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

• Main Authors: S. Fiedler, B. S. Höll, A. Freibauer, K. Stahr, M. Drösler, M. Schloter, H. F. Jungkunst
• Format: Article
• Language: English
• Published: Copernicus Publications 2008-12-01
• Series: Biogeosciences
• Online Access: http://www.biogeosciences.net/5/1615/2008/bg-5-1615-2008.pdf

Numerous studies have dealt with carbon (C) contents in Histosols, but there are no studies quantifying the relative importance of the individual C components in pore waters. For this study, measurements were taken of all the carbon components (particulate organic carbon, POC; dissolved organic carbon, DOC; dissolved inorganic carbon, DIC; dissolved methane, CH<sub>4</sub>) in the soil pore water of calcareous fens under three different water management regimes (re-wetted, deeply and moderately drained). Pore water was collected weekly or biweekly (April 2004 to April 2006) at depths between 10 and 150 cm. <br><br> The main results obtained were: (1) DIC (94–280 mg C l<sup>−1</sup>) was the main C-component. (2) POC and DOC concentrations in the pore water (14–125 mg C l<sup>−1</sup> vs. 41–95 mg C l<sup>−1</sup>) were pari passu. (3) Dissolved CH<sub>4</sub> was the smallest C component (0.005–0.9 mg C l<sup>−1</sup>). Interestingly, about 30% of the POM particles were colonized by microbes indicating that they are active in the internal C turnover. Certainly, both POC and DOC fractions are essential components of the C budget of peatlands. Furthermore, dissolved CO<sub>2</sub> in all forms of DIC appears to be an important part of peatland C-balance.