Relationship between space distribution of the benthic macroinvertebrates community and trophic state in a Neotropical reservoir (Itupararanga, Brazil)

The purpose of this work was to verify the benthic macroinvertebrates community responses through environmental factors along a headwater tropical reservoir. Samplings were taken with a Van-Veen grab along the reservoir in littoral and profundal regions and in the headwater, next to the dam and the middle of the reservoir. Samples were taken during both wet and dry seasons. Dissolved oxygen concentrations, electric conductivity, temperature and pH near the sediment have been performed in situ, at every sampling station by using a multiprobe and Secchi disc. Total water phosphorus and chlorophyll a concentrations were analyzed to determine the trophic state index. Sediment's organic matter, total phosphorus, nitrogen concentrations and granulometric composition were measured. In order to verify which environmental variables would have more influence over the benthic macroinvertebrates community, a canonical correspondence analysis (CCA) was performed. The total number of recorded taxa was 28. Among them, the family Chironomidae (Diptera) was the richest group (19 taxa). It can be proposed that the benthic macroinvertebrates community may be influenced by environmental conditions such as nutrient and organic matter availability, as well as dissolved oxygen concentration. Macroinvertebrates are adequate bioindicators of water quality due to their sensibility to environmental changes mentioned before. Chironomus sp, Limnodrilus hoffmeisteri and Branchiura sowerbyi comprises a group that can be considered bio-indicators of eutrophic conditions. A second group can be considered as indicator of mesotrophic conditions. The presence of two or more members from that group which comprises Tanytarsini spp, Fissimentum sp, Pelomus sp and Goeldichironomus sp, like predominant taxa, may indicates mesotrophic conditions.

Macroalgal composition and its association with local hydrodynamics in the Laje de Santos Marine State Park, southwestern Atlantic, São Paulo, Brazil

The Laje de Santos Marine State Park (LSMSP), located in southeastern Brazil, is the only marine park in São Paulo State. This conservation unit has been established as a protected area of high biological diversity. Despite its importance for the conservation of the marine biota, little is known about the park's seaweed flora. The objectives of this study were as follows: to furnish increased knowledge of the composition of the macroalgae in the Park area; to relate the area's macroalgal composition to the presence of an important water mass in the region, the South Atlantic Central Water (SACW); and to investigate the possible influence of the Port of Santos on the composition of the macroalgae of the LSMSP. This study registered 31 new records for the LSMSP, 11 for São Paulo State, four for Brazil, one for the western Atlantic and one for the South Atlantic Ocean, in addition to the possible occurrence of one new species of Osmundea (Rhodomelaceae) and one new genus belonging to Ceramiaceae. The taxonomic composition of the macroalgae had a direct correlation with the arrival of the SACW in the summer-fall season. The SACW generated a strong thermocline and increased the supply of nutrients in the water column. Hydrodynamic and dispersion modeling analyses suggested that the Port of Santos influenced the composition of the LSMSP phycoflora.

A new species of Hydrogamasellus (Acari: Mesostigmata: Ologamasidae) from Brazil, with a key to the world species of the genus

Hydrogamasellus alagoensis n. sp. is described based on the morphology of adult females and males collected from litter in the State of Alagoas, Brazil. Six new combinations are proposed, namely Acugamasus avium (Karg, 1976) n. comb., Ologamasus lanceolatus (Karg, 1976) n. comb., Ologamasus microcrinis (Karg, 1979) n. comb., Ologamasus testudinis (Karg, 1976) n. comb., Rykellus longopilus (Karg, 1976) n. comb. and Rykellus ubatubaensis (Hirschmann, 1966) n. comb., and a key for the separation of females of the eighteen recognizable world Hydrogamasellus species is provided.

Population biology of the barbel drum Ctenosciaena gracilicirrhus (Metzelaar, 1919) (Perciformes: Sciaenidae) in Caraguatatuba Bay, Southeastern Brazil

This study evaluated the population biology of Ctenosciaena gracilicirrhus (Perciformes: Sciaenidae) in a shallow non-estuarine coastal area of southeastern Brazil. Monthly samples were taken from October 2003 through October 2004, in two distinct areas at depths from 1 to 4 m. C. gracilicirrhus was generally among the most abundant fish species during the period. Its density was significantly higher in a single sampling month, May 2004, in the South area, which may be explained by its migratory behavior together with its preference for deeper areas. Such behavior may lead to bias in community estimates that use few or only seasonal samples. C. gracilicirrhus individuals ranged from 4.0 to 10.2 cm long, with a main mode from 7.5 to 9.0 cm and a significant decrease in mean size from June onward. The estimation of body growth parameters was compromised by this population feature. Similarly, the prey spectrum was difficult to determine because of the deteriorated condition of the stomach contents, although crustaceans were clearly the most important items ingested. Amphipoda was the only subgroup that could be identified more precisely, mainly by the construction of their tubes.

Systematics of interstitial encrusting bryozoans from southeastern Brazil

This paper describes 22 species of marine bryozoans found in the sand-grain-encrusting interstitial epifauna of the northeast coast of São Paulo state, Brazil: one new cyclostome, Disporella calcitrapa sp. nov., and 21 cheilostomes. Sixteen of the cheilostomes are new species, and three represent new genera. They are Ammatophora arenacea sp. nov., Discoporella gemmulifera sp. nov., Puellina caraguata sp. nov., Puellina tuba sp. nov., Rosulapelta rosetta gen. et sp. nov., Collarina spicata sp. nov., Hippothoa calcicola sp. nov., Trypostega ilhabelae sp. nov., Reptadeonella granulosa sp. nov., Drepanophora irregularis sp. nov., Allotherenia sabulosa gen. et sp. nov., Bryopesanser tilbrooki sp. nov., Psammocleidochasma tridentatum gen. et sp. nov., Celleporina abstrusa sp. nov., Hippoporella castellana sp. nov., and Hippoporella sabulonis sp. nov. Other species found in this habitat, Alderina smitti, Cymulopora uniserialis, Vibracellina laxibasis, Akatopora leucocypha, and Smittipora sawayai, have previously been described. The family Cymuloporidae fam. nov. is erected for Cymulopora and Crepis. The occurrence in this habitat of living colonies of bryozoans more characteristic of larger subtidal shell substrata indicates the potential importance of an interstitial refuge in maintaining and dispersing encrusting bryozoan populations along continental shelves where larger substrata are absent or rare.

Distribución espacial de metales pesados y As en sedimentos superficiales de fondo del estuario del Río de la Plata

Los sedimentos estuarinos actúan como sumidero dediversos tipos de contaminantes, por lo que son utilizados como indicadores del impacto antropogénico. Entre estos aportes, los metales se destacan debido a que pueden generar efectos tóxicos y/o letales para la biota. Además son bioacumulables y se biomagnifican a través de la trama trófica acuática. El estuario del Río de la Plata (RdlP) constituye un área de desove y cría de peces y otros organismos de interés comercial, por lo que resulta relevante conocer la contaminación metálica. El RdlP tiene una superficie de 38.800 km2 y un caudal promedio de 24.045 m3s-1, siendo sus principales afluente los Ríos Paraná y Uruguay. El presente estudio analizó muestras de sedimento superficial de fondo, colectado en 26 sitios (año 2010). Se cuantificó el contenido de Al, As, Cd, Cr, Cu, Fe, Ni, Pb, Sc y Zn, a través del método USEPA 3050b y la técnica analítica ICP-OES. La exactitud y la precisión del método fueron evaluadas por material de referencia certificado. La granulometría del sedimento estudiado indicó la predominancia de sedimentos finos (limos y arcillas), en sitios con mayores contenidos metálicos. Las concentraciones obtenidas se compararon con los valores guía del Criteria for the Assessment of Sediment Quality in Quebec and Application Frameworks (de Canadá), utilizados como criterio de evaluación para legislación ambiental: TEL (threshold effect level) y PEL (probable effect level); además se utilizaron los niveles REL (rare effect level), OEL (occasional effect level) y FEL (frequent effect level). La concentración de As y Cu fue mayor al nivel TEL en varios sitios analizados (7,2 y 19 mg/kg respectivamente). Para ningún elemento la concentración fue mayor que el PEL. Este criterio de evaluación constituye una herramienta válida para el monitoreo de la contaminación de los sedimentos del estuario, indicando posibles efectos negativos sobre la biota del RdlP