Dissolved inorganic carbon and pCO2 in two small streams draining different soil types in Southwestern Amazonia, Brazil

Sousa, E. dos S. de

doi:10.4136/ambi-agua.51

Cited by 6 publications

(8 citation statements)

References 17 publications

(17 reference statements)

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“…Similar to elsewhere in the Amazon Basin our study streams have relatively low pH and electrical conductivity [ Johnson et al ., ; Monteiro et al ., ; Neu et al ., ; Sousa et al ., ; Waterloo et al ., ]. The range of [DIC], 0.6–9.3 mg C L −1 , observed at our site was similar to previous studies within the basin.…”

Section: Discussionmentioning

confidence: 99%

“…Heavy rain events usually result in a peak [DOC] but the time since previous rain event and the intensity of rain influence this relationship [ Monteiro et al ., ]. DIC concentration, [DIC], has been found to be maximal at low water levels [ Salimon et al ., ; Sousa et al ., ] with the timing of maximum export flux depending on the balance between the increased discharge and the dilution effect. As the C concentrations and fluxes vary seasonally, according to hydrological controls, quantifying an annual export budget requires data capture over the full hydrological range.…”

Section: Introductionmentioning

confidence: 99%

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Fluvial carbon export from a lowland Amazonian rainforest in relation to atmospheric fluxes

et al. 2016

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We constructed a whole carbon budget for a catchment in the Western Amazon Basin, combining drainage water analyses with eddy covariance (EC) measured terrestrial CO2 fluxes. As fluvial C export can represent permanent C export it must be included in assessments of whole site C balance, but it is rarely done. The footprint area of the flux tower is drained by two small streams (~5–7 km2) from which we measured the dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), particulate organic carbon (POC) export, and CO2 efflux. The EC measurements showed the site C balance to be +0.7 ± 9.7 Mg C ha−1 yr−1 (a source to the atmosphere) and fluvial export was 0.3 ± 0.04 Mg C ha−1 yr−1. Of the total fluvial loss 34% was DIC, 37% DOC, and 29% POC. The wet season was most important for fluvial C export. There was a large uncertainty associated with the EC results and with previous biomass plot studies (−0.5 ± 4.1 Mg C ha−1 yr−1); hence, it cannot be concluded with certainty whether the site is C sink or source. The fluvial export corresponds to only 3–7% of the uncertainty related to the site C balance; thus, other factors need to be considered to reduce the uncertainty and refine the estimated C balance. However, stream C export is significant, especially for almost neutral sites where fluvial loss may determine the direction of the site C balance. The fate of C downstream then dictates the overall climate impact of fluvial export.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Fluvial carbon export from a lowland Amazonian rainforest in relation to atmospheric fluxes

et al. 2016

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“…In the Rola River, the HCO 3 -contribution was higher (65% of total DIC) in the dry season, while in the Judia stream, free CO 2 contributed to more than 68% of the total DIC in the wet season. This lower predominance of bicarbonate in the Rola River and the Judia Stream in the dry season can be explained by drainage of more weathered soils, such as gleysols and oxisols, which tend to have lower cation concentrations (Sousa et al 2008).…”

Section: Doc and Dic Concentrationsmentioning

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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“…1,200 ha located in Senador Guiomard, state of Acre (10°04' S and 67°37' W). It has a gently rolling topography with predominance of oxisols and to a lesser extent ultisols (Acre 2006); the A and B horizons are predominantly formed by sand (62 and 47%, respectively) and the pH is approximately 4.0 (Sousa et al 2008 ) was significantly (p < 0.001) higher than in the interior (2.39 ± 0.18 mm a -1 ), Table 1. Diameter growth at 10-30 cm DBH at the edge was significantly (ANOVA: F = 3.8 p = 0.05) higher than the forest interior.…”

Section: Study Areamentioning

confidence: 99%

Tree mortality, recruitment and growth in a bamboo dominated forest fragment in southwestern Amazonia, Brazil

et al. 2013

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Forest fragmentation affects the structure and dynamics of plant communities, leading to biodiversity loss in forest remnants. In this paper we show that in a bamboo (Guadua weberbaueri Pilger) dominated forest fragment in southwestern Amazonia edge effect may be confounded by bamboo effect, which also occur inside the forest. We measured growth, mortality and, recruitment rate of trees with DBH ≥ 10 cm, in a fragment of bamboo dominated open forest in southwestern Amazonia, state of Acre, Brazil, in 15 plots at the forest edge and 15 plots inside the forest fragment, 500 m away from the border. Time interval between censuses was 1.8 years. The average diameter growth rate differed significantly between edge (3.82 ± 0.10 mm a-1) and interior (2.39 ± 0.18 mm a-1); but there were no differences in annual mortality rate (edge = 3.8 ± 2.5 % a-1 CV = 65.7%; interior = 3.6 ± 2.6% a-1 CV = 72.2%) or in annual recruitment rate (edge = 7.1 ± 3.2% a-1 CV = 45%; interior = 8.9 ± 7.9% a-1 CV = 88.7%). Diameter growth rate, particularly of pioneer and fast-growing trees, is favored by the environmental conditions of the edge, where bamboo abundance is higher. However, the absence of an edge effect on mortality and recruitment could be due to the particular dynamics of bamboo patches, which could be mimicking forest edges and therefore masking possible edge effect in this fragment. We speculate that the mortality and recruitment patterns in fragmented forests of southwestern Amazonia is different from other areas in Amazonia and that bamboo is one of the key controllers of successional processes in these fragments.

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Dissolved inorganic carbon and pCO2 in two small streams draining different soil types in Southwestern Amazonia, Brazil

Cited by 6 publications

References 17 publications

Fluvial carbon export from a lowland Amazonian rainforest in relation to atmospheric fluxes

Fluvial carbon export from a lowland Amazonian rainforest in relation to atmospheric fluxes

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

Tree mortality, recruitment and growth in a bamboo dominated forest fragment in southwestern Amazonia, Brazil

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