Get started
Work

Summer drought enhances diurnal amplitude of CO2 in two German rivers of different size

Year: 2024
Type: article
Abstract: • Drought increases diel CO 2 amplitude in rivers. • This holds true for rivers dominated by benthic or pelagic primary producers. • Water depth is the major driver in amplifying diel CO 2 amplitude in rivers. Drought is becoming increasingly prevalent globally, stimulating research into its effects on river ecosystems. However, our understanding of how droughts affect riverine CO 2 dynamics on a daily scale remains limited, particularly considering the likelihood of future drought occurrence. Here, we seize the opportunity to compare daily CO 2 cycles between a non-drought summer and an unprecedented drought summer. We developed a new diel CO 2 process model to examine how droughts affect diel change in riverine CO 2 . Our findings reveal that summer drought amplifies diurnal CO 2 fluctuations and the pattern holds true across rivers of varying sizes, with increases of 62% for the stream and 24% for the river during drought conditions. We demonstrate that, in comparison to higher radiation and temperature induced by droughts, diel amplitude is more sensitive to low water depths. A decrease in water depth by 43% and 44% corresponded to 13% and 25% less gas exchange in the studied stream and river, respectively, while decreasing ecosystem respiration by 26% and 57%. Our model effectively captures diel CO 2 variations driven by drought considering river size, contributing valuable insights into aquatic ecosystem behavior and refining CO 2 emission estimates. We emphasize the vulnerability of shallow rivers to drought, and carbon emissions from shallower waters should be explicitly assessed at sub-daily scales to improve the estimates of daily CO 2 emissions.
DOI: 10.1016/j.watres.2024.122870
Language: English
Open Access status: hybrid
Estimated APC paid: $4,520
OpenAlex ID: W4404812298
FWCI: 0.354
Cites: 57
Cited by: 2
Related to: 10