Baseflow CO₂ fluxes in small tropical rivers driven by hydrological dynamics

IF 8.2 1区环境科学与生态学 Q1 ENVIRONMENTAL SCIENCES Science of the Total Environment Pub Date : 2025-03-05 DOI:10.1016/j.scitotenv.2025.179015

Daniela Vasconcelos Machado , Eduardo Duarte Marques , Andréa da Consolação de Oliveira Carvalho , Eduardo Paim Viglio , Everton Assunção Martins dos Santos , Rozane Valente Marins , Gerson Cardoso da Silva Júnior , Emmanoel Vieira Silva-Filho

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Abstract

Dry season CO₂ fluxes were estimated for 1418 small rivers and streams in the Upper São Francisco Basin (USFB), Brazil. This first basin-scale estimate revealed a substantial contribution of 1.52 Pg C yr⁻¹ (95 % confidence interval: 1.40 to 1.64 Pg C yr⁻¹). pCO₂ values, calculated from pH and total alkalinity (TA) and subsequently corrected, ranged from 66 to 20,200 μatm (2191 ± 1791 μatm; coefficient of variation of 82 %). Approximately 95 % of rivers exhibited evasive fluxes with bed friction dissipation as the dominant control on turbulence in over 85 %. Analysis of gas transfer velocity (k₆₀₀) parameterizations revealed significant inter-equation differences, high spatial variability, and strong slope influence. These findings highlight the potentially role of small tropical rivers and streams in global carbon cycling and provide the first CO₂ emission estimate for the USFB.

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来源期刊

Science of the Total Environment 环境科学-环境科学

CiteScore

17.60

自引率

10.20%

发文量

8726

审稿时长

2.4 months

期刊介绍： The Science of the Total Environment is an international journal dedicated to scientific research on the environment and its interaction with humanity. It covers a wide range of disciplines and seeks to publish innovative, hypothesis-driven, and impactful research that explores the entire environment, including the atmosphere, lithosphere, hydrosphere, biosphere, and anthroposphere. The journal's updated Aims & Scope emphasizes the importance of interdisciplinary environmental research with broad impact. Priority is given to studies that advance fundamental understanding and explore the interconnectedness of multiple environmental spheres. Field studies are preferred, while laboratory experiments must demonstrate significant methodological advancements or mechanistic insights with direct relevance to the environment.