Short-term changes and longitudinal distribution of carbon metabolism in the Piauí River estuary (Sergipe, Brazil)

Souza, Marcelo Friederichs Landim de; Couto, Erminda da Conceição Guerreiro

doi:10.1590/s0034-71081999000200003

Cited by 5 publications

(6 citation statements)

References 14 publications

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“…6), suggesting that there was equilibrium between autotrophic/heterotrophic processes, in agreement with previous results of Souza and Couto (1999) in November 1994. The event of net autotrophy observed in May 18 seems to be the result of the large fluvial inputs in the beginning of the rainy season (March).…”

Section: Net Pelagic Metabolismsupporting

confidence: 93%

“…After this transport, strong CO 2 consumption was measured at stations 6 and 7, where net primary production/respiration alternated during the rest of the year. The magnitude of CO 2 consumption contrasted with that reported by Souza and Couto (1999) in a preliminary sampling at the same stations in this estuary (−0.7 to +0.6 mmol CO 2 m −2 day −1 , November 1994). Compared to the seasonal changes between autotrophy/ heterotrophy observed in temperate embayments as Tomales Bay (Smith and Hollibaugh 1997), South San Francisco Bay (Caffrey et al 1998), and the tropical coastal lagoon of Saquarema (Carmouze 1994), the Piauí River estuary was characterized by spatial patchiness and pulses of net heterotrophy as a response to freshwater discharge, anthropogenic inputs, and the fluxes of organic matter and nutrients.…”

Section: Net Ecosystem Metabolismcontrasting

confidence: 85%

“…It is important to observe that high net autotrophic rates occurred during periods of CO 2 supersaturation (e.g., May). This suggests sharp changes in the prevailing metabolic processes, as observed previously in this (Souza and Couto 1999) and another tropical systems (Carmouze 1994).…”

Section: Net Ecosystem Metabolismsupporting

confidence: 85%

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Net Ecosystem Metabolism and Nonconservative Fluxes of Organic Matter in a Tropical Mangrove Estuary, Piauí River (NE of Brazil)

Souza

Gomes

Freitas

et al. 2008

Estuaries and Coasts

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Net ecosystem metabolism (NEM) was measured in the Piauí River estuary, NE Brazil. A mass balance of C, N, and P was used to infer its sources and sinks. Dissolved inorganic carbon (DIC) concentrations and fluxes were measured over a year along this mangrove dominated estuary. DIC concentrations were high in all estuarine sections, particularly at the fluvial end member at the beginning of the rainy season. Carbon dioxide concentrations in the entire estuary were supersaturated throughout the year and highest in the upper estuarine compartment and freshwater, particularly at the rainy season, due to washout effects of carbonaceous soils and different organic anthropogenic effluents. The estuary served as a source of DIC to the atmosphere with an estimated flux of 13 mol CO 2 m −2 year −1 . Input from the river was 46 mol CO 2 m −2 year −1 . The metabolism of the system was heterotrophic, but short periods of autotrophy occurred in the lower more marine portions of the estuary. The pelagic system was more or less balanced between auto-and heterotrophy, whereas the benthic and intertidal mangrove region was heterotrophic. Estimated annual NEM yielded a total DIC production in the order of 18 mol CO 2 m −2 year −1 . The anthropogenic inputs of particulate C, N, and P, dissolved inorganic P (DIP), and DIC were significant. The fluvial loading of particulate organic carbon and dissolved inorganic nitrogen (DIN) was largely retained in two flow regulation and hydroelectric reservoirs, promoting a reduction of C:N and C:P particulate ratios in the estuary. The net nonconservative fluxes obtained by a mass balance approach revealed that the estuary acts as a source of DIP, DIN, and DIC, the latter one being almost equivalent to the losses to the atmosphere. Mangrove forests and tidal mudflats were responsible for most of NEM rates and are the main sites of organic decomposition to sustain net heterotrophy. The main sources for this organic matter are the fluvial and anthropogenic inputs. The mangrove areas are the highest estuarine sources of DIP, DIC, and DIN.

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Section: Net Pelagic Metabolismsupporting

confidence: 93%

Section: Net Ecosystem Metabolismcontrasting

confidence: 85%

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Net Ecosystem Metabolism and Nonconservative Fluxes of Organic Matter in a Tropical Mangrove Estuary, Piauí River (NE of Brazil)

Souza

Gomes

Freitas

et al. 2008

Estuaries and Coasts

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“…The upper estuary receives wastewater discharges from domestic sources, textile industries, and juice and food processing industries located in the city of Estancia. 34,35 Surface water samples were collected during periods of both low and high tides, at eight sites distributed along the estuary ( Figure S1). Polyethylene receptacles were used, and the samples were stored in ice in the dark, until arrival at the laboratory.…”

Section: Sampling Proceduresmentioning

confidence: 99%

Characterization of dissolved organic matter in the Piauí river estuary, Northeast Brazil

Costa¹,

Passos²,

Garcia³

et al. 2011

J. Braz. Chem. Soc.

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A espectroscopia de fluorescência e o carbono orgânico dissolvido (COD) foram utilizados para caracterização da matéria orgânica dissolvida (MOD) no estuário do Rio Piauí, um estuário tropical situado no Estado de Sergipe, nordeste do Brasil. As intensidades de fluorescência foram maiores no período chuvoso e menores no período seco, evidenciando que a variabilidade das propriedades fluorescentes da MOD é ditada, principalmente, pela descarga fluvial e pelo processo de diluição no estuário. No período chuvoso, os compostos tipo triptofano e húmicos predominaram na composição da MOD, enquanto no período seco ocorreu um aumento significativo dos constituintes tipo proteínas. As relações das intensidades de fluorescência com a salinidade sugerem um comportamento não conservativo para a MOD fluorescente. O COD mostrou um comportamento conservativo no período seco e não conservativo no período chuvoso, com produção de COD na parte superior do estuário. A complexação da MOD com o Cu(II), estudada usando a técnica de supressão da fluorescência, evidenciou o potencial de complexação dos fluoróforos tipo proteínas, tripofano e húmico.Fluorescence spectroscopy and dissolved organic carbon (DOC) measurements were used to characterize the dissolved organic matter (DOM) in the Piauí River estuary, a tropical estuary situated in the State of Sergipe, Northeast Brazil. Fluorescence intensities were greater during the rainy period than the dry period, demonstrating that variability in the fluorescence properties of the DOM was determined mainly by the fluvial discharge and the dilution processes occurring in the estuary. During the rainy period, tryptophan-like and humic substances were the main components of the DOM, while during the dry period there was a significant increase of proteinlike constituents. Relationships identified between fluorescence intensities and salinity were indicative of non-conservative behavior of the fluorescent DOM. DOC showed behavior that was conservative during the dry period, and non-conservative during the rainy period, with production of DOC in the upper reaches of the estuary. The complexation of DOM with Cu(II), studied using the fluorescence suppression technique, showed the complexation potentials of protein, tryptophan and humic type fluorophores.Keywords: natural organic matter, Piauí River, estuary, fluorescence IntroductionDissolved organic matter (DOM) is a complex heterogeneous mixture of macromolecules formed by the decomposition of biological material derived from animals or plants. DOM represents one of the main reservoirs of carbon on the Earth's surface, and exhibits a variety of ecologically and geochemically important properties including the ability to absorb light, bind with trace metals and organic pollutants, adsorb substances onto its surface and undergo aggregation, as well as photochemical reactivity. [1][2][3] The DOM present in natural waters can have either autochtone or allochtone origins. Allochtone organic matter is introduced into aquatic systems by leaching from ...

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“…275 to 355 ppmv), which may affect the current planetary feedback mechanisms (Falkowski, 1994), (ii) vertical fluxes of carbon from trophogenic to tropholitic zone (biological pump) (Hansell et al, 1997) and, (iii) metabolism of aquatic systems (autotrophic-production vs. heterotrophic-mineralization), which is ecologically related to their structure and function (Carmouze et al, 1991(Carmouze et al, , 1994del Giorgio & Peters, 1993;Souza & Couto, 1999). Other issues related to DIC are the influence of pCO 2(aq) on the stable carbon isotopic fractionation (e.g.…”

Section: Introductionmentioning

confidence: 99%

Dissolved inorganic carbon and metabolism of an eutrophic lacustrine system: variations from a 36-hours study

Pedrosa

Rezende

2000

Rev. Bras. Biol.

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Based on variations of pelagial dissolved inorganic carbon (DIC) concentrations this article provides estimations of net primary productivity and net mineralization -net carbon metabolism -in Cima Lake (Rio de Janeiro State). DIC concentrations varied from 203 to 773 µmol L -1 and %CO 2(aq) (saturation) from 339 to 4,901. Net carbon metabolism per light/dark periods from the 36 hours of study ranged, respectively, from -556 to 503 mmol DIC m -2 12 h -1 . Marked variations in daily net carbon metabolism of the lake were also observed. The values ranged from -25 to -194 mmol DIC m -2 day -1 . The findings were discussed as indicators of dynamic biological behavior toward production or mineralization of organic matter in the system. And, the system seemed to shift from heterotrophy to autotrophy. Additionally, in the light of our results we emphasize the axial influence of both sampling strategy and treatment of scientific data for a characterization/interpretation of aquatic systems' metabolism.Key words: DIC, carbon metabolism, net primary productivity, mineralization, eutrophic lake. Os resultados são discutidos como indicadores de um comportamento bioló-gico dinâmico direcionado à produção ou mineralização da matéria orgânica no sistema. E o sistema pareceu deslocar-se de uma função heterotrófica para autotrófica. Em adição, orientados pelos resultados obtidos, enfatizamos a importância axial da estratégia de amostragem e do tratamento científico de dados obtidos para a caracterização/interpretação do metabolismo de sistemas aquáticos. RESUMOPalavras-chave: CID, metabolismo do carbono, produtividade primária líquida, mineralização, lagoa eutrófica.Rev. Brasil. Biol., 60(4): 607-614 608 PEDROSA, P. and REZENDE, C. E.

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Short-term changes and longitudinal distribution of carbon metabolism in the Piauí River estuary (Sergipe, Brazil)

Cited by 5 publications

References 14 publications

Net Ecosystem Metabolism and Nonconservative Fluxes of Organic Matter in a Tropical Mangrove Estuary, Piauí River (NE of Brazil)

Net Ecosystem Metabolism and Nonconservative Fluxes of Organic Matter in a Tropical Mangrove Estuary, Piauí River (NE of Brazil)

Characterization of dissolved organic matter in the Piauí river estuary, Northeast Brazil

Dissolved inorganic carbon and metabolism of an eutrophic lacustrine system: variations from a 36-hours study

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