Navegando por Assunto "Eutrophication"

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Acesso aberto (Open Access)
Especiação do fósforo em rios urbanos: um estudo de caso dos rios Tucunduba e Tamandaré, Belém/Pará
(Universidade Federal do Pará, 2023-05-24) COIMBRA, Marcus Vinicius Rodrigues; MONTEIRO, Sury de Moura; http://lattes.cnpq.br/4309806566068586; https://orcid.org/0000-0001-9449-7043
Phosphorus (P) is a bioliminating macronutrient that plays an essential role in regulating ecosystem functions and primary productivity in marine and coastal environments. However, when in excessive concentrations, P assumes the role of a pollutant, negatively influencing the ecosystem and causing eutrophication. In Brazil, the problem is maximized in urban centers cut by canals, where there is an intensification of the process of changing the natural conditions of the environment. The speciation of P associated with hydrodynamic processes and the type of urbanization of the environment allows identifying the eutrophication status of these environments. Therefore, the present study seeks to promote understanding of the dynamics of P speciation in two urban rivers, the Tucunduba and Tamandaré rivers, located in the metropolitan region of Belém (Northern Brazil), with the objective of evaluating whether there is variation in P speciation. phosphorus in urban rivers at different time scales. To this end, samples of suspended particulate matter (SPM) were carried out using two different methodologies: the horizontal flow trap (portable traps) and the vertical flow trap (fixed traps). For the extraction of P, the sequential extraction method SEDEX was adopted, which allowed the extraction of five forms: P-Ex, P-Fe, P-Au, PDe and P-Org, in addition to P-Bio. In the Tucunduba river, Total-P concentrations ranged from 20.52 to 100.78 μmol.g-1, with predominance of the P-Fe fraction. In the Tamandaré River, concentrations ranged from 42.36 to 173.88 μmol.g-1 with P-Au predominance. Thus, it was possible to verify that the urban rivers Tucunduba and Tamandaré have high concentrations of P and its species. With these data, it is clear the need to deepen this type of study in these rivers and other urban rivers present in Belém, as well as the need for policies aimed at the recovery and preservation of these, in order to mitigate the problem involving phosphorus and restore the capacity ecosystems of these environments.
Acesso aberto (Open Access)
Qualidade das águas superficiais e avaliação do estado trófico do Rio Arari (Ilha de Marajó, norte do Brasil)
(Instituto Nacional de Pesquisas da Amazônia, 2012-03) ALVES, Igor Charles Castor; EL-ROBRINI, Maâmar; SANTOS, Maria de Lourdes Souza; MONTEIRO, Sury de Moura; BARBOSA, Leandro Patrick Ferreira; GUIMARÃES, José Tasso Felix
The deterioration of the water quality may be caused either by the result of human pressure on aquatic environments in larger scales, or by natural factors in smaller scales, such as part of the Arari River basin (Marajó Island, Pará state, Brazil) .This work aimed to evaluate the surface water's quality and the trophic state of the Arari River, between Santana and Cachoeira do Arari localities, taking into account the seasonal and spatial variations of physical, chemical and biological parameters in two different hydrological periods in 2009: the maximum discharge (April to May) and minimum discharge (September to November). The Water Quality Index (WQI) and Trophic State Index (TSI) were determined simultaneously in water surface's samples collected during 12 consecutive hours in three stations along the Arari River. The WQI data ranged from "Poor" and "Regular" and are probably related to the high levels of fecal coliform, low concentrations of dissolved oxygen and acid pH of the Arari River. Regards the TSI, the river may be classified as "supereutrophic" and "hipereutrophic", indicating the wide availability of nutrients (e.g. phosphorus) and high phytoplankton biomass in terms of chlorophyll a content. The Arari River is under a natural eutrophication, since the sources of anthropic contamination are still incipient, although they may contribute to the long-term process of artificial eutrophication.
Acesso aberto (Open Access)
Seasonal effects of wastewater to the water quality of the Caeté river estuary, Brazilian Amazon
(Academia Brasileira de Ciências, 2010-06) PEREIRA, Luci Cajueiro Carneiro; BERNARDI, Marcela Cunha Monteiro; GUIMARÃES, Danielly de Oliveira; QUEIROZ, Jislene Brito Matos; COSTA, Rauquírio André Albuquerque Marinho da
Bragança's socioeconomic situation is highly dependent on estuarine and marine biological resources that are influenced by tidal cycles and climatology. Field measurements (hydrological, hydrodynamic and microbiological variables) were taken in the most urbanized zone from Caeté estuary to characterise the quality of the local environment. During the dry period, the estuary was more eutrophic and presented the highest temperature (30.5 °C in Oct./06), salinity (17 psu in Feb./07), pH (8.24 in Feb./07) and fecal coliform (> 1000 MPN/100 ml in Dec./06 and Feb./07) values. The phytoplankton Cyclotella meneghiniana, Coscinodiscus centralis and other r-strategist species were observed. The lack of basic hydric canalization was responsible for the local contamination, especially during the dry period when more concentrated wastewater from the city was emitted into the estuary, showing the human influence on the reduction of local estuarine water quality. In Bragança, the fishery is considered one of the main economic activities so, this contamination is worrisome because a large part of the local economy depends on biological resources and, thus, the contamination could negatively affect the environmental health of this Amazon ecosystem.