Fluvial Hydrogeochemistry in a Sub-Tropical Coastal Watershed in Brazil

Figueiredo, R. O.; Ovalle, Á. R. C.

doi:10.1007/978-94-017-0906-4_36

Cited by 3 publications

(2 citation statements)

References 6 publications

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“…Perhaps the most pronounced effect of land use change on water quality within the Amazon Basin will result from urbanization rather than from management of agricultural lands. A similar result has been demonstrated regarding the importance of human sewage for N inputs to rivers in agricultural regions of southern Brazil [Figueiredo et al, 1998;Martinelli et al, 1999a]. However, the effect of Amazonian urbanization on water quality has received little attention.…”

Section: Understudied Topics Pertaining To Nutrient Losses Following supporting

confidence: 69%

Loss of nutrients from terrestrial ecosystems to streams and the atmosphere following land use change in Amazonia

Davidson

Neill

Krusche

et al. 2004

Ecosystems and Land Use Change

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Rates of deforestation in the Amazon region have been accelerating, but the quantity and timing of nutrient losses from forested and deforested ecosystems are poorly understood. This paper investigates the broad variation in soil properties of the Amazon Basin as they influence transfers of plant nutrients from the terrestrial biosphere to the atmosphere and the aquatic biosphere. The dominant lowland soils are highly weathered Oxisols and Ultisols, but significant areas of Alfisols also exist, resulting in a wide range of weatherable primary minerals. Despite this considerable variation among Amazonian soils, a common feature in most mature lowland Amazonian forests is a conservative P cycle and excess N availability. In cattle pastures and secondary forests, however, low rates of internal terrestrial N cycling, low N export to streams, and low gaseous N emissions from soils are common, due to significant previous losses of N through repeated fire. Export of P to streams may increase or remain nearly undetectable after forest-to-pasture conversion, depending on soil type. Oxisols exhibit very low P export, whereas increased P export to pasture streams has been observed in Ultisols of western Amazonia. Calcium is mostly retained in terrestrial ecosystems following deforestation, although increased inputs to streams can be detected when background fluxes are naturally low. Because soil mineralogy and soil texture are both variable and important, the effects of land-use change on nutrient export to aquatic ecosystems and to the atmosphere must be understood within the context of varying soil properties across the Amazon Basin.

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Section: Understudied Topics Pertaining To Nutrient Losses Following supporting

confidence: 69%

Loss of nutrients from terrestrial ecosystems to streams and the atmosphere following land use change in Amazonia

Davidson

Neill

Krusche

et al. 2004

Ecosystems and Land Use Change

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“…In the Brazilian Southeast, several studies have shown the consequences of raw sewage effluent in water bodies (Krusche et al 2002;Ballester et al 1999;Daniel et al 2002;Figueiredo and Ovalle 1998); systems in which untreated wastes have been released have experienced severe changes to their biogeochemical composition, with significant alterations in ionic concentrations, biochemical oxygen demand, composition of particulate and dissolved organic matter, dissolved organic and inorganic carbon (DOC and DIC) concentrations, and other riverine water parameters. However, in the Amazon Basin, studies of the urban impacts on the biogeochemistry of the aquatic environment are still scarce.…”

Section: Introductionmentioning

confidence: 99%

Dissolved carbon in an urban area of a river in the Brazilian Amazon

et al. 2011

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The main objective of this study was to evaluate dissolved organic and inorganic carbon dynamics along upstream and downstream reaches of the Acre River draining the city of Rio Branco, in the state of Acre, Brazil. Dissolved organic carbon (DOC) concentrations in the Acre River were significantly higher during the wet season, ranging from 385 ± 160 to 430 ± 131 lM among the stations, with no difference in upstream and downstream concentrations. Dissolved inorganic carbon (DIC) showed an inverse pattern, with higher concentrations in the dry season, ranging from 816 ± 215 to 998 ± 754 lM among the stations, as well as no difference in upstream and downstream DIC concentrations. Bicarbonate was the dominant DIC fraction and was mainly observed during the dry season. Due to lower pH values during the wet season, CO 2 partial pressure (pCO 2 ) in the Acre River was higher in the wet season, with values ranging from 4,567 ± 1,813 to 4,893 ± 837 ppm among the stations. Our results indicate that, although the Acre River drains a large city with significant sewage disposal into the river, seasonal hydrological processes are the main driver of dissolved carbon dynamics, even in the downstream study reach directly influenced by urbanization.

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A preliminary investigation of the polar lipids in recent tropical sediments from aquatic environments at Campos dos Goytacazes, Brazil

Azevedo¹

2003

J. Braz. Chem. Soc.

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As frações polares dos extratos de sedimentos dos rios Imbé, Urubu e Ururaí e da Lagoa de Cima foram analisados por cromatografia gasosa e por cromatografia gasosa acoplada a espectrometria de massas. Os seguintes compostos se encontravam dominantes entre os esteróis: colest-5-en-3β-ol, 24-metilcolest-5-en-3β-ol, 24-etilcolest-5-en-3β-ol, 24-etilcolest-5,22-dien-3β-ol e seus respectivos 5α-isômeros. Nos sedimentos desses sistemas aquáticos, os esteróis C29 se encontravam mais abundantes, enfatizando a alta contribuição de plantas superiores para a matéria orgânica. Já no Rio Ururaí, há um predomínio do colesterol, refletindo a maior contribuição de algas/bactérias. Olean-12-en-3β-ol (β-amirina) e friedelan-3-ona foram os triterpenóides que prevaleceram nos sedimentos dos rios Imbé e Urubu, mas não foram detectados na Lagoa de Cima. As informações retiradas das análises dos quatro sedimentos apontaram para uma contribuição mista para a matéria orgânica: plantas superiores e alga/zooplancton.The polar fractions extracted from sediments of the Imbé, Urubu, and Ururaí rivers and from Lake de Cima were analyzed using gas chromatography and gas chromatography-mass spectrometry. In the samples, cholest-5-en-3β-ol, 24-methylcholest-5-en-3β-ol, 24-ethylcholest-5-en-3β-ol, 24-ethylcholesta-5,22-dien-3β-ol and their 5α-counterparts were dominant among the sterols. Sediments of theses water bodies have the C 29 sterols as the most abundant, emphasizing a higher plant input. In the Ururaí River, cholest-5-en-3β-ol predominated, reflecting a major algal contribution. Olean-12-en-3β-ol (β-amyrin) and friedelan-3-one were prevalent among the triterpenoids in the Imbé and the Urubu sediments, but were not detected at Lake de Cima. Samples of the Imbé and Urubu rivers contained appreciable concentrations of n-alkanols. They ranged from C 14 to C 32 with a maximum at C 16 and with a second maximum in C 28 . Results of all four sediments point to a mixed contribution of higher plants and algae/zooplankton. Alkanols found in these water bodies indicate a greater contribution of higher plant material, while in sediments from the Ururaí algae/zooplankton were the main sources of the organic matter.

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Fluvial Hydrogeochemistry in a Sub-Tropical Coastal Watershed in Brazil

Cited by 3 publications

References 6 publications

Loss of nutrients from terrestrial ecosystems to streams and the atmosphere following land use change in Amazonia

Loss of nutrients from terrestrial ecosystems to streams and the atmosphere following land use change in Amazonia

Dissolved carbon in an urban area of a river in the Brazilian Amazon

A preliminary investigation of the polar lipids in recent tropical sediments from aquatic environments at Campos dos Goytacazes, Brazil

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