CO2 uptake by roots: the myth

Tom Barr

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SpringerLink - Journal Article

Some have claimed the sediment is the source, but , not by translocation it's not.
Bacteria might mineralize organic carbon, then the CO2 gas is given off, then it's taken up by the plants in the water column perhaps, but I'd argue that most of the CO2 given off this, much like most of the CO2 gas we add for enrichment is lost to the air above.

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Tom Barr
 

VaughnH

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That is very interesting! If the CO2 given off by the substrate isn't the major source for carbon for the plants, what is? The dissolved atmospheric CO2? Why do you think most of the substrate CO2 ends up outgassing? Intuitively I would expect that most of it would be taken up by the plant leaves - it is produced right down where the leaves have good access to it, and plants consume a lot of CO2 in growing.

In that referenced article, would the CO2 released by the subsoil, if taken up by the plant leaves, be indistinguishable from any root absorption of CO2? I would think it would be, so that would indicate that the plants get whatever CO2 they need from other than the CO2 from the substrate, however it is absorbed.