Publication Details

Category Text Publication
Reference Category Journals
DOI 10.1016/j.watres.2024.122870
Licence creative commons licence
Title (Primary) Summer drought enhances diurnal amplitude of CO2 in two German rivers of different size
Author Leng, P. ORCID logo ; Rode, M. ORCID logo ; Koschorreck, M.
Source Titel Water Research
Year 2025
Department ASAM; SEEFO
Volume 271
Page From art. 122870
Language englisch
Topic T5 Future Landscapes
T4 Coastal System
Supplements https://ars.els-cdn.com/content/image/1-s2.0-S0043135424017706-mmc1.docx
Keywords Diel CO2 dynamics; stream and river; ecosystem metabolism; droughts; process-based model
Abstract Drought is becoming increasingly prevalent globally, stimulating research into its effects on river ecosystems. However, our understanding of how droughts affect riverine CO2 dynamic on a daily scale remains limited, particularly considering the likelihood of future drought occurrence. Here, we seize the opportunity to compare daily CO2 cycles between a non-drought summer and an unprecedented drought summer. We developed a new diel CO2 process model to examine how droughts affect diel change in riverine CO2. Our findings reveal that summer drought amplifies diurnal CO2 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 CO2 variations driven by drought considering river size, contributing valuable insights into aquatic ecosystem behavior and refining CO2 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 CO2 emissions.
Persistent UFZ Identifier https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=29982
Leng, P., Rode, M., Koschorreck, M. (2025):
Summer drought enhances diurnal amplitude of CO2 in two German rivers of different size
Water Res. 271 , art. 122870 10.1016/j.watres.2024.122870