Deforestation modifying terrestrial organic transport in the Rio Tapajós, Brazilian Amazon

Farella, N.; Lucotte, Marc; Louchouarn, Patrick; Roulet, M.

doi:10.1016/s0146-6380(01)00103-6

Cited by 126 publications

(87 citation statements)

References 52 publications

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“…In contrast, under undisturbed watershed conditions, the enhanced sorption of hydrophobic soil DOM on fine clays and hydroxide particles (Kaiser and Guggenberger 2000;Hagedorn et al 2000) may impart a selective signature to fine particulates reaching aquatic systems particularly under hydrodynamic sorting conditions (c.f. Louchouarn et al 1999;Farella et al 2001;Bianchi et al 2002).…”

Section: Discussionmentioning

confidence: 99%

“…Multiproxy studies involving molecular, isotopic, and elemental signatures of sedimentary organic matter have been used successfully in the past to reconstruct shifts in water column productivity and anthropogenic organic matter inputs to lake sediments due to large-scale transformations in their basins such as overload of agricultural fertilizers and increased urbanization (Filley et al 2001;Routh et al 2004). However, we are aware of only a few studies that have used soil signatures to reconstruct allochthonous organic matter inputs to aquatic systems with a particular emphasis on tracing disturbances to their watersheds Farella et al 2001). Using soil signatures, rather than fresh plant end-members, during source reconstructions carries the considerable advantage of integrating diagenetic changes that may have altered terrigenous organic matter prior to its introduction to the aquatic environment and permits a more meaningful reconstruction of terrigenous organic matter inputs to aquatic systems.…”

Section: Acknowledgmentsmentioning

confidence: 99%

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Translocation of soil organic matter following reservoir impoundment in boreal systems: Implications for in situ productivity

et al. 2006

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To evaluate the effect of reservoir flooding on carbon cycling over time, we studied sedimentary environments in three natural lakes that existed prior to impoundment and that have been incorporated in the larger lentic system of a 70-yr-old boreal reservoir in Quebec. Elemental and biomarker analyses were determined in all core intervals and three soil profiles to characterize source inputs of organic matter to sediments. Following impoundment, a twoto threefold increase in lignin concentrations (5 to 10-25 mg [10 g dry wt]Ϫ1 ) associated with similar decreases in selected terrigenous biomarker ratios (cinnamyl phenols : vanillyl phenols, C : V, 1.0-2.0 to 0.2-0.5; 3,5-dihydroxybenzoic acid : vanillyl phenols, 3,5-Bd : V, 0.2-0.5 to 0.1-0.2; and p-hydroxyl phenols : sum of vanillyl and syringyl phenols, P : [VϩS], 0.3-0.7 to 0.1-0.4) illustrate the effect of soil erosion and subsequent translocation of surface soil organic matter (SOM) to sedimentary deposits. Using a mixing model based on mass-normalized biomarker yields in identified surface and mineral soil end-members, we show that although the proportion of mineral-derived SOM predominates in the receiving sedimentary systems during preflooding conditions (97-99% of allochthonous inputs), translocated surface SOM increased in postflooding sediments to comprise up to 5-30% of the total allochthonous organic matter inputs. Using a similar quantitative mixing model based on elemental C and N contents in the autochthonous and the mixed allochthonous end-members, we estimated that concomitant to the redistribution of eroded soil organic matter, reservoir flooding induces a 1.5-to 2-fold increase in the fraction of autochthonous organic matter transferred to sedimentary environments of the reservoir. Results presented here suggest that reservoir flooding induces a change of state in lake systems that may perdure over time scales of decades to centuries.

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Section: Discussionmentioning

confidence: 99%

Section: Acknowledgmentsmentioning

confidence: 99%

Translocation of soil organic matter following reservoir impoundment in boreal systems: Implications for in situ productivity

et al. 2006

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“…In environmental science, it proved to be helpful in the appreciation of past land use and recent anthropogenic impacts to soil (e.g, Farella et al, 2001;Heim et al, 2010;Huang et al, 2011;Lavrieux et al, 2011) as well as in tracing river pollution caused by paper mills (e.g. Leeming and Nichols, 1998;Wang at al., 2007).…”

Section: Introductionmentioning

confidence: 99%

Determination of the molecular signature of fossil conifers by experimental palaeochemotaxonomy – Part 1: The Araucariaceae family

Hautevelle

Michels

2013

Biogeosciences

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Twelve species of the conifer family Araucariaceae, including Araucaria (6 species), Agathis (3 species) and Wollemia (1 species) genera, were submitted to artificial maturation by confined pyrolysis. The aim of these experiments is to transform the biomolecules synthesized by these species into their homologous geomolecules in laboratory conditions. Determination of the diagenetic molecular signatures of Araucariaceae through experimentation on extant representatives allows us to complete our knowledge in botanical palaeochemotaxonomy. Such knowledge is relevant to palaeoenvironmental, environmental and archaeology purposes. All artificially diagenetic species of Araucariaceae are firstly characterized by a predominance of saturated tetracyclic diterpenoids including ent-beyerane, phyllocladanes and ent-kauranes. Moreover, Araucaria genus shows a high relative abundance of bicyclic sesquiterpenoids, particularly the cadalane-type compounds accompanied by those of eudesmane and bisabolane types as well as chamazulene and pentamethyl-dihydroindenes. Diterpenoids are of labdane, isopimarane and abietane types (essentially derived from abietanoic acids) as well as isohexyl alkylaromatic hydrocarbons. Compared to the tetracyclic diterpenoids, these compounds show a relatively lower abundance, reaching trace levels in the case of saturated abietanes. Distributions of sesquiterpenoids and diterpenoids of Agathis show some similarities to that of Araucaria, with the exception of one species, in which the tetracyclic compounds are absent and the abietane type (essentially derived from abietanoic acids) predominant. High similarities between the Wollemia and Araucaria genera are observed. Both are characterized by some high relative abundance of tetracyclic compounds with no predominance of other specific diterpenoids

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“…Roulet et al (2000), who examined mercury contamination in lacustrine sediments following deforestation, suggest that the environmental changes initiated between 1950 and 1970, which coincide with the first colonizing projects in the Amazon, probably correspond to the beginning of mercury leaching into the rivers. The resulting mercury pollution of the aquatic environment is taken up by the halieutic resources (Farella et al, 2001;Roulet et al, 2001). These important pathways of exposure, later confirmed for other watersheds of the Amazonian Basin (Fostier et al, 2000;Lechler et al, 2000;Fadini and Jardim, 2001;Wasserman et al, 2003;Lacerda et al, 2004;Almeida et al, 2005;Bastos et al, 2006;Farella et al, 2006Farella et al, , 2007Mainville et al, 2006), constitute a continuous source of mercury exposure for the large number of traditional and immigrant communities of the region that rely on fish consumption as a dietary mainstay.…”

Section: Introductionmentioning

confidence: 99%

Daily mercury intake in fish-eating populations in the Brazilian Amazon

Passos

Silva

Lemire

et al. 2007

J Expo Sci Environ Epidemiol

113

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Although high levels of fish consumption and bioindicators of mercury exposure have been reported for traditional populations in the Amazon, little is known about their actual daily intake of Hg. Using an ecosystem approach, calculate daily mercury intake in adult fish-eaters, examine the relations between mercury intake and bioindicators of exposure and the factors that influence these relations. A cross-sectional dietary survey on fish and fruit consumption frequency was carried out with 256 persons from six villages of the Tapajo´s River. Fish portion per meal was determined. Mercury concentration was determined for 1123 local fish specimens. Daily mercury intake (mg/kg/day) was determined for men and women from each village using the average fish-mercury concentration for the fish caught in their fishing zone, the average quantity of fish per meal, fish-species frequency consumption and participants' body weight. Fish-mercury averaged 0.33 mg/g70.33. Daily mercury intake varied between 0 and 11.8 mg/kg/day (mean 0.92 mg/kg/day70.89) and varied by gender and village. Mean blood-and hair-mercury were 58.7736.1 mg/l and 17.9711.5 mg/g, respectively. There was a strong and positive relation between blood-mercury and daily mercury intake, with an inverse relation for fruit intake and schooling; significant variations were observed with immigrant status, and among villages. Hair-mercury was directly associated with daily mercury intake and inversely related to schooling and fruit consumption. Fruit consumption modified the relation between daily mercury intake and blood-mercury levels: for the same daily mercury intake, persons eating more fruit had lower blood-mercury concentrations (ANCOVA Interaction term: F ¼ 10.9, Po0.0001). The median difference of the ratio of blood-mercury to daily mercury intake between low and high fruit consumers was 26, representing a 26.3% reduction. These findings reveal high levels of daily mercury intake. Rigorous studies for developing risk-based reference doses in the Amazon should be undertaken to orient viable risk-management strategies to reduce exposure, while maintaining fish diet.

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Deforestation modifying terrestrial organic transport in the Rio Tapajós, Brazilian Amazon

Cited by 126 publications

References 52 publications

Translocation of soil organic matter following reservoir impoundment in boreal systems: Implications for in situ productivity

Translocation of soil organic matter following reservoir impoundment in boreal systems: Implications for in situ productivity

Determination of the molecular signature of fossil conifers by experimental palaeochemotaxonomy – Part 1: The Araucariaceae family

Daily mercury intake in fish-eating populations in the Brazilian Amazon

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