Artigo

Dissolved organic matter and terrestrial-lotic linkages in the central Amazon basin of Brazil

We evaluate the hypothesis that decomposition and adsorption reactions operating in upland soils of headwater catchments control the concentration and composition of dissolved and fine particulate organic matter in rivers of the Amazon basin. In two contrasting first-order catchments characteristic...

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Autor principal: McClain, Michael E.
Outros Autores: Richey, Jeffrey E., Brandes, Jay A., Pimentel, Tânia Pena
Grau: Artigo
Idioma: English
Publicado em: Global Biogeochemical Cycles 2020
Assuntos:
Riparia
Acesso em linha: https://repositorio.inpa.gov.br/handle/1/19366
id oai:repositorio:1-19366
recordtype dspace
spelling oai:repositorio:1-19366 Dissolved organic matter and terrestrial-lotic linkages in the central Amazon basin of Brazil McClain, Michael E. Richey, Jeffrey E. Brandes, Jay A. Pimentel, Tânia Pena Riparia We evaluate the hypothesis that decomposition and adsorption reactions operating in upland soils of headwater catchments control the concentration and composition of dissolved and fine particulate organic matter in rivers of the Amazon basin. In two contrasting first-order catchments characteristic of the central Amazon basin, we analyzed plant, litter, soil, groundwater, and stream water chemistry. Our results indicate that clear and persistent differences exist in the concentration and elemental composition of dissolved organic matter (DOM) in stream waters and groundwaters from the two catchments, due mainly to corresponding differences in soil texture and chemistry. Within the more oxide and clay rich Oxisols underlying terra firme forest, groundwater DOM concentrations were uniformly low (120 μMC) and C/N ratios averaged 10. Conversely, within the oxide and clay deficient Spodosols underlying campinarana forest, groundwater DOM concentrations were greatly elevated (3000 μMC), and C/N ratios averaged near 60. We found that, in the terra firme/Oxisol terrain, the majority of DOM contributions to the stream derived from the riparian zone, while in the campinarana/Spodosol terrain, upland groundwater contributions could account for the concentration and composition of DOM in the stream. The implications of our findings are that in the terra firme terrains which dominate the region, upland soil profiles are not the site of definitive processes which impart compositional signatures to organic matter carried by the largest rivers of the Amazon basin, as was hypothesized. Instead, we suggest that definitive reactions are focused primarily in the river corridor. 2020-06-15T22:07:51Z 2020-06-15T22:07:51Z 1997 Artigo https://repositorio.inpa.gov.br/handle/1/19366 10.1029/97GB01056 en Volume 11, Número 3, Pags. 295-311 Restrito Global Biogeochemical Cycles
institution Instituto Nacional de Pesquisas da Amazônia - Repositório Institucional
collection INPA-RI
language English
topic Riparia
spellingShingle Riparia
McClain, Michael E.
Dissolved organic matter and terrestrial-lotic linkages in the central Amazon basin of Brazil
topic_facet Riparia
description We evaluate the hypothesis that decomposition and adsorption reactions operating in upland soils of headwater catchments control the concentration and composition of dissolved and fine particulate organic matter in rivers of the Amazon basin. In two contrasting first-order catchments characteristic of the central Amazon basin, we analyzed plant, litter, soil, groundwater, and stream water chemistry. Our results indicate that clear and persistent differences exist in the concentration and elemental composition of dissolved organic matter (DOM) in stream waters and groundwaters from the two catchments, due mainly to corresponding differences in soil texture and chemistry. Within the more oxide and clay rich Oxisols underlying terra firme forest, groundwater DOM concentrations were uniformly low (120 μMC) and C/N ratios averaged 10. Conversely, within the oxide and clay deficient Spodosols underlying campinarana forest, groundwater DOM concentrations were greatly elevated (3000 μMC), and C/N ratios averaged near 60. We found that, in the terra firme/Oxisol terrain, the majority of DOM contributions to the stream derived from the riparian zone, while in the campinarana/Spodosol terrain, upland groundwater contributions could account for the concentration and composition of DOM in the stream. The implications of our findings are that in the terra firme terrains which dominate the region, upland soil profiles are not the site of definitive processes which impart compositional signatures to organic matter carried by the largest rivers of the Amazon basin, as was hypothesized. Instead, we suggest that definitive reactions are focused primarily in the river corridor.
format Artigo
author McClain, Michael E.
author2 Richey, Jeffrey E.
Brandes, Jay A.
Pimentel, Tânia Pena
author2Str Richey, Jeffrey E.
Brandes, Jay A.
Pimentel, Tânia Pena
title Dissolved organic matter and terrestrial-lotic linkages in the central Amazon basin of Brazil
title_short Dissolved organic matter and terrestrial-lotic linkages in the central Amazon basin of Brazil
title_full Dissolved organic matter and terrestrial-lotic linkages in the central Amazon basin of Brazil
title_fullStr Dissolved organic matter and terrestrial-lotic linkages in the central Amazon basin of Brazil
title_full_unstemmed Dissolved organic matter and terrestrial-lotic linkages in the central Amazon basin of Brazil
title_sort dissolved organic matter and terrestrial-lotic linkages in the central amazon basin of brazil
publisher Global Biogeochemical Cycles
publishDate 2020
url https://repositorio.inpa.gov.br/handle/1/19366
_version_ 1787142117828591616
score 11.755432

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