O (in)imaginável elefante mal-ajambrado: a questão de limites entre o Ceará e o Rio Grande do Norte e o exame da formação espacial e identitária norte-rio-grandense na Primeira República

This study s main goal is to analyze the way the limits between Ceará and Rio Grande do Norte states, the so called Grossos matter, has been associated to the norte-rio-grandense spacial and identity formation during the first republic period. Thus, a consistet number of sources: RN and CE old newspapers, as well as a república from Natal and Fortaleza and o mossoroense ; historical drafts from the historical and geographical institute associated and historical, gographical and anthropological institute of Ceará; the Ação Cível Originária de nº 6 from the supreme federal tribunal and many other cartographies. The documents haven t been hierarchized, neither accepted as proof effects, but understood as the base matter for this text composition by the deconstruction of the analyzed discusses. In order to do that the ablação or bricolagem method, without quotations marks or long quotations themselves, has been used. Along the three analyzed charpters: the two phases the litigious was found, since its beginning yet in the XVIII century until 1888 and its return within the republic proclamation, in the 1920 resolution; the development of the documental, historical and identity dispute between IHGA-CE and IHG-RN; and, at last, the political game existing between the Albuquerque Maranhão oligarchy , Manuel Pereira Reis and Rui Barbosa, explaining the intentions, silent and miths built along the time by these intellectual participations

analise da dispersao de ondas de superficie na provincia borborema, Nordeste do Brasil

The Borborema Province, Northeastern Brazil, had its internal structure investigated by different geophysical methods like gravity, magnetics and seismics. Additionally, many geological studies were also carried out to define the structural domains of this province. Despite the plethora of studies, there are still many important open aspects about its evolution. Here, we study the velocity structure of S-wave in the crust using dispersion of surface waves. The dispersion of surface waves allows an estimate of the average thickness of the crust across the region between the stations. The inversion of the velocity structure was carried out using the inter-station dispersion of surface waves of Rayleigh and Love types. The teleseismic events are mainly from the edges of the South and North American plates. The period of data collection occurred between 2007 and 2010 and we selected 7 events with magnitude above 5.0 MW and up to 40 km depth. The difference between the events back-azimuths and the interstation path was not greater than 10. We also know the depth of the Moho, results from Receiver Functions (Novo Barbosa, 2008), and use those as constrains in inversion. Even using different parameterizations of models for the inversion, our results were very similar the mean profiles velocity structure of S-wave. In pairs of stations located in the Cear´a Central Domain Borborema the province, there are ranges of depths for which the velocities of S are very close. Most of the results in the profile near the Moho complicate their interpretation at that depth, coinciding with the geology of the region, where there are many shear zones. In particular, the profile that have the route Potiguar Bacia in inter-station, had low velocities in the crust. We combine these results to the results of gravimetry and magnetometry (Oliveira, 2008) and receptor function (Novo Barbosa, 2008). We finally, the first results on the behavior of the velocity structure of S-wave with depth in the Province Borborema

Avaliação do efeito da adição de resíduo de borracha de pneu e brita calcária na formulação de compósitos cimentíceos

Researches have shown that the introduction of rubber in concrete improves the features of its deformability, as well as contributes to environmental disposal of waste generated in the tire retreading process. Furthermore, there is a high availability of limestone within RN and CE country. Ignorance about this stone, does not allow its wide use as aggregate, leaving, this abundant supply idle. A composite of limestone gravel, with proportions of tire rubber waste which could be used as concrete would be an alternative to concrete for low applications. Therefore, this research aims to evaluate the characteristics of concrete containing limestone gravel and proportions of little aggregate replacement (sand) by tire rubber waste. To this goal, the material components of the concrete were characterized, concrete specimens with limestone gravel were made, from the dash 1.0: 2.5: 3.5, varying the water/cement ratio, and inserting a commercial plasticizer, without a proportion of residue, known as reference. From this, concrete with and without the presence of the additive in the same proportions were chosen, as well as these with the use of granite gravel, for being the most used. Selected the references, to these, replacements of little aggregate (sand) were added replaced by rubber waste from the tire retreading process, treated with 1M NaOH in proportions from 5.0 to 20.0 % by mass, cured and exposed to the semiarid environment. The results indicate the possibility of using limestone gravel in the concrete composition with workability correction using plasticizer. There was a decrease in the mechanical properties of the concrete with increments of waste rubber, but there is an improvement in toughness and deformability of the composite, which makes it interesting for the construction of non-structural concrete floors, as well as, the rubber waste delayed the hardening process, continuing to gain resistance after 28 days

Estruturas tectônicas cenozóicas na porção leste da Bacia Potiguar - RN

This thesis encompasses the integration of geological, geophysical, and seismological data in the east part of the Potiguar basin, northeastern Brazil. The northeastern region is located in South American passive margin, which exhibits important areas that present neotectonic activity. The definition of the chronology of events, geometry of structures generated by these events, and definition of which structures have been reactivated is a necessary task in the region. The aims of this thesis are the following: (1) to identify the geometry and kinematics of neotectonic faults in the east part of the Potiguar basin; (2) to date the tectonic events related to these structures and related them to paleoseismicity in the region; (3) to present evolutional models that could explain evolution of Neogene structures; (4) and to investigate the origin of the reactivation process, mainly the type of related structure associated with faulting. The main type of data used comprised structural field data, well and resistivity data, remote sensing imagery, chronology of sediments, morphotectonic analysis, x-ray analysis, seismological and aeromagnetic data. Paleostress analysis indicates that at least two tectonic stress fields occurred in the study area: NSoriented compression and EW-oriented extension from the late Campanian to the early Miocene and EW-oriented compression and NS-oriented extension from the early Miocene to the Holocene. These stress fields reactivated NE-SW- and NW-SE-trending faults. Both set of faults exhibit right-lateral strike-slip kinematics, associated with a minor normal component. It was possible to determine the en echelon geometry of the Samambaia fault, which is ~63 km long, 13 km deep, presents NE-SW trend and strong dip to NW. Sedimentfilled faults in granite rocks yielded Optically Stimulated Luminescence (OSL) and Single-Aliquot Regeneration (SAR) ages at 8.000 - 9.000, 11.000 - 15.000, 16.000 - 24.000, 37.000 - 45.500, 53.609 - 67.959 e 83.000 - 84.000 yr BP. The analysis of the ductile fabric in the João Câmara area indicate that the regional foliation is NE-SW-oriented (032o - 042o), which coincides with the orientation of the epicenters and Si-rich veins. The collective evidence points to reactivation of preexisting structures. Paleoseismological data suggest paleoseismic activity much higher than the one indicated by the short historical and instrumental record

Estudo geológico e geofísico da falha de carnaubais, Bacia Potiguar-RN, e implicações neotectônicas

The segment of Carnaubais Fault located in the southeasthern portion of Guamaré Graben (Potiguar Basin) was studied. Several structures were detected and some of them strongly suggest that the last movements in Carnaubais Fault are of Neotectonic age. The study comprises an integrated interpretation of geologic, geomorphologic and geophysical data (gravimetry, magnetometry, resistivity, and self potential methods). According to the size of the studied areas, two approaches were used in this research. The first approach is of a regional nature and was conducted in an area, hereafter named Regional Area, having approximately 6,000 km2 and localized in the northern portion of Rio Grande do Norte state, around Macau city. The second approach comprises detailled studies of two small areas inside the Regional Area: the Camurupim and São Bento areas. Gravimetric and topographic data were used in the Regional Area. A separation into regional and residual components were conducted both on gravimetric and topographic data. The interpretation of the residual component of the gravimetric data allows a precise mapping of the borders of the Guamaré Graben. The regional component features of the topographic data are controlled by the pair of conjugate faults composed by the Carnaubais Fault (NE direction) and the Afonso Bezerra Fault (NW direction). On the other hand, the residual component of the topographic data shows that river valleis of NW direction are sharply interrupted where they intersect Carnaubais Fault. This fact is interpreted as an evidency that the last significant moviments occured in the Carnaubais Fault. Geologic, geomorphologic and geophysical data (magnetometry, resistivity, and self potential methods) were used in the Camurupim Area. The geologic mapping allows to identify five lithophacies unities. The first two unities (from base to top) were interpreted as composing a marine (or transitional) depositional sequency while the other were interpreted is composing a continental depositional sequence. The two sequences are clearly separated of an erosional discordance. The unities grouped in the marine sequence are composed by calcarenites (Unity A) and mudstones (Unity B). Unity A was deposited in a shalow plataform while Unity B, in a tidal flat. The unities grouped in the continental sequence are composed of conglomerate (Unity C) and sandstones (Unities D and E). Unities C and D are fluvial deposits while unity E is an eolian deposit. Unities A and B can be stratigraphycally correlated with Guamaré Formation. Unities C and D present three possible correlations. They may be correlated with Tibau Formation; or with Barreiras Formation; or with a clastic sediment deposit, commonly found in some rivers of Rio Grande do Norte state, and statigraphycally positioned above Barreiras Formation. Based on the decrease of the grain sizes from base to top both on unities C and D, it is proposed that these unities are correlated with the clastic sediment above mentioned. In this case, these unities would have, at least, Pleistocenic age. Finally, it is proposed that Unity E represent an eolian deposit that sufferred recent changes (at least in the Quaternary). The integrated interpretation of hydrographic, morphologic and geophysical data from Camurupim Area shows that Carnaubais Fault is locally composed by a system of several paralel subvertical faults. The fault presenting the larger vertical slip controls the valley of Camurupim river and separates the area in two blocks; in the nothern block the top of the Jandaira limestone is deeper than in the southern block. In addition, at least one of the faults in the northern block is cutting the whole sedimentary section. Because unities C , D, and/or E may be of Quaternary age, tectonic moviments possibly occured in Carnaubais Fault during this period. Detailled geologic mapping were conducted in beachrocks found in São Bento Area. This area is located at the intersection of the coast line with the Carnaubais Fault. The detected structures in the beachrocks are very similar to those caused by fragile deformations. The structures mapped in the beachrocks are consistent with a stress field with maximun compressional stress in E-W direction and extensional stress in the N-S direction. Since the Carnaubais Fault has a NE direction, it is optimally positioned to suffer tectonic movements under the action of such stress field. In addition, the shape of the coastal line appear to be controlled by the Carnaubais Fault. Furthemore, the observed structures in Camurupim Área are consistent with this stress field. These facts are interpreted as evidences that Carnaubais Fault and beachrocks suffered coupled tectonic movements. These moviments are of Neotectonic age because the beachrocks present ages less than 16,000 years

Pirometamorfismo provocado por intrusões básicas cenozoicas em rochas da Bacia Potiguar, RN: integração de dados geológicos e petrofísicos

The Potiguar Basin is located in the Brazilian Equatorial Margin and presents sedimentary rocks affected by Cenozoic basic igneous intrusions, known as Macau Magmatism. The most prominent effect related to these intrusions is the formation of buchites, pyrometamorphic rocks that occur at very high temperatures and very low pressures in the sanidinite metamorphic facies. Through literature review, field observations, petrographic and petrophysical data, accessing the database of previous studies and results from this research, it was possible to characterize and estimate the effects produced in the thermal aureole of some hypabyssal bodies in the basin. The most relevant features associated with the intrusions are: compactation, hydraulic fracturing, partial melting and recrystallization of country rocks. According to the observed mineral occurrences, temperature of 800 to 1200 °C and pressure below 0,5 kbar were estimated at the contacts of the igneous bodies. The thermal modeling of the São João plug indicates thermal effects extending up to 150 m away from the contact and cooling time of approximately 265,000 years. After the peak of temperature, followed a cooling phase registered by remobilization and precipitation of minerals at low-temperature in faults, fractures and geodes, interpreted as derived from reactions with sedimentary rocks and metasomatic / hydrothermal fluids with abundant carbonatization and silicification.

Pirometamorfismo provocado por intrusões básicas cenozoicas em rochas da Bacia Potiguar, RN: integração de dados geológicos e petrofísicos

The Potiguar Basin is located in the Brazilian Equatorial Margin and presents sedimentary rocks affected by Cenozoic basic igneous intrusions, known as Macau Magmatism. The most prominent effect related to these intrusions is the formation of buchites, pyrometamorphic rocks that occur at very high temperatures and very low pressures in the sanidinite metamorphic facies. Through literature review, field observations, petrographic and petrophysical data, accessing the database of previous studies and results from this research, it was possible to characterize and estimate the effects produced in the thermal aureole of some hypabyssal bodies in the basin. The most relevant features associated with the intrusions are: compactation, hydraulic fracturing, partial melting and recrystallization of country rocks. According to the observed mineral occurrences, temperature of 800 to 1200 °C and pressure below 0,5 kbar were estimated at the contacts of the igneous bodies. The thermal modeling of the São João plug indicates thermal effects extending up to 150 m away from the contact and cooling time of approximately 265,000 years. After the peak of temperature, followed a cooling phase registered by remobilization and precipitation of minerals at low-temperature in faults, fractures and geodes, interpreted as derived from reactions with sedimentary rocks and metasomatic / hydrothermal fluids with abundant carbonatization and silicification.

As cidades medias no desenvolvimento regional: um estudo sobre Pau dos Ferros (RN)

Esta tese versa sobre as cidades médias no atual contexto do desenvolvimento urbano brasileiro e nordestino. Na região Nordeste, o processo de urbanização foi lento, atomizado, geográfico e economicamente disperso, o que resultou numa rede urbana truncada, constituída principalmente por suas nove capitais regionais e cerca de duas dezenas de cidades de porte médio, em sua maioria, interiorizadas. Foi a partir dessa rede urbana nordestina interiorizada que nos propomos a estudar Pau dos Ferros, no Rio Grande do Norte e o papel que ela desempenha na rede urbana nordestina e potiguar. Compreender os determinantes da produção do espaço urbano-regional de Pau dos Ferros que o caracterizam como cidade média, com fins a refletir sobre o seu papel no desenvolvimento regional foi o objetivo geral desta pesquisa. Nossa hipótese é que, a despeito de um contingente populacional pequeno, Pau dos Ferros vem desempenhando na rede urbana do Nordeste e do Rio Grande do Norte as funções de cidade média, particularmente, na oferta dos serviços de educação superior e saúde, além da oferta de empregos, notadamente no comércio e nos serviços públicos, o que nos permitiu tratá-la à priori, a partir do conceito de cidade (inter) média. Para esta investigação, partimos da proposta de estudo e do pensamento de autores como Faria (1978), Benko (1999) e Brandão (2007), os quais propõem o estudo do urbano a partir de situações concretas que permitam compreender os fenomenos em sua múltiplas causalidades. Dessa forma, o fio condutor desta análise foi o modo como vem se reconfigurando as cidades médias e como essa reconfiguração tem afetado de diferentes formas as relações entre as cidades e entre as cidades e as regiões. Os resultados das análises apontaram que os investimentos públicos em saúde e educação têm contribuído para a atração de investimentos privados em suas respectivas áreas, e também em outras, o que tem ajudado a dinamizar a economia da cidade, inclusive modificado parcialmente sua estrutura ocupacional. Pau dos Ferros se destacou como um polo comercial e de serviços na rede urbana potiguar, formando um outlier no Alto Oeste, organizando uma bacia de empregos na sua área de influência que constatamos ser composta por 55 municípios do RN, CE e PB. Ao se consolidar como polo regional na oferta dos serviços de saúde e de educação superior, ampliou-se o fluxo de pessoas que realizam movimento pendular para trabalho e estudo. Em síntese, constatou-se que, a despeito do pequeno contingente populacional, a configuração urbano-regional de Pau dos Ferros, tanto em termos de sua dinâmica urbana, como de sua abrangência regional, fazem dela uma cidade média na rede urbana nordestina interiorizada

Estudos in silico da proteína AlkB e prospecção de bactérias alcanotróficas em solos da bacia petrolífera potiguar

Some microorganisms from virgin ecosystems are able to use petroleum it as source of carbon and energy. The knowledge of microbial biodiversity can help to reveal new metabolic systems for utilization alkanes with biotechnological importance. The aim of this study is: i) Accomplish an in silico study of the AlkB protein aimed to understand the probable mechanism involved on selectivity of alkanes in Gram positive and Gram negative bactéria. ii) prospect and analyze the response of the microbial alkanotrophics communities in soil and mangrove sediments of BPP RN and soil of Atlantic forest in the Horto Dois Irmãos Reserve area/PE using the molecular biomarker, gene alkB; with the PCR and PCR-DGGE approach

Pirometamorfismo em calcários da formação Jandaíra, bacia potiguar, nordeste do Brasil

The present study aims the characterization of thermally affected carbonate rocks from Jandaíra Formation in contact with Paleogene and Neogene basic intrusions in the region of the Pedro Avelino and Jandaíra municipalities (RN), northeastern Brazil. For this study, field, petrographic, x-ray diffraction, electron microprobe, and whole rock litogeochemistry data of carbonates were undertaken. The thermally unaffected limestones are classified like wackstones, grainstones and packstones. They may constitute carbonates grains of benthic foraminifera, echinoderm spines, ostracods, algae, corals, bivalves, gastropods, peloids and intraclasts. The porosities are classified like vug, intraparticle, interparticle, intercrystal and moldic types. The major minerals are calcite, ankerite and dolomite; the detrital are montmorillonite, pyrite, limonite, quartz and microcline. The thermally affected limestones are very coarse to very fine-grained and light to dark gray color. The fossiliferous components totally disappear, and the porosity tends to disappear. With the data obtained, it can be inferred that the carbonate protoliths would be calciferous to dolomitic limestones, both with small amount of clay minerals. Crystalline carbonates from dolomitic protolith have rhombohedral calcite and iron oxides / hydroxides, making the rocks much darker. The carbonates from calciferous protolith have a wide variation of grain size according to the recrystallization degree, increasing toward contact with the basic bodies. In this group, it was identified the minerals lizardite and spinel in weakly to moderately affected samples, and spinel and spurrite in strongly affected rocks, as well as calcite, that occur everywhere. The geological context (shallow level diabase intrusions), the crystallization of the pyrometamorphic minerals spurrite and olivine, and comparison with diagrams from the literature allow estimating temperatures and pressures around 1050-1200 °C and 0.5-1.0 kbar, respectively, for PTOTAL=PCO2. The post-intrusion cooling would have afforded the releasing of metasomatic / hydrothermal fluids, allowing the opening of the metamorphic system, with possible contribution of chemical elements from host units (sandstones, shales) and from basic intrusions. This would induce hydration of previous phases, allowing the formation of serpentine, chlorite and brucite. The results discussed here reveal the strong influence of the heat from basic intrusions within the sedimentary pile. Whereas in the offshore portion of the basin occur sills with up to 1000 m thickness, the understanding of pyrometamorphism might be useful for understanding and measuring the thermally affected rocks.

Pirometamorfismo em calcários da formação Jandaíra, bacia potiguar, nordeste do Brasil

The present study aims the characterization of thermally affected carbonate rocks from Jandaíra Formation in contact with Paleogene and Neogene basic intrusions in the region of the Pedro Avelino and Jandaíra municipalities (RN), northeastern Brazil. For this study, field, petrographic, x-ray diffraction, electron microprobe, and whole rock litogeochemistry data of carbonates were undertaken. The thermally unaffected limestones are classified like wackstones, grainstones and packstones. They may constitute carbonates grains of benthic foraminifera, echinoderm spines, ostracods, algae, corals, bivalves, gastropods, peloids and intraclasts. The porosities are classified like vug, intraparticle, interparticle, intercrystal and moldic types. The major minerals are calcite, ankerite and dolomite; the detrital are montmorillonite, pyrite, limonite, quartz and microcline. The thermally affected limestones are very coarse to very fine-grained and light to dark gray color. The fossiliferous components totally disappear, and the porosity tends to disappear. With the data obtained, it can be inferred that the carbonate protoliths would be calciferous to dolomitic limestones, both with small amount of clay minerals. Crystalline carbonates from dolomitic protolith have rhombohedral calcite and iron oxides / hydroxides, making the rocks much darker. The carbonates from calciferous protolith have a wide variation of grain size according to the recrystallization degree, increasing toward contact with the basic bodies. In this group, it was identified the minerals lizardite and spinel in weakly to moderately affected samples, and spinel and spurrite in strongly affected rocks, as well as calcite, that occur everywhere. The geological context (shallow level diabase intrusions), the crystallization of the pyrometamorphic minerals spurrite and olivine, and comparison with diagrams from the literature allow estimating temperatures and pressures around 1050-1200 °C and 0.5-1.0 kbar, respectively, for PTOTAL=PCO2. The post-intrusion cooling would have afforded the releasing of metasomatic / hydrothermal fluids, allowing the opening of the metamorphic system, with possible contribution of chemical elements from host units (sandstones, shales) and from basic intrusions. This would induce hydration of previous phases, allowing the formation of serpentine, chlorite and brucite. The results discussed here reveal the strong influence of the heat from basic intrusions within the sedimentary pile. Whereas in the offshore portion of the basin occur sills with up to 1000 m thickness, the understanding of pyrometamorphism might be useful for understanding and measuring the thermally affected rocks.

Dinâmica da série nitrogenada nas águas da bacia hidrográfica Apodi/Mossoró - RN - Brasil

A bacia hidrográfica Apodi/Mossoró é um dos mais importantes recursos hídricos do Rio Grande do Norte. Estudos recentes mostraram que os compostos nitrogenados destacam-se entre os principais contaminantes deste corpo aquático, mostrando a necessidade de relacioná-los com outras propriedades físico-químicas que influenciam na dinâmica das suas formas. Deste modo, este trabalho tem por objetivo correlacionar as concentrações de NO3-, NO2- e NH3 com os valores de pH, T, Eh e OD nas águas desta bacia. Os resultados indicam o predomínio de um meio fortemente oxidante, destacando o NO3- como a principal forma de nitrogênio presente, mesmo nos locais onde foram observadas reduções significativas de Eh e OD. Este trabalho busca contribuir para o desenvolvimento de medidas de controle e manejo das fontes poluidoras e o melhor gerenciamento deste recurso hídrico.

Filhos da independência: etnografando os estudantes bissau-guineenses do PEC-G em Fortaleza-CE e Natal-RN

Notre travail propose de comprendre l`immigration africaine contemporaine du Brésil à travers l'univers des étudiants guinéens participant au Programme Étudiants « Convênio de Graduação » (PEC-G) dans les villes de Fortaleza dans l'Etat Ceará et Natal dans l'Etat de Rio Grande do Norte, en étudiant leurs stratégies de convivialité et d'adaptation. Les étudiants étrangers sélectionnés dans ce programme font leur licence gratuitement dans les Instituts d'Enseignement Supérieur (IES). Pour accéder à ce programme ils doivent répondre à certains critères : montrer qu'ils sont en mesure de payer leurs frais au Brésil, avoir le bac ou un diplôme équivalent et maîtriser la langue portugaise lorsqu'ils sont originaires d'un pays n'appartenant pas à la Communauté de Pays de Langue Portugaise (CPLP). Les étudiants qui participent à des programmes de développement socio-économique contractés entre le Brésil et leurs pays d'origine sont prioritaires. Ces accords les contraignent à rentrer dans leurs pays d'origine et de travailler dans le domaine dans lequel ils ont été diplômés une fois les études terminées. Les étudiants, qui arrivent au Brésil porteurs de leurs identités ethniques guinéennes, entrent en contact avec la société brésilienne et acquièrent ainsi une « identité hybride ». C'est dans ce contexte que ce travail analyse le quotidien des étudiants africaines au Brésil avec un regard porté sur les étudiants de Guinée-Bissau à Fortaleza et à Natal comprendre l'expérience des étudiants qui vivent en terre étrangère. Ainsi, le lieu (Brésil) prend toute sa valeur par rapport au distant (Guinée) autrefois lié par l'histoire coloniale et aujourd'hui lié par des relations internationales ou diplomatiques. Finalement, la construction d'une « nouvelle » identité ethnique, d'une culture guinéenne au Brésil s'opère dans une célébration mobile c'est-à-dire successivement formée et transformée en relation avec les formes à travers lesquelles l'individu est représenté ou interpelé dans les systèmes culturels dans lesquels il est impliqué.

Eutrofização e capacidade de carga de fósforo de seis reservatórios a bacia do Rio Seridó, região semi-árida do Estado do RN

The eutrofization is a natural process of accumulation of nutrients in aquatic´s body that it has been accelerated for the human´s actives, mainly the related with the activities of camp, industrial and the inadequate disposition of the domestic sewage. The enrichment of the aquatic´s body with nutrients, mainly the nitrogen and the phosphorus, and the consequent proliferation of algae and Cyanobacteria can commit the quality of the water for the public provisioning, for the fish farming and for other ends. The problem becomes more critical when there is a shortage of water naturally as in the semi-arid area of the Brazilian northeast. Before that problem this work had as objective evaluates the trophic state of six reservoirs of the basin of River Seridó of Rio Grande of Norte and also estimate the capacity of load of match of the reservoir and risk probabilities based on the established limits by the resolution Conama 357/05. The results demonstrate that the six reservoirs are eutrofization, with concentration of total phosphorus and cloro a in the water upster to 50 e 12 μg l-1. The results show that space homogeneity exists in the state trophic of the reservoirs, but a significant variation interanual in function of the increase of the concentrations of nutrients and decrease of the transparency of the water with the reduction of the body of water accumulated in the reservoirs.The results of the simulation risk estocastic show that the reservoirs could receive annually from 72 to 216 Kg of P, assuming a risk of 10% of increasing in more than 30 μg l-1 the annual medium concentrations of total match in the water of these reservoirs. This load could be high in until 360 kg of P a year in case the managers assume a risk of 10% of increasing in more than 50 μg l-1 the annual medium concentrations of total phosphorus in the waters of these reservoirs

Diversidade Ictiofaunística e Ecologia reprodutiva de uma espécie nativa de peixe da Bacia Piranhas-Assu, RN

The Caatinga biome is rich in endemic fish species fauna. The present study the results of fish faunal surveys conducted in the hydrographic basin of Piranhas-Assu of the Brazilian Caatinga biome. The fish samples collected were distributed in four orders (Characiformes, Perciformes, Siluriformes and Synbranchiformes), 11 families (Characidae, Curimatidae, Auchenipteridae, Anostomidae, Prochilodontidae, Erythrinidae, Cichlidae, Sciaenidae, Heptapteridae, Loricariidae, Synbranchidae) and 22 species, of which 17 are endemic and five have been introduced from other basins. The order Characiformes was the most representative in number of species (46,35% ) followed by Perciformes (35,38%), Siluriformes (17,44%) and Synbranchiformes (0,5%). The Nile tilapia, Oreochomis niloticus, the only exotic species, was most expressive in number of individuals (24.92%) followed by the native species piau preto, Leporinus piau (18,77 %). Considering the relative frequency of occurrence of the 22 species, 13 were constant, five were accessory and four were occasional. This study investigated the reproductive ecology of an endemic fish black piau, Leporinus piau from the Marechal Dutra reservoir, Acari, Rio Grande do Norte. Samplings were done on a monthly basis from January to December 2009, and a total of 211 specimens were captured. The environmental parameters such as rainfall, temperature, pH, electrical conductivity and dissolved oxygen of water were recorded. The sampled population showed a slight predominance of males (55%), however females were larger and heavier. Both sexes of L. piau showed positive allometric growth, indicating a higher increase of weight than length. The first sexual maturation of males occurred at smaller size, with 16.5 cm in total length than females (20.5 cm). During the reproductive period, the condition factor and gonadosomatic index (GSI) of L. piau were negatively correlated. This species has large oocytes with a high mean fecundity of 54.966 with synchronous oocyte development and total spawning