Navegando por Assunto "Salinidade"

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Acesso aberto (Open Access)
Análise de processos oceanográficos no estuário do rio Pará
(Universidade Federal do Pará, 2016-11-04) ROSÁRIO, Renan Peixoto; ROLLNIC, Marcelo; http://lattes.cnpq.br/6585442266149471
This thesis investigated physical oceanographic processes in the Pará River estuary, focusing on saline intrusion and hydrodynamic process. The choice of this topic arose from the motivation to consolidate the understanding of hydrodynamic and hydrographic issues in the Pará River estuary since this region of the Amazon Coastal Zone still a challenge to researchers. The first step was to define the methods and parameter to get better data in time and space difference. In this context, direct observations were conducted in the estuary in two moments, the low and high river discharge, using velocity, salinity profile (longitudinal and vertical), and temperature profile. Furthermore, in an unprecedented way, it was conducted over a year and ten months salinity and water level (tide) monitoring at strategic points of the estuary. The main conclusions of this research obtained from this data set was the identification of salt water intrusion in the estuary of the Pará River, entering about 100 km from the mouth. The sensitivity of salinity intrusion is affected by river discharge (seasonal variability), and tide energy (daily variability). The Stokes drift generated by tidal propagation in the estuary was the responsible for the net salt flux landward. The innermost portion of the estuary (more than 60 km from the mouth) does not show gravitational circulation and the estuary salt transport above is performed entirely by turbulent diffusion; and the outer portion of the resulting stream reverts to the depth and advective and diffusive processes are important to contribute to the salt transport in the estuary.
Acesso aberto (Open Access)
Analysis of fish assemblages in sectors along a salinity gradient based on species, families and functional groups
(2013-12) PASSOS, Ana Carolina dos; CONTENTE, Riguel Feltrin; ABBATEPAULO, Felippe Veneziani; SPACH, Henry Louis; VILA, Ciro Colodetti; JOYEUX, Jean Christophe; CARTAGENA, Beatriz Fernanda Chinchilla; FÁVARO, Luis Fernando
Here we test the effects of the east-west salinity gradient in the subtropical Paranaguá Bay Estuarine Complex (PEC) on the structure of shallow water fish fauna, determined according to taxonomic (families and species) and functional composition metrics. A total of 152 species were observed. The families with the largest number of species were the Sciaenidae, Carangidae, Haemulidae and Gobiidae. The most abundant species were Atherinella brasiliensis, Harengula clupeola, Anchoa januaria and Anchoa tricolor. Marine stragglers dominated in number of species, followed by marine migrants and estuarine species. Most species were zoobenthivores, followed by piscivores and zooplanktivores. Families and species more frequently associated with estuarine conditions dominated in the mesohaline sector, and those more frequently associated with marine conditions dominated in the euhaline sector. The fish assemblages along the estuarine salinity gradient were found to be better characterized by taxonomic metrics than by functional ones. This is most likely because individuals of all functional groups inhabit all salinity sectors, and thus these metrics are not useful for differentiating assemblages along salinity gradients. Our results differ from those of other studies in tropical and subtropical estuaries, which have emphasized the importance of functional groups in determining fish assemblages along salinity gradients.
Acesso aberto (Open Access)
Efeito da salinidade e da frequência alimentar durante a larvicultura dos ornamentais amazônicos acará bandeira Pterophyllum scalare (SCHULTZE, 1823) e acará severo Heros severus (HECKEL, 1840)
(Universidade Federal do Pará, 2016-07-21) EIRAS, Bruno José Corecha Fernandes; VERAS, Galileu Crovatto; http://lattes.cnpq.br/4497651649653210; COSTA, Rauquírio André Albuquerque Marinho da; http://lattes.cnpq.br/4504677939464624
With the study aimed to evaluate the effect of salinity and feeding frequency on growth, uniformity and survival of the angelfish Pterophyllum scalare and banded cichlid post-larvae. Were conducted two experiments in a completely randomized in a factorial 5 x 2, with five different sodium chloride concentrations (0; 2; 4; 6 and 8 g L-1) and two feed frequency (2 and 4 times per day). It was observed the water salinity and feeding frequency influenced significantly (p < 0,05) in torso length and body height in the angelfish larviculture. The eye diameter, was affected (p < 0,05) only by salinity, while the final standard length, standard length gain, head length, torso length, post-anal length, head height, body height, final weight, weight gain, specific growth rate and allometric condition factor differed significantly (p < 0,05) only for the feeding frequency. In the banded cichlid larviculture, there was a significant difference (p < 0,05) in the head length, post-anal length, head height and allometric condition factor by salinity and feeding frequency. The water salinity influenced significantly (p < 0,05) the final standard length, standard length gain, torso length, eye diameter, body height, survival hate and uniformity in weight. The feeding frequency influenced significantly (p < 0,05) the final weight, weight gain and specific growth rate. It was concluded that angelfish post-larvae can be grown with salinity up to 4 g L-1 without problems for the development and survival. On the other hand, the banded cichlid post-larvae had better survival hate in water without salt add. The feeding frequency of four times a day with artemia nauplii is the most recommended for the both species.
Acesso aberto (Open Access)
O efeito da salinidade no desenvolvimento larval do caranguejo-uçá, Ucides cordatus (Linnaeus, 1763) (Decapoda: Ocypodidae) no Norte do Brasil
(Instituto Nacional de Pesquisas da Amazônia, 2008) SIMITH, Darlan de Jesus de Brito; DIELE, Karen
The present work studied the effect of salinity on the survival and duration of larval development of the mangrove crab, Ucides cordatus (from the Caeté River estuary, North of Brazil) until the megalopal phase in seven salinity treatments (0, 5, 10, 15, 20, 25 e 30). Salinity significantly affected the survival of the zoea larvae, however it did not affect the duration of the larval development (20.77 ± 1.56 days). In salinity 0, 5 and 10 all zoea larvae died. Only from off salinity 15, complete development until the megalopal phase occurred. The survival rate was highest in salinity 30 (72%) and lowest in 15 (16%). The reduced survival rate of the U. cordatus zoea larvae, in low salinities, indicates the necessity of larval dispersion from the estuary to coastal waters, where salinity conditions for larval development are more favorable. Otherwise, if there was no dispersion, the reduced salinity of estuarine waters in the rainy season would cause a high mortality thereby affecting the recruitment, maintenance and growth of the U. cordatus population in the mangroves.
Acesso aberto (Open Access)
Estudo dos cátions cálcio, magnésio, sódio, potássio e da salinidade na água intersticial do sedimento do manguezal de Bragança - NE do Pará
(Universidade Federal do Pará, 2000-08-01) COSTA, Marlene Furtado da; RAMOS, José Francisco da Fonseca; http://lattes.cnpq.br/8189651755374537
Acesso aberto (Open Access)
Identificação e caracterização das massas d´água da Plataforma Continental do Maranhão, durante os períodos seco (Novembro, 1997) e chuvoso (Junho 1999)
(Universidade Federal do Pará, 2007-10-26) PONTES, Paulo Henrique Parente; KAMPEL, Milton; http://lattes.cnpq.br/0063119667740811; EL-ROBRINI, Maâmar; http://lattes.cnpq.br/5707365981163429; https://orcid.org/0000-0001-7850-1217
The Maranhão Continental Shelf (MCS) between the mouths of Gurupi and Parnaíba rivers is 203 km wide on the occidental coast and 72 km from Tubarão Bay toward southeast. The Maranhão coast is distinct: there are Maranhenses Reentrances in the Northwest; the dunes coast in the eastern side, being separated by the Golfão Maranhense, where the Mearim river, whose discharge is about 770 m3/s, discharges its fresh water. Other small rivers like Gurupi, Maracaçumé, Turiaçu, Itapecuru and Parnaíba discharge fresh water on the shore. The parameters of temperature, salinity and density were used to identify and characterize the water masses during dry season (november, 1997) and rainy season (june, 1999) in order to study seasonal variability of the local water masses. Images of Sea SurfaceTemperature (SST) obtained from Advanced Very High Resolution Radiometer (AVHRR) from NOAA satellites were used to observe its variation and verify some oceanographic features. The time series of monthly averages of images from AVHRR Pathfinder of SST with 4 km resolution (from 1985 to 2001), obtained from Instituto Nacional de Pesquisas Espaciais (INPE), was used to study the temporal and spatial SST variability through the calculation of climatological mean and its monthly SST changes in three points of the MCS to see if there are substantial changes in the features of the MCS waters during El-Niño/La-Niña seasons, since those phenomena can provoke (or not) great changes in the superficial water masses and in the local circulation. During the dry season (1997), it was observed that only Tropical Water, which is a water mass occurred, proving that at this season the continental water does not act on the MCS. However, during rainy season (1999) there were Coastal Water, Mixture Water, Tropical Water and South Atlantic Central Water. The Coastal Water is a water mass that comes from the rivers that discharge in the MCS. Mixture Water is a mixture of oceanic and continental water. So the presence of these two masses in the MCS proves that continental water occurred in the field of study during that period. The MCS water masses have the following physical characteristics: (i) Tropical Water: salinity over 36, temperature between 26,6° and 28,7°C and density between 23 kg/m³ and 23,8 kg/m³, which during the dry season occurs since the surface until more than 60 m of depth, while during rainy season it only occurs 40 km from the coast, from the surface until deeper 60 m; (ii) Coastal Water: salinity under 33, temperature between 28° and 29,4°C and density between 19 kg/m³ and 21,4 kg/m³, it occurs along 10km from the coast being also found from the surface until 28 m; (iii) Mixture Water: has salinity values between 33 and 36, temperature between 25,8º and 28,75ºC and density between 21,8 kg/m3 and 23,8 kg/m3 , and can be observed until 60 km from the coast along surface until 60 m; (iv) South Atlantic Central Water has salinity between 35,6 and 36, temperature under 18ºC and density between 23,9 kg/m3 and 25,8 kg/m3 that can be found 31 km from the coast and over 50 m depth. In the MCS, the AVHRR/NOAA images has shown low variation the SST field over the MCS. In November, 1997 maximum SST variation was 2,5ºC (minimum of 27°C and maximum of 29,5ºC) almost the same data obtained in situ where the maximum of SST was 28,6°C and minimum of 27,1°C. In the images of june, 1999, the oscillation of this parameter was between 27° and 29°C, similar to the data obtained during the ocean cruse of the same year that were of 27,4°C (minimum) and 29,2ºC (maximum). The graphics of SST anomaly in three different geographical sites of the MCS show a slight SST anomaly oscillation during the 1997/98 El-Niño event. The SST anomaly is higher in the MCS during 1998, which is between this work’s oceanographic expeditions. Therefore there was no significant influence of this phenomenon on the water masses of the MCS temperature characteristics during the data acquisition period. The occurrence of different water masses in the MCS region is related mainly to the seasonality on the area of study, which presents larger estuarine influence during the rainy season and little or no influence during the dry period, as can be confirmed through the predominance of oceanic waters (Tropical Waters) during the dry period and the presence of coastal waters and mixture water in the rainy season, determining clearer water stratification.