2022-09-302022-09-302009-09-09MONTEIRO, Sury de Moura. Dinâmica dos parâmetros abióticos na zona de mistura do estuário do rio Paracauari, ilha do Marajó-Pa. Orientador; Maâmar El-Robrini. 2009. 137 f. Dissertação (Mestrado em Geologia) - Programa de Pós-Graduação em Geologia e Geoquímica. Instituto de Geociências, Universidade Federal do Pará, Belém, 2009. Disponível em: http://repositorio.ufpa.br:8080/jspui/handle/2011/14804. Acesso em:.https://repositorio.ufpa.br/handle/2011/14804This 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 AbertoAttribution-NonCommercial-NoDerivs 3.0 Brazilhttp://creativecommons.org/licenses/by-nc-nd/3.0/br/Estuário – Rio ParacauariNutrientesMeso e macro-maréVariação sazonalZona de misturaMarajó, Ilha de (PA)DissertaçãoCNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS::GEOLOGIAGEOLOGIA MARINHA E COSTEIRAGEOLOGIA