Publication Details |
| Category | Text Publication |
| Reference Category | Journals |
| DOI | 10.5194/bg-18-1619-2021 |
Licence  |
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| Title (Primary) | Technical note: CO2 is not like CH4 – limits of and corrections to the headspace method to analyse pCO2 in fresh water |
| Author | Koschorreck, M.; Prairie, Y.T.; Kim, J.; Marcé, R. |
| Source Titel | Biogeosciences |
| Year | 2021 |
| Department | SEEFO |
| Volume | 18 |
| Issue | 5 |
| Page From | 1619 |
| Page To | 1627 |
| Language | englisch |
| Topic | T5 Future Landscapes |
| Data and Software links | https://doi.org/10.5281/zenodo.4577401 |
| Supplements | https://bg.copernicus.org/articles/18/1619/2021/bg-18-1619-2021-supplement.zip https://bg.copernicus.org/articles/18/1619/2021/#section5 https://bg.copernicus.org/articles/18/1619/2021/#section6 |
| Abstract | Headspace analysis of CO2 frequently has been used to quantify the concentration of CO2 in fresh water. According to basic chemical theory, not considering chemical equilibration of the carbonate system in the sample vials will result in a systematic error. By analysing the potential error for different types of water and experimental conditions, we show that the error incurred by headspace analysis of CO2 is less than 5 % for typical samples from boreal systems which have low alkalinity (< 900 µmol L−1), with pH < 7.5, and high pCO2 (> 1000 µatm). However, the simple headspace calculation can lead to high error (up to −300 %) or even impossibly negative values in highly undersaturated samples equilibrated with ambient air, unless the shift in carbonate equilibrium is explicitly considered. The precision of the method can be improved by lowering the headspace ratio and/or the equilibration temperature. We provide a convenient and direct method implemented in an R script or a JMP add-in to correct CO2 headspace results using separately measured alkalinity. |
| Persistent UFZ Identifier | https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=24364 |
| Koschorreck, M., Prairie, Y.T., Kim, J., Marcé, R. (2021): Technical note: CO2 is not like CH4 – limits of and corrections to the headspace method to analyse pCO2 in fresh water Biogeosciences 18 (5), 1619 - 1627 10.5194/bg-18-1619-2021 |
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