| Full text | |
| Author(s): |
Silva, Jonismar S.
;
Pinel, Sebastien
;
van Asperen, Hella
;
Amaral, Joao H. F.
;
Pimental, Tania P.
;
da Cunha, Hillandia B.
;
Krusche, Alex V.
;
Forsberg, Bruce R.
Total Authors: 8
|
| Document type: | Journal article |
| Source: | Fundamental and Applied Limnology; v. N/A, p. 15-pg., 2025-01-31. |
| Abstract | |
Methane (CH4) is a potent greenhouse gas, mainly produced in anoxic environments through the degradation of organic matter. Measurements of dissolved CH4 concentrations and environmental variables were made in the two largest tributaries of the Amazon, the Negro and Solim & otilde;es river, between 2005 and 2011, including years of exceptional high and low water levels. Diffusive CH4 emissions were estimated from CH4 concentrations. These rivers have distinct chemical and physical properties and are of unique economic and cultural significance to their riverine populations. Both rivers were consistently over-saturated with CH4 in relation to the atmosphere, with the Negro River generally presenting higher concentrations (between 0.004 mu M and 0.223 mu M) than the Solim & otilde;es River (between 0.005 mu M and 0.037 mu M). Diffusive fluxes were also found to be larger for the Negro River (0.09 to 8.6 mmol m- 2 d-1) than for the Solim & otilde;es River (0.04 to 1.07 mmol m- 2 d-1). A clear seasonal pattern was observed for both rivers with respect to dissolved CH4 concentrations and diffusive fluxes: the highest concentrations and diffusive fluxes of CH4 were found during LW, while the lowest concentrations and fluxes were found during HW. This seasonal trend was more pronounced in years of severe or atypical flood or drought events. Regression models indicated that water depth and temperature can explain the variation in the dissolved CH4 concentration in the Negro (70 %) and Solim & otilde;es River (58 %). This study shows the potentially strong effects of interannual hydrological variation on river CH4 concentrations and the subsequent river CH4 outgassing. (AU) | |
| FAPESP's process: | 10/19091-8 - O papel dos rios no ciclo regional do carbono |
| Grantee: | Maria de Fátima Fernandes Lamy Rasera |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |
| FAPESP's process: | 08/58089-9 - The role of rivers on the regional carbon cycle |
| Grantee: | Maria Victoria Ramos Ballester |
| Support Opportunities: | Research Program on Global Climate Change - Thematic Grants |