Articles | Volume 12, issue 1
Biogeosciences, 12, 67–78, 2015
Biogeosciences, 12, 67–78, 2015

Technical note 06 Jan 2015

Technical note | 06 Jan 2015

Technical Note: Large overestimation of pCO2 calculated from pH and alkalinity in acidic, organic-rich freshwaters

G. Abril et al.


Interactive discussion

Status: closed
Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
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Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision
AR by Anna Wenzel on behalf of the Authors (19 Nov 2014)  Author's response    Manuscript
ED: Publish subject to technical corrections (24 Nov 2014) by Jack Middelburg
Short summary
We compared pCO2 data calculated from pH and alkalinity from those measured directly in a large array of temperate and tropical freshwaters. This revealed a large overestimation (up to 300%) of calculated pCO2 in the case of acidic and organic-rich waters, due to a contribution of organic acids anions to alkalinity and a lower buffering capacity of the carbonate system at acidic pH. Given the widespread distribution of acidic freshwaters, direct measurements of water pCO2 are encouraged.
Final-revised paper