在小型热带河流中,基流二氧化碳流动是由水文动态驱动的
Daniela Vasconcelos Machado1, Eduardo Duarte Marques2, Andréa da Consolação de Oliveira Carvalho3
1Fluminense Federal University (UFF). Niteroi, Post-Graduate Program in Geosciences (Environmental Geochemistry), Chemistry Institute, RJ, Brazil; Federal University of Rio de Janeiro (UFRJ), Post-Graduate Program in Geology, Geosciences Institute, Rio de Janeiro, RJ, Brazil.
The Science of the total environment
|March 6, 2025
概括
巴西上圣弗朗西斯科流域的小河流在干旱季节排放的二氧化碳 (CO2) 量为1.52. 这项研究为该地区提供了第一个盆地规模的CO2排放估计.
科学领域:
- 环境科学 环境科学
- 水文学的水文学
- 生物地质化学生物地质化学
背景情况:
- 小河流是全球水生网络的重要组成部分.
- 从这些系统中估计二氧化碳 (CO2) 流量对于理解全球碳循环至关重要.
- 巴西的上圣弗朗西斯科流域 (USFB) 缺乏来自其河流系统的CO2排放的全面数据.
研究的目的:
- 为了估计USFB的1418条河流和溪流的旱季CO2流量.
- 为了确定这些水生系统的盆地规模CO2排放贡献.
- 分析控制CO2度和气体转移速度的因素.
主要方法:
- 物理化学参数 (pH,总性) 的现场测量.
- 计算和纠正CO的部分压力 (pCO).
- 使用气体转移速度 (k600) 参数化和流控制的分析,估计CO2流量.
主要成果:
- 据估计,干旱季节的盆地范围的CO2流量为1.52 Pg C yr-1.
- pCO2值差异很大 (66至20200μatm),平均值为2191μatm.
- 超过95%的河流显示CO2逃逸,床上的摩擦在85%的情况下是主要的流驱动因素.
- 在k600参数化中发现了显著的差异和高的空间可变性.
结论:
- 小热带河流在区域和潜在的全球碳循环中发挥着重要作用.
- 这项研究为USFB提供了第一个CO2排放估计,强调了小水体的重要性.
- 需要进一步的研究来完善各种河流环境的气体转移速度模型.
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