Response to Interpreting the ash trend within ombrotrophic bog profiles: atmospheric dust depositions vs. mineralization processes. The Etang de la Gruère case study

Abstract

In ‘Interpreting the ash trend within ombrotrophic bog profiles: atmospheric dust depositions vs. mineralization processes. The Etang de la Gruere case study’, Zaccone et al. (2011a) question our interpretation of enhanced ash contents in depth profiles of ombrotrophic bogs. We see them as an indication for C-loss through peat decay (Leifeld et al. 2011). We highly appreciate the work by Claudio Zaccone, William Shotyk and co-authors on peatlands, including their discussion of methods and their limitations. The approach described in Leifeld et al. (2011) has the potential to overcome some limitations of other methods to estimate C-loss from disturbed peatlands but needs to be carefully evaluated. The criticism of Zaccone et al. (2011a) relates to one (EGr) of the four different bogs discussed in our study. EGr is a rather small bog (5 ha). Therefore, the concerns raised in this single case may not be generalized. In our study, EGr served as a reference site and its ash peak has been attributed mainly to human disturbance but less to changing patterns in atmospheric deposition or drainage. Zaccone et al. (2011a) challenge this assumption and raise three points of concern, (1) sampling methodology, (2) normalization of ash peaks to depth, and (3) discussion and interpretation of ash peaks. We reply to each of them.