Particulate organic carbon (POC) in relation to other pore water carbon fractions in drained and rewetted fens in Southern Germany

摘要

Numerous studies have dealt with carbon (C) contents in Histosols, butthere are no studies quantifying the relative importance of the individual Ccomponents in pore waters. For this study, measurements were taken of allthe carbon components (particulate organic carbon, POC; dissolved organiccarbon, DOC; dissolved inorganic carbon, DIC; dissolved methane, CH₄)in the soil pore water of calcareous fens under three different watermanagement regimes (re-wetted, deeply and moderately drained). Pore waterwas collected weekly or biweekly (April 2004 to April 2006) at depthsbetween 10 and 150 cm.The main results obtained were: (1) DIC (94–280 mg C l−1) was the mainC-component. (2) POC and DOC concentrations in the pore water(14–125 mg C l−1 vs. 41–95 mg C l−1) were pari passu. (3) Dissolved CH₄was the smallest C component (0.005–0.9 mg C l−1). Interestingly,about 30% of the POM particles were colonized by microbes indicatingthat they are active in the internal C turnover. Certainly, both POC and DOCfractions are essential components of the C budget of peatlands.Furthermore, dissolved CO₂ in all forms of DIC appears to be animportant part of peatland C-balance.