926 resultados para southeastern bay
SEASONAL DYNAMICS OF MACROALGAL COMMUNITIES IN THE PRETO RIVER BASIN, SAO-PAULO, SOUTHEASTERN BRAZIL
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Macroalgal seasonality was analyzed in nine stream segments of the Preto River basin: five of these were sampled monthly for one year and four bimonthly during two years. Seasonal variation of macroalgae was correlated with stream variables (temperature, current velocity, specific conductance, turbidity, surface light, pH and oxygen). Multiple linear regression was applied to evaluate the macroalgal seasonal variability determined by a combination of temperature, current velocity and turbidity, the most influential environmental parameters on macroalgal seasonality. Most species revealed a clear seasonal trend, such that late fall through early spring was the period with highest macroalgal abundance in most sites. Temperature, current velocity and turbidity account for 24 to 83 % of macroalgal species number variation and 24 to 79 % of macroalgal abundance in the basin. The results suggest that the seasonal flow determined by the precipitation regime associated with turbidity and temperature were the major factors influencing the seasonal dynamics of macroalgal communities. The highest values of macroalgal species number and abundance were found under cooler temperatures, lower current velocities and lower values of turbidity.
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Aluminum numbered bands have been used to mark Brazilian hummingbirds since 1993 to obtain biological data as well as ascertain movements and longevities. Bands should be made as narrow as possible by cutting close to the numbers because of the short length of the hummingbird tarsus. Different band lengths should be determined for different species.
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For many vector-borne organisms, dogs can be used as sentinels to estimate the risk of human infection. The objective of this study was to use dogs as sentinels for multiple vector-borne organisms in order to evaluate the potential for human infection with these agents in southeastern Brazil. Blood from 198 sick dogs with clinicopathological abnormalities consistent with tick-borne infections were selected at the São Paulo State University Veterinary Teaching Hospital in Botucatu and tested for DNA and/or antibodies against specific vector-borne pathogens. At least one organism was detected in 88% of the dogs, and Ehrlichia canis DNA was amplified from 78% of the blood samples. Bartonella spp. seroreactivity was found in 3.6%. Leishmania chagasi antibodies were detected in 1% of the dogs. There was no serological or polymerase chain reaction evidence of infection with Anaplasma phagocytophilum, Borrelia burgdorferi, Ehrlichia chaffeensis, Ehrlichia ewingii, and Rickettsia rickettsii. The full E. canis 16S rRNA gene sequence of one of the Brazilian strains obtained in this study was identical to the causative agent of human ehrlichiosis in Venezuela. Ehrlichia canis may pose a human health hazard and may be undiagnosed in southeastern Brazil, whereas exposure to the other organisms examined in this study is presumably infrequent.
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A new species of leptodactylid frog is described from the Serra das Cabras in São Paulo, southeastern Brazil. The new species is a member of the Hylodes lateristrigatus group and is characterized by its small size and high number of notes per call. Descriptions of the tadpole and advertisement call and information on natural history are provided.
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A new species of leptodactylid frog, Physalaemus atlanticus, is described from Ubatuba, northern coast of São Paulo in southeastern Brazil. The new species belongs to the Physalaemus signifer species group and is characterized by the following set of characters: small size (males 20.1-22.1 mm SVL, females 21.0-23.9 mm SVL); canthus rostralis distinct; dorsal skin texture smooth to slightly rugose; belly orange in life; advertisement call with duration of 0.6-0.84 s and frequency between 0.9-1.8 kHz. Descriptions of the advertisement call and tadpole are provided, as well as information on natural history.
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The reproductive phenology of the entire climber community (96 species of lianas and 40 species of vines) in a semideciduous forest in Southeastern Brazil (22 degrees 49'45''S; 47 degrees 06'33''W and 670 m altitude) was observed from March 1988 to February 1991. Phenological observations were made weekly by walking along a 10.5 km trail in the interior and at the forest edges of the Santa Genebra Reserve (SGR). The most species-rich families of climbers were Bignoniaceae (22), Malpighiaceae (17), Sapindaceae (12) and Asteraceae (12). Flowering patterns for woody lianas and herbaceous vines differed. Lianas had two flowering peaks: a minor peak in March in the transition from wet to dry season, and a major peak in October during the transition from dry to wet season. The flowering peak for herbaceous vines was in April. Fruiting of lianas was highly seasonal, with one peak in the late dry season (July-August). Fruiting for vines was less seasonal with a slight peak in March. These differences were consistent with the predominance of wind-dispersed fruits among lianas (72% of species) versus vines (52%). Low rainfall, high leaf fall, and strong winds during the dry season favor wind dispersal. More species of vines (40%) have animal-dispersed seeds than lianas (19%), and most vines fruited during the wet season. Phenological patterns of climbers and trees and treelets at SGR differed. The life form of lianas and their system of reserve economy may allow them to reproduce during periods unfavorable to trees. Displacement of peak flowering periods of trees and climbers pollinated by bees and small generalist insects may decrease competition for pollen vectors among species of these two groups of plants. Whereas the fruiting patterns of wind-dispersed trees and climbers at SGR were similar (most species fruiting during the dry season), animal-dispersed trees and treelets fruited throughout the year while animal-dispersed climbers exhibited a pronounced peak in late wet season. The distinct phenological patterns of climbers, generally complementary to those presented by trees, resulted in constant availability of Bowers and fruits throughout the year and enhances the importance of this plant group in Neotropical forests.
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This work aims to analyse the composition, abundance and distribution of the Penaeidea species which occur in the Ubatuba Bay (23 degrees 26'S and 45 degrees 02'W). The samples were monthly collected from October/1992 to September/1993. Each collect was composed of two parallel radials: the first (radial ''A'') was carried out in the mid region of the bay and the second one (radial ''B'') in the bay mouth. The trawls took one hour in a boat equipped with one otter-trawl (10 mm of mesh). The registered environmental factors were depth, bottom water temperature, granulometric composition and organic content of the sediment. After the trawls, the shrimp were separated from other marine organisms and counted. Eight species of shrimp were obtained: Xiphopenaeus kroyeri; Artemesia longinaris; Penaeus (L.) schmitti; P. (F.) brasiliensis; Trachypenaeus; constrictus; Sicyonia typica; S. dorsalis and Pleoticus muelleri. The most abundant species were X. kroyeri, A. longinaris, P. muelleri and T. constrictus. It was verified a very strong seasonality among the species. The X. kroyeri species occurred in both radials along the months but its abundance decreased from a November to March. Such fact is attributed to the temperature which reached a minimum value of 20 degrees C during this period. The species A. longinaris and P. muelleri were more frequent in the radial B which was caracterized by 14 +/- 1.3 m of depth, low organic content in the sediment (2.97%) and granulometric composition of medium sand. The distribution and abundance of these shrimps in the bay, beyond the hydrological features can be related to biotic factors as food availability, migration, inter and intra specific relations (competition, predation, etc.).
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A new species of hylid frog, from the genus Scinax, is described from Ilha de Porcos Pequena at the southern coast of São Paulo State, southeastern Brazil. The new species belongs to the Scinax perpusillus species group and is diagnosed by the following set of characters: moderate-size (males 16.2-18.8 turn SVL, female 18.8-20.6 mm SVL); canthus rostralis distinct and well defined; V-shaped depression between nostrils; eyes protruding and prominent, glandular skin surface of legs. This new species is found only on Ilha de Porcos Pequena, an island of approximately 24 ha and, therefore, is threatened because of restricted range size and susceptibility to habitat modification.
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A new species of treefrog, Hyla luctuosa, is described from the Serra do Japi in southeastern Brazil. The new species is a member of the Hyla circumdata group characterized by large size, large tympanum, and rounded subarticular tubercles on the fingers. Descriptions of the tadpole and advertisement call and information on natural history are provided.
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This study evaluated the presence and seasonal activity of free-living ticks in remaining marsh areas by the Parana river, in Brazil. Eight field trips (once per season) for collection of ticks were performed during 2 years. Using CO2 traps, dragging, and visual inspection of vegetation, five free-living tick species were collected, in the following order of abundance: Amblyomma cajennense, Amblyom\ma dubitatum, Amblyomma triste, Amblyomma coelebs, and Amblyomma nodosum. The seasonal pattern of A. cajennense was characterized by the highest peaks for adult ticks in the summer/spring months, for nymphs in the winter and for larvae in the autumn and winter. A. dubitatum and A. triste presented similar seasonal patterns characterized by peaks of adult ticks in the autumn. Nymphs of A. dubitatum peaked in the winter of the first year and in the winter/spring of the second year. A. triste was the only species to be collected in significantly higher numbers in the marsh than in surrounding drier areas such as forest patches. Among domestic animals living close the marsh areas, horses were infested by Anocentor nitens, A. cajennense, and Boophilus microplus, bovines were infested solely by B. microplus, and dogs were infested by Rhipicephalus sanguineus. Adults of A. triste showed to be well adapted to the marsh environment. This result, at least partially, explains local previous observations on the association of A. triste with marsh deer, as this vertebrate host inhabits mainly the marsh area. (c) 2006 Published by Elsevier B.V.
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Microfacies analysis of marine carbonates cored by Petrobras well 1-SPS-6 in the offshore Santos Basin (southeastern Brazil) has revealed a remarkable fossil assemblage of calpionellids (colomiellids), favusellids, hedbergellids, globigerinelloidids, buliminids, radiolarians, inoceramid prisms, roveacrinids, and saccocomids(?) preserved in lower Albian calcimudstones-wackestones of the lower part of the Guaruja Formation. This assemblage represents an allochtonous accumulation in a deep neritic to shallow bathyal hypoxic environment. Besides 'saccocomid-like' sections, the only determinable sections of roveacrinids are thecal plates of Poecilocrinus dispandus elongatus Peck, 1943. This species was previously only known from the Weno Formation of Texas. The Brazilian material extends its records farther south from at least the lower Albian, which then represents the earliest occurrence of this peculiar family in the South Atlantic region. Taking into account their Albian global distribution and the location of their oldest representative (Hauterivian near Alicante, Spain), the Roveacrinidae dispersed westward throughout all of Cretaceous Tethys. The Tethyan origin of Roveacrinidae is further evidence that, during late Aptian-Albian times, the northern South Atlantic (north of the Walvis-SBo Paulo Ridge) was supplied by a Tethyan water mass. (C) 2001 Elsevier B.V. Ltd. All rights reserved.
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Over the last decades, increasing water demands have fostered research to obtain high well yields in crystalline terrains where, besides the intrinsic properties of rocks, the groundwater flow depends on several factors. The depth of the wells, the lithotypes, the presence and thickness of sedimentary coverings and weathered layers, the landforms, the geological structures, and the effects of tectonic stresses are among the most investigated factors considered as determinant of well productivity. The influence of these factors on productivity of wells that exploit the Crystalline Aquifer System in the Jundiai-River Catchment, southeastern Brazil, is investigated in this work. The largest region of the studied area is located on the Precambrian Basement, partially covered by sedimentary deposits. The results show that the sedimentary deposits and the weathered layer are important for high well yield, but it also depends on the existence of a net of open fractures, in order to maintain high productivity. The sites that have more possibility of occurrence of such structures are the regional shear and fault zones and other minor structures with NW-SE and E-W directions, which characterize areas subjected to transtensional stress related to the neotectonics.
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Microhabitat distribution was investigated in three populations of C. coeruleus to determine the distributional patterns and their controlling factors, as well as morphometric adaptations to varying conditions on a scale of a few centimetres. Morphometric variations and their relations with physical variables (current velocity, irradiance, depth and type of substratum) revealed some particular characteristics for each population and indicate particular adaptations. However, some trends were clear: 1) larger plants (length and/or diameter) produced a higher quantity of monosporangia in the three populations; 2) plant length and diameter were positively correlated in two populations; 3) plant diameter was positively correlated with current velocity in two populations; 4) higher percent cover was associated with substrata composed of macrophytes in two populations. C. coeruleus occurred under relatively wide microhabitat conditions and had high niche width values, suggesting a tolerance to considerable variation in physical variables. These characteristics contribute to the species' wide distribution in Brazilian streams, both spatial (at distinct scales) and seasonal. (C) ADAC / Elsevier, Paris.