Rudorff, Conrado M.
Melack, John M.
Barbosa, Claudio C. F.
Novo, Evlyn M. L. M.
Número total de Autores: 5
Afiliação do(s) autor(es):
 Univ Calif Santa Barbara, Bren Sch Environm Sci & Management, Santa Barbara, CA 93106 - USA
 Univ Calif Santa Barbara, Inst Marine Sci, Santa Barbara, CA 93106 - USA
 Inst Nacl Pesquisas Espaciais, BR-12227010 Sao Jose Dos Campos, SP - Brazil
Número total de Afiliações: 3
Tipo de documento:
JOURNAL OF GEOPHYSICAL RESEARCH;
OCT 20 2011.
Citações Web of Science:
The inundation status of the Amazon floodplain affects biogenic gas production and evasion. We analyzed spatial variability of dissolved CO2 concentration and gas evasion in a large floodplain lake in the lower reach of the Amazon River in four hydrological phases. We calculated surficial CO2 concentrations from measurements of pH, dissolved inorganic carbon, temperature, and conductivity and used meteorological data to calculate gas transfer coefficients to estimate CO2 evasion. Gas transfer coefficients that take into account both wind and heating and cooling at the lake's surface are on the order of 10 cm hr(-1), approximately four times higher than values previously used in regional estimates of gas evasion from lakes on the Amazon floodplain. Supersaturation of CO2 occurred throughout the lake and was higher in the littoral zone and in regions receiving Amazon River inflows. CO2 concentration was reduced in regions with phytoplankton blooms. The range of CO2 concentrations was least at low water, 47 mu M to 233 mu M, and largest at high water, 1 mu M to 656 mu M; the average annual value was 125 mu M. We estimate mean (+/- standard deviation) fluxes from open-water in L. Curuai to the atmosphere of 44 +/- 15, 348 +/- 13, 371 +/- 23, and 364 +/- 20 mmol CO2 m(-2) d(-1) during receding, low, rising, and high water, respectively. The error associated with these values reflects, for each hydrological phase, the spatial variation in CO2 concentration in L. Curuai, a likely range in atmospheric CO2 levels and temporal variations in gas transfer coefficient within 10-day periods. (AU)