Hidroquímica na Amazônia Central. II. Flutuações no fluxo de saída de nitrogênio e fósforo em dois ecossistemas na Amazônia ()

Ribeiro, Jorge S.; Bringel, Sérgio Roberto Bulcão; Santos, Aurilene Barros dos

doi:10.1590/1809-43921978083409

Cited by 3 publications

(3 citation statements)

References 2 publications

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“…Isso se nota nitidamente na floresta pluvial amazônica sobre podzol hidromórfico (caatinga ou campinarana), onde o sistema radicular se encontra quase exclusivamente na camada orgânica superficial (KLINGE 1973 b, d). Mais claramente que na parte terrestre da floresta pluvial, nota-se nas próprias águas a expressão da oligotrofia extrema da Amazônia Central (RIBEIRO et al, 1978). A água dos igarapés e rios que cruzam a floresta não é mais rica de nutrientes que a água da chuva da própria região (Anôn., 1972b, FITTKAU, 1973a.…”

Section: Discussionunclassified

Estrutura e funcionamento de um ecossistema florestal amazônico de terra firme junto à Reserva Florestal Walter Egler, município de Rio Preto da Eva, Amazonas, Brasil

Rodrigues¹,

Klinge²,

Fittkau³

2000

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Para se determinar a estrutura e fitomassa de um ecossistema florestal amazônico de terra firme, mapeou-se e colheu-se a vegetação de uma área demarcada de 0,2 ha localizada nas adjacências do limite leste da Reserva Florestal W. Egler (km 64 da estrada Manaus- Itacoatiara (AM-1), Município de Rio Preto da Eva, Amazonas, Brasil. Os resultados obtidos são apresentados e discutidos em comparação com os dados da literatura. ABSTRACT For the determination of structure and phytomass of a Central Amazonian lowland rain forest ecosystem, its vegetation was mapped and harvested on 0.2-ha, very near the Forest Reserve W. Egler, situated at the east side of the Manaus-Itacoatiara road (AM-1), km 64, Municipality of Rio Preto da Eva, Amazonas, Brazil. The main results are presented and discussed in comparison to data from the literature. RÉSUMÉ Pour déterminer la structure et la phytomasse de la forêt amazonienne dense humide de terre ferme, très proche de la limite de la Réserve Forestière W. Egler, localisée sur la route AM-1 (Manaus à Itacoatiara), km 64, Etat dAmazonas, Brésil, la végétation de 0,2 ha a été cataloguée et récoltée entiérement. Les résultats sont présentés et discutés par repport aux données disponibles de la littérature.

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Section: Discussionunclassified

Estrutura e funcionamento de um ecossistema florestal amazônico de terra firme junto à Reserva Florestal Walter Egler, município de Rio Preto da Eva, Amazonas, Brasil

Rodrigues¹,

Klinge²,

Fittkau³

2000

ABPar

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“…A few studies have reported nitrogen exports from small Amazonian catchments (Ribeiro et al 1978;Salati et al 1982;Brinkmann 1983;Lesack 1993) and nitrogen concentrations in groundwater (dos Santos & Ribeiro 1975;Brinkmann 1985), but no study had yet addressed transformations in nitrogen chemistry across terrestrial-lotic interfaces of the basin. Increasing interest in nutrient cycles of Amazonian forests and the tendency to associate stream chemistry with forest nutrient status provide a considerable impetus to improve our understanding of nitrogen dynamics at Amazon terrestrial-lotic interfaces.…”

Section: Introductionmentioning

confidence: 99%

Groundwater nitrogen dynamics at the terrestrial-lotic interface of a small catchment in the Central Amazon basin

1994

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Abstract. Processes operating at the terrestrial-lotic interface may significantly alter dissolved nitrogen concentrations in groundwater as a result of shifting redox conditions and microbial communities. We monitored concentrations of total dissolved nitrogen, NO,, NH: ,a and ~e * + for 10 months along two transects tracing groundwater flow from an upland (terra firme) forest, beneath the riparian forest, and into the stream channel of a small Central Amazonian catchment. Our aim was to examine the role of near-stream processes in regulating groundwater transfers of dissolved nitrogen from terrestrial to lotic ecosystems in the Central Amazon. We found pronounced compositional differences in inorganic nitrogen chemistry between upland, riparian, and stream hydrologic compartments. Nitrate dominated (average 89% of total inorganic nitrogen; TIN) the inorganic nitrogen chemistry of oxygenated upland groundwater but decreased markedly upon crossing the upland-riparian margin. Conversely, NH; dominated (average 93% of TIN) the inorganic chemistry of apparently anoxic riparian groundwater; NH: and TIN concentrations decreased markedly across the riparian-stream channel margin. In the oxygenated streamwater, NO, again dominated (average 82% of TIN) inorganic nitrogen chemistry. Denitrification followed by continued ammonification is hypothesized to effect the shift in speciation observed at the upland-riparian margin, while a combination of several pmcessesmay control the shift in speciation andloss of TIN observed at the riparian-stream margin. Dissolved organic nitrogen concentrations did not vary significantly between upland and riparian groundwater, but decreased across the riparian-stream margin. Our data suggest that extensive transformation reactions focused at the upland and stream margins of the riparian zone strongly regulate and diminish transfers of inorganic nitrogen from groundwater to streamwater in the catchment. This suggestion questions the veracity of attempts in the literature to link stream nitrogen chemistry with nutrient status in adjacent forests of similar catchments in the Central Amazon. It also complicates efforts to model nitrogen transfers across terrestrial-lotic interfaces in response to deforestation and changing climate.

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“…Os resultados dos compostos de nitrogênio na maioria dos afluentes estudados sao considerados normais, em relação aos trabalhos de Schmidt (1972), Ribeiro et al 1978. Has, os rios Haipendi, Cuiuini e Padauari merecem destaque face aos elevados teores le nitrogênio em suas águas. Possivelmente, esses altos, teores estejam vinculados ãs üversas condições de ordem frsico-química e biológica, os quais a seguir:…”

Section: Introductionunclassified

Rios da Bacia Amazônica. I. Afluentes do rio Negro

et al. 1984

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Hidroquímica na Amazônia Central. II. Flutuações no fluxo de saída de nitrogênio e fósforo em dois ecossistemas na Amazônia ()

Cited by 3 publications

References 2 publications

Estrutura e funcionamento de um ecossistema florestal amazônico de terra firme junto à Reserva Florestal Walter Egler, município de Rio Preto da Eva, Amazonas, Brasil

Estrutura e funcionamento de um ecossistema florestal amazônico de terra firme junto à Reserva Florestal Walter Egler, município de Rio Preto da Eva, Amazonas, Brasil

Groundwater nitrogen dynamics at the terrestrial-lotic interface of a small catchment in the Central Amazon basin

Rios da Bacia Amazônica. I. Afluentes do rio Negro

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