Navegando por Assunto "Nutrientes"

Agora exibindo 1 - 8 de 8

Acesso aberto (Open Access)
Atributos químicos do solo e composição química de folhas de mangue vermelho (Rhizophora mangle L.) em um manguezal e área transicional em São João de Pirabas, Pará
(Universidade Federal do Pará, 2015) NASCIMENTO, Bruno Delano Chaves do; RUIVO, Maria de Lourdes Pinheiro; http://lattes.cnpq.br/9419564604488031
Mangroves are characteristic coastal ecosystems of tropical and subtropical regions of great social and ecological importance. At Amazon these ecosystems represent more than half of mangrove areas of Brazil (about 70%) and are renowned for their great exuberance and magnitude related to regular distribution of rainfall, high temperatures, the large tidal range (> 4m) and the supply of sediments from the rivers of this region. Changes in water characteristics and physic-chemical soil properties can cause changes in nutrient dynamics in these ecosystems. In transitional environments these characteristics are altered and may have effects on the concentration of nutrients in the ecosystem compartments. In order to differentiate these transitional environments and the actual mangrove environments for the concentration of nutrients, this study aims to determine the nutrient content in the soil, in Rhizophora mangle L. leaves and leaf litter in these two types of environments in two seasonal periods, in a mangrove of the Amazon coast. Samples were collected in the drier month (September 2011) and in the rainy month (April 2012) in the two areas and subjected to chemical analysis for the concentration of macro (Ca, Mg, Na, K, Al, S, P, N, C) and micro nutrients (Cu, Zn, Mn, Fe). We also analyzed the physico-chemical properties of the soil (Eh, pH and salinity) and the granulometry of the ground. The results show higher nutrient concentrations in the fringe mangrove soil when compared to the transition zone (mangrove x secondary forest), indicating that the Eh, which is lower in the first influenced by the proximity to the sea and the highest frequency of flooding by tides, is the main differentiating factor in the concentration of soil nutrients. The nutrients in the Rhizophora mangle L. leaves not differ significantly from one environment to another and do not follow the same pattern of soil concentration on the two areas studied, however, the leaves nutrients are more influenced by the difference of a climatic period for other. Thus, the red mangrove trees of the transition zone can maintain a concentration of nutrients similar to the fringe of the forest, and the structural difference of the woods is more related to soil particle size than the nutritional relationship, since these trees have physiological mechanisms for the maintenance and selection of nutrients, such as N which could be a limiting nutrient in these environments.
Acesso aberto (Open Access)
Caracterização hidroquímica do rio Murubira, Mosqueiro-PA.
(Universidade Federal do Pará, 2001-10-10) SANTOS, Ivanilce Costa; CORRÊA, José Augusto Martins; http://lattes.cnpq.br/6527800269860568
Acesso aberto (Open Access)
Comportamento biogeoquímico de nutrientes no estuário do Rio Bacanga, Ilha de São Luís-MA
(Universidade Federal do Pará, 1998-10-08) MELO, Odilon Teixeira de; LIMA, Waterloo Napoleão de; http://lattes.cnpq.br/1229104235556506
The Bacanga River is a sub-estuary of the São Marcos Bay and is located in the metropolitan region of São Luís. It is a region that has multiple uses (fishing, drinking water collection, domestic sewage disposal, recreation and leisure, etc.). The cycle of essential nutrients has been studied in several estuarine systems, interactions with biota (primary production), with suspended and bottom sediments, influence of river runoff, enrichment of coastal waters, fertilization by domestic sewage, constitute the main lines of research in these environments. In the Bacanga estuary, the enrichment of nitrogen and phosphorus has contributed to the eutrophication process of the estuarine zone. On the other hand, the construction of a dam downstream (Figure 2.1), reduced the inflow of coastal waters during the ebb and flow of the tide and, on the other hand, an upstream dam reduced the flow of fresh water to the mixing zone. The main objective of this work was to characterize the biogeochemical behavior of essential nutrients (C, N, P and Si), through a spatio-temporal distribution, interaction with primary production and phytoplankton biomass (chlorophyll “a”) and its relationships with some physical, physical-chemical and chemical parameters. Six field campaigns were carried out during 1997, three in the rainy season (February, April and June) and three in the dry season (August, October and December), with sampling, in each campaign, in twelve collection stations in a profile horizontal and in an extension of 12 km between upstream and downstream. A vertical profile was also carried out at collection stations number 2, 8 and 11 in order to observe the existence of stratification in the estuarine zone. In the field, temperature, conductivity and transparency were measured and water samples were collected for the different physical-chemical and chemical parameters. In the laboratory, classical titrimetric methods, ultraviolet-visible and atomic absorption spectrophotometry were used. The results showed (downstream) the following values for the chemical species: ammonium 4 to 100µM, nitrite 0.6 to 9.7µM, nitrate 1.3 to 7.3µM, urea 2.9µM, phosphate 2 to 14.5µM and silicate 19 to 89µM; and, upstream 0.3 to 3µM ammonium, 0.2 to 1.2µM nitrite, 0.8 to 2.8µM nitrite, 1 to 2µM urea, 0.15 to 1.96µM phosphate and 82 to 196µM silicate. These high values, in the downstream part of the estuarine system, show that the main source of these nutrients is domestic sewage, since the sewage discharge points are concentrated in this area of the estuary. The values found in the upstream part can be considered as natural (background) for the region. Dissolved oxygen ranged from 2 to 5.5ml/L, considering the longitudinal profile, from downstream to upstream, depending on the biogeochemical processes in which it participates. In the downstream part, the values are low (1.9 to 3ml/L) due to weak turbulence and low primary production. On the contrary, in the downstream part, the greater turbulence and the influence of the coastal waters richer in oxygen, justifies those higher values (above 4ml/L). Hydrogen sulfide gas was determined only in the months of April and October and ranged from 1 to 3.4mg/L, also in the longitudinal profile. Primary production showed maximum values (26 to 138mgC/m3/h) in August and considering three depth levels (1, 50 and 100%) of the euphotic zone and chlorophyll “a” from 10 to 44mg/m3 in the longitudinal profile. . This high primary production in this zone of the estuarine system can be explained by several factors, such as low turbulence, the availability of nutrients and sunlight that month. The major ions (Na+, K+, Ca2+, Mg2+ and SO42-) showed the following values: sodium from 12 to 9400mg/L, potassium from 2.6 to 340mg/L, calcium from 10 to 360mg/L, magnesium from 15 to 1143mg/L and sulfate from 5.8 to 2375mg/L, considering the variation between the months of April and October, which correspond to the dry and rainy seasons. The salinity ranged from 0 to 32%, the temperature from 24.5 to 31.3°C, both in the longitudinal profile. This shows that the spring waters are cold and of zero salinity. The vertical profiles showed that there is a thermal, haline and chemical stratification (dissolved gases: oxygen and hydrogen sulphide) that can lead to bottom waters and a deficiency or absence of oxygen. This oxygen deficiency can be induced by thermohaline stratification and by the decomposition of organic matter of natural (mangrove and river runoff) and anthropogenic (domestic sewage) origin. Conservative behavior was evidenced for salinity, temperature, conductivity and major ions and non-conservative for essential nutrients (N, P and Si). Fertilization of Bacanga's estuarine waters occurs mainly through domestic sewage, allowing the environment to present high rates of primary production. However, excessive fertilization can lead to anoxia of the water column with possible death of fish and animals.
Acesso aberto (Open Access)
Dinâmica de nutrientes e da matéria orgânica no manguezal do Igarapé Nunca Mais - Ilha de São Luís (MA)
(Universidade Federal do Pará, 2002-11-22) MELO, Odilon Teixeira de; LIMA, Waterloo Napoleão de; http://lattes.cnpq.br/1229104235556506
It is well known that the State of Maranhão has more than fourty percent of the Brazilian mangroves covering an área with almost 4800km2 and along of 640km of coastline. These mangrove swamps border a number of tidal channels, bays, gulfs, and others estuarine systems, where the macro-tidal system gives a singular condition to this environment, that it is different from the others Brazilian áreas. The exportation of macro-particles from the mangroves to the coastal waters is well known. However, there is a discussion if the mangroves import or export micro-particles and dissolved nutrients to the coastal areas. Few studies have been developed in this subject due to the methodological complexities of the flow calculations. The choice of the pilot-area for this study is the igarapé Nunca Mais, a tidal channel surrounded by an area of 1.22km2 of mangrove ecosystem, situated in the Northeastern portion of the São Luís Island. This choice is due bay the fact that in this area occurs exchanges with the coastal waters from the Maranhão Gulf take place. This tidal channel is the main transport pathway between the mangrove and the coastal waters. During the spring tides this mangrove is completly flooded. The main aim of this study was to evaluate the role of a mangrove region — Maranhão Gulf — in a macro-tidal area in exchanging of materials with the coastal waters. The characterization and quantification of the dissolved inorganic nutrients and the organic matter were the main focuses of this study. For this purpose were utilized flows calculations from "Eulerian" method. During the period of 13 months (from April 2000 to April 2001), in the neap and spring fluxes of the dissolved inorganic nutrients (ammonium, nitrite, nitrate, phosphate, and silicate) and those of the organic matter (organic carbon, organic nitrogen, and organic phosphorus) were determined along 52 tidal cycles. For the characterization of organic matter were used elemental ratio C/N, isotopes 13C and 15N ratio, and by the identification of dissolved humic substances as tracers for organic matter sources. The differences on day clear and orvernight show average values from 0960 for the pH and salinity, positive values of 5, 6, 8 and 11%, respectively, for nitrate, phosphate, ammonium, and silicate, and negative values for the oxygen (-10%), and for the dissolved and particulate organic matter (-1% to -6%). The dissolved nutrients and organic matter varies such as tidal ranges showing maximum values in the low tile, indicating flow from intersticial water of the mangrove for the tidal channel. Particulate organic matter values show variations relationships with current velocity showing resuspension and sediment transport. This fact confirms that the biological processes, such as nutrient consumption and organic matter deposition, in the tidal channel, and the tidal dynamics were relevants in the lief variations. The results obtained in this study show a seasonal variation with minium values in the dry season, except for the silicate, and maximum values in the rainy season, showing the raro precipitation influence in the transport from mangrove for the coastal waters. In addition, in the dry period, occurs maximum consumption of nutrient by phytoplancton, as well as, observed on primary production. It was evidencied also lower values in the concentration of particulate organic matter during this dry season due the lower fluxes values from the mangrove. The net exportation of inorganic nutrients and the organic matter in the mangroves of the São Luís Island (Maranhão State, Brazil), in the tidal channel Igarapé Nunca Mais, is evidencied in this study by interpretation of the flows calculations and the values from C/N. rations, elemental and isotopic. The isotopes of C and N used here as tracers lead to the identification of the primary sources of the organic matter in the tidal channel, i.e., the originated from mangroves, the coastal waters, and the resulting from allochthonous production. During the rainy period there are dominance of the organic matter (dissolved and particulate) transported from the mangrove, while in the dry period the marine and autochthonous sources are more considerables. The photosynthesis of the phytoplancton, in the tidal channel, justifies the autochthonous production. The net exportation of the dissolved organic matter for the coastal waters is slightly superior to the particulate organic matter (DOM, 14mM-2.day-1; POM, 20mM.m.-2.day-1). Perhaps this difference is due a fast sedimentation in the intermediary zune of the tidal channel that have the biggest profundity; this fact leads a minor quantity of particulates exported for coastal waters. It infers that this organic matter is constititued, dominantly, by humic substances because they are more refractory to the bacterial activity and consequently they can be transported by tidal currents for the adjacent coastal waters. Of course, the tidal amplitude ranges and pluviometric precipitation are relevant factors in these exportation processes. By this exposition, this study confirms the important role of mangrove for the fertilization of the coastal waters of Maranhão Gulf.
Acesso aberto (Open Access)
Dinâmica dos parâmetros abióticos na zona de mistura do estuário do rio Paracauari, ilha do Marajó-Pa
(Universidade Federal do Pará, 2009-09-09) MONTEIRO, Sury de Moura; EL-ROBRINI, Maâmar; http://lattes.cnpq.br/5707365981163429; https://orcid.org/0000-0001-7850-1217
This paper evaluate the seasonal (2008) and longitudinal dynamics of abiotics parameters in water column in the mixing zone of the estuary of Paracauari River (Marajo Island-PA). This estuary is located in the eastern portion of the Marajo island – PA, and it is influenced by a wet tropical climate, with annual average temperature of 27oC, rainfall of 2.566 mm/year with two distinct seasons of rainy (that occurs from December to May and less rainy from July to November); and presents a system from meso to macrotide (3 to 5 m), half-day time. Three campaigns were carried out using a mesh of 15 stations distributed over the estuary, and a fixed station at the mouth of the river during a half of a tidal cycle. The campaigns were carried: rainy (March), intermediate (June) and less rainy (September). Were measured in situ physicochemical parameters, temperature, pH, OD, salinity, CE and TDS using a multiparameter, transparency through Secchi disc and collected water samples for laboratorial analysis of the nutrients through methods spectrophotometer and MPS by the gravimetric method. In the fixed station, the analytical results are due to the variation of the tide, in general, with a sinusoidal behavior, with the exception of water temperature which ranged to the time of gathering. As rainy, intermediary and less rainy period, pH, OD and PO4 3- had a direct proportion to the variance of tide, the highest indexes occurred during flood tides. The CE, TDS and salinity, during the rainy period, was maximum during low tide; during the intermediary and less rainy the maximum value occurred in the tide floods, due penetration of marine waters. The NO3 -, NO2 – and Si(OH)4, however, observed minimum concentrations during flood tide periods analysed, as the marine waters are impoverished these compounds. For MPS maximum values were observed during the ebb tide and the minimum during flood tide in the rainy, intermediate and less rainy periods, but the transparency analysis did not provide a direct proportion to the change of the tide, but with time of gathering. The analytical results of samples collected along the estuary of the river Paracauari showed that the estuarine waters do not have large seasonal variations in the concentrations of the studied parameters. The water temperature has been constant, 28.70°C average with 1.5°C variation in three periods, confirming the homogeneity of the thermal waters. The pH was acid with averaging 5,87 and 6,77 during the rainy period and intermediary, respectively, and alkaline during the period less rainy (7,37) reflecting the influence of marine waters in the estuary. The transparency of these waters is 10 cm averaging, during the rainy period as a result of the large suspended solids load (order 93,72 mg/l), which produces a dirty aspect in the region; already during the intermediary and less rainy, the concentration of suspended solids was 37,19 and 15,18 mg/l, respectively, causing higher transparencies, around 43 cm. The concentration of OD showed that estuarine waters there is low levels during the rainy and intermediary period, with 3,11 and 4,32 mg/L, average levels, respectively, and high level during rainy season (average 6,30 mg/l). All dissolved nutrients analyzed showed high average levels during the rainy period due to natural dump from adjacent areas, averages values: NO2 - 0,08 μM/l; NO3 - 6,52 μM/l; n-ammoniacal 0,46 μM/l; PO4 3- 0,89 μM/l; and Si(OH)4 60,14 μM/l. In the intermediate and less rainy period, there is a significant reduction in these average levels, particulary in the mouth, where there is greater influence of marine waters. The CE, TDS and salinity showed an expressive seasonal variation, with respective minimum values during the rainy period of 256 μS/cm, 125,66 mg/l and 0,12, maximum in less rainy of 11002 μS/cm, 5505,03 and 6,18, and in all of these periods the highest value occurred in the mouth, where there is a marine water influence. Longitudinal changes in parameters analyzed in the Paracauari River estuary are controlled mainly by dump from rivers, precipitation, wind and tide. Which allows you to suggest that this estuary is influenced by continental waters during the rainy and intermediary period, and oceanic during the less rainy, which the ocean waters penetrate in the estuary around 40 km from the mouth. Keywords: Estuary, Paracauari River, Nutrients, meso and macro-tidal, seasonal variation, the mixing zone, Marajo, Island of the (PA).
Acesso aberto (Open Access)
Mapeamento do halo de dispersão formado por efluentes industriais lançados na Baía do Guajará no trecho compreendido entre o bairro de Val-de-Cães e o Distrito de Icoaraci
(Universidade Federal do Pará, 2006-09-18) MOURA, Elyana Melo; RAMOS, José Francisco da Fonseca; http://lattes.cnpq.br/8189651755374537
The region metropolitan of Belém concentrates a big number of industries in the following between the neighborhood of Val de Cães and the district of Icoaraci. Those industries, among the which, of the catch, brewery and other, liberate efluentes for the bay of the Guajará many times without no handling. The estuary has an intense hydrodynamics and consequently a big capacity of dilution of the pollutants thrown by the industries installed to its margins. However, if the concentration of those infection substances exceed certain limits, the waters of the estuary can lose the capacity of dilution of exhale. In order to be decided to capacity of the bay of the Guajará in scatter the contaminante, thrown by the industries installed to his margins, were carried out three campaigns for superficial water samples collection in a stretch understood between the neighborhoods of Val de Cães and the district of Icoaraci. To first campaign was carried out in the month of May, corresponding to the rainy period, and the other two in the months of August, period of dry spell and November, beginning of the rainy period, all in 2005. The samples were collected to 0, 50, 100, 200 and 400 meters of the margin of the estuary, in front of the company of catch, brewery and slaughterhouse, where were analyzed the parameters pH,electric transmit, color, whirlwind, stuff of suspended particles, oxygen dissolved, oxygen consumed, CO2 free, nitrate, total match, sulphate, alkalined total and the kátions Na, K, Ca and Mg. The values of oxygen dissolved in the stretch studied short saints considered for the region, with values increasing in direction to the interior of the bay, being that the biggest concentrations were obtained in the rainy period. The oxygen consumed, by his time, has inverse behavior, with the biggest values obtained near alongside the bay, where does it influence of the sewers and, consequently, the content of organic matter is bigger. The nitrate obeys to no standard of spatial distribution, however, regarding the seasonal variation, presents bigger values in the month of December. The total match presents sharp difference of quantities between the rainy and dry periods. Being the biggest values recorded in the rainy period. Spatially, the distribution of that increased nutrient in the quota 100m, due to the presence of the tubing of industrial sewers that throw efluentes to 100m of the margin. The sulphate reaches bigger concentrations in the month of November, not having been observed cross and longitudinal standards in his distribution, what suggests that this nutrient does not have relation with the launching of sewers in the waters of the bay. The kátions present his bigger concentrations in the period of dry spell, what suggests minor dilution by the waters. Spatially, the distribution of kátions increased in the sense Val de Cães - Icoaraci due to the biggest one influences of the ocean waters. In general, some parameters as pH,eletric transmission, color, stuff of suspended particles, whirlwind, CO2 free and alkalinide do not suffer significant changes in the values regarding his spatial distribution, already others parameters like the oxygen dissolved and the nutrients present changes to the long one of the 400 meters of the margin of the estuary, mainly due to the influence anthropologic. However, all of the parameters present modifications regarding the seasonal variation, where the biggest values are observed during the period of dry spell, when there is water capacity minor in the bay.
Acesso aberto (Open Access)
Nutrients in Amazonian Black Earth from Caxiuanã Region
(2011) LEMOS, Vanda Porpino; MEIRELES, Antônio Roberto de Oliveira; DANTAS, Kelly das Graças Fernandes; MORAES, Milena Carvalho de; COSTA, Marcondes Lima da; SILVA, Any Kelly Terra da; KERN, Dirse Clara
Dispersion of nutrients in Amazonian black earth (ABE) can provide information on human activities of the inhabitants of the Amazon region. Studies on the pH, available phosphorus (P), organic matter (OM) and the exchangeable cations Ca2+ e Mg2+ were performed on soil samples from horizons A1 and A2 over an area with TPA (north-south and east-west) at a site called Ilha de Terra, located in the Conservation Unit Caxiuanã National Forest, Melgaço County, Brazil. The results indicated that the OM and Ca2+ are the ones with greater dispersion. Higher correlations were found between OM-Ca-Mg to near the central area. This leads to the inference that the dispersion geochemistry of MO, Ca, Mg and P in archaeological sites with TPA is related to past human activities.
Acesso aberto (Open Access)
Variabilidade sazonal e espacial da qualidade de água em dois lagos amazônicos: Água Preta e Bolonha, Belém, Pará, Brasil
(Universidade Federal do Pará, 2025-04-04) ROMÃO, Cryssia da Costa; ROLLNIC, Marcelo; http://lattes.cnpq.br/6585442266149471; https://orcid.org/0000-0002-8601-1514
Located in the Utinga State Park (PEUt), the Bolonha and Água Preta lakes are the main bodies of water that supply the Metropolitan Region of Belém (RMB) with drinking water through the Companhia de Saneamento do Pará (COSANPA), which is responsible for 75% of the supply to this population. Studying and understanding the hydrochemistry of these lakes is of fundamental importance, as environmental conditions and ecosystem services are directly related to the quality of the water in the lakes. The sources of input, such as pumping from the Guamá River, in natura effluent discharges and continental runoff from rainfall, require an enhanced sampling effort throughout the system. Therefore, the aim of this study was to analyze the water quality of the Bolonha and Água Preta lakes in order to identify sources of contamination and their effects on the ecosystem and public health. In order to understand and identify the physical-chemical processes and their interactions with anthropogenic activities, hydrodynamics and climate, monthly measurements were taken over 12 months at 20 points in Água Preta Lake and 4 points in Bolonha Lake. Samples were taken at 2 depths (surface and bottom) to obtain water temperature, pH, electrical conductivity, dissolved oxygen (DO), turbidity and total dissolved solids (TDS) using a HORIBA multi-parameter probe. Aliquots were separated for laboratory determination of the following parameters: ammonium, nitrite, nitrate, phosphate, nitrogen and total phosphorus, biochemical oxygen demand, thermotolerant coliforms, chlorophyll-a and total alkalinity. The measured data was statistically analyzed between points and seasonal stations, and the Trophic State Index (TSI) and Water Quality Index (WQI) were calculated.