Potengi River Research Articles

First record of Perkinsus marinus infecting Crassostrea sp. in Rio Grande do Norte, Brazil, using real-time PCR

A pathogen with high virulence potential in some host species, Perkinsus marinus remains a challenge for the ecological integrity of marine ecosystems and the health of bivalve molluscs. This study investigates the occurrence of P. marinus in Crassostrea sp. in estuaries of the Potengi River and the Guaraíras lagoon in Rio Grande do Norte, Brazil. A total of 203 oyster samples that tested positive for Perkinsus sp. in Ray's fluid thioglycollate medium (RFTM) were subjected to species-specific quantitiative PCR, where 61 animals (30.05 %) presented amplification graphs with a melting temperature of 80.1 ± 0.6 °C matching the positive control. This was the first record of P. marinus in oysters in these estuaries using qPCR as a diagnostic tool.

O ESTUÁRIO DO RIO POTENGI, PASSADO E PRESENTE: CARTA DE ZONEAMENTO ARQUEOLÓGICO SUBAQUÁTICO DO SÉCULO XVII

This article is the result of the final course work entitled “In the waters of the Potengi River: Underwater Archaeological Zoning Chart (17th century)” presented to the undergraduate course in History at the Federal University of Rio Grande do Norte. The Potengi River, also known in the 16th and 17th centuries as Pottiou, Rio Grande, Puttigi, Potiji, among others, was already known as a favorable space for navigation, as evidenced by cartographies, iconography and accounts of french, portuguese and dutch travelers from the century 16th and 17th. Using an interdisciplinary approach between History and Archaeology, this article aims to present the areas of underwater archaeological potential in the Potengi River estuary from the 17th century, taking into account the disturbances of the archaeological context over the years, finally presenting the archaeological zoning chart of the area, an important tool for the management of the municipal underwater archaeological heritage.

THE ESTUARY OF THE POTENGI RIVER, PAST AND PRESENT: LETTER OF ARCHAEOLOGICAL ZONING OF THE SEVENTEENTH CENTURY

This article is the result of the final course work entitled “In the waters of the Potengi River: Underwater Archaeological Zoning Chart (17th century)” presented to the undergraduate course in History at the Federal University of Rio Grande do Norte. The Potengi River, also known in the 16th and 17th centuries as Pottiou, Rio Grande, Puttigi, Potiji, among others, was already known as a favorable space for navigation, as evidenced by cartographies, iconography and accounts of french, portuguese and dutch travelers from the century 16th and 17th. Using an interdisciplinary approach between History and Archaeology, this article aims to present the areas of underwater archaeological potential in the Potengi River estuary from the 17th century, taking into account the disturbances of the archaeological context over the years, finally presenting the archaeological zoning chart of the area, an important tool for the management of the municipal underwater archaeological heritage.

Environmental changes recorded in the Holocene sedimentary infill of a tropical estuary

Early-to late Holocene sedimentary infill of the Potengi-Jundiai Estuary (Brazil) was studied in a 31.5 m long sediment core. The borehole was drilled in a mangrove area within the central part of the flood tide delta. The sedimentary record, encompassing the last 10 kyr, was studied for sediment texture and for the n-alkanes composition of organic matter (OM). Sediments rich in OM and bivalve shells accumulated during the period of sea-level rise, mostly in an intertidal environment of mangrove forest, mudflat and subtidal estuarine flood delta. The characterization of n-alkanes (C10-C33) and lignin methoxyphenols by means of direct analytical pyrolysis (Py-GC/MS) technique allowed determining the sources of the extant OM. Downcore fluctuations were observed in n-alkanes and in several n-alkane based indices, such as long chain carbon preference index (CPI C24-C33), long to short chain ratio (L/S) and average chain length (ACL), as well as in the relative proportion of lignin derived compounds. The n-alkanes distribution points to changing sources of OM input to the estuarine sediments over most of the Holocene period. Major inputs of terrestrial vegetation alternated with periods of mixed input from aquatic macrophytes as the rate of sea-level rise changed over time. The n-alkanes distribution and the lignin markers were useful for reconstructing paleoenvironmental conditions, particularly during the early Holocene when the lower Potengi River valley (now an estuarine area) could accommodate terrestrial forest vegetation before switching to halophytic mangroves as sea levels rose.

SEDIMENT CHARACTERISTICS AND FORAMINIFERAL ASSEMBLAGES IN THE NEARSHORE BENTHOS AT PONTA NEGRA, RN, BRAZIL

This study examined sediments and foraminiferal assemblages on the inner continental shelf adjacent to Ponta Negra Beach, an important tourist destination in northeast Brazil. Eighteen sediment samples were collected in October 2013, nine each at depths of 5 m and 10 m. The predominance of sandy textures (64–99%), the very limited amounts of organic matter ( 2 concentrations, indicate that hydrodynamics, including waves and currents, are major influences on the sedimentary environment. Foraminiferal species richness was very low; only 11 species were identified in the most species-rich sample and the median for the 18 samples was 5 species. The dominant species were Ammonia tepida, Quinqueloculina angulata , Q. atlantica, Textularia gramen, Bolivina translucens and Pseudononion atlanticum , which are common nearshore shelf taxa. At the 5 m stations, A. tepida and Q. angulata dominated, while at the 10 m stations, T. gramen dominated. Principal Components Analysis revealed four major factors: sand, depth, % gravel and % silt and clay; % gravel correlated positively with % carbonate and % total organic matter in the sediments. Cluster analysis of the foraminiferal data produced two distinct groups corresponding to the 5 m and 10 m stations. In a multidimensional-scaling plot, each group spread along a linear trend from low to higher % carbonate, with slightly higher organic matter in the 10 m samples. Ammonia tepida , an opportunistic and hypoxia-tolerant species, was most dominant near the outlet of the heavily urbanized Potengi River.

First record of Potimirim potimirim (Müller, 1881) (Crustacea, Decapoda, Atyidae) from Rio Grande do Norte, northeastern Brazil

Potimirim potimirim (Müller, 1881), a species of coastal freshwater shrimp, is recorded for the first time from the state of Rio Grande do Norte, northeastern of Brazil, where it was collected in a small tributary of the Potengi River. This record extends the distribution of this species about 220 km north along Brazilian coast. New records, such as this, reinforce the need for greater research efforts in the northeastern freshwater ecosystems of Brazil to provide better understand the region’s biodiversity and establish better parameters for conservation actions.

Sea-level rise since 8.2ka recorded in the sediments of the Potengi–Jundiai Estuary, NE Brasil

Abstract We present the first data set on the evolution and Holocene infilling of the Potengi River Estuary at the NE Brazilian Continental Margin near the city of Natal. The study is based on integrated sedimentological, geochemical and palaeontological information from 6 boreholes drilled in the area of estuarine mangroves, complemented by radiocarbon dating of the in situ remains of mangrove vegetation. Four samples taken close to the pre-inundation substratum set the baseline of reference points for the sea-level reconstruction. This palaeoenvironmental reconstruction, coupled with a 14 C age model, complements previous sea-level studies along the Rio Grande do Norte coast, which have been based primarily on beach-rocks and other on-shore exposed sedimentary materials. A rapid sea-level rise, at an averaged rate of approximately 6.1 mm/yr − 1 , occurred between 8300 and 7000 cal. yr BP. Since then, the pace of relative sea-level rise slowed and non-eustatic factors, namely terrigenous sediment supply and coastal dynamics, became dominant in the evolution of the estuary. The post-transgression period witnessed the decline of mangroves, whose remnants were identified mostly in the initial 2 m of Holocene estuarine sediments. Accelerated sea-level rise, combined with geomorphological confinement of the studied intertidal zone, was probably responsible for the demise of halophyte vegetation, which thrived again in the late Holocene.

O rio Potengi e a cidade do Natal em cinco tempos históricos. Aproximações e distanciamentos

A cidade do Natal, capital do Rio Grande do Norte, nasceu e se desenvolveu “à sombra” de um Rio, o Potengi. Em sua história de mais de quatrocentos anos, a cidade ora se aproxima, ora se distancia do rio, num movimento que não é somente físico, mas também social e simbólico. Este trabalho propõe a análise dessa relação segundo cinco períodos históricos - aqui chamados de “Tempos” – que expressam, em termos de predominância, esse movimento de certa maneira contraditório de aproximação e distanciamento entre cidade e rio ou entre rio e cidade. São eles: Tempo 1. O rio como aliado da cidade nascente (1599-1614); Tempo 2. O comércio, o rio e a cidade (1700-1900); Tempo 3. O rio como obstáculo para a cidade (1850-1916); Tempo 4. A aviação. Aproximando o rio à cidade (1920-1945); Tempo 5. O rio “invisível” para a cidade (desde 1945). Sem qualquer pretensão de completude – afinal, são mais de quatro séculos de história - o trabalho destaca, contudo, expressões pontuais de processos históricos bem mais longos envolvendo a relação entre a cidade do Natal e o Rio Potengi.

Resíduos sólidos em manguezal no rio Potengi (Natal, RN, Brasil): relação com a localização e usos

Mangroves are one of the most important ecosystems on Earth; however, its potential is affected by intense human activities and urban sprawl. The increase of the populations in localities near the coast has been pressing this and other natural biological systems. One of the main impacts on mangroves is solid waste disposal from anthropogenic origin. Studies on the impact of solid waste in coastal regions are quite widespread and well known, but are generally made with a focus on the beaches or in the marine environment, while research on mangroves are quite scarce. The estuary of Potengi river (Natal-RN) has a great environmental and socio-economic importance; in its mangroves, about 1,200 families survive by collecting crustacean and shellfish. According to local studies, the estuary is affected by intense changes that occurred during the last century, mainly due to disorderly growth of Natal city. The objective of this work was to carry out an assessment of solid waste pollution in two mangrove areas associated with the estuary of the Potengi River, establishing its relationship with the

SELECTION, ISOLATION AND GROWTH KINETIC STUDY OF A BACTERIAL CONSORTIUM OBTAINED FROM THE POTENGI MANGROVE IN THE PRESENCE OF CRUDE OIL

The selection, isolation and kinetic study of a bacterial consortium obtained from a sample of soil from the Potengi mangrove, located in the city of Natal, Rio Grande do Norte, Brazil, has been carried out using the enrichment culture technique to observe aspects such as the evaluation of main growth parameters. The kinetic study used a rotary incubator shaker at 150rpm, under 30°C. The bacterial consortium isolated from the estuary of the Potengi River showed a good acclimation in minimum mineral medium with 1% (v/v) of oil. The cell concentration reached 2.55 g/L at 16h of cultivation and surface tension dropped. The maximum productivity in cells obtained was of 0.3 g/L.h, the specific velocity of growth was of 0.075h -1 , with a generation time (tg) of 9.24h. This study seeks to demonstrate that the consortium can be used as inoculants in biological treatments, capable of reducing the waste’s degradation time.

Foraminíferos bentônicos e atividade bacteriana como ferramenta para análise ambiental no Estuário do Rio Pontegi, Rio Grande do Norte, Brasil

The aim of this study was to identify possible zonation patterns and assess the environmental impact on the Potengi River Estuary, Rio Grande do Norte State, through the distribution of benthic foraminifera associated to bacterial activity and abiotic parameters. Six sediment samples were collected from locations that presented clear signs of pollution. The environment was predominantly anaerobic and fermentation occurred at all sites. Forty-two species of foraminifera were identified. The dominant species were Ammonia tepida and Arenoparrella mexicana, which are known to be opportunistic, and able to adapt to rapidly changing conditions. CCA analyses showed that salinity and organic matter, followed by bacterial carbon, were more strongly linked to organism distribution in the Potengi River Estuary. Dissolved oxygen concentration, temperature and total organic matter were higher at the estuary mouth than at the other sites, creating favorable conditions for foraminiferal growth and allowing the faunistic succession on the upper estuary. As foraminifera assemblages when associated to environmental parameters can be used as efficient proxies for environmental diagnosis, these results suggest that the Potengi Estuary is under great stress from the surrounding urban development.

Aspectos da biologia pesqueira em fêmeas de Cathrops spixii do estuário do rio Potengi, Natal/RN, com ênfase nos índices biométricos

This study describes the analysis of bimestral mean variations of repletion index, replection mean grade and condition factor of 445 females of Cathrops spixii , from Potengi river, Natal/RN, Brazil, captured between March, 1997 and February, 1998. The liver weight variation found is related to the transference of the energetic reserve necessary to the vitellogenesis process. The gonadosomatic index is a good indicative of the reproduction period. The condition factor, the repletion index and repletion mean grade indicate the time when fish are in their best feeding condition

Estruturas rasas de gás em sedimentos no estuário Potengi (nordeste do Brasil)

Áreas com acumulações e escape de gás foram identificadas no estuário Potengi. As várias ocorrências de gás foram classificadas em quatro tipos, de acordo com suas assinaturas sísmicas específicas: (1) blankets ou coberturas acústicas, (2) cortinas acústicas, (3) colunas acústicas e (4) turbidez acústica. Ao mesmo tempo, dois tipos diferentes de escape de gás foram identificados: (1) plumas acústicas e (2) pockmarks . A atividade neotectônica na porção fluvial do sistema Potengi pode ser um dos responsáveis pela migração de gases provenientes das sismofácies localizadas abaixo do atual nível do rio, onde é possível reconhecer a conexão com o nível da fonte do gás, através da assinatura sísmica do tipo coluna acústica. Conclui-se que a fácies sedimentar é provavelmente o fator determinante da acumulação e escape de gás, como também do tipo específico de acumulação ou escape em cada local.

Concentration, stock and transport rate of heavy metals in a tropical red mangrove, Natal, Brazil

This paper discusses distribution, dynamics and mass budget of heavy metals in a red mangrove forest of the Potengi River estuary, northern Brazil. Tidal hydrology, net primary productivity, decomposing rate of leaf and standing stock of leaf litter in a red mangrove forest were taken into consideration. The belowground roots represented the main mass budget of Fe, Zn and Pb (419.73 mol ha − 1 , 2.29 mol ha − 1 and 0.72 mol ha − 1 ). Differently, Al (683.05 mol ha − 1 ) was mostly present in aerial roots, Cd (1.33 mol ha − 1 ) in the branches and Ni in the trunks (4.43 mol ha − 1 ). Cr showed no significant difference among the structures of Rhizophora mangle (from 0.02 μmol ha − 1 to 0.96 mol ha − 1 ). The average litter fall value was 12.3 t ha − 1 year − 1 whereas the leaves contributed with 9.5 t ha − 1 year − 1 (78%), the reproductive parts with 1.4 t ha − 1 year − 1 (11%) and the branches with 1.4 t ha − 1 year − 1 (11%). The annual average transfer rates of heavy metals from the tree canopy to the sediment through leaf fall were: 0.56, 1.11, 0.01, 0.02 and 0.07 mol ha − 1 for Fe, Al, Pb, Zn and Ni respectively. Cu, Cr and Cd fluxes were less than 0.02 mol ha − 1 . An experiment on yellow leaf decomposition was carried out for different periods: 1, 2, 3, 7, 30, 60 and 90 days. The leaves in the litter bags lost 50% of their dry weight in 30 days. The rate of mass loss was faster in the first 7 days when the leaves lost 21.02% of their initial mass. Concentrations of heavy metals in the decomposing leaves showed a sharp rise from the beginning up to 90 days. However, since the residence time of leaves in the sediments was only 15 days, the leaf litter exported from the mangrove forest is still relatively low in metal concentrations. Considering that 7% of leaf fall (0.7 t ha − 1 year − 1 ) is exported to the marginal marine system, the average export of heavy metals through leaf litter is: 0.36, 0.02, 0.004, 0.01, 0.001, 0.005, 0.03 and 0.74 μmol ha − 1 year − 1 for Fe, Zn, Cr, Cu, Cd, Pb, Ni and Al, respectively. These data support the opinion that mangrove forest is an efficient biogeochemical barrier to the transport of heavy metals to Brazilian coastal areas.

Two new serovars of Salmonella: S. Natal and S. potengi, isolated from fluvial water in Natal, Rio Grande do Norte State, Brazil

Two new serovars of Salmonella from estuary waters of potengi river in Natal, Rio Grande do Norte, were isolated. They were named S. natal (9,12: z4, z24:-) and S. potengi (18;z: -). Both types belong to the subgenus I, or subspecies 1, thought they showed atypical behaviour (KCN +).