Carbon dioxide (CO2) concentrations and emission in the newly constructed Belo Monte hydropower complex in the Xingu River, Amazonia

Autor(es)

de Araujo, Kleiton R. ^[1] ; Sawakuchi, Henrique O. ^{[2, 3, 4]} ; Bertassoli, Jr., Dailson J. ^[5] ; Sawakuchi, Andre O. ^{[1, 5]} ; da Silva, Karina D. ^{[1, 6]} ; Vieira, Thiago B. ^{[1, 6]} ; Ward, Nicholas D. ^{[7, 8]} ; Pereira, Tatiana S. ^{[1, 6]}

Afiliação do(s) autor(es)

^[1] Univ Fed Para, Programa Posgrad Biodiversidade & Conservacao, BR-68372040 Altamira - Brazil

^[2] Univ Sao Paulo, Ctr Energia Nucl Agr, Piracicaba - Brazil

^[3] Umea Univ, Dept Ecol & Environm Sci, S-90187 Umea - Sweden

^[4] Linkoping Univ, Dept Themat Studies, Environm Change, S-58183 Linkoping - Sweden

^[5] Univ Sao Paulo, Inst Geociencias, Dept Geol Sedimentar & Ambiental, Sao Paulo - Brazil

^[6] Univ Fed Para, Fac Ciencias Biol, BR-68372040 Altamira - Brazil

^[7] Univ Washington, Sch Oceanog, Seattle, WA 98195 - USA

^[8] Pacific Northwest Natl Lab, Marine Sci Lab, Sequim, WA 98382 - USA

• Tipo de documento: Artigo Científico
• Fonte: BIOGEOSCIENCES; v. 16, n. 18, p. 3527-3542, SEP 18 2019.
• Citações Web of Science: 1

Resumo

The Belo Monte hydropower complex located in the Xingu River is the largest run-of-the-river (ROR) hydroelectric system in the world and has one of the highest energy production capacities among dams. Its construction received significant media attention due to its potential social and environmental impacts. It is composed of two ROR reservoirs: the Xingu Reservoir (XR) in the Xingu's main branch and the Intermediate Reservoir (IR), an artificial reservoir fed by waters diverted from the Xingu River with longer water residence time compared to XR. We aimed to evaluate spatiotemporal variations in CO2 partial pressure (pCO(2)) and CO2 fluxes (FCO2) during the first 2 years after the Xingu River impoundment under the hypothesis that each reservoir has contrasting FCO2 and pCO(2) as vegetation clearing reduces flooded area emissions. Time of the year had a significant influence on pCO(2) with the highest average values observed during the high-water season. Spatial heterogeneity throughout the entire study area was observed for pCO(2) during both low-and high-water seasons. FCO2, on the other hand, only showed significant spatial heterogeneity during the high-water period. FCO2 (0.90 +/- 0.47 and 1.08 +/- 0.62 mu mol m(2) d(-1) for XR and IR, respectively) and pCO(2) (1647 +/- 698 and 1676 +/- 323 mu atm for XR and IR, respectively) measured during the high-water season were on the same order of magnitude as previous observations in other Amazonian clearwater rivers unaffected by impoundment during the same season. In contrast, during the low-water season FCO2 (0.69 +/- 0.28 and 7.32 +/- 4.07 mu mol m(2) d(-1) for XR and IR, respectively) and pCO(2) (839 +/- 646 and 1797 +/- 354 mu atm for XR and IR, respectively) in IR were an order of magnitude higher than literature FCO2 observations in clearwater rivers with naturally flowing waters. When CO2 emissions are compared between reservoirs, IR emissions were 90% higher than values from the XR during low-water season, reinforcing the clear influence of reservoir characteristics on CO2 emissions. Based on our observations in the Belo Monte hydropower complex, CO2 emissions from ROR reservoirs to the atmosphere are in the range of natural Amazonian rivers. However, the associated reservoir (IR) may exceed natural river emission rates due to the preimpounding vegetation influence. Since many reservoirs are still planned to be constructed in the Amazon and throughout the world, it is critical to evaluate the implications of reservoir traits on FCO2 over their entire life cycle in order to improve estimates of CO2 emissions per kilowatt for hydropower projects planned for tropical rivers. (AU)

• Processo FAPESP: 16/11141-2 - Variabilidade hidrológica e aporte sedimentar dos rios Xingu e Tapajós: impactos de mudanças climáticas e antrópicas em rios do leste da Amazônia durante o Holoceno
• Beneficiário: Dailson José Bertassoli Junior
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 16/02656-9 - A resposta da dinâmica sedimentar dos rios Xingu e Tapajós às mudanças climáticas e barragens de usinas hidrelétricas: riscos para conservação da biodiversidade e produção de energia na Amazônia
• Beneficiário: André Oliveira Sawakuchi
• Modalidade de apoio: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Regular