Navegando por Assunto "Rio Tocantins - PA"

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Aporte hídrico e de material particulado em suspensão para a Baía do Marajó: contribuições dos rios Jacaré Grande, Pará e Tocantins
(Universidade Federal do Pará, 2014-03-19) COSTA, Maurício da Silva da; ROLLNIC, Marcelo; http://lattes.cnpq.br/6585442266149471; SOUZA FILHO, Pedro Walfir Martins e; http://lattes.cnpq.br/3282736820907252
The Amazon estuary is influenced by the tide and river discharge systems variations that modify the currents and contribute with inputs of suspended particulate matter (SPM) resulting in morphological changes along the river. The quantification of these parameters provides an understanding of the rates of export and import of materials or volume and its implications in the estuarine geomorphology. The aim of this study is to evaluate the hydrodynamic, volume transport and SPM in different periods in Jacaré Grande, Pará and Tocantins rivers. Speed and current direction, tide, turbidity, volume transport and SPM data were collected over a tide cycle in the dry (2012) and rainy (2013) periods. The Pará river the exported volume in both periods, while the Tocantins river imported during the dry period and the exported in the rainy period. The Jacaré Grande river, influenced by the Amazon river, imported in the rainy season and exported in the dry period. The analysis of the volume transport methods showed a trend of export toward Amazon river and Marajó Bay in the dry season and only toward the Marajó Bay during the rainy season. SPM values were higher in the rainy season and descending from Jacaré Grande river to the Tocantins river in dry and rainy season, respectively. Turbidity followed the same trend of SPM with tide, with maximum values during the flood. SPM transportation methods showed similar values and the same direction. The Jacaré Grande river served as an exporter during the dry period and as an exporter in the dry period, the Para river as an exporter in both periods and the Tocantins river in the dry season as an importer and as an exporter during the rainy season. The system formed by the three rivers showed the same trend of export in both periods, with two exportation routes in the dry season (Amazon river and Marajó Bay), and only one exportation route in the rainy period (Marajó Bay). Annually the system exports between 5 and 7.2 million tons and possibly the Marajó Bay receives 3.7 to 5.8 million tons. The volume transported to the ocean can be much higher. SPM flows, associated with the variability of environmental conditions, molds the estuary, as seen in the mouth of the Tocantins river and Guajará Bay. Thus, it important a continuous monitoring due to the potential boating accidents, oil spills or any contamination in the region that can result in damage the enviroment.
Acesso aberto (Open Access)
Aspectos neotectônicos e ecologia da paisagem em parte da área dos municípios do NE do estado do Pará (Tucurui, Baião, Breu Branco, Goianésia, Moju e Tailândia)
(Universidade Federal do Pará, 2007-10-30) SOUZA, Francileide de Fátima Rocha; BORGES, Maurício da Silva; http://lattes.cnpq.br/1580207189205228
This work inside investigated the aspects of the landscape and geologic and geomorphological evidences of the neotectonic context in the region that understands the Tucurui Cities until Thailand (Pará). In this region the incidence of neotectonics processes was responsible for the generation of structures, sedimentary sequences, standards of draining net (Basin of the Tocantins River) and relief System. For execution of this study had been used Landsat ETM+ images for the digital processing in platform ENVI 4,0, digital Models of rise supplied by the SRTM/NASA and images of radar SAR analysis of the relief, draining and recognition of the lineaments expressives, analogical bases elaboration of cartographic bases in environment ArcGIS 9.1. The Analysis of the relief, in the investigated area, allowed to identify as genetic groups: ) Group of Degradation - Constituted of System of Mountain ranges (Mountain range of the Trucará) with flattened topos of amplitude varying between 253 and 290 meters, System of Mounts with angular topos up to 180 meters and Colinoso System with 0 amplitude varying it enters m (base level) up to 120 meters, which constitute most of the paisagística expression; b) Group of Agradação - Englobando Aluvial Plain Systems and System of Fluvial Terraces. These systems are shown with geometrias whose joints if give through the installation of discontinuities, characterizing morfoestrutural compartimentação. The integration of the data, deriving of the analysis of the relief, as well as the characterization of the anomalies of draining and the discontinuities, allowed to the recognition of "landorfms" elementary schools tectonics associates the beams of guided lineaments the E-W, NW-SE, NE-SW and N-S. The joint enters beams of neotectonics imperfections gives way to define one extensional romboedro to south of the parallel 3030"S. The romboedral structure is defined by the arrangement between beams of guided discontinuities to NW-SE, with symmetrical trend and apparent transtensive nature and guided beams of discontinuities the E-W, to the center of the area, with probable dominant component "strike-slip". This geometry is cut by to complicate structures guided to NE-SW. Three main beams of guided discontinuities the N-S affect the inquiry area, and represent "landforms" elementary schools tectonics with extensional trend. These structures had been interpreted as decurrent of the reactivation of the Cinturão Araguaia. They are organized in an anti-symmetrical structure with dominant diving for East and in the height of the meridian 49038W they seem to have strong bond with the tracing of the Tocantins River and imposes fort has controlled to the quaternary deposits. The draining net adjusts it to these standards of structural tropia readily, which answer for the presence of anomalous feições as arcs and elbows, and for the installation of standards in treliça, with strong asymmetry, some partially interpreted as treliça of imperfection. Morfogênese of the area in appraise, in that it concerns to its tectônics aspects was admitted as tied to the performance of a binary guided dextral the E-W, fruit of the dynamics established for the current phase of drift of the American South Plate for West.
Acesso aberto (Open Access)
Description of a new species of Ituglanis (Siluriformes: Trichomycteridae) from Serra dos Carajás, rio Tocantins basin
(2012-09) WOSIACKI, Wolmar Benjamin; DUTRA, Guilherme Moreira; MENDONÇA, Marina Barreira
A new species of Ituglanis is described from the rio Tocantins basin, State of Pará, Brazil. Ituglanis ina, new species, is distinguished from its congeners by the presence of a dark vertical bar over the base of the caudal-fin rays (vs. no bars over caudal-fin base); and by the presence of a middle trunk line of tiny neuromasts extending along the flank until the vertical through the dorsal fin, or near the caudal-fin base (vs. no middle trunk line of tiny neuromasts). Ituglanis ina can be further distinguished by a combination of characters related to color pattern and morphology. Comments on the relationship between Ituglanis species are presented.
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Distribuição espacial e temporal da comunidade de rotifera na usina hidrelétrica de Tucuruí-PA, Brasil
(Universidade Federal do Pará, 2015) BEZERRA, Márcia Francineli da Cunha; NAKAYAMA, Luiza; http://lattes.cnpq.br/3771896759209007; OHASHI, Otávio Mitio; http://lattes.cnpq.br/5547874183666459
Acesso aberto (Open Access)
Efeitos de fragmentação de hábitat sobre a prevalência de parasitoses intestinais em alouatta belzebul (Primates, Platyrrhini) na Amazônia Oriental
(Universidade Federal do Pará, 2002-05-17) MARTINS, Simone de Souza; FERRARI, Stephen Francis; http://lattes.cnpq.br/3447608036151352
Parasitological studies of natural populations of neotropical primates are relatively rare, and few data were available previously for the red-handed howler monkey, Alouatta belzebul. In the present study, populations of A. belzebul were sampled at five sites in the area of the reservoir of the Tucuruí hydro-electric dam in southeastem Brazilian Amazonia, corresponding to the right bank of the Rio Tocantins. Sites included continuous forest and fragments of habitat on islands varying in area from 180 to 484 hectares. A primary aim of the study was the evaluation of the effects of habitat perturbation on patterns of infestation for endoparasites. Population density was estimated at each site using standard line transect surveys of 100-108 km per site. Fecal samples were collected from six to fourteen groups at each site, with a total of 40- 46 individual samples per site (n = 212). Samples were fixed in MIF (Mercury Chromed, Iodine and Formaldehyde), and observed under a 400x optic microscope. Population density varied between 66,4 and 191,5 individuals per square kilometer. Overall, 76,4% of the samples were positive for at least one species of endoparasite, and a total of thirteen species were identified, including eight species of heiminthes and five protozoans. Individual samples contained as many as five different species of endoparasites. At a given site, the number of species identified varied between seven and twelve, and infection rates between 67,5% and 86%. No systematic pattern of parasite diversity or infection rates was found in relation to variables such as population size or density, or habitat fragmentation. Diversity and infection rates varied as much between the two continuous forest sites as among the forest fragments, and were lowest overall at the site with the lowest population density. The only exception was Trypanoxyuris minutus, a common oxyurid transmitted through direct contact, for which a strong correlation was found between infection rates and population density. Overall, little evidence was found to support the hypothesis that habitat fragmentation has a systematic effect on infestation patterns in A. belzebul, although more detailed studies will be recommend before more definitive conclusions can be drawn.
Acesso aberto (Open Access)
Genetic structure of red-handed howler monkey populations in the fragmented landscape of Eastern Brazilian Amazonia
(2010) BASTOS, Heitor Burlamaqui; GONÇALVES, Evonnildo Costa; FERRARI, Stephen Francis; SILVA, Artur Luiz da Costa da; SCHNEIDER, Maria Paula Cruz
We genotyped 15 microsatellite loci in order to evaluate the effects of habitat fragmentation, caused by flooding of the Tucuruí reservoir, on the genetic structure of Alouatta belzebul in eastern Amazonia. The analysis included two populations sampled in 1984, representing both margins of the Tocantins river, and three populations sampled 18 years later. Minimal differences in the diversity levels between present-day (Ho = 0.62-0.69 and AR = 6.07-7.21) and pre-flooding (Ho = 0.60-0.62 and AR = 6.27-6.77) populations indicated there was no significant loss of genetic variability, possibly because of successful management strategies applied during the flooding. The changes observed were limited to shifts in the composition of alleles, which presumably reflect the admixture of subpopulations during flooding. Given this, there were significant differences in the Rst values (p = 0.05) in all but one between-site comparison. Both present-day and original populations showed a deficit of heterozygotes, which suggests that this may be typical of the species, at least at a local level, perhaps because of specific ecological characteristics. The relatively large number of private alleles recorded in all populations may be a consequence of the Wahlund effect resulting from population admixture or a process of expansion rather than the loss of rare alleles through genetic drift. Additionally, the levels of genetic variability observed in this study were higher than those reported for other species of Neotropical primates, suggesting good fitness levels in these A. belzebul populations. Regular genetic monitoring of remnant populations, especially on islands, should nevertheless be an integral component of long-term management strategies.
Acesso aberto (Open Access)
Modelagem Hidrológica Estocástica Aplicada ao Rio Tocantins para a Cidade de Marabá-PA
(Universidade Federal do Pará, 2016-03) CÂMARA, Renata Kelen Cardoso; ROCHA, Edson José Paulino da; PROTÁZIO, João Marcelo Brazão; QUEIROZ, Joaquim Carlos Barbosa; RIBEIRO, Wanda Maria do Nascimento; SIQUEIRA, Ionara Santos; LIMA, Aline Maria Meiguins de
Hydrology studies show that it is possible to avoid natural disasters through the proper use of hydrological forecasts. In this work we used the Box-Jenkins Methodology (Time Series Analysis) to model the daily level of the Tocantins river in the city of Maraba - PA, in order to predict floods caused by its regular increase, an event that usually puts the resident population of risk areas in vulnerable situations. For the study, we used the daily levels of data observed in gauged stations of Maraba and Carolina and Conceição do Araguaia National Water Agency (ANA), the period of 01/12/2008 to 31/03/2011. It was evident that the adjusted model was able to capture the dynamics of time series with good prognosis for a period of seven days with a maximum absolute error of 0.08 m and with precision in forecasting over 99%. The forecasting model showed good results and can then be used as support tools for Civil Defense, assisting in the planning and preparation of preventive actions for the city of Maraba.
Acesso aberto (Open Access)
Ocorrência de ostras perlíferas no Marajó, rio Pará
(2002-03) HOHN, Helmut; COSTA, Marcondes Lima da
The occurrence of perliferous freshwater oysters in the southern region of Marajó Island, at the mouth of Amazon River, is reported. The oyster's shell presents a thick layer of conchioline. A set of 12 freshwater pearls present white to dark gray colors with nacarous luster, some with golden metallic hue; sizes from 3 to 11 mm and spheric to cylindrical (with belts) to barroc forms. At long wave UV light, two samples present strong and one presents medium blue color. Paler blue colors are shown at short wave UV light. The inner side of the shell presents pale blue colors at both, long and short wave UV light. This occurrence represents, probably, the first important region in Brazil with natural pearls, opening a perspective for freshwater pearl cultivation.
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Planta-me no pó e não tenhas de mim dó: agricultura no Grão-Pará setecentista (1730- 1822)
(Universidade Federal do Pará, 2017-12-18) BARBOSA, Carlos Eduardo Costa; NUNES, Francivaldo Alves; http://lattes.cnpq.br/4125313573133140
The eighteenth century is an important moment for agriculture in Grão-Pará, through various documentary sources, we could highlight the process of occupation of the Tocantins river gutter, a region that could be understood as the first densely populated agricultural circle under the dominion of Belém, an influence observable by the territorial organization and the rearrangement of the family units in relatively autonomous structures of production and consumption, as part of the agrarian project, which was characterized by the introduction of new productive techniques, incorporation of new lands to agriculture followed by new genera and cultivation methods. The agrarian project reflected on the various subjects that made up the rural world of Paraense throughout the 7th Century, mainly in the Tocantins River valley region due to the proximity of Belém. In this region, we observe colonist migration, miscegenation, and the dispersal process as factors that contributed to generate families with endogenous preconditions to live and produce without difficulties in the Amazonian environment, reproducing only by the work of its members. In this sense, this dispersed population will seize the possible spaces and develop agro-extractive activities. What we need to understand clearly is that colonial agriculture balances within a diverse range of influences that determine its conditions and characteristics, as well as perceive the multiple composition of the rural world. In this sense, this paper seeks to emphasize the participation of this dispersed population, contributing to an understanding of the complexity of colonial society organization and dynamism in the region of the Tocantins River Valley.
Acesso aberto (Open Access)
Polinização de Cacauí (Theobroma speciosum Willd. ex Spreng. - Sterculiaceae): implicações para conservação
(Universidade Federal do Pará, 2003-02-14) SILVA, Alessandra de Azevedo Rodrigues da; MARTINS, Marlúcia Bonifácio; http://lattes.cnpq.br/8882047165338427
Cacauhy (Theobroma speciosum) is a common tree in Amazonian Brazil whose decaying flowers attract flies. The flies utilize various parts of the plant, including the flowers, which are used for food and as breeding sites. This study is a comparison between the pollination systems of two widely separated populations of T. speciosum, each population growing in an area representing a different biodiversity conservation strategy: ex situ and in situ. Fieldwork took place between 2000 and 2002 in the "Addison O'Neil" genrnplasm collection of the Brasilian Agroforestry Research Institute's Center for Humid Tropical Research (ex situ site) and in the "Emílio Goeldr Natural History Museum's "Ferreira Penna" Research Station (in situ site). This investigation included studies of population structure and phenology of T. speciosum, field observations of insect behavior, the collection of flowers and their insect visitors, analyses of pollen load, and the identification of insects collected and those emerging in the lab from collected flowers. Both populations of cacauhy studied flowered during the driest part of the year and produced fruit during the wettest. The lack of juveniles and subadults in the ex situ (i.e., cultivated) population indicates zero population turnover and demonstrates the fragility of the system established. The inflorescences of T. speciosum are utilized by a wide variety of invertebrates. Individuals from 9 insect orders and at least two other invertebrate orders were observed visiting T. speciosum flowers. Most visitors were in the Hymenoptera, Thysanoptera, Diptera, and Coleoptera. The insect visitors were classified as opportunists, predators, and pollinators. Drosophilids were the observed to be the principal pollinators, with the possibility that some phorids also participated in pollination. The drosophilid guilds were different in the two areas and were most diverse in the in situ area. Four species were common to both areas. The loss of diversity and alteration in the composition of the guild of pollinators in the ex situ area does not seem to have effected the population of T. speciosum. Although the pollination system was greatly altered the ex situ population of T. speciosum still shows signs of viability.
Acesso aberto (Open Access)
Tocantins river as an effective barrier to gene flow in Saguinus niger populations
(2006) SOUZA, Marcelo Nazareno Vallinoto de; SILVA, Juliana Araripe Gomes da; RÊGO, Péricles Sena do; TAGLIARO, Claudia Helena; SAMPAIO, Maria Iracilda da Cunha; SCHNEIDER, Horacio
The Saguinus represent the basal genus of the Callitrichinae subfamily. Traditionally this genus is divided into three groups: Hairy, Mottled and Bare-face, however, molecular data failed to validate these groups as monophyletic units, as well as raised some subspecies to the species status. This is the case of the former subspecies Saguinus midas midas and S. midas niger, which are now considered as different species. In the present study, we sequenced a portion of the D-loop mtDNA region in populations from the East bank of the Xingu and from both banks of the Tocantins river, in order to test the effectiveness of large rivers as barriers to the gene flow in Saguinus. According to our results, the populations from the East and West banks of the Tocantins river are more divergent than true species like S. mystax and S. imperator. The Tocantins river may be acting as a barrier to gene flow, and consequently these very divergent populations may represent distinct taxonomic entities (species?).
Acesso aberto (Open Access)
Variação sazonal e espacial da estrutura de comunidades dos peixes demersais da Região de Foz dos Rios Amazonas e Tocantins - PA (0º 10'S - 2º30'N; 47º50'W - 50º30'W) - Brasil
(Universidade Federal do Pará, 1999-11-23) TORRES, Marcelo Ferreira; BARTHEM, Ronaldo Borges; http://lattes.cnpq.br/4192105831997326
The composition, abundance and frequency of the demersal fish fauna from the Amazon estuary were studied in three areas which ones were defined as circumscribed within the isobath ranges of 5-10 m, 10-20 m and 20-50 m. The main objectives of this work were to compare the diversity, abundance and distribution of demersal fish fauna in these three areas during one hydrological cycle, and evaluate the infiuence of environmental variables on the community structure. Samples were taken on board of two piramutaba fishing vessels, using a bottom trawl net, for a given seasonal survey of six 15-day trips in the dry season (March and Apri1/97) and in the rainy season (August and September/97). A number of 91 species were caught in a total of 237 samples and Sciaenidae and Ariidae were the most diverse families, represented by 25% of total species. The Ariidae' species which ocurred in the area were very abundant. The most abundant species were Macrodon ancylodon (Sciaenidae) (56,2%) and Brachyplatystoma vaillantii (Pimelodidae) (13,6%) in the rainy season, and Macrodon ancylodon (31%) and Stellifer rastrifer (15,8%) (Sciaenidae) in the dry season. In area 1 Brachyplatystoma vaillantli (Pimelodidae) and Macrodon ancylodon (Sciaenidae) were the most abundant species in both periods, and the same occurred for Macrodon ancylodon and Stellifèr rastrifer (Sciaenidae) in area 2, and for Macrodon ancylodon (Sciaenidae) and Bagre bagre (Ariidae) in area 3. The most frequent species sampled were Macrodon ancylodon (Sciaenidae) (40,9%) and Anchoa spinifer (Engraulididae) (35%) in the rainy season, and Macrodon ancylodon (Sciaenidae) (45,6%) and Anus grandicassis (Ariidae) (38,4%) in the dry season. In area 1 Brachyplatystoma vaillantii and Brachyplatystoma flavicans (Pimelodidae) were the most frequent species, considering each period; the same was observed for Macrodon ancylodon (Sciaenidae) and Bagre bagre (Ariidae) in area 2, and Macrodon ancylodon (Sciaenidae) and Anchoa spinifér (Engraulididae), in area 3. The dominant species were: Macrodon ancylodon (Sciaenidae) in the rainy season (56% of the specimens collected); and Macrodon ancylodon, Stellifér rastrifer (Sciaenidae) and Anus quadriscutis (Ariidae) in dry season, which represented 61% of fishes caught. In area 1, Brachypiatystoma vaillantii (Pimelodidae) and Macrodon ancylodon (Sciaenidae), were dominant (73%) in the rainy season, and both of them together with Anus grandicassis (Ariidae) were dominant (53%) in the dry season. area 2 only Adacrodon ancylodon (Sciaenidae) was dominant (64%) in the rainy season, and Macrodon ancylodon and Stellifer rastrifèr (Sciaenidae) were dominant (53%) in the dry season. In area 3, just one species Macrodon ancylodon (Sciaenidae) was considered dominant (70% in the rainy season and 49% in the dry season). Distribution patterns were influenced by salinity. Area 1 presented the greatest diversity and evenness as compared with the others. Area 2 presented the greatest richness, and area 3 presented the highest dominance. Three communities were identified: one characterized by species from continental waters that explore shallow areas at depths of less than 20 m; another one formed by salinity resistant species, distributed through a wide range from the estuary, mostly in the area circumscribed within the isobath range of 10-20 m; and a third one with marine species distributed in areas at depths of 10 m to 50 m.