly collected through snorkelling. The caprellids were identified, counted, classified by sex and separated into size classes. Caprella danilevskii was the most abundant species, with 14939 specimens recorded. The body size of males was larger than that of females for C. danilevskii and C. equilibra, and the sex ratio was skewed toward males for all species. The size-frequency distribution was polymodal for C. danilevskii and C. scaura and bimodal for C. equilibra. Mature males of C. scaura and C. equilibra were recorded in all size classes. The last size classes (from 8.3–9.4 to 12.7–13.8 mm) were dominated by mature males. Mature and ovigerous females were more frequent in intermediate size classes. Significant temporal variations were recorded for the three species with higher densities in spring and summer that are related to higher algal biomass; but other environmental factors are certainly important for explaining caprellid density variation.

Forty-four taxa belonging to 14 genera of testate amoebae were recorded in three biotopes: benthal, benthal with an overgrowth of aquatic vegetation and phytal from the coastal zone of the "Marsh Malak Preslavets" protected area. It is found that in regard to taxonomic richness the testacean fauna in investigated biotopes is quite similar. Concerning the species composition and number of specimens in different biotopes, however, some differences were found, which leads to the conclusion that each biotope is characterized by specific testate amoebae fauna. The abundance and structure of the testacean communities depend on the type of biotope, although all three are from the coastal zone of the marsh. Only eleven testate amoebae (or 25%) were found in all studied biotopes. About 47.7% of species were established only in one biotope. [ABSTRACT FROM AUTHOR]

Benthic macroalgae are very important in structuring the biota of coastal reefs and are colonized by several species of animals and plants. The present study describes the polychaete assemblages associated with the macroalgae Gelidiella acerosa , Palisada perforata , Padina gymnospora , and Ulva lactuca on tropical sandstone reefs on the Brazilian coast and correlates the complexity of the macroalgae with the polychaete assemblages. Samples (10 fronds of each macroalgal species) were collected randomly during the dry (December 2018 and February 2019) and rainy (April and June 2019) seasons. The height, fractal dimension of the area and perimeter, and the Index of interstices were determined from macroalga photographs using the ImageJ software. Significant seasonal differences were found in the architecture of the macroalgae, and G. acerosa and P. perforata had the most complex structure. The macroalgae were colonized by 25 taxa of mobile polychaetes from seven families (Dorvilleidae, Eunicidae, Heisionidae, Polynoidae, Phyllodocidae, Syllidae and Nereididae), with dominance of syllids and nereidids in both seasons. Polychaetes were mostly carnivores and omnivores in the dry and rainy seasons, respectively. Platynereis dumerillii was the most abundant and frequent polychaete species. The structure of the assemblages varied significantly among macroalgae. G. acerosa and P. perforata had the most species-rich assemblages. The most important traits of macroalgae that structure polychaete assemblages are height, diameter of the area (Da), and diameter of the perimeter (Dp), with slight variation these traits between macroalgal species. Seasonal changes and macroalgal complexity (traits) were important drivers for polychaete assemblages on macroalgae in tropical coastal sandstone reefs. • Polychaetes associated with macroalgae are mobile herbivores, omnivores or carnivores. • Seasonality and macroalgae complexity drivers of the polychaete assemblages. • Macroalgae morphological complexity exerts a strong influence on the polychaetes. [ABSTRACT FROM AUTHOR]

Frondose macroalgae usually harbors a diverse epifaunal community, whereas sediment among the fronds tends to decrease species richness and diversity. The macroalga Caulerpa racemosa is found in shallow waters and can trap sediment among its stolons. We investigated how the peracarid assemblages from two shores in southeastern Brazil are related to temporal changes in the algal biomass, sediment quantity trapped in C. racemosa patches, and organic matter content from adjacent areas. On both shores, there was no significant difference in the algal biomass through time. Algal clumps from Fortaleza retained at least four times more sediment than from Cigarras, and similar temporal trends of sediment retention were observed at both shores. Overall, 47 species of peracarids were identified. Assemblages from Cigarras were richer and more diverse but remained constant through time. Assemblages from Fortaleza had variation in peracarid species and feeding habits through time, with omnivorous and detritivorous species dominating periods of high loads of sediment. While the presence of sediment seems to negatively affect the abundance and diversity of the epifaunal assemblage, it may favor the presence of detritivores, and tube-building species. [ABSTRACT FROM AUTHOR]

A depth gradient may influence both macrophytes and their associated epiphytic community through variations in hydrodynamics and light conditions, which in turn may affect the mobile organisms living on them. We investigated how a narrow depth gradient affects the associated peracarid assemblages in a Sargassum cymosum bed. This study was conducted on a rocky shore in Southeastern Brazil. A 20 × 3 m sampling area was defined parallel to the shore line, within which three perpendicular transects were sampled in October 1997 (spring), January 1998 (summer), April 1998 (fall), and July 1998 (winter). In each transect, three samples of Sargassum were randomly collected at three different depths—shallow (1 m), intermediate (2 m), and deep (3 m). Peracarid fauna was identified, quantified, and classified into feeding groups. Depth affected both species richness and total density only in January, with fewer species and individuals at the shallow depth, more species at the intermediate depth, and more individuals at the deep depth. The taxonomic and feeding group composition of peracarid assemblages were also affected by depth, with differences depending on the sampling period. Herbivores and omnivores were commonly more abundant at the shallow depth, while detritivores were more abundant at the deep depth. Carnivores seemed not to be affected by depth. Small-scale distribution patterns can be related to how peracarid species deal with the variability in turbulence and food availability imposed by a depth gradient, with morphological attributes and feeding habits guiding how species are distributed in the space and thus the peracarid assemblage as a whole. [ABSTRACT FROM AUTHOR]

ABSTRACT Brazilian marine molluscs, especially Gastropoda and Bivalvia, are relatively well studied. However, information on the class Polyplacophora is more scarce, particularly on reef-dwelling forms. This study aimed to qualitatively and quantitatively analyze aspects of polyplacophorans from reef ecosystems and their associations with macroalgae on the coast of Maceió (state of Alagoas, Brazilian Northeast). The study area included five coral reefs at Ipioca, Ponta do Prego, Ponta do Meirim, Riacho Doce and Ponta Verde, as well as two sandstone reefs, located in Guaxuma and Sereia. The samples were obtained by snorkelling along the intertidal and subtidal reef zones to a depth of up to five meters during low tides, between 2009 and 2011. In addition, the chitons associated with three macroalgae of the Ponta Verde coral reef were studied based on collections made over 12 years (from the summer of 1998 to the winter of 2009). Three replicates with an area of 25 cm2 were collected from each of the following species of macroalgal phytals: Amphiroa fragilissima (Rhodophyta), Caulerpa racemosa (Chlorophyta) and Dictyota cervicornis (Phaeophyta). A total of 715 individuals (110 juveniles and 605 adults) were identified, including Acanthochitona terezae Guerra, 1983, Ischnochiton striolatus (Gray, 1828) and Ischnoplax pectinata (Sowerby II, 1840). Acanthochitona terezae was found for the first time in the area. Ischnochiton striolatus was the most abundant species in the reef ecosystem and in association with macroalgae. The greatest number of individuals of all three polyplacophorans identified (adults and juveniles) was found on the phytal A. fragilissima.

The structural complexity of algae is an important factor driving the structure of epifaunal assemblages associated with marine macroalgae. We tested how the structural complexity of four Sargassum species is related to the structure of gammarid assemblages. We measured different algae traits (frond length, number of branches, and epiphytic hydroid and algae cover) and different ecological descriptors of gammarid assemblages (richness, density, diversity, and evenness). Samples were obtained in southeastern Brazil in early and late summer. Structural complexity was associated with the occurrence of significantly different gammarid assemblages. Sargassum cymosum had more branches and greater hydroid coverage, and a higher gammarid species richness, diversity, and density. The characteristics of the gammarids inhabiting the different Sargassum species were similar between sampling periods, indicating that the relationships between the Sargassum traits and associated gammarids are strong and persistent. Species richness, diversity, and density were all more dependent on habitat heterogeneity (number of branches and coverage of epiphytic hydroid) than the quantity of habitable space, i.e., frond length. Overall, the variation in structural complexity among Sargassum species had a significant effect on gammarid assemblage structure. [ABSTRACT FROM AUTHOR]

Species diversity is regulated by historical, neutral and niche processes, with species tolerance, dispersal and productivity guiding diversity at larger scales, while habitat heterogeneity and biotic interactions acts in smaller scales. In rocky shores, several organisms provide secondary substrates for mobile fauna, with macroalgae being the most abundant and diverse ones. The patchiness promoted by different macroalgae hosts enhances small-scale heterogeneity and may increase and maintain the diversity of the mobile organisms, since there is a close relationship between the associated fauna and its hosts. In this study we selected three morphologically different macroalgae that coexist in the same rocky shore height in the Araçá Bay, an area under the threat of the nearby harbor expansion, and evaluated the fauna associated to each algal host. Even under similar abiotic pressure (same rocky shore height), the associated fauna of each algal host varied in number and composition, revealing a close relationship. The poorly branched foliose Ulva lactuca sustained a lower density of organisms and was dominated by isopods, while the heavily branched turf and Bostrychietum community showed a high density of organisms, with a dominance of peracarid crustaceans and annelids on the turf and more resistant groups, such as bivalves, acaris and terrestrial insects on the Bostrychietum. Previous studies in the Araçá Bay already revealed a large spatial heterogeneity in the processes and sessile organisms distribution, and here we highlight that this heterogeneity can be observed in an even smaller scale, with different algal hosts mediating the turnover of species in a scale of centimeters and meters, resulting in diversity maintenance of the associated fauna. Since the harbor expansion may prevent the occurrence of macroalgae as a result of light limitation by suspended platforms, we may expect not only a decrease in algal cover but also in the total diversity of the associated fauna in the Araçá Bay. [ABSTRACT FROM AUTHOR]

Phytal communities are characterized by spatial and temporal variation and are influenced by fluctuating biological and physical parameters. This study aimed to describe and compare the gastropods associated with Ulva spp., at three sites of the Espirito Santo coast with ferruginous laterite substrate and different modes of wave exposure. Camburi is characterized by the presence of iron ore particles. Samples were collected bimonthly. At each site, five sampling quadrats were launched at random in the intertidal region. Individuals of Ulva spp. were collected (2964 individuals) and 53 taxa were found. In Camburi the dominant species was Amphitalamus vallei (Barleeidae), while in Capuba and Manguinhos Eulithidium affine (Phasianellidae) predominated. The analyses indicated that Camburi is distinct from the other sites. The lesser wave impacts and the more complex structure of the algae in Camburi, due to the presence of iron ore, may explain this variation.

Coastal regions are subject to various forms of environmental impacts, such as spills of crude oil and associated products, with a wide range of effects on benthic biodiversity. This study characterized the patterns of recolonization of the macrofauna associated with the brown alga Sargassum cymosum(C. Agardh), on fronds contaminated by diesel oil in a small-scale field experiment. We collected 40 fronds of S. cymosum from an algal bed in southeastern Brazil and defaunated each frond by immersion in fresh water. Half of the fronds were then immersed in seawater (control group) and the other half in a mixture of 50% diesel oil and 50% seawater (impacted group). The test fronds were returned to the algal bed, and natural recolonization took place over a period of 12 days. Samples of the vagile macrofauna were taken randomly at three-day intervals over the course of the recolonization period. No significant differences in the densities of most taxa were found between the impact treatment (IG) and control treatment (CG). At the end of the recolonization period (day 12), the faunal composition of the treated fronds was very similar to the natural conditions, indicating a high rate of community recovery and suggesting that benthic associations can be rather resilient to diesel-oil impacts on a small scale.

The aims of this study were to characterize the macrofauna associated with the articulated calcareous algae occurring on a hydrodynamic gradient off the Vitória metropolitan area, Espírito Santo State, Brazil, and to describe its temporal distribution. Physicochemical variables were measured in situ, and samples of sediment, water and phytal were taken from three sites along the coast in August and November 2005 (winter and spring, respectively) and in February and May 2006 (summer and fall, respectively). Twenty random samples were taken from the rocky surface in the lower midlittoral zone at each site, each season. Six species of articulated algae harboring 9,651 animal specimens distributed among 189 taxa were collected. The dominant taxonomic groups were Mollusca, Polychaeta and Crustacea. The main patterns revealed by statistical analysis related to differences in the abundance and richness at the sample sites, as well as to the correlation between the physicochemical variables and community distance matrices, indicating the importance of the physicochemical variables in the differentiation of the communities. Results also indicated that the variable which most influenced the physicochemical and community properties was the hydrodynamic character of the sites: a high level of hydrodynamism resulting in the calcareous algae´s sheltering a lower abundance and diversity of animal species than a lower level one.Os objetivos deste estudo foram caracterizar a macrofauna associada às algas calcárias articuladas num gradiente de hidrodinamismo no litoral da região metropolitana de Vitória, Espírito Santo, Brasil, e descrever a distribuição temporal. Variáveis fisicoquímicas foram medidas in situ, e amostras do sedimento, água e fital foram feitas em três pontos amostrais do litoral em agosto e novembro de 2005 (inverno e primavera, respectivamente) e fevereiro e maio de 2006 (verão e outono, respectivamente). Em cada ponto, e por estação do ano, foram obtidas 20 amostras aleatórias da superfície do costão rochoso na região do mediolitoral inferior. Seis espécies de algas calcárias articuladas foram coletadas e abrigaram 9.651 espécimes animais distribuídos em 189 táxons. Os grupos taxonômicos dominantes foram Mollusca, Polychaeta e Crustacea. Os principais padrões revelados pelas análises estatísticas foram diferenças na abundância e riqueza entre os pontos amostrais e correlação entre as variáveis fisicoquímicas e a comunidade, indicando que os parâmetros fisicoquímicos foram importantes para a caracterização destas. Os resultados indicaram ainda que a variável que mais influenciou as propriedades fisicoquímicas e da comunidade foi o grau de hidrodinamismo: locais com hidrodinamismo elevado permitem que algas calcárias abriguem uma menor abundância e diversidade de espécies animais do que locais com hidrodinamismo elevado.

Studies were carried out to investigate the temporal variation in Sargassum biomass, Hypnea epiphytism and associated fauna. There was a marked variation in the biomass of Sargassum and Hypnea among various sampling periods. Low values for Sargassum were recorded in August and November, while the lower value for Hypnea biomass was recorded in August. An inverse relationship was found between Sargassum biomass and the intensity of Hypnea epiphytism. The density of the total fauna associated to Sargassum showed a marked reduction in May. This variation was influenced by the variation patterns of the dominant faunistic groups (Gastropoda, Gammaridea, Isopoda and Caridea). Significant positive relationships were found between the biomass of Sargassum and Sargassum+Hypnea with the total density of all faunistic groups (per macroalgae biomass unit). However, the influence of Hypnea epiphytism on the phytal organisms was not evidenced.

The monthly fluctuations of amphipods associated to the algae Bryocladia trysigera was described from March 1997 to February 1998 at the rocky shore known as Poço de Anchieta in the Peruíbe Beach, Itanhaém, Southeastern Brazil. A total of 75,344 individuals were sampled, belonging to 10 species and 9 families. Three species dominated the phytal in number: Hyale nigra, Caprella danileviskii and Caprella penantis. Despite the alternation in dominance of the 3 most abundant species, the amphipod species composition remained generally unchanged, so that the majority of the species were observed in all sampling months. The temporally changing pattern of the community structure, with a decline in amphipod abundance in winter followed by an increase in spring, was probably due to a higher predation pressure in winter period.

In this study, the meiofauna associated with Sargassum cymosum was qualitatively and quantitatively analyzed between December 1990 and July 1991. Sampling was carried out on a moderately exposed shore at Lázaro Beach, Ubatuba (32°S - 45°W). Each alga was washed in a formaldehyde solution and the fauna in suspension was washed through a series of 500, 250, 120 and 60 µm mesh sieves. The biomass of each taxonomic group was estimated as ash-free dry weight (AFDW) according to size categories. Algae volume and dry weight were determined, incIuding epiphytes. Densities of epifauna ranged from 502.9 to 2706.6 ind.20 ml-1 as algae volume. The biomass values (326.6 to 1214.4 µg.20 ml-1 AFDW) represented a low standing stock. Harpacticoid copepods and their nauplii were the dominant group and also showed the highest biomass values, being represented by larger individuaIs (250 to 120 µm). Higher values were observed between the end of the summer and the beginning of the fali (March and April), decreasing until winter (July). This variation may be explained by habitat complexity changes, or reproduction of some taxa, as higher meiofaunal densities were found on the 60 µm mesh sieve, incIuding high percentages of nauplii.Este trabalho avalia qualitativa e quantitativamente a meiofauna associada a Sargassum cymosum estimando-se a densidade e biomassa da fauna, assim como uma possível variação temporal. As coletas foram realizadas à nordeste da Praia do Lázaro, Ubatuba (23°S - 45°W), de dez/90 a jul/91. As frondes foram mergulhadas em solução de água e formaldeído, e os organismos em suspensão retidos em uma série de malhas (500,250, 120 e 60 µm). Para cada grupo taxonômico foi estimada a biomassa em µg de peso seco livre de cinzas. Como medida de substrato foi determinado o volume e a biomassa em peso seco de alga, incluindo-se as algas epífitas. Os valores de densidade da meiofauna variaram entre 502,9 a 2706,6 ind.20 mrl de alga. A biomassa estimada por sua vez apresentou valores baixos, entre 326,6 a 1214,41-µg.20 ml-1 peso seco livre de cinzas. Copepoda Harpacticoida e seus náuplios foram dominantes numericamente e em relação à biomassa. Os valores de densidade e biomassa da meiofauna foram altos no final do verão (março) e início do outono (abril), e diminuíram gradativamente até o início do inverno (julho). Esta variação pode ser explicada por mudanças na complexidade do habitat ou, ainda, devido ao período reprodutivo de alguns táxons, já que a maior quantidade de meiofauna ocorreu na malha de 60 µm (náuplios).

Brazilian marine molluscs, especially Gastropoda and Bivalvia, are relatively well studied. However, information on the class Polyplacophora is more scarce, particularly on reef-dwelling forms. This study aimed to qualitatively and quantitatively analyze aspects of polyplacophorans from reef ecosystems and their associations with macroalgae on the coast of Maceió (state of Alagoas, Brazilian Northeast). The study area included five coral reefs at Ipioca, Ponta do Prego, Ponta do Meirim, Riacho Doce and Ponta Verde, as well as two sandstone reefs, located in Guaxuma and Sereia. The samples were obtained by snorkelling along the intertidal and subtidal reef zones to a depth of up to five meters during low tides, between 2009 and 2011. In addition, the chitons associated with three macroalgae of the Ponta Verde coral reef were studied based on collections made over 12 years (from the summer of 1998 to the winter of 2009). Three replicates with an area of 25 cm² were collected from each of the following species of macroalgal phytals: Amphiroa fragilissima (Rhodophyta), Caulerpa racemosa (Chlorophyta) and Dictyota cervicornis (Phaeophyta). A total of 715 individuals (110 juveniles and 605 adults) were identified, including Acanthochitona terezae Guerra, 1983, Ischnochiton striolatus (Gray, 1828) and Ischnoplax pectinata (Sowerby II, 1840). Acanthochitona terezae was found for the first time in the area. Ischnochiton striolatus was the most abundant species in the reef ecosystem and in association with macroalgae. The greatest number of individuals of all three polyplacophorans identified (adults and juveniles) was found on the phytal A. fragilissima. [ABSTRACT FROM AUTHOR]

Phytal communities are characterized by spatial and temporal variation and are influenced by fluctuating biological and physical parameters. This study aimed to describe and compare the gastropods associated with Ulva spp., at three sites of the Espirito Santo coast with ferruginous laterite substrate and different modes of wave exposure. Camburi is characterized by the presence of iron ore particles. Samples were collected bimonthly. At each site, five sampling quadrats were launched at random in the intertidal region. Individuals of Ulva spp. were collected (2964 individuals) and 53 taxa were found. In Camburi the dominant species was Amphitalamus vallei (Barleeidae), while in Capuba and Manguinhos Eulithidium affine (Phasianellidae) predominated. The analyses indicated that Camburi is distinct from the other sites. The lesser wave impacts and the more complex structure of the algae in Camburi, due to the presence of iron ore, may explain this variation. [ABSTRACT FROM AUTHOR]

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The number of studies demonstrating the susceptibility of benthic reef communities to anthropogenic impacts is growing. However, for some of the components of reef fauna, such as meiobenthic harpacticoid copepods, information is still lacking. Here, different diversity and taxonomic distinctness indexes and multivariate analyses were used to test whether the assemblage of harpacticoid copepods colonizing Artificial Substrate Units (ASUs) is an appropriate tool for the identification of reefs subjected to different levels of anthropogenic pressure. Furthermore, we also evaluate if diffused, persistent, anthropogenic impacts generate the homogenization and simplification of Harpacticoida assemblages. Six reefs were organized into two groups along the coast, depending on their proximity to very large urban centers. ASUs were used for meiofauna colonization and, for each reef, 320 Harpacticoida individuals were separated for identification at the species level. Abiotic parameters were analyzed, and significant differences were found between the two groups of reefs, with an increase in dissolved inorganic nutrients found in areas near large urban centers. Both the multivariate analyses and the indexes of diversity showed a clear separation between the reefs closer to the urban zones and those further away, as a response to the anthropogenic pressure. As hypothesized, in the impacted reef areas, there was a strong simplification and homogenization of the harpacticoid copepod assemblages. However, the results of the indexes, based on taxonomic distinctness, suggest that there was no phylogenetic signal of anthropogenic impact on coral reef harpacticoid copepods. [ABSTRACT FROM AUTHOR]

The monthly fluctuations of amphipods associated to the algae Bryocladia trysigera was described from March 1997 to February 1998 at the rocky shore known as Poço de Anchieta in the Peruíbe Beach, Itanhaém, Southeastern Brazil. A total of 75,344 individuals were sampled, belonging to 10 species and 9 families. Three species dominated the phytal in number: Hyale nigra, Caprella danileviskii and Caprella penantis. Despite the alternation in dominance of the 3 most abundant species, the amphipod species composition remained generally unchanged, so that the majority of the species were observed in all sampling months. The temporally changing pattern of the community structure, with a decline in amphipod abundance in winter followed by an increase in spring, was probably due to a higher predation pressure in winter period.