Brazilian Journal of Oceanography

Abstract The short-term variability of mesozooplankton distribution and physicochemical variables was examined in two different channels of the Bahía Blanca Estuary, Argentina, during two tidal cycles. All the physicochemical measurements and mesozooplankton sampling were performed at a fixed site during approximately 22-23 h at 3-h intervals. Pumps were used to obtain surface and bottom mesozooplankton samples and the water speed of each stratum was measured with an Acoustic Doppler Current Profiler (ADCP). In all, 23 mesozooplanktonic taxa belonging to four phyla (Arthropoda, Annelida, Echinodermata and Chordata) were identified. The most abundant taxa during the two tidal cycles were Balanus glandula larvae, Eurytemora americana and Acartia tonsa. A discernible variability in the water conditions and vertical mesozooplankton distribution (VMD) different from that known for the estuary's main channel, was found in the other two selected channels. VMD varied during the tidal cycle in both channels in accordance with the channel's geomorphology and water dynamic characteristics of each of them. The variation of the abundance of the different taxa during ebb and flood currents might indicate the existence of a tidal vertical migration of the mesozooplankton as a response to particular dynamic water conditions.

The circulation and transport of suspended particulate matter in the Caravelas Estuary are assessed. Nearly-synoptic hourly hydrographic, current (ADCP velocity and volume transport) and suspended particulate matter data were collected during a full semidiurnal spring tide, on the two transects Boca do Tomba and Barra Velha and on longitudinal sections at low and high tide. On the first transect the peak ebb currents (-1.5 ms-1) were almost twice as strong as those of the wider and shallow Barra Velha inlet (-0.80 ms-1) and the peak flood currents were 0.75 and 0.60 ms-1, respectively. Due to the strong tidal currents both inlets had weak vertical salinity stratification and were classified with the Stratification-circulation Diagram as Type 2a (partially mixed-weakly stratified) and Type 1a (well mixed). Volume transports were very close, ranging from -3,500 to 3,100 m³s-1 at the ebb and flood, respectively, with a residual -630 m³s-1. The concentration of the suspended particulate matter was closely related to the tidal variation and decreased landwards from 50 mg.L-1 at the estuary mouth, to 10 mg.L-1 at distances of 9 and 16 km for the low and high tide experiments, respectively. The total residual SPM transport was out of the estuary at rates of -18 tons per tidal cycle.

Deployment depth of artificial reefs is one of the most important issue in planning stage and future success. Most of the studies aimed at determination of fish community around artificial reefs were conducted mainly 10-25m depths in Mediterranean and Aegean Sea. The goals of this study are determine and compare of fish community structure around artificial reefs which deployed 20, 30 and 40 m depths. Underwater visual census technique was used to determine fish species, number of individual and size estimation. There was no statistical difference (p>0.05) in mean fish biomass and number of individual between the depths. But mean species number was significantly greater on 20 m in comparison to 30 m and 40 m depths (p<0.05). Furthermore, calculated values of Jaccard and Bray-Curtis indexes showed low similarity (min. 3% - max. %37) between depths.

The diet of chaetognath species were studied by examining the gut contents of 9466 specimens collected off Ubatuba region, Sao Paulo State. The greatest proportion of chaetognaths (7119 individuals) showed their gut contents empty. Copepods, mollusc eggs, appendicularians, cladocerans and annelids were the most common food items in the gut contents of juveniles and mature stages. Cannibalism occurred in low frequency. In Summer the copepods Temora stylifera and Paracalanus spp were more abundant, whereas Oncaea spp and mollusc eggs were heavily preyed in Winter. There was a clear trend of increasing prey size with the developmental stage.

The marine sediment samples collected from the northeastern Brazilian continental shelf, at water depths between 20 and 80 m, consisted mainly of sands with an almost total absence of gravel and granules. Medium, coarse and very coarse sand grains are mostly composed of halimeda, lithothamnium, rodoliths and bioclastic sands with a carbonate content varying between 77 and 96 %. The chemistry in general shows a decreasing content of Ca (86.1 %) &gt;Si (6 %) &gt; Cl (3.6 %) &gt; Sr (0.8 %) &gt; K (0.66 %) &gt; S (0.62 %) &gt; Al (0.6 %) &gt; Na (0.55%) &gt; Mg (0.43 %) &gt; Fe (0.4 %) &gt; P (0.2 %) &gt; Br (0.04 %) in the samples. There was no correlation between CaCO3 and chemical contents and grain size with depth and bio-components. With the exception of Sr of marine origin, all other elements (P, S, Br, Cl, Fe) are of continental origin. The lithothamnium of some offshore samples shows higher CaCO3 content, while Mg and Na are present only in halimedas. Bioclastic sands contain no Br, and silt and clay fractions are rare and characterize samples closer to the coast. These marine bioclastic granulates are of very pure biogenic calcium carbonates and are thus highly to be recommended for economic purposes.

The Principal Component Analysis was applied to three sets of data, generated from the results of grain size analysis of 153 surface sediment samples of Ilha Grande Bay, Rio de Janeiro. State. The results show the advantages of the method in the interpretation of the different textural facies of the sediments of the area, in comparison to the classification methods of Shepard (1954) and Folk & Ward (1957). The results show also that the grain size frequencies are the best set of data for the application of the analysis.

A survey of the petroleum aromatic hydrocarbons levels on the surface waters of the Sao Sebastiao Channel, Sao Paulo, Brazil is presented. The survey was done in order to assess the influence of the biggest maritime oil terminal of Brazil on the petroleum hydrocarbons levels of the area. Fourty four samples taken from 1 m depth were analysed by fluorescence spectroscopy. The highest level, 45.29 µg.1-1, was found on the side of an anchored tanker and the lowest detectable level was 0.19 µg.1-1.

Num trabalho anterior (NONATO & LUNA, 1969) discutimos as especies de poliquetas de escama que fazem parte de uma colecao proveniente de dragagens executadas pelo Laboratorio de Ciencias do Mar da Universidade Federal de Pernambuco, no Nordeste do Brasil. No atual, sao tratadas as especies desprovidas de escamas, em numero de 71. Informacoes sobre a area amostrada estao contidas nos trabalhos de CAVALCANTI & colab. e de MABESOONE & TINOCO, 1967. Especies pequenas e delicadas que constituem parte ponderavel das populacoes bentonicas foram muito raras nesta area. Isto pode ser devido a condicoes eventualmente adversas ou, muito mais provavelmente, e consequencia de sua destruicao durante a coleta e triagem. Os fundos duros predominantes, com superficie irregular e constituidos em grande parte por blocos ou cascalho de algas calcarias e corais, tornam particularmente ardua a amostragem biologica. Nessas condicoes e dificil preservar a integridade de seres de corpo delicado como os poliquetas, da acao trituradora, dentro dos aparelhos de coleta. Devemos ter em conta essa circunstância ao avaliar a densidade aparente da fauna. Os poliquetas nao devem ser tao pouco frequentes como indica o resultado da prospeccao atual. Acreditamos que o uso de melhores tecnicas permitira apreciar a sua verdadeira densidade e conhecer melhor sua distribuicao. A pesca noturna, com luz submersa, por exemplo, podera ser um excelente metodo para atrair especies do substrato ou de habitats de outra forma inaccessiveis. Das 71 especies, apenas uma foi considerada como nova para a ciencia. Scoloplis agrestis sp. nov. assemelha-se a S. robustus Rullier e a S. madagascarensis Fauvel, diferindo de ambas pelo numero de setigeros toracicos e pelo numero reduzido de cerdas aciculares dos neuropodios toracicos. Os Eunicea sao o grupo melhor representado, com 26 especies, das quais a mais comum e Eunice longicirrata Webster (108 exemplares em 19 estacoes). Diopatra spiribranchis Augener e Hypsicomus elegans Webster sao consideradas boas especies. Somente dois Flabelligerideos foram capturados em toda a area; um deles e um especimem bem conservado de Pherusa scutigera (Ehlers) e o outro um Piromis sp. A maior parte das especies desta colecao e constituida por formas semelhantes as encontradas na regiao das Antilhas, como, alias, seria de se esperar. Porem, algumas aproximam-se de especies do Pacifico e do Indico, como e o caso de Glycera longipinnis Grube, Onuphis litoralis Monro e Vermiliopsis acanthophora Augener, cujas caracteristicas concordam perfeitamente com as descricoes a que tivemos acesso.

A type of platform, known as a table, is now being used for mangrove oyster farming. In Fortim, Ceará, Brazil, this activity was begun in June 2000 and covers an area of 50 m² overlying a sand-clay substrate. The present study has the following main objectives: to identify and catalogue the ichthyofauna colonizing the Crassostrea rhizophorae farming platforms; to evaluate ecological aspects, such as the possible correlation between the physical and chemical variables for water quality and the occurrence of the ichthyofauna; and to observe the differences in the fish species found during tidal variations. Specimens were identified and quantified using the linear-transect, visual census methodology. The ichthyofauna observed comprised 3,030 individuals belonging to 28 species and 20 families. Of the 28 species found in the area studied, 14 were marine transients, 12 marine dependent, and only 2 permanent residents. A significant association was observed between the abundance of 11 species and the physical and chemical variables studied. Based on these results, it may be concluded that the platforms act as artificial reefs for the ichthyofauna, being colonized by at least 28 species, and providing protection from predators as well as a source of food and a reproductive substrate.

Abstract The purpose of the present study is to describe the juvenile fish use of the shallow zone of beaches of the Cananéia-Iguape coastal system, São Paulo, Brazil, analyzing its occurrence period and the patterns of utilization for the most abundant species. Using a beach seine monthly for one year, we sampled 13861 individuals, of 57 species and 24 families. The fish species used the study area for different proposes: Atherinella brasiliensis was sampled in all phases of gonadal development and considered as resident, juveniles of Trachinotus goodei used the beaches for growth and juveniles of Mugil curema and Mugil liza used the beaches as a route from the ocean to the estuary. Our results showed the importance of the sandy beaches for juvenile fish, especially in spring and summer when most juveniles occur and recruit. Unfortunately, this is the period of the most intense tourist activity. As many of the species studied are commercially important, this study highlighted the necessity of coastal habitat preservation for better fishery management.

is an obligate phototroph due to the presence of a cryptomonad as an endosymbiot (Hibberd, 1977). Although the strong symbiosis between the ciliate and its host assures an autotrophic function, in general it is not commonly included as a phytoplankter. On the other hand, studies of the overall phytoplankton assemblage have shown that

This study aimed to identify the incrusting and sedentary animals associated with the hull of a tugboat active in the ports of Pernambuco and later loaned to the port of Natal, Rio Grande do Norte. Thus, areas with dense biofouling were scraped and the species then classified in terms of their bioinvasive status for the Brazilian coast. Six were native to Brazil, two were cryptogenic and 16 nonindigenous; nine of the latter were classified as established (Musculus lateralis, Sphenia fragilis, Balanus trigonus, Biflustra savartii, Botrylloides nigrum, Didemnum psammatodes, Herdmania pallida, Microscosmus exasperatus, and Symplegma rubra) and three as invasive (Mytilopsis leucophaeta, Amphibalanus reticulatus, and Striatobalanus amaryllis). The presence of M. leucophaeata, Amphibalanus eburneus and A. reticulatus on the boat's hull propitiated their introduction onto the Natal coast. The occurrence of a great number of tunicate species in Natal reflected the port area's benthic diversity and facilitated the inclusion of two bivalves - Musculus lateralis and Sphenia fragilis - found in their siphons and in the interstices between colonies or individuals, respectively. The results show the role of biofouling on boat hulls in the introduction of nonindigenous species and that the port of Recife acts as a source of some species.