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EDistribution of carbon originating from CO2 on

different components of soil organic matterA. Miltner, H.-H. Richnow, F.-D. Kopinke and M. Kästner

Department of Remediation Research, UFZ - Centre for Environmental Research Leipzig - Halle, Permoserstr. 15, 04318 Leipzig, Germany

soil (ca. 21 g) + farmyard manure (5 mg g-1)

Na 2

13C

O3 +

H+

Na+

+ 1

3C

O2 +

H2O

CH

Cl 3

(fun

igat

ed c

ontr

ols

only

)

0.25 mmol 13CO2

Fig. 1: concentrations (A) and 13C (B) of phospholipid fatty acids

Fig. 2: concentrations (A) and 13C (B) of total fatty acids

atmosphere0.03% CO2

13C -7 ‰

soil organic matter13C -28 ‰

plants13C -28 ‰

soil air, 1 - 5% CO2, 13C -28 ‰

CO2 fixation

has been shown to

occur in soils, al-

though normally quan-

titatively less impor-

tant than respiration

is a process essential

to life

may have effect on

isotopic composition

of soil organic matter

may account for part

of the "bound residue"

formation as deter-

mined by studies with

radioactively labeled

compounds